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Rethinking the focusing effect in decision-making
Acta Psychologica 113 (2003) 67–81 www.elsevier.com/locate/actpsy
Rethinking the focusing effect in decision-making Paolo Cherubini
a,*
, Ketti Mazzocco b, Rino Rumiati
c
a
c
Department of Psychology, University of Milano, Bicocca, Piazza Ateneo Nuovo 1, 20126 Milano, Italy b Cognitive Science Lab, University of Trento, 38068 Trento, Italy Department of Computer Science and Economics, University of Trento, 38100 Trento, Italy
Received 5 February 2002; received in revised form 1 October 2002; accepted 15 November 2002
Abstract According to Legrenzi et al. [Cognition 49 (1993) 37], in making a choice people consider only the alternatives explicitly represented in their mental model of the decision situation. Their idea has found empirical support in the ‘‘focusing effect’’: Individuals focus on the alternatives explicitly stated in the problem context, and do not take into account other possibilities. In their original study, Legrenzi and colleagues considered only one factor to account for the explicit representation of an alternative––i.e., its explicit verbal formulation in the decision problem. Recent theories of relevance and information gain can help articulate their original idea, suggesting that individuals explicitly represent relevant alternatives, whether or not they are explicitly formulated in the decision problem. In three experiments we first replicated Legrenzi et al.Õs original experiment, and then showed that the explicit verbal mention of an alternative is neither sufficient nor necessary to focus on it. The results suggest that individuals are able to consider relevant alternatives, even when they are not made explicit in the verbal formulation of a decision problem. Ó 2003 Elsevier Science B.V. All rights reserved. PsycINFO classification: 2340; 2346 Keywords: Decision-making; Attention; Relevance; Mental models
1. Introduction To make a rational decision, an individual must compare different alternatives, choosing the one most practical to her or his actual goals. In economic theories of *
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0001-6918/03/$ - see front matter Ó 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0001-6918(02)00155-5
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decision-making (e.g. Von Neumann & Morgenstern, 1947), the range of alternatives, their attributes, and the value attached to each attribute are supposed to be exhaustively known a priori; but in real life they seldom are. Before making a choice one must figure out: (a) which alternatives are available, (b) which attributes are relevant to describe each alternative, and (c) which parameters are relevant to evaluate the ‘‘utility’’ of each attribute. All of these tasks are affected by cognitive constraints. The psychology of decision-making has widely addressed the cognitive processes involved in (b) and (c) (e.g., Baron, 1994; Kahneman & Tverky, 1979; Kahneman, Slovic, & Tversky, 1982; Payne, Bettman, & Johnson, 1988), but has devoted less attention to (a). That is, most of the experimental studies in decision-making have used problems in which the alternatives were given a priori, in order to study the mechanisms and strategies that people apply to evaluate the alternatives and choose between them. Only a few studies have investigated the mechanisms involved in spontaneously figuring out available alternatives. Legrenzi, Girotto, and JohnsonLaird (1993) addressed this topic from the point of view of the mental models theory. According to them, in making a choice, individuals consider only those alternatives that are explicitly represented in their mental models of the situation. This idea has found empirical support in the ‘‘focusing effect’’: Before making a choice individuals gather information about alternatives explicitly stated in the problem context and do not pay attention to other possibilities. In their experiment, Legrenzi and colleagues asked the participants which information they needed in order to decide whether or not to do an activity (e.g., going to a movie). They found that most participants gathered information about the explicit alternative (e.g., which movie, which actors, and so on), and not about other possible alternatives (e.g., doing something different from going to a movie). Where the context explicitly suggested the existence of other alternatives (the participants were told to be in a tourist city for that day only), the participants ‘‘defocused’’, seeking information about other possible activities. The original results were later replicated by Jones, Frisch, Yurak, and Kim (1998). Legrenzi and colleaguesÕ proposal is highly plausible, empirically supported, and grounded on a sound general theory of reasoning and decision-making. However, it does not explain which factors cause the explicit representation of an alternative in the mental model of the decision situation, and consequently the focusing on it. The only experimental factor considered in the original study was the explicit verbal mention of the alternative/s in the decision problem. This suggests a picture of individuals as highly irrational decision-makers. 1 This is not necessarily so, according to the general principles of mental models theory (Johnson-Laird, 1983; Johnson-Laird & Byrne, 1991). In this research we teased out another factor, more rationality preserving, which causes an alternative to be explicitly represented in the mental model of decision problems similar to the ones used by Legrenzi et al. (1993).
1 ‘‘Irrational’’ here is meant in the sense of ‘‘not in keeping with rationality 1’’. ‘‘Rationality1 ’’ (Evans & Over, 1996) is the ability to reason and decide efficiently in trying to reach oneÕs own immediate behavioral goals. A decision-maker that considers only what is explicitly told to her or him would presumably be highly irrational.
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Sperber and WilsonÕs (1995) ‘‘relevance theory’’ (Sperber, Cara, & Girotto, 1995) suggests that in understanding a problem individuals consider (i.e., explicitly represents) only ‘‘relevant’’ information. According to Sperber and colleagues, ‘‘relevance’’ is a function of the cognitive effect that new information has on previous knowledge. Oaksford and ChaterÕs (1995, 1998) ‘‘information gain’’ approach further develops this core idea, suggesting that relevance is a function of informativeness (in the strict sense formalized by the information theory). Informally, the newer, more unexpected, and more surprising one piece of information is, the more informative it is (Manktelow, 1999); and the more informative it is, the more relevant it is. In our view, a useful link can be found between mental models theoryÕs general proposal as described in Legrenzi et al. (1993) and the relevance/information gain approach. We suggest that the explicit alternatives in the mental model of a decision problem are not limited to the ones explicitly mentioned by the problem, but rather they include the relevant alternatives––i.e., following Oaksford and Chater, the alternatives that are relatively ‘‘new’’ to the decision-maker. In other words, the decisionmaker will not focus her or his attention on irrelevant alternatives 2 whether or not they are explicitly mentioned in the problem (and/or in the mental model of the problem). Rather, the decision-maker will focus on relevant alternatives whether or not they are explicitly mentioned in the problem, searching for information about them and, therefore, building an explicit mental model of them. This tendency would be independent of which alternatives are linguistically explicit in the problem. An attentional mechanism similar to the one that we are suggesting is known to operate in the visual exploration of environment, and has received massive experimental support in the last two decades (for recent studies, see Bennett & Pratt, 2001; Hommel, Pratt, Colzato, & Godijn, 2001; for classical studies, see Posner, 1980; Posner & Cohen, 1984). Also known as ‘‘inhibition of return’’, it has been described as a general tendency not to return attention to spatial locations that have been recently explored as to increase the chances of gathering novel information (Posner & Cohen, 1984; recently, Fuentes, Vivas, & Humphreys, 1999, have found that the very same mechanism operates not only in vision, but also in the semantic domain). The basic tendency not to pay attention to what is assumed to be already known could be useful for higher-level processes as well, like the ones involved in decision-making. In this study, after having replicated Legrenzi et al.Õs (1993) original findings (Experiment 1), we found that the explicit linguistic mention of an alternative is not sufficient to focus on that alternative (Experiment 2), and that individuals can focus on alternatives that are not linguistically explicit in the problem, as long as the only explicit ones are irrelevant (Experiment 3). Our aim is to show that people, in spontaneously sorting out the possible alternatives in a choice, are not completely
2
According to the previous definition of relevance, ‘‘irrelevant alternatives’’ are uninformative alternatives: Informally, all those alternatives that prefigure possible situations that are not novel, like the actual situation, and/or any other well known situation. We termed this set of situations ‘‘status quo’’.
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dependent on the linguistic description of the situation; they are also strongly influenced by the relevance of the available alternatives. 2. Experiment 1 This was a preliminary replication of the original experiment by Legrenzi et al. (1993), mostly done to gather further support for the focusing effect and to rule out a possible confound of the original study. In the original study, the decision problem was presented either in a ‘‘no context’’ condition or in a ‘‘tourist context’’ condition. In the no context condition, participants were asked to decide whether or not to do an activity, and were allowed to ask all the information that they needed in order to do so. In the tourist context condition, the task was the same, but participants were told that they were visiting an interesting tourist city for one day only, and that the experimenter was an expert of that city. A possible confound is that in the no context condition participants may have understood that they were asked which attributes to consider in evaluating the activity (as opposed to choosing between it and other activities). To check this possible confound, we added a ‘‘familiar context’’ condition to the two original conditions. In the familiar context condition, the participants were asked to imagine that they were in their hometown and to decide whether or not to do a certain activity. The dependent variable was the number of questions made about an alternative. We used this dependent variable for two reasons: First, it was the one used by Legrenzi et al. (1993), and we wished to maintain our methodology as similar as possible to theirs; second, different measures of attentional focusing used in decision studies (e.g., eye movements, as in Payne et al., 1988; or fixation time, as in Evans, 1996) were not viable in this study because they required that all the alternatives in the decision problem are explicitly presented to the participants. 2.1. Method 2.1.1. Participants Forty-five undergraduate students (17 females and 28 males, age range: 19–32) from the University of Padua volunteered to participate in the experiment. 2.1.2. Materials and procedure Each participant was randomly assigned to one of the three experimental conditions. In the no context condition, participants were told the following: ‘‘You have to decide to whether or not (do a certain activity). 3 I will give you any information you want in order to decide. Once you have all the information that you need, make your choice’’. In the familiar context condition, the participants were told the same instructions, introduced by the following clause: ‘‘Imagine that you are in the city 3 The activities were: ‘‘go to a movie’’, ‘‘attend a sporting event’’, ‘‘visit an art exhibition’’, ‘‘attend an auction’’, ‘‘have dinner at a particular restaurant’’.
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where you usually live’’. In the tourist context condition, the instructions were preceded by the following clause: ‘‘Imagine that you are visiting (an interesting tourist city) 4 for the first time and for one day only’’. The pairings of cities and activities were balanced across the participants. Each participant was examined individually, and made five decisions in random order. In order to answer to the participantsÕ questions, the experimenter had previously prepared four alternative descriptions of each event, comprising the details most commonly asked in a pilot study. The description from which to draw the information was drawn at random. Each experimental session lasted about 20Õ and was audiotape-recorded. 2.2. Results The first two authors, acting as independent judges, counted the questions made by each participant and evaluated whether they concerned the explicitly mentioned activity or other alternatives. Disagreements arose in the scorings for 19 participants. Paired comparisons between the scorings by the two judges did not show any significant difference between them (Wilcoxon signed-rank test). Having ascertained the global homogeneity of the counting, disagreements were solved by discussion and mutual agreement. Table 1 reports the mean number of questions concerning the explicitly mentioned activity and other possible alternatives in the three experimental conditions. In all the conditions, there were more questions about explicit alternatives than about other alternatives (Wilcoxon signed-rank test; no context, p < 0:001; familiar context and tourist context, p < 0:005). This result replicated the focusing effect originally found by Legrenzi et al. (1993). The frequencies of questions about explicit alternatives were significantly different across the three conditions (Kruskal–Wallis test; H ¼ 13; 95; df ¼ 2; p < 0:001). The participants asked more questions about explicit activities in the no context condition than in the ‘‘familiar condition’’ (Mann–Whitney test, p < 0:05) and in the ‘‘tourist condition’’ (Mann–Whitney test, p < 0:005), and more in the familiar context condition than in the tourist context condition (Mann–Whitney test, p < 0:05). A Kruskal–Wallis test showed that there were no significant differences in the questions about ‘‘other alternatives’’ across the three conditions. In the original study by Legrenzi et al. (1993), the defocusing effect in the tourist context was found in analyzing the number of participants who asked at least one question about other alternatives. In keeping with their procedure, Table 2 reports the number of participants who asked at least one question about other alternatives in our study. A series of v2 tests (analyzing both the whole table and its sub-tables) showed that there were no significant differences across the conditions. Searching further for evidence of a defocusing effect in the tourist-context condition we analyzed the proportion of questions about the explicit alternatives (see Table 3), and found no significant differences (Kruskal–Wallis test, p ¼ 0:16).
4
The cities were: ‘‘Prague’’, ‘‘New York’’, ‘‘Rome’’, ‘‘Athens’’, ‘‘Paris’’.
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Table 1 Mean number of questions in Experiment 1 Condition
Mean number of questions About the explicit activity
About other alternatives
No context Familiar context Tourist context
16.6 11.1 7.7
1.2 2 2.6
Table 2 Participants who asked at least one question about implicit alternatives in Experiment 1 Condition
Questions about other alternatives None
At least one
No context Familiar context Tourist context
10 10 6
5 5 9
Table 3 Mean proportion of questions about the explicit alternatives in Experiment 1 Condition
Questions about explicit alternatives/total questions
No context Familiar context Tourist context
0.94 0.92 0.81
2.3. Discussion The main finding by Legrenzi et al. (1993), that it is the tendency to gather more information about the explicit alternatives than about other alternatives (i.e., the ‘‘focusing effect’’), has been replicated. The only reliable difference between the familiar context condition and the no context condition was in the number of questions asked about the explicit alternative, and this could be accounted for by the fact that in the no context condition the participants received less overall information. This supports the robustness of the focusing effect, dispelling our doubts about the pragmatic suitability of the no context condition. The defocusing effect found by Legrenzi et al. in the ‘‘tourist context’’ group was not replicated, although a tendency towards it can be seen in the data (Tables 2 and 3). However, the failed replication of the defocusing effect, if anything, strengthens the original interpretation of the results, showing that focusing on the linguistically explicit alternative is strong even in a suggestive context. 3. Experiment 2 This experiment investigated whether the explicit verbal mention of an alternative is sufficient for the participants to focus on it; or rather, is focusing influenced by the
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alternativeÕs relevance? We used three experimental conditions: (1) The standard nocontext condition, referred to as ‘‘activity–not activity’’ here, in which the participants were given one explicit alternative only (e.g., going to a movie or not); (2) the ‘‘activity–home’’ condition, in which the participants were given two explicit alternatives, one of them being well known and thus irrelevant (the ‘‘status quo’’ alternative––e.g., going to a movie or staying at home); (3) the ‘‘activity–activity’’ condition, in which the participants were given two explicit alternatives, both of them being different from the status quo (e.g., going to a movie or attending a sporting event). We hypothesized that individuals do not necessarily focus on linguistically explicit alternatives, but rather on relevant alternatives. Therefore, we expected that the participants would focus on the alternatives different from the status quo in both the activity–not activity and the activity–home conditions, even though the status quo was a linguistically explicit alternative in the latter. We expected that in the activity–activity condition the participants would gather information about both alternatives, because both of them were different from the status quo. 3.1. Method 3.1.1. Participants Forty-six undergraduate students (27 female and 19 males; age range: 20–36) from the University of Padua volunteered to take part in the experiment. 3.1.2. Materials and procedure Each participant was randomly assigned to one of three conditions and received a booklet with four decision problems. In the activity–not activity condition the problem was: ‘‘You must decide to whether or not [do an activity]. 5 Write in the following spaces all the information that you would need to make your choice’’. In the activity–home condition the problem was: ‘‘You must decide to whether [do an activity] 5 or stay at home.’’ (the following lines were the same as above, in all the conditions). In the activity–activity condition the problem was: ‘‘You must decide to whether [do activity 1] 5 or [do activity 2] 6. . .’’ The participants were not actually given the requested information, and they were not asked to make the choices. At the end of the booklet, the participants were requested to rate on two sevenpoint Likert scales (1) how often they usually performed each activity mentioned in the problems, and (2) how interested they were in each activity. These evaluations were meant as further controls for possible confounds in the design.
5
The activities were randomly drawn from the following set: go to a movie, attend a sporting event, visit an art exhibition, have dinner in a particular restaurant, go to the theatre, go to the disco, go to a pub, attend a concert. For each participant, each problem concerned a different activity. 6 The two activities were randomly drawn from the same list (note 5), but they were constrained not to be the same.
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3.2. Results and analyses Two independent judges sorted the requests made by the participants into four categories. Disagreements arose for 11 participants. Inter-judge reliability was checked by comparing the scorings by the two judges for each category, by means of the Wilcoxon test (as explained in Experiment 1). No significant differences were observed between the scorings of the two judges. Disagreements were then solved by discussion and mutual agreement. The two main categories were the questions about ‘‘alternative 1’’ and ‘‘alternative 2’’ (a few typical examples of the questions are reported in Appendix A). In all the conditions alternative 1 was the verbally explicit first activity. Alternative 2 was a set of implicit alternatives in the activity–not activity condition, the verbally explicit status quo (‘‘staying at home’’) in the activity–home condition and the second explicitly mentioned activity in the activity–activity condition. Two further categories were needed to account for questions that could not be easily assigned to the two main categories. These were questions about ‘‘prerequisites’’ (e.g., asking what the weather was like; this is not, strictly speaking, a question about either ‘‘going to a movie’’ or staying at home; it concerns both of them) and ‘‘personal dispositions’’ (e.g., asking whether one is sad or happy; again, these sort of questions concerns both alternatives). We analyzed these questions separately. Table 4 reports the mean total number of questions about the alternatives, the mean number of questions about alternative 1 and alternative 2, and the proportion of questions concerning alternative 1. The total number of questions did not differ significantly across the three conditions (Kruskal–Wallis test). The difference between alternative 1 and alternative 2 was significant in the activity–not activity and activity–home conditions (Wilcoxon test, p < 0:001 in both conditions), and not significant in the activity–activity condition. There were significant differences in the number of questions about alternative 1 (Kruskal–Wallis test; H ¼ 14:1; df ¼ 2; p < 0:001). In particular, there were significantly more questions about alternative 1 in the activity–not activity (Mann– Whitney test; p < 0:001) and activity–home (p < 0:01) conditions than in the activity–activity condition, and significantly more questions about alternative 2 in the activity–activity condition than in the activity–not activity condition (p < 0:0001) and in the activity–home condition (p < 0:0001).
Table 4 Questionsa in Experiment 2 Condition Activity–not activity Activity–home Activity–activity a
Mean number of questions About alternative 1
About alternative 2
Total
Proportion of questions about alternative 1
13.2 11.4 8
1.1 1.8 7.7
14.3 13.2 15.7
0.93 0.87 0.50
Excluding questions about prerequisites and personal dispositions.
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Table 5 Mean number of questions about prerequisites and personal dispositions in Experiment 2 Condition
Prerequisites
Personal dispositions
Activity–not activity Activity–home Activity–activity
0.88 3.4 1.6
1.81 2 1.73
There were significant differences in the proportions of questions about alternative 1 (Kruskal–Wallis test; H ¼ 26:66; df ¼ 2; p < 0:0001). Specifically, the proportion was significantly smaller in the activity–activity condition than in the other two conditions (Mann–Whitney test; p < 0:0001 for both comparisons); it did not differ between the activity–not activity and the activity–home conditions. Table 5 reports the mean number of questions concerning prerequisites and personal dispositions in the three conditions. The questions about personal dispositions were not different across the conditions. There were significant differences in the questions about prerequisites (Kruskal–Wallis test; H ¼ 12:16; df ¼ 2; p < 0:005). There were more prerequisites questions in the activity–home condition than in the activity–activity condition (Mann–Whitney test; p: < 05) and in the activity–not activity conditions (p < 0:005). The interest and frequency ratings associated to each activity were not significantly correlated with the number of questions made about it, suggesting that the number of questions was not systematically influenced by the participantsÕ actual preferences. 3.3. Discussion The results show that the explicit verbal statement of an alternative is not sufficient for an individual to focus her or his attention on it. The participants focused on the explicitly mentioned activities only when it was different from the status quo. That is, although staying at home was a verbally explicit alternative in the activity–home condition, the participants did not focus on it. This finding suggests that the implicit alternatives in the activity–not activity conditions and in the no contextÕ conditions in Experiment 1 and in Legrenzi et al. (1993) were treated as if they were the irrelevant status quo situation, and thus they were not further investigated. 4. Experiment 3 The previous experiment showed that the explicit verbal formulation of an alternative is not sufficient for an individual to focus attention on it. In this last experiment we checked whether the explicit mention of an alternative is necessary for an individual to focus attention on. To do so, we added to the three conditions of Experiment 2 a fourth condition (‘‘home–not home’’), in which the only verbally explicit alternative was the status quo staying at home. We expected that, in this latter condition, the participants would focus on the implicit alternatives, exploring possible activities not explicitly mentioned in the decision problem.
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4.1. Method 4.1.1. Participants Sixty-one undergraduate students (44 female and 17 male age range: 19–24) from the University of Trento volunteered to take part in the experiment. 4.1.2. Materials and procedure Each participant was randomly assigned to one of four conditions and was given a decision problem. The participants were told to read the problem and write down all the information that they needed in order to make a choice. The participants were neither given the requested information nor asked to make the choice. The activity– not activity (14 participants), activity–home (16 participants) and activity–activity (15 participants) conditions were exactly the same conditions as in Experiment 2 (except that each participant was given one problem instead of four because we had only one problem available for the home–not home condition). The problems in these conditions were randomly drawn from those used in Experiment 2. The problem in the fourth condition (home–not home, 16 participants) was presented as follows: ‘‘You must decide to whether stay at home or not. Write in the following spaces all the information that you need to make your choice’’. 4.2. Results Two independent judges sorted the questions in to four categories, as in Experiment 2. Disagreements arose for 14 subjects, but the differences between the scorings by the two judges were not significant in any condition (Wilcoxon tests), and were solved by mutual agreement. Table 6 reports the mean number of questions about alternative 1 and alternative 2, the mean total number of questions, and the proportion of questions about alternative 1. In the first three conditions the two alternatives were as described in Experiment 2. In the new home–not home condition, alternative 1 was the irrelevant, but verbally explicit, mention of the status quo, whereas alternative 2 was the implicit set of all the possible alternatives. 7 Some examples of typical questions asked in each condition are reported in Appendix A. In the activity–activity condition, there were no significant differences between the questions concerning the two alternatives (Wilcoxon test, p ¼ 0:34). In the activity– home and in the activity–not activity condition, there were significantly more questions about alternative 1 than about alternative 2 (Wilcoxon tests; p < 0:001 and p < 0:005 respectively). These results exactly replicated those obtained in the identical conditions of Experiment 2. In the home–not home condition, there were more questions about alternative 2 than about alternative 1 (Wilcoxon test; p < 0:005).
7 In order to compare the data in Table 6 to those in Table 4 (Experiment 2), the values in the latter should be divided by 4 (they refer to the questions made over four problems, whereas in Experiment 3 only one problem was given to each participant). Of course, the proportions reported in the two tables are directly comparable.
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Table 6 Questionsa in Experiment 3 Condition
Mean number of questions About alternative 1
About alternative 2
Total
Proportion of questions about alternative 1
Activity–not activity Activity–home Activity–activity Home–not home
4.87 3.78 3.17 0.86
1 0.61 2.92 2.75
5.56 4.39 6.08 3.63
0.77 0.84 0.56 0.23
a
Excluding questions about prerequisites and personal dispositions.
The total number of questions was significantly different across the conditions (Kruskal–Wallis test; H ¼ 8:28; df ¼ 3; p < 0:05), because the activity–not activity condition had significantly more questions than the activity–home condition (Mann–Whitney test; p < 0:05) and the home–not home condition (p < 0:01). The questions about alternative 1 were significantly different across the conditions (Kruskal–Wallis test; H ¼ 28:58; df ¼ 3; p < 0:0001), notably because the home–not home condition had less questions than the other three conditions (Mann–Whitney test, p<0.0001 in each comparison). There was also a significant difference between the questions about alternative 1 in the activity–activity and in the activity–not activity conditions (p < 0:05). There were significant differences in the questions about alternative 2 (Kruskal– Wallis test; H ¼ 24:62; df ¼ 3; p < 0:0001). In detail, there were more of them in the activity–activity than in the activity–not activity condition (Mann–Whitney test, p < 0:01) and in the activity–home condition (p < 0:001), as occurred in Experiment 2. The home–not home condition had more questions about alternative 2 than the activity–not activity condition (p < 0:001) and the activity–home condition (p < 0:0001). Finally, there were significant differences in the proportion of questions about alternative 1 (Kruskal–Wallis test; H ¼ 39:64; df ¼ 3; p < 0:0001) which was significantly smaller in the home–not home condition than in the activity–not activity, the activity–home conditions (Mann–Whitney test, p < 0:0001 for both comparisons), and the activity–activity condition (p < 0:001). Furthermore, the proportion was significantly smaller in the activity–activity condition than in the activity–not activity and activity–home conditions (p < 0:001 for both comparisons).
Table 7 Mean number of questions about prerequisites and personal dispositions in Experiment 3 Condition
Prerequisites
Personal dispositions
Activity–not activity Activity–home Activity–activity Home–not home
1.06 1 0.84 1.69
0.81 0.33 0.5 1.49
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The mean number of questions concerning general prerequisites to action and personal dispositions is reported in Table 7. Contrary to Experiment 2, there were no significant differences across the conditions for the questions about prerequisites, whereas there were differences concerning questions about personal dispositions (Kruskal–Wallis test; H ¼ 12:34; df ¼ 3; p < 0:01). In particular, there were more questions about dispositions in the home–not home condition than in the activity–home condition (Mann–Whitney test, p < 0:001) and in the activity–activity condition (p < 0:01). 4.3. Discussion The results of the first three conditions replicated the main results of Experiment 2, confirming that the explicit verbal mention of an alternative is not sufficient for the participants to focus on that alternative. The new home–not home condition showed that the explicit verbal mention of an alternative is not even necessary for an individual to focus her or his attention on: The participants gathered information about the possible activities that they could do instead of staying at home (even if none of these activities were explicitly mentioned in the problem), and they made very few questions about the explicitly mentioned alternative (staying at home). This result supports the hypothesis that people focus on relevant/novel alternatives (whether or not they are verbally explicit in the problem), and do not seek further information concerning irrelevant alternatives, that are assumed to be known. The results concerning the questions about prerequisites and personal disposition were different from those found in Experiment 2, making impossible a theoretical interpretation of the real bearing of these questions. However, both in Experiments 2 and 3 most of these questions occurred in conditions explicitly mentioning the status quo, suggesting that the explicit request of a choice concerning the status quo makes the decision-maker consider very general ‘‘prerequisites to action’’ (including personal dispositions), like ‘‘howÕs the weather?’’ or ‘‘what do I feel like?’’ rather than details about the status quo itself. Further research is needed to clarify this point.
5. Conclusion In making a choice, individuals focus their attention on the alternatives that are explicitly represented in their mental model of the decision problem (Legrenzi et al., 1993), or at least on some of them. This focusing effect has been replicated in all of our experiments. However, according to Legrenzi et al. focusing is mainly determined by the explicit verbal mention of the alternative, whereas our Experiments 2 and 3 showed that the explicit verbal mention of an alternative is neither sufficient nor necessary to focus attention. Actually, individuals do not focus on an explicitly mentioned alternative if that alternative is already well known (Experiment 2); and
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when the only explicit alternative is well known, individuals focus on alternatives that have not been explicitly mentioned (nor suggested by the context, Experiment 3). These findings suggest that an important factor in building explicit mental models of a decision problem is the amount of information attached to each alternative. In the case that the explicitly mentioned alternatives are not informative, the individuals gather information to build explicit models of novel alternatives. In sum, in making a choice, people do not stick exclusively to the alternatives that have been offered to them: If all the explicitly available alternatives seem irrelevant to them, they spontaneously consider novel alternatives. This attenuates the intrinsic irrationality of the decision processes that seemed to emerge from Legrenzi et al.Õs (1993) reading of the focusing effect. The results are in line with recent theories of relevance (Sperber & Wilson, 1995; Sperber et al., 1995) and information gain (Oaksford & Chater, 1995, 1998), suggesting that mental models theory could be usefully supplemented by some of the principles of those theories (at least, as far as the mechanisms that allow building explicit models are concerned).
Appendix A Examples of typical questions asked in Experiments 2 and 3.
Condition Activity–activity (examples drawn from the movie-concert problem)
Examples of questions About alternative 1
About alternative 2
WhatÕs the movie? What genre? WhatÕs its plot? How much does it cost? WhoÕs coming with me?
Where is the concert? WhoÕs coming with me? WhoÕs playing? What sort of music? What sort of audience?
Activity–home (examples Is it far? Have I got a drawn from the concert- car? How much does it home problem) cost? WhoÕs playing? What sort of music? When does it begin?
Is anything important happening at home? Have I planned to do anything at home (like studying)? WhoÕs at home?
Activity–not activity (examples drawn from the movie–not movie problem)
Have I got anything better to do at home? What could I do if I do not go to the cinema? Have I got any other plan for that evening?
WhatÕs the movie? How long is it? How much does it cost? Does it interest me? Does it show in a nice movie theatre? Should I go alone? How far is it?
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Condition Home–not home
Examples of questions About alternative 1
About alternative 2
Is there something interesting on the TV? Am I alone at home? Who would stay with me? Is there something that I must do at home? Am I waiting at home for someone to come? Is there a stressful emotional climate at home?
The plans for the evening are interesting? Is there anything in particular that I could do out, like going to a movie? Do I like the people who would go with me, and how many of them there are? Where would we go? When would we go out? How long would I stay out? WhoÕs inviting me? Should I go far? Have I got a suitable vehicle? How much money would I spend?
References Baron, J. (1994). Thinking and deciding. Cambridge, UK: Cambridge University Press. Bennett, P. J., & Pratt, J. (2001). The spatial distribution of inhibition of return. Psychological Science, 12, 76–80. Evans, J. St. B. T. (1996). Deciding before you think: Relevance and reasoning in the selection task. British Journal of Psychology, 87, 223–240. Evans, J. St. B. T., & Over, D. E. (1996). Rationality and reasoning. Hove, UK: Psychology Press. Fuentes, L. J., Vivas, A. B., & Humphreys, G. W. (1999). Inhibitory mechanisms of attentional networks: Spatial and semantic inhibition processing. Journal of Experimental Psychology: Human Perception and Performance, 25, 1114–1126. Hommel, B., Pratt, J., Colzato, L., & Godijn, R. (2001). Symbolic control of visual attention. Psychological Science, 12, 360–365. Johnson-Laird, P. N. (1983). Mental models: Toward a cognitive science of language, inference, and consciousness. Cambridge, MA: Harvard University Press. Johnson-Laird, P. N., & Byrne, R. M. (1991). Deduction. Hillsdale, NJ: Erlbaum. Jones, S. K., Frisch, D., Yurak, T. J., & Kim, E. (1998). Choice and opportunities: Another effect of framing on decisions. Journal of Behavioral Decision Making, 11, 211–226. Kahneman, D., & Tverky, A. (1979). Prospect theory: An analysis of decision under risk. Econometrica, 47, 263–291. Kahneman, D., Slovic, P., & Tversky, A. (1982). Judgment under uncertainty: Heuristics and biases. Cambridge, UK: Cambridge University Press. Legrenzi, P., Girotto, V., & Johnson-Laird, P. N. (1993). Focusing in reasoning and decision making. Cognition, 49, 37–66. Manktelow, K. (1999). Reasoning and thinking. Hove, UK: Psychology Press. Oaksford, M., & Chater, N. (1998). Rationality in an uncertain world. Hove, UK: Psychology Press. Oaksford, M. R., & Chater, N. (1995). Information gain explains relevance which explains the selection task. Cognition, 57, 97–108. Payne, J. W., Bettman, J. R., & Johnson, E. J. (1988). Adaptive strategy selection in decision making. Journal of Experimental Psychology: Learning, Memory and Cognition, 14, 534–552.
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Posner, M. I. (1980). Orienting of attention. Quarterly Journal of Experimental Psychology, 32, 3–25. Posner, M. I., & Cohen, Y. (1984). Components of visual orienting. In H. Bouma & D. Bouwhuis (Eds.), Attention and performance X (pp. 531–556). Hillsdale, NJ: Erlbaum. Sperber, D., & Wilson, D. (1995). Relevance (2nd ed.). Oxford: Blackwell. Sperber, D., Cara, F., & Girotto, V. (1995). Relevance theory explains the selection task. Cognition, 57, 31–95. Von Neumann, J., & Morgenstern, O. (1947). Theory of games and economic behavior. Princeton: Princeton University Press.
Rethinking the focusing effect in decision-making Paolo Cherubini
a,*
, Ketti Mazzocco b, Rino Rumiati
c
a
c
Department of Psychology, University of Milano, Bicocca, Piazza Ateneo Nuovo 1, 20126 Milano, Italy b Cognitive Science Lab, University of Trento, 38068 Trento, Italy Department of Computer Science and Economics, University of Trento, 38100 Trento, Italy
Received 5 February 2002; received in revised form 1 October 2002; accepted 15 November 2002
Abstract According to Legrenzi et al. [Cognition 49 (1993) 37], in making a choice people consider only the alternatives explicitly represented in their mental model of the decision situation. Their idea has found empirical support in the ‘‘focusing effect’’: Individuals focus on the alternatives explicitly stated in the problem context, and do not take into account other possibilities. In their original study, Legrenzi and colleagues considered only one factor to account for the explicit representation of an alternative––i.e., its explicit verbal formulation in the decision problem. Recent theories of relevance and information gain can help articulate their original idea, suggesting that individuals explicitly represent relevant alternatives, whether or not they are explicitly formulated in the decision problem. In three experiments we first replicated Legrenzi et al.Õs original experiment, and then showed that the explicit verbal mention of an alternative is neither sufficient nor necessary to focus on it. The results suggest that individuals are able to consider relevant alternatives, even when they are not made explicit in the verbal formulation of a decision problem. Ó 2003 Elsevier Science B.V. All rights reserved. PsycINFO classification: 2340; 2346 Keywords: Decision-making; Attention; Relevance; Mental models
1. Introduction To make a rational decision, an individual must compare different alternatives, choosing the one most practical to her or his actual goals. In economic theories of *
Corresponding author. Tel.: +39-02-64486432; fax: +39-02-64486706. E-mail address: [email protected] (P. Cherubini).
0001-6918/03/$ - see front matter Ó 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0001-6918(02)00155-5
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decision-making (e.g. Von Neumann & Morgenstern, 1947), the range of alternatives, their attributes, and the value attached to each attribute are supposed to be exhaustively known a priori; but in real life they seldom are. Before making a choice one must figure out: (a) which alternatives are available, (b) which attributes are relevant to describe each alternative, and (c) which parameters are relevant to evaluate the ‘‘utility’’ of each attribute. All of these tasks are affected by cognitive constraints. The psychology of decision-making has widely addressed the cognitive processes involved in (b) and (c) (e.g., Baron, 1994; Kahneman & Tverky, 1979; Kahneman, Slovic, & Tversky, 1982; Payne, Bettman, & Johnson, 1988), but has devoted less attention to (a). That is, most of the experimental studies in decision-making have used problems in which the alternatives were given a priori, in order to study the mechanisms and strategies that people apply to evaluate the alternatives and choose between them. Only a few studies have investigated the mechanisms involved in spontaneously figuring out available alternatives. Legrenzi, Girotto, and JohnsonLaird (1993) addressed this topic from the point of view of the mental models theory. According to them, in making a choice, individuals consider only those alternatives that are explicitly represented in their mental models of the situation. This idea has found empirical support in the ‘‘focusing effect’’: Before making a choice individuals gather information about alternatives explicitly stated in the problem context and do not pay attention to other possibilities. In their experiment, Legrenzi and colleagues asked the participants which information they needed in order to decide whether or not to do an activity (e.g., going to a movie). They found that most participants gathered information about the explicit alternative (e.g., which movie, which actors, and so on), and not about other possible alternatives (e.g., doing something different from going to a movie). Where the context explicitly suggested the existence of other alternatives (the participants were told to be in a tourist city for that day only), the participants ‘‘defocused’’, seeking information about other possible activities. The original results were later replicated by Jones, Frisch, Yurak, and Kim (1998). Legrenzi and colleaguesÕ proposal is highly plausible, empirically supported, and grounded on a sound general theory of reasoning and decision-making. However, it does not explain which factors cause the explicit representation of an alternative in the mental model of the decision situation, and consequently the focusing on it. The only experimental factor considered in the original study was the explicit verbal mention of the alternative/s in the decision problem. This suggests a picture of individuals as highly irrational decision-makers. 1 This is not necessarily so, according to the general principles of mental models theory (Johnson-Laird, 1983; Johnson-Laird & Byrne, 1991). In this research we teased out another factor, more rationality preserving, which causes an alternative to be explicitly represented in the mental model of decision problems similar to the ones used by Legrenzi et al. (1993).
1 ‘‘Irrational’’ here is meant in the sense of ‘‘not in keeping with rationality 1’’. ‘‘Rationality1 ’’ (Evans & Over, 1996) is the ability to reason and decide efficiently in trying to reach oneÕs own immediate behavioral goals. A decision-maker that considers only what is explicitly told to her or him would presumably be highly irrational.
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Sperber and WilsonÕs (1995) ‘‘relevance theory’’ (Sperber, Cara, & Girotto, 1995) suggests that in understanding a problem individuals consider (i.e., explicitly represents) only ‘‘relevant’’ information. According to Sperber and colleagues, ‘‘relevance’’ is a function of the cognitive effect that new information has on previous knowledge. Oaksford and ChaterÕs (1995, 1998) ‘‘information gain’’ approach further develops this core idea, suggesting that relevance is a function of informativeness (in the strict sense formalized by the information theory). Informally, the newer, more unexpected, and more surprising one piece of information is, the more informative it is (Manktelow, 1999); and the more informative it is, the more relevant it is. In our view, a useful link can be found between mental models theoryÕs general proposal as described in Legrenzi et al. (1993) and the relevance/information gain approach. We suggest that the explicit alternatives in the mental model of a decision problem are not limited to the ones explicitly mentioned by the problem, but rather they include the relevant alternatives––i.e., following Oaksford and Chater, the alternatives that are relatively ‘‘new’’ to the decision-maker. In other words, the decisionmaker will not focus her or his attention on irrelevant alternatives 2 whether or not they are explicitly mentioned in the problem (and/or in the mental model of the problem). Rather, the decision-maker will focus on relevant alternatives whether or not they are explicitly mentioned in the problem, searching for information about them and, therefore, building an explicit mental model of them. This tendency would be independent of which alternatives are linguistically explicit in the problem. An attentional mechanism similar to the one that we are suggesting is known to operate in the visual exploration of environment, and has received massive experimental support in the last two decades (for recent studies, see Bennett & Pratt, 2001; Hommel, Pratt, Colzato, & Godijn, 2001; for classical studies, see Posner, 1980; Posner & Cohen, 1984). Also known as ‘‘inhibition of return’’, it has been described as a general tendency not to return attention to spatial locations that have been recently explored as to increase the chances of gathering novel information (Posner & Cohen, 1984; recently, Fuentes, Vivas, & Humphreys, 1999, have found that the very same mechanism operates not only in vision, but also in the semantic domain). The basic tendency not to pay attention to what is assumed to be already known could be useful for higher-level processes as well, like the ones involved in decision-making. In this study, after having replicated Legrenzi et al.Õs (1993) original findings (Experiment 1), we found that the explicit linguistic mention of an alternative is not sufficient to focus on that alternative (Experiment 2), and that individuals can focus on alternatives that are not linguistically explicit in the problem, as long as the only explicit ones are irrelevant (Experiment 3). Our aim is to show that people, in spontaneously sorting out the possible alternatives in a choice, are not completely
2
According to the previous definition of relevance, ‘‘irrelevant alternatives’’ are uninformative alternatives: Informally, all those alternatives that prefigure possible situations that are not novel, like the actual situation, and/or any other well known situation. We termed this set of situations ‘‘status quo’’.
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dependent on the linguistic description of the situation; they are also strongly influenced by the relevance of the available alternatives. 2. Experiment 1 This was a preliminary replication of the original experiment by Legrenzi et al. (1993), mostly done to gather further support for the focusing effect and to rule out a possible confound of the original study. In the original study, the decision problem was presented either in a ‘‘no context’’ condition or in a ‘‘tourist context’’ condition. In the no context condition, participants were asked to decide whether or not to do an activity, and were allowed to ask all the information that they needed in order to do so. In the tourist context condition, the task was the same, but participants were told that they were visiting an interesting tourist city for one day only, and that the experimenter was an expert of that city. A possible confound is that in the no context condition participants may have understood that they were asked which attributes to consider in evaluating the activity (as opposed to choosing between it and other activities). To check this possible confound, we added a ‘‘familiar context’’ condition to the two original conditions. In the familiar context condition, the participants were asked to imagine that they were in their hometown and to decide whether or not to do a certain activity. The dependent variable was the number of questions made about an alternative. We used this dependent variable for two reasons: First, it was the one used by Legrenzi et al. (1993), and we wished to maintain our methodology as similar as possible to theirs; second, different measures of attentional focusing used in decision studies (e.g., eye movements, as in Payne et al., 1988; or fixation time, as in Evans, 1996) were not viable in this study because they required that all the alternatives in the decision problem are explicitly presented to the participants. 2.1. Method 2.1.1. Participants Forty-five undergraduate students (17 females and 28 males, age range: 19–32) from the University of Padua volunteered to participate in the experiment. 2.1.2. Materials and procedure Each participant was randomly assigned to one of the three experimental conditions. In the no context condition, participants were told the following: ‘‘You have to decide to whether or not (do a certain activity). 3 I will give you any information you want in order to decide. Once you have all the information that you need, make your choice’’. In the familiar context condition, the participants were told the same instructions, introduced by the following clause: ‘‘Imagine that you are in the city 3 The activities were: ‘‘go to a movie’’, ‘‘attend a sporting event’’, ‘‘visit an art exhibition’’, ‘‘attend an auction’’, ‘‘have dinner at a particular restaurant’’.
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where you usually live’’. In the tourist context condition, the instructions were preceded by the following clause: ‘‘Imagine that you are visiting (an interesting tourist city) 4 for the first time and for one day only’’. The pairings of cities and activities were balanced across the participants. Each participant was examined individually, and made five decisions in random order. In order to answer to the participantsÕ questions, the experimenter had previously prepared four alternative descriptions of each event, comprising the details most commonly asked in a pilot study. The description from which to draw the information was drawn at random. Each experimental session lasted about 20Õ and was audiotape-recorded. 2.2. Results The first two authors, acting as independent judges, counted the questions made by each participant and evaluated whether they concerned the explicitly mentioned activity or other alternatives. Disagreements arose in the scorings for 19 participants. Paired comparisons between the scorings by the two judges did not show any significant difference between them (Wilcoxon signed-rank test). Having ascertained the global homogeneity of the counting, disagreements were solved by discussion and mutual agreement. Table 1 reports the mean number of questions concerning the explicitly mentioned activity and other possible alternatives in the three experimental conditions. In all the conditions, there were more questions about explicit alternatives than about other alternatives (Wilcoxon signed-rank test; no context, p < 0:001; familiar context and tourist context, p < 0:005). This result replicated the focusing effect originally found by Legrenzi et al. (1993). The frequencies of questions about explicit alternatives were significantly different across the three conditions (Kruskal–Wallis test; H ¼ 13; 95; df ¼ 2; p < 0:001). The participants asked more questions about explicit activities in the no context condition than in the ‘‘familiar condition’’ (Mann–Whitney test, p < 0:05) and in the ‘‘tourist condition’’ (Mann–Whitney test, p < 0:005), and more in the familiar context condition than in the tourist context condition (Mann–Whitney test, p < 0:05). A Kruskal–Wallis test showed that there were no significant differences in the questions about ‘‘other alternatives’’ across the three conditions. In the original study by Legrenzi et al. (1993), the defocusing effect in the tourist context was found in analyzing the number of participants who asked at least one question about other alternatives. In keeping with their procedure, Table 2 reports the number of participants who asked at least one question about other alternatives in our study. A series of v2 tests (analyzing both the whole table and its sub-tables) showed that there were no significant differences across the conditions. Searching further for evidence of a defocusing effect in the tourist-context condition we analyzed the proportion of questions about the explicit alternatives (see Table 3), and found no significant differences (Kruskal–Wallis test, p ¼ 0:16).
4
The cities were: ‘‘Prague’’, ‘‘New York’’, ‘‘Rome’’, ‘‘Athens’’, ‘‘Paris’’.
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Table 1 Mean number of questions in Experiment 1 Condition
Mean number of questions About the explicit activity
About other alternatives
No context Familiar context Tourist context
16.6 11.1 7.7
1.2 2 2.6
Table 2 Participants who asked at least one question about implicit alternatives in Experiment 1 Condition
Questions about other alternatives None
At least one
No context Familiar context Tourist context
10 10 6
5 5 9
Table 3 Mean proportion of questions about the explicit alternatives in Experiment 1 Condition
Questions about explicit alternatives/total questions
No context Familiar context Tourist context
0.94 0.92 0.81
2.3. Discussion The main finding by Legrenzi et al. (1993), that it is the tendency to gather more information about the explicit alternatives than about other alternatives (i.e., the ‘‘focusing effect’’), has been replicated. The only reliable difference between the familiar context condition and the no context condition was in the number of questions asked about the explicit alternative, and this could be accounted for by the fact that in the no context condition the participants received less overall information. This supports the robustness of the focusing effect, dispelling our doubts about the pragmatic suitability of the no context condition. The defocusing effect found by Legrenzi et al. in the ‘‘tourist context’’ group was not replicated, although a tendency towards it can be seen in the data (Tables 2 and 3). However, the failed replication of the defocusing effect, if anything, strengthens the original interpretation of the results, showing that focusing on the linguistically explicit alternative is strong even in a suggestive context. 3. Experiment 2 This experiment investigated whether the explicit verbal mention of an alternative is sufficient for the participants to focus on it; or rather, is focusing influenced by the
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alternativeÕs relevance? We used three experimental conditions: (1) The standard nocontext condition, referred to as ‘‘activity–not activity’’ here, in which the participants were given one explicit alternative only (e.g., going to a movie or not); (2) the ‘‘activity–home’’ condition, in which the participants were given two explicit alternatives, one of them being well known and thus irrelevant (the ‘‘status quo’’ alternative––e.g., going to a movie or staying at home); (3) the ‘‘activity–activity’’ condition, in which the participants were given two explicit alternatives, both of them being different from the status quo (e.g., going to a movie or attending a sporting event). We hypothesized that individuals do not necessarily focus on linguistically explicit alternatives, but rather on relevant alternatives. Therefore, we expected that the participants would focus on the alternatives different from the status quo in both the activity–not activity and the activity–home conditions, even though the status quo was a linguistically explicit alternative in the latter. We expected that in the activity–activity condition the participants would gather information about both alternatives, because both of them were different from the status quo. 3.1. Method 3.1.1. Participants Forty-six undergraduate students (27 female and 19 males; age range: 20–36) from the University of Padua volunteered to take part in the experiment. 3.1.2. Materials and procedure Each participant was randomly assigned to one of three conditions and received a booklet with four decision problems. In the activity–not activity condition the problem was: ‘‘You must decide to whether or not [do an activity]. 5 Write in the following spaces all the information that you would need to make your choice’’. In the activity–home condition the problem was: ‘‘You must decide to whether [do an activity] 5 or stay at home.’’ (the following lines were the same as above, in all the conditions). In the activity–activity condition the problem was: ‘‘You must decide to whether [do activity 1] 5 or [do activity 2] 6. . .’’ The participants were not actually given the requested information, and they were not asked to make the choices. At the end of the booklet, the participants were requested to rate on two sevenpoint Likert scales (1) how often they usually performed each activity mentioned in the problems, and (2) how interested they were in each activity. These evaluations were meant as further controls for possible confounds in the design.
5
The activities were randomly drawn from the following set: go to a movie, attend a sporting event, visit an art exhibition, have dinner in a particular restaurant, go to the theatre, go to the disco, go to a pub, attend a concert. For each participant, each problem concerned a different activity. 6 The two activities were randomly drawn from the same list (note 5), but they were constrained not to be the same.
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3.2. Results and analyses Two independent judges sorted the requests made by the participants into four categories. Disagreements arose for 11 participants. Inter-judge reliability was checked by comparing the scorings by the two judges for each category, by means of the Wilcoxon test (as explained in Experiment 1). No significant differences were observed between the scorings of the two judges. Disagreements were then solved by discussion and mutual agreement. The two main categories were the questions about ‘‘alternative 1’’ and ‘‘alternative 2’’ (a few typical examples of the questions are reported in Appendix A). In all the conditions alternative 1 was the verbally explicit first activity. Alternative 2 was a set of implicit alternatives in the activity–not activity condition, the verbally explicit status quo (‘‘staying at home’’) in the activity–home condition and the second explicitly mentioned activity in the activity–activity condition. Two further categories were needed to account for questions that could not be easily assigned to the two main categories. These were questions about ‘‘prerequisites’’ (e.g., asking what the weather was like; this is not, strictly speaking, a question about either ‘‘going to a movie’’ or staying at home; it concerns both of them) and ‘‘personal dispositions’’ (e.g., asking whether one is sad or happy; again, these sort of questions concerns both alternatives). We analyzed these questions separately. Table 4 reports the mean total number of questions about the alternatives, the mean number of questions about alternative 1 and alternative 2, and the proportion of questions concerning alternative 1. The total number of questions did not differ significantly across the three conditions (Kruskal–Wallis test). The difference between alternative 1 and alternative 2 was significant in the activity–not activity and activity–home conditions (Wilcoxon test, p < 0:001 in both conditions), and not significant in the activity–activity condition. There were significant differences in the number of questions about alternative 1 (Kruskal–Wallis test; H ¼ 14:1; df ¼ 2; p < 0:001). In particular, there were significantly more questions about alternative 1 in the activity–not activity (Mann– Whitney test; p < 0:001) and activity–home (p < 0:01) conditions than in the activity–activity condition, and significantly more questions about alternative 2 in the activity–activity condition than in the activity–not activity condition (p < 0:0001) and in the activity–home condition (p < 0:0001).
Table 4 Questionsa in Experiment 2 Condition Activity–not activity Activity–home Activity–activity a
Mean number of questions About alternative 1
About alternative 2
Total
Proportion of questions about alternative 1
13.2 11.4 8
1.1 1.8 7.7
14.3 13.2 15.7
0.93 0.87 0.50
Excluding questions about prerequisites and personal dispositions.
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Table 5 Mean number of questions about prerequisites and personal dispositions in Experiment 2 Condition
Prerequisites
Personal dispositions
Activity–not activity Activity–home Activity–activity
0.88 3.4 1.6
1.81 2 1.73
There were significant differences in the proportions of questions about alternative 1 (Kruskal–Wallis test; H ¼ 26:66; df ¼ 2; p < 0:0001). Specifically, the proportion was significantly smaller in the activity–activity condition than in the other two conditions (Mann–Whitney test; p < 0:0001 for both comparisons); it did not differ between the activity–not activity and the activity–home conditions. Table 5 reports the mean number of questions concerning prerequisites and personal dispositions in the three conditions. The questions about personal dispositions were not different across the conditions. There were significant differences in the questions about prerequisites (Kruskal–Wallis test; H ¼ 12:16; df ¼ 2; p < 0:005). There were more prerequisites questions in the activity–home condition than in the activity–activity condition (Mann–Whitney test; p: < 05) and in the activity–not activity conditions (p < 0:005). The interest and frequency ratings associated to each activity were not significantly correlated with the number of questions made about it, suggesting that the number of questions was not systematically influenced by the participantsÕ actual preferences. 3.3. Discussion The results show that the explicit verbal statement of an alternative is not sufficient for an individual to focus her or his attention on it. The participants focused on the explicitly mentioned activities only when it was different from the status quo. That is, although staying at home was a verbally explicit alternative in the activity–home condition, the participants did not focus on it. This finding suggests that the implicit alternatives in the activity–not activity conditions and in the no contextÕ conditions in Experiment 1 and in Legrenzi et al. (1993) were treated as if they were the irrelevant status quo situation, and thus they were not further investigated. 4. Experiment 3 The previous experiment showed that the explicit verbal formulation of an alternative is not sufficient for an individual to focus attention on it. In this last experiment we checked whether the explicit mention of an alternative is necessary for an individual to focus attention on. To do so, we added to the three conditions of Experiment 2 a fourth condition (‘‘home–not home’’), in which the only verbally explicit alternative was the status quo staying at home. We expected that, in this latter condition, the participants would focus on the implicit alternatives, exploring possible activities not explicitly mentioned in the decision problem.
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4.1. Method 4.1.1. Participants Sixty-one undergraduate students (44 female and 17 male age range: 19–24) from the University of Trento volunteered to take part in the experiment. 4.1.2. Materials and procedure Each participant was randomly assigned to one of four conditions and was given a decision problem. The participants were told to read the problem and write down all the information that they needed in order to make a choice. The participants were neither given the requested information nor asked to make the choice. The activity– not activity (14 participants), activity–home (16 participants) and activity–activity (15 participants) conditions were exactly the same conditions as in Experiment 2 (except that each participant was given one problem instead of four because we had only one problem available for the home–not home condition). The problems in these conditions were randomly drawn from those used in Experiment 2. The problem in the fourth condition (home–not home, 16 participants) was presented as follows: ‘‘You must decide to whether stay at home or not. Write in the following spaces all the information that you need to make your choice’’. 4.2. Results Two independent judges sorted the questions in to four categories, as in Experiment 2. Disagreements arose for 14 subjects, but the differences between the scorings by the two judges were not significant in any condition (Wilcoxon tests), and were solved by mutual agreement. Table 6 reports the mean number of questions about alternative 1 and alternative 2, the mean total number of questions, and the proportion of questions about alternative 1. In the first three conditions the two alternatives were as described in Experiment 2. In the new home–not home condition, alternative 1 was the irrelevant, but verbally explicit, mention of the status quo, whereas alternative 2 was the implicit set of all the possible alternatives. 7 Some examples of typical questions asked in each condition are reported in Appendix A. In the activity–activity condition, there were no significant differences between the questions concerning the two alternatives (Wilcoxon test, p ¼ 0:34). In the activity– home and in the activity–not activity condition, there were significantly more questions about alternative 1 than about alternative 2 (Wilcoxon tests; p < 0:001 and p < 0:005 respectively). These results exactly replicated those obtained in the identical conditions of Experiment 2. In the home–not home condition, there were more questions about alternative 2 than about alternative 1 (Wilcoxon test; p < 0:005).
7 In order to compare the data in Table 6 to those in Table 4 (Experiment 2), the values in the latter should be divided by 4 (they refer to the questions made over four problems, whereas in Experiment 3 only one problem was given to each participant). Of course, the proportions reported in the two tables are directly comparable.
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Table 6 Questionsa in Experiment 3 Condition
Mean number of questions About alternative 1
About alternative 2
Total
Proportion of questions about alternative 1
Activity–not activity Activity–home Activity–activity Home–not home
4.87 3.78 3.17 0.86
1 0.61 2.92 2.75
5.56 4.39 6.08 3.63
0.77 0.84 0.56 0.23
a
Excluding questions about prerequisites and personal dispositions.
The total number of questions was significantly different across the conditions (Kruskal–Wallis test; H ¼ 8:28; df ¼ 3; p < 0:05), because the activity–not activity condition had significantly more questions than the activity–home condition (Mann–Whitney test; p < 0:05) and the home–not home condition (p < 0:01). The questions about alternative 1 were significantly different across the conditions (Kruskal–Wallis test; H ¼ 28:58; df ¼ 3; p < 0:0001), notably because the home–not home condition had less questions than the other three conditions (Mann–Whitney test, p<0.0001 in each comparison). There was also a significant difference between the questions about alternative 1 in the activity–activity and in the activity–not activity conditions (p < 0:05). There were significant differences in the questions about alternative 2 (Kruskal– Wallis test; H ¼ 24:62; df ¼ 3; p < 0:0001). In detail, there were more of them in the activity–activity than in the activity–not activity condition (Mann–Whitney test, p < 0:01) and in the activity–home condition (p < 0:001), as occurred in Experiment 2. The home–not home condition had more questions about alternative 2 than the activity–not activity condition (p < 0:001) and the activity–home condition (p < 0:0001). Finally, there were significant differences in the proportion of questions about alternative 1 (Kruskal–Wallis test; H ¼ 39:64; df ¼ 3; p < 0:0001) which was significantly smaller in the home–not home condition than in the activity–not activity, the activity–home conditions (Mann–Whitney test, p < 0:0001 for both comparisons), and the activity–activity condition (p < 0:001). Furthermore, the proportion was significantly smaller in the activity–activity condition than in the activity–not activity and activity–home conditions (p < 0:001 for both comparisons).
Table 7 Mean number of questions about prerequisites and personal dispositions in Experiment 3 Condition
Prerequisites
Personal dispositions
Activity–not activity Activity–home Activity–activity Home–not home
1.06 1 0.84 1.69
0.81 0.33 0.5 1.49
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The mean number of questions concerning general prerequisites to action and personal dispositions is reported in Table 7. Contrary to Experiment 2, there were no significant differences across the conditions for the questions about prerequisites, whereas there were differences concerning questions about personal dispositions (Kruskal–Wallis test; H ¼ 12:34; df ¼ 3; p < 0:01). In particular, there were more questions about dispositions in the home–not home condition than in the activity–home condition (Mann–Whitney test, p < 0:001) and in the activity–activity condition (p < 0:01). 4.3. Discussion The results of the first three conditions replicated the main results of Experiment 2, confirming that the explicit verbal mention of an alternative is not sufficient for the participants to focus on that alternative. The new home–not home condition showed that the explicit verbal mention of an alternative is not even necessary for an individual to focus her or his attention on: The participants gathered information about the possible activities that they could do instead of staying at home (even if none of these activities were explicitly mentioned in the problem), and they made very few questions about the explicitly mentioned alternative (staying at home). This result supports the hypothesis that people focus on relevant/novel alternatives (whether or not they are verbally explicit in the problem), and do not seek further information concerning irrelevant alternatives, that are assumed to be known. The results concerning the questions about prerequisites and personal disposition were different from those found in Experiment 2, making impossible a theoretical interpretation of the real bearing of these questions. However, both in Experiments 2 and 3 most of these questions occurred in conditions explicitly mentioning the status quo, suggesting that the explicit request of a choice concerning the status quo makes the decision-maker consider very general ‘‘prerequisites to action’’ (including personal dispositions), like ‘‘howÕs the weather?’’ or ‘‘what do I feel like?’’ rather than details about the status quo itself. Further research is needed to clarify this point.
5. Conclusion In making a choice, individuals focus their attention on the alternatives that are explicitly represented in their mental model of the decision problem (Legrenzi et al., 1993), or at least on some of them. This focusing effect has been replicated in all of our experiments. However, according to Legrenzi et al. focusing is mainly determined by the explicit verbal mention of the alternative, whereas our Experiments 2 and 3 showed that the explicit verbal mention of an alternative is neither sufficient nor necessary to focus attention. Actually, individuals do not focus on an explicitly mentioned alternative if that alternative is already well known (Experiment 2); and
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when the only explicit alternative is well known, individuals focus on alternatives that have not been explicitly mentioned (nor suggested by the context, Experiment 3). These findings suggest that an important factor in building explicit mental models of a decision problem is the amount of information attached to each alternative. In the case that the explicitly mentioned alternatives are not informative, the individuals gather information to build explicit models of novel alternatives. In sum, in making a choice, people do not stick exclusively to the alternatives that have been offered to them: If all the explicitly available alternatives seem irrelevant to them, they spontaneously consider novel alternatives. This attenuates the intrinsic irrationality of the decision processes that seemed to emerge from Legrenzi et al.Õs (1993) reading of the focusing effect. The results are in line with recent theories of relevance (Sperber & Wilson, 1995; Sperber et al., 1995) and information gain (Oaksford & Chater, 1995, 1998), suggesting that mental models theory could be usefully supplemented by some of the principles of those theories (at least, as far as the mechanisms that allow building explicit models are concerned).
Appendix A Examples of typical questions asked in Experiments 2 and 3.
Condition Activity–activity (examples drawn from the movie-concert problem)
Examples of questions About alternative 1
About alternative 2
WhatÕs the movie? What genre? WhatÕs its plot? How much does it cost? WhoÕs coming with me?
Where is the concert? WhoÕs coming with me? WhoÕs playing? What sort of music? What sort of audience?
Activity–home (examples Is it far? Have I got a drawn from the concert- car? How much does it home problem) cost? WhoÕs playing? What sort of music? When does it begin?
Is anything important happening at home? Have I planned to do anything at home (like studying)? WhoÕs at home?
Activity–not activity (examples drawn from the movie–not movie problem)
Have I got anything better to do at home? What could I do if I do not go to the cinema? Have I got any other plan for that evening?
WhatÕs the movie? How long is it? How much does it cost? Does it interest me? Does it show in a nice movie theatre? Should I go alone? How far is it?
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Condition Home–not home
Examples of questions About alternative 1
About alternative 2
Is there something interesting on the TV? Am I alone at home? Who would stay with me? Is there something that I must do at home? Am I waiting at home for someone to come? Is there a stressful emotional climate at home?
The plans for the evening are interesting? Is there anything in particular that I could do out, like going to a movie? Do I like the people who would go with me, and how many of them there are? Where would we go? When would we go out? How long would I stay out? WhoÕs inviting me? Should I go far? Have I got a suitable vehicle? How much money would I spend?
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