- Email: [email protected]
The relativity of unrealistic optimism
acta psychologica ELSEVIER
Acta Psychologica 93 (1996) 121-131
The relativity of unrealistic optimism Dan Zakay * Department of Psychology, Tel-Aviv UniversiO', Ramat-Az'iv 69978, Israel
Abstract The influence of the interaction between the valence of a future event and its perceived controllability on the degree of unrealistic optimism (UO) was tested. It was hypothesized that participants, while comparing themselves to an unknown comparison-target, will assign higher occurrence probabilities for positive-controllable events, and lower occurrence probabilities for negative events to themselves, than respective probabilities assigned to a vague comparison-target. It was further hypothesized that in the case of positive-uncontrollable events the probabilities assigned to oneself might be equal or even lower than those assigned to a comparison-target. These hypotheses were supported in a study in which 62 high school students assigned occurrence probabilities to 12 relevant future events representing 4 categories of events, i.e., positive events perceived as controllable or uncontrollable, and negative events perceived as controllable or uncontrollable. The findings are discussed in terms of cognitive and motivational processes. PsvclNFO classification." 3040 Keywords: Unrealistic optimism; Perceived control; Effects of comparison-targets
1. Introduction Unrealistic optimism (UO) is revealed when nonvictims appear to have an 'illusion of unique invulnerability' in which they view themselves as less vulnerable to victimization than they view most other people (Perloff, 1983). UO is also revealed regarding positive events. In many cases, people think that positive events are more likely to occur to themselves than to unknown comparison-targets (e.g. Zakay, 1984). Weinstein (1989) concluded that UO is a robust and widespread bias, which is linked with diverse hazards and appears when different questions are used to elicit personal risk ratings. Indeed, UO was found in many laboratory studies (e.g., Weinstein, 1980; Weinstein and Lachendro,
* E-mail: [email protected], Fax: +972 3 6409547. 0001-6918/96/$15.00 Copyright © 1996 Elsevier Science B.V. All rights reserved. PII S0001-69 I 8(96)00025-X
122
D. Zakay/Acta Psychologica 93 (1996) 121-131
1982; Drake, 1984, 1985; Zakay, 1984; Perloff and Fetzer, 1986) and applied settings (e.g., Svenson, 1981; DeJoy, 1987). Perceived controllability of an event was found to be an important determinant of UO. Weinstein (1980) found support for UO only with controllable events and not with uncontrollable ones. He suggested that the latter represent luck, either good or bad, whereas controllable events enable one to imagine that it is in one's power to change the course of events. Similarly, McKenna (1993) claims that the finding that people underestimate their personal probability of encountering negative events should be interpreted in terms of an illusion of control. The specificity of a comparison-target is an important determinant of UO (Weinstein, 1980; Zakay, 1983, 1984). Perloff and Fetzer (1986) found that UO is significantly reduced when a comparison-target is vague, relative to when the target is specific. Similarly, Alicke et al. (1995) found that people were less biased when they compared themselves with an individuated target than when they compared themselves with a nonindividuated target. Several explanations were offered for the UO phenomenon. Weinstein and Lachendro (1982) suggested that egocentric tendencies might lead people to think only about themselves even when asked to make comparative judgments and cause people to focus their attention on factors that might improve their own chances while ignoring factors which might improve others' chances. Weinstein (1980) further proposed that people tend to perceive others in terms of unrealistic stereotypes, namely, as people who tend to do little to improve their chances. When subjects received information about others, or were asked to identify with others via a role-playing procedure (Weinstein and Lachendro, 1982), the degree of UO was significantly reduced. It appears that lack of information contributes to the use of stereotypical images and to the operation of egocentrism. Therefore, the provision of information about others reduced either the tendency to ignore others or to negatively stereotype them, thereby leading to reduced UO. Perloff and Fetzer (1986) suggested that downward comparisons comprise another process leading to UO. Downward comparisons reflect the claim by Brown (1986) and Taylor and Brown (1988) that people are motivated to maintain and enhance a positive view of themselves. Consequently, they are differentiated from others in ways that show themselves in the most favorable light. Alicke et al. (1995) suggest that "the tendency for people to evaluate themselves more favorably than others may be viewed as a heuristic that serves a number of adaptive functions, the most important of which is to maintain a relatively high level of self-esteem" (p. 824). The reduction of UO regarding a vague comparison-target is explained, accordingly, by the facilitation of downward comparisons caused by the vagueness of a comparison-target. It is of interest to note, however, that in most of the UO studies the full range of interactions between valence and degree of perceived controllability of future events and the nature of a comparison-target was not examined. In many studies (e.g., Perloff and Fetzer, 1986; McKenna, 1993; Alicke et al., 1995), uncontrollable negative future events are in the focus of research. In the present paper it is suggested that UO should have a different pattern regarding positive events perceived as uncontrollable (e.g., to win first prize in the lottery) as
D. Zakay/Acta Psychologica 93 (1996) 121-131
123
compared with negative events perceived as uncontrollable and both negative and positive events perceived as controllable. More specifically, it is presently proposed that self-other judgments in the case of positive uncontrollable future events should yield a lower level of UO than that obtained for positive-controllable and negative future events. It is also possible that for some positive-uncontrollable events UO will be eliminated, even when making a comparison between oneself and a vague comparison-target. The rationale behind this hypothesis is that positive-uncontrollable events are not expected to activate the processes suggested as leading to UO. Downward social comparisons or the tendency to enhance one's self-perception, are motivated mainly by the wish to maintain one's high self-esteem or feeling of safety, and serve an ego-defense function. However, the outcome of an uncontrollable positive event does not imply anything about one's abilities, lower his/her self-esteem or make h i m / h e r vulnerable to victimization. Furthermore, it does not pose a threat to one's ego when it does not happen to oneself or even when it does materialize to a vague, unknown comparison-target. When a friend or someone I do not know wins the first prize in the lottery, I am not hurt, nor does this make the lucky winner better than me in any respect, except luck. Treating a vague comparison-target as an unrealistic stereotype also does not lower his/her perceived chances of winning the lottery. On the contrary, such events are mostly associated with unknown persons, and therefore the availability heuristic (Tversky and Kahneman, 1973) might support the assignment of higher occurrence probabilities to a comparison-target than to oneself. In the case of negativeuncontrollable events, different processes are implied. Though the availability heuristic might be activated in the negative case as well, it supports the generation of UO since the negative outcome is a threat to one's safety. Therefore, wishful thinking might lead to the assignment of lower occurrence probabilities to oneself, as in the classic "it won't happen to m e " case (Weinstein, 1984). To conclude, it is hypothesized that: (1) Likelihood ratings should be higher for controllable than for uncontrollable events. (2) In the case of positive-controllable events (PC), negative-controllable (NC), and negative-uncontrollable (NU) events, the 'better than average' effect will be found regarding a vague comparison-target. The degree of UO in these three events' categories will be reduced or eliminated when a close and specific comparison-target is used. (3) The pattern of UO will be different in the case of positive-uncontrollable (PU) events. Though occurrence probabilities assigned to PU events are expected to be higher than those assigned for NU events, the 'better than average effect' should not be found, regardless of the nature of the comparison-target.
2. Method 2.1. Participants
Sixty-eight female and 59 male high school students ranging in age between 17 and 18 years, agreed to participate in the experiment. All participants were students from four classes in a high school located in the northern part of Israel. Two classes with a total of 36 females and 29 males were randomly selected to participate in the first part of
124
D. Zakay/Acta Psychologica 93 (1996) 121-131
the study - the event generation part. Event generation was performed separately from assigning occurrence probabilities to events in order to eliminate possible influences of explicit rating of events' valence and perceived controllability on probabilities' rating. 2.2. Part 1 - Events generation 2.2.1. Materials and procedure
Participants in this part were asked to write down as many events as they could think of which were relevant for high school students of their own age. The four categories (PC, PU, NC, and NU) of events were defined and it was requested that their lists include events of all four types. It was also requested that each event be rated on the following 10-point scale: (1) Valence scale - the degree to which an event's outcomes are negative or positive, 1 standing for 'very negative' and 10 standing for 'very positive', and (2) Perceived controllability of an event - the degree to which a target has control over event's outcomes, 1 standing for 'completely uncontrollable' and 10 for 'completely controllable'. 2.2.2. Selection of events
Twelve events (see Appendix A) which met the following criteria were selected: (1) at least 50% of the participants (male and female) suggested the event, (2) the event was not sex-specific, and (3) the event clearly belonged to one of the four events' categories. A positive-controllable event (PC) should have valence and controllability ratings in the upper quartile of the distribution of each scale. A positive-uncontrollable event (PU) should have a valence rating in the upper quartile and a controllability rating in the lower quartile. A negative-controllable event (NC) should have a valence score in the lower quartile and a controllability rating in the upper quartile, and negative-uncontrollable events (NU) should have valence and controllability ratings in the lower quartiles. In order to validate the selection of events, the valence and controllability ratings were subjected to three-way ANOVA's (school classes × valence × perceived controllability) with repeated measures within class. No significant differences were found between the two classes to which participants belonged and therefore the ratings were collapsed across classes and two-way ANOVA's were used for the analyses. The internal consistencies of the ratings within each group ranged between 0.68 and 0.75 (alpha Cronbach's values). Means and standard deviations of the ratings are presented in Table 1.
Table 1 Means and standard deviations (in parentheses) of events' ratings of valence and controllability (n = 65) Event's controllability
Event's valence Positive
Controllable Uncontrollable
Negative
Valence ratings
Controllability ratings
Valence ratings
Controllability ratings
7.53 (1.10) 7.84 (1.75)
7.82 (1.55) 2.93 (1.42)
2.47 (1.10) 1.83 (1.20)
7.47 (1.49) 2.30 (0.92)
D. Zakay / Acta Psychologica 93 (1996) 121-131
125
For valence ratings a significant main effect of valence (F(1,64) = 501.11; p < 0.01) was obtained. As expected, positive events were rates as having a higher valence than negative events. The main effect of controllability (F(1,64) = 2.03) was not significant, but the interaction between valence and controllability (F(1,64) = 12.77; p < 0.01) was significant, because controllable negative events were perceived as more positive than uncontrollable negative events. For perceived controllability ratings the main effects of valence (F(1,64) = 16.06; p < 0.01) and of controllability (F(1,64) = 741.12; p < 0.01) were significant, but the interaction ( F ( 1 , 6 4 ) = 3.03; p = 0.08), was not significant. Controllable events were perceived as more controllable than uncontrollable events and positive events were perceived as more controllable than negative events. It can be concluded that the selection of events yielded four distinct groups in terms of valence and perceived controllability. The distinctiveness of each category is assured by post hoc comparisons (Duncan). The valence ratings of PU and PC do not differ significantly and each one of them differs significantly from valence ratings of NC and NU, but controllability ratings of PU and PC differ significantly. Similar findings were obtained for NC and NU regarding valence and controllability ratings. 2.3. Part 2 - Testing unrealistic optimism 2.3.1. Materials and procedure
Participants were told (as in Perloff and Fetzer, 1986) that they were participating in a study of the beliefs high school students of their own age have about themselves and others. The study was conducted in a class setting, participants were not required to write their names on the questionnaires and were assured that the study would not influence their grades in any way. The participants were then asked to think about two comparison-targets defined (after Perloff and Fetzer, 1986) as 'the average high school student of your sex and age in the northern part of Israel' and 'your closest friend in your class'. Following that, the 12 events, selected in the first part, were administered in random order and participants were asked to give three ratings regarding each one of the 12 events. Presentation order of comparison-targets was random. The ratings were made on a scale (a modification of a scale used by Alicke et al., 1995, study 5) ranging between - 100 and + 100 where - 100 stood for 'very unlikely' and + 100 for 'very likely'. Like in Alicke et al. (1995, study 5) the scales were prefaced with the question " H o w likely is this to happen to you (or to 'your closest friend in class', or to 'the average high school student of your own age and sex in the northern part of Israel') in the following 24 months".
3. Results Average likelihood ratings for each event and each comparison-target are presented in Appendix A. The likelihood ratings assigned for each comparison-target in each event were subjected to one-way ANOVA's with repeated measures. The F-values are a m presented in Appendix A. Analyses at events' level indicate that in all the belonging to the PC, NC and NU categories, the difference between compar"
126
D. Zakay /Acta Psychologica 93 (1996) 121-131
was significant and in the expected direction, namely, higher likelihood ratings for oneself than for the average comparison-target in PC events, and a reverse pattern in NC and NU events. In all these three categories the likelihood ratings assigned for the close comparison-target are much more closer to those assigned for oneself than for those assigned for the average comparison-target. The pattern is different in PU events. Regarding the event of winning a large prize in the lottery, the likelihood ratings assigned for the average comparison-target are closer to those assigned for the close comparison-target than to those assigned for oneself and both are higher than those assigned for oneself. Regarding the other two PU events, the differences between likelihood ratings assigned for the three comparison-targets are not significant. Averages of likelihood ratings in each event's category were calculated. The means and standard deviations of these averages are presented in Table 2. The likelihood ratings were subjected to four-way ANOVA (class X valence X comparison-target X perceived controllability), but since the effect of class was not found to be significant by itself or as an interaction with any one of the other independent variables, the ratings were collapsed across class and subjected to three-way ANOVA with repeated measures. The main effects of valence (F(1,61) = 110.10; p < 0.01), of controllability (F(I,61) = 32.94; p < 0.01), and of comparison-target (F(2,122) = 22.23; p < 0.01) were significant. Likelihood ratings were higher for positive than for negative events and for controllable than for uncontrollable events. The interaction between valence and controllability (F(1,61 = 2.92; p = 0.09) was not significant but the interactions between valence and comparison-target (F(2,122) = 37.70; p < 0.01), controllability and comparison-target (F(2,122) = 6.81; p < 0.01), and the triple interaction between valence, controllability and comparison-target (F(2,122)= 19.74; p <0.01) were significant. In order to better understand these interactions, simple effects of comparison-targets in each event's category were computed, and were found to be significant in all cases. In PC events (F(2,122)= 19.15; p < 0.01) likelihood ratings assigned for oneself were higher than those assigned for the average comparison-target. The opposite was the case for PU (F(2,122)= 7.18; p < 0.01); NC (F(2,122) = 37.01; p < 0.01); and NU (F(2,122) --- 26.19; p < 0.01). Next, simple effects for each comparison-target were calculated. In the case of oneself, significant effects were found for valence (F(1,61) = 86.50; p < 0.01), for controllability (F(1,61) = 30.80; p < 0.01), and for the interaction (F(I,61) = 19.87; p < 0.01). Likelihood ratings were similar for negative events and lower than those assigned for Table 2 Means and standard deviations (in parentheses) of likelihood ratings (n = 62) Event's controllability
Event's valence Negative comparison target
Positive comparison target Self Controllable Uncontrollable
49.48 (33.20) 8.79 (42.11)
Close
Average
41.18
23.86
(32.24) 22.97 (34.79)
(32.05) 23.66 (29.88)
Self - 22.03
(36.70) - 23.97 (43.71 )
Close
Average
- 8.55
18.48
(32.77) - 22.69 (45.28)
(28.13) 7.91 (32.37)
D. Zakay/Acta Psychologica 93 (1996) 121-131
127
positive events but were much higher for PC than for PU events. In the case of a close comparison-target, significant effects were obtained for valence ( F ( 1 , 6 1 ) = 102.27; p < 0 . 0 1 ) , and for controllability ( F ( 1 , 6 1 ) = 18.12; p < 0 . 0 1 ) , but the interaction (F(1,61) = 0.19) was not significant. Likelihood ratings were higher for positive than for negative events and for controllable than for uncontrollable events. In the case of average comparison-target the effects of valence (F(1,61) = 12.79; p < 0.01) and of controllability (F(1,61) = 3.85; p < 0.05) were significant and the interaction (F(1,61) = 2.88; p = 0.09) was not significant. Likelihood ratings assigned for PC and PU events were very similar and higher for NC than for NU events. The overall pattern of results indicates that the triple interaction between valence, controllability and comparison-target is the key for understanding UO. It is clear that PU events have a different impact on assigning likelihood ratings for each comparison-target than PC events. In order to make this distinction visible, a new score of optimism (OPT) was calculated by subtracting the likelihood rating assigned for a comparison-target from that assigned for oneself for positive events and by subtracting oneself rating from a comparison-target rating for negative events. Thus, a higher OPT score indicates higher level of UO. Two OPT scores were computed: Self-Close, between oneself and the close comparison-target, and Self-Average, between oneself and the average comparison-target. The CloseAverage OPT score was not computed since it is dependent on the other two scores. Means and standard deviations of OPT scores are presented in Table 3. OPT scores were analyzed by two-way ANOVA's (valence X controllability) with repeated measures. For Self-Close OPT scores, the effects of valence ( F ( 1 , 6 1 ) = 9 . 9 8 ; p < 0.01) and of controllability ( F ( 1 , 6 1 ) = 25.34; p < 0.01) were significant, indicating that UO was higher for positive than for negative events and also for controllable than for uncontrollable events. The interaction (F(1,61) = 1.25) was not significant. These findings indicate that whereas UO was induced by PC, NC and to a lower degree by NU events, UO was not induced by PU events. For Self-Average OPT the effects of valence (F(I,61) = 31.29; p < 0.01), controllability (F(1,61) = 29.00; p < 0.01) and the interaction (F(1,61) = 12.76; p < 0.01) were significant. In this case, UO was clearly induced by PC, NC and NU events, but not by PU events. Another three-way ANOVA with repeated measures (valence X controllability x OPT type) was conducted. The interesting effect yielded by this analysis is the triple interaction between
Table 3 Means and standard deviations (in parentheses) of OPT scores a (n = 62) Event's controllability
Event's valence Positive
Controllable Uncontrollable
Negative
Self-Close
Self-Average
Self-Close
Self-Average
7.85 (33.43) - 13.95 (32.39)
25.36 (32.57) - 14.11 (41.01 )
13.86 (33.80) 1.50 (30.94)
40.72 (43.66) 31.89 (41.93)
Higher scores indicate a higher level of UO.
D. Zakay /Acta Psychologica 93 (1996) 121-131
128
OPT 50 45
[]
Self-Close
40
[]
Self-Average
40.72 ~-.~
35
~N,"~ .\\\
31.89
30 25
25.36
55x
20
\\\
\\\
13.86 X,,"-,~
15
-
10 5 ,X\\
0
r- ,
~\",
-5 -10 -15
-13.95 -i4.11
-20
PC
PU
NC
NU
Fig. 1. OPT scores according to events' type and comparison-target.
valence, controllability and OPT type (F(I,61) = 63.35; p < 0.01). UO was obtained for both comparison-targets for PC and NC events. For NU events UO was obtained for the average comparison-target, but not for the close comparison-target. However, in the case of PU events, UO was not obtained for either of the two comparison-targets. The triple interaction is presented in Fig. 1.
4. Discussion The results obtained in the two experiments lend support to the hypotheses tested. Participants assigned higher likelihood ratings for controllable than for uncontrollable events regardless of which comparison-target was involved. The 'better than average' aspect of UO, however, was replicated only for negative events and for positive-controllable events, but not for positive-uncontrollable events. Thus, the major hypothesis of the present study was supported. This distinction of PU events is clearly manifested in the analyses of each event by itself and also by the analyses of the OPT scores. The PU category differs from the other three events' categories in terms of the comparison-target effect. The decrease in degree of UO when the comparison-target is close and familiar to the participant, as compared with a vague comparison-target (Perloff and Fetzer, 1986; Alicke et al., 1995) was replicated for PC, NC and NU events. This was not the case regarding PU events.
D. Zakay/Acta Psychologica 93 (1996) 121-131
129
UO is most plausibly resulting from the operation of motivational processes such as defensiveness and wishful thinking (Miller and Ross, 1975). Self-serving biases in the attribution process (e.g., Weary, 1979) might also play a role here. Egocentric tendencies (Weinstein and Lachendro, 1982) add their share by directing people's attention to focus only inward. The present findings, however, indicate that the interaction between event's valence and its degree of perceived controllability should also be taken into account in order to fully understand the processes underlying UO. Negative events differ from positive ones by being more ego-threatening (Duck and Mullin, 1995). Taylor (1991) claims that negative events evoke strong and rapid physiological, cognitive, emotional, and social responses and mobilize the organism much more intensively than neutral or positive events. Thus, when one is presented with a possible future negative event, whether or not perceived as controllable, ego-defense mechanisms are most plausibly activated. Similar defensive effects should be expected in the case of positive-controllable events since failing such an event or achieving worse results than an unknown vague comparison-target, can be ego-threatening. Positive future events which are not perceived as controllable, on the other hand, should not pose a real threat to one's ego and self-esteem. Achieving less than a remote or a close comparison-target in such an event, does not indicate incompetence on the one hand, and does not shake the status quo, since unlike in an uncontrollable negative outcome, one's life status is not threatened or worsened. Therefore, ego-defense mechanisms do not have to be activated. Consequently, for PU events likelihood ratings of oneself might be equal to or less than those assigned to a close or a remote comparison-target. In the present study each event's category was represented by three events only, though all three were highly relevant for the participants. Zakay (1995) found similar results to those obtained here in a study in which occurrence probabilities of 40 events (10 representing each category) were rated by Kibbutz members with ages ranging between 20 and 45 years. Nevertheless, further experimentation involving a variety of events and various population is required in order to identify the determinants of UO and define how they interact. The importance of this is both theoretical and applied, since UO might be an important factor in many personal, social, and political decisions.
Acknowledgements The author wishes to thank two anonymous reviewers for their helpful comments on an earlier draft of the paper. The help of Galit Askayo in the collection of data is highly appreciated.
Appendix A Table 4 presents the means of valence, controllability and likelihood ratings of events.
D. Zakay /Acta Psychologica 93 (1996) 121-131
130 Table 4 Event No.
Valence
Controllability
Likelihood rating Self
Close
F(comparison targets) Average
PC 1 2 3
8.60 7.55 6.44
6.62 8.76 8.09
50.44 35.84 62.18
56.88 31.12 35.54
26.12 22.00 24.09
F(2,120) = 10.10 * * F(2,120) = 3.00 * F(2,120) = 18.59 * '
7.49 7.60 8.43
3.12 1.61 4.06
-25.01 20.14 31.24
0.27 25.46 43.19
2.59 16.96 51.43
F(2,120) = 10.44 * * F(2,122) = 0.72 n.s. F(2,122) = 2.55; p = 0.08
2.79 1.90 2.78
6.56 8.32 7.53
- 12.79 -27.73 -25.59
10.68 - 18.15 - 17.46
17.42 26.10 13.43
F(2,120) = 8.57 * * F(2,118) = 20.88 * * F(2,122) = 14.42 ' *
1.82 2.29 2.29
1.75 3.40 3.40
- 13.66 - 23.32 -34.94
- 18.47 - 22.98 -26.52
13.69 5.72 4.33
F ( 2 , 1 1 6 ) = 12.42 * * F(2,116) = 8.20 * * F(2,108) = 16.03 * "
PU 4 5 6
NC 7 8 9
NU 10 11 12
Note: Participants who rated valence and controllability did not rate events' likelihood. p < 0.05. * * p < 0.01. '
Event's description: (1) to be selected for an officer's course in the army; (2) to get high grades in matriculation exams; (3) to succeed in achieving good social relations; (4) to win a large prize in the lottery; (5) 'love at first sight' in an unexpected accidental meeting; (6) to be chosen to participate in a popular TV show; (7) to fail in an important exam; (8) failure in maintaining an important social relation; (9) to cause a traffic accident as a driver; (10) severe illness of one of the family members; (11) severe illness of oneself; (12) being a victim of a terror attack.
References Alicke, M.D., M.L. Klatz, D.L. Breitenbecher, T.J. Yurak and D.S. Vredenburg, 1995. Personal contact, individuation, and the better-than-average effect. Journal of Personality and Social Psychology 65(5), 804-825. Brown, J.D., 1986. Evaluation of self and othrs: Self-enhancement biases in social judgments. Social Cognition 4, 353-376. DeJoy, D.M., 1987. The optimism bias and traffic safety. Proceedings of the Human Factors Society, 31st Annual M e e t i n g ( p p . 756-759). Drake, R.A., 1984. Lateral asymmetry of personal optimism. Journal of Research in personality 18, 497-507. Drake, R.A., 1985. Lateral asymmetry of risky recommendations. Personality and Social Psychology Bulletin 11(4), 4 0 9 - 4 1 7 . Duck, J.M. and B.A. Mullin, 1995. The perceived impact of the mass media: Reconsidering the third person effect. European Journal of Social Psychology 25, 7 7 - 9 3 . McKenna, F.P., 1993. It w o n ' t happen to me: Unrealistic optimism or illusion of control? British Journal of Psychology 84, 3 9 - 5 0 . Miller, D.T. and M. Ross, 1975. Self-serving biases in the attribution of causality: Fact or fiction? Psychological Bulletin 82, 213-225. Perloff, L.S., 1983. Perceptions of vulnerability to victimization. Journal of Social Issues 39, 4 1 - 6 1 .
D. Zakay / Acta Psychologica 93 (1996) 121-131
131
Perloff, L.S. and B.K. Fetzer, 1986. Self-other Judgments and Perceived Vulnerability to Victimization, Journal of Personality and Social Psychology 50, 502-510. Svenson, O., 1981. Are we all less risky and more skillful than our fellow drivers? Acta Psychologica 47, 143-148. Taylor, S.E., 1991. Assymetrical effects of positive and negative events: The mobilization-minimization hypothesis. Psychological Bulletin 110(1), 67-85. Taylor, S.E. and J.D. Brown, 1988. Illusion and well-being: A social psychological perspective on mental health. Psychological Bulletin 103, 193-210. Tversky, A. and D. Kahneman, 1973. Availability: A heuristic for judging frequency and probability. Cognitive Psychology 5, 207-232. Weary, G., 1979. Self-serving attributional biases: Perceptual or response distortions? Journal of Personality and Social Psychology 37, 1418-1420. Weinstein, N.D., 1980. Unrealistic optimism about future life events. Journal of Personality and Social Psychology 39, 806-820. Weinstein, N.D., 1984. Why it won't happen to me: Perceptions of risk factors and susceptibility. Health Psychology 3, 431-457. Weinstein, N.D., 1989. Optimistic biases about personal risks. Science 264, 1232-1233. Weinstein, N.D. and E. Lachendro, 1982. Egocentrism as a source of unrealistic optimism. Personality and Social Psychology Bulletin 8, 195-200. Zakay, D., 1983. The relationship between the probability assessor and the outcomes of an event as a determiner of subjective probability. Acta Psychologica 53, 271-280. Zakay, D., 1984. The influence of perceived event's controllability on its subjective occurrence probability. The Psychological Record 34, 233-240. Zakay, D., 1995. Unrealistic optimism in the case of positive-uncontrollable events. Unpublished manuscript. Tel-Aviv University.
Acta Psychologica 93 (1996) 121-131
The relativity of unrealistic optimism Dan Zakay * Department of Psychology, Tel-Aviv UniversiO', Ramat-Az'iv 69978, Israel
Abstract The influence of the interaction between the valence of a future event and its perceived controllability on the degree of unrealistic optimism (UO) was tested. It was hypothesized that participants, while comparing themselves to an unknown comparison-target, will assign higher occurrence probabilities for positive-controllable events, and lower occurrence probabilities for negative events to themselves, than respective probabilities assigned to a vague comparison-target. It was further hypothesized that in the case of positive-uncontrollable events the probabilities assigned to oneself might be equal or even lower than those assigned to a comparison-target. These hypotheses were supported in a study in which 62 high school students assigned occurrence probabilities to 12 relevant future events representing 4 categories of events, i.e., positive events perceived as controllable or uncontrollable, and negative events perceived as controllable or uncontrollable. The findings are discussed in terms of cognitive and motivational processes. PsvclNFO classification." 3040 Keywords: Unrealistic optimism; Perceived control; Effects of comparison-targets
1. Introduction Unrealistic optimism (UO) is revealed when nonvictims appear to have an 'illusion of unique invulnerability' in which they view themselves as less vulnerable to victimization than they view most other people (Perloff, 1983). UO is also revealed regarding positive events. In many cases, people think that positive events are more likely to occur to themselves than to unknown comparison-targets (e.g. Zakay, 1984). Weinstein (1989) concluded that UO is a robust and widespread bias, which is linked with diverse hazards and appears when different questions are used to elicit personal risk ratings. Indeed, UO was found in many laboratory studies (e.g., Weinstein, 1980; Weinstein and Lachendro,
* E-mail: [email protected], Fax: +972 3 6409547. 0001-6918/96/$15.00 Copyright © 1996 Elsevier Science B.V. All rights reserved. PII S0001-69 I 8(96)00025-X
122
D. Zakay/Acta Psychologica 93 (1996) 121-131
1982; Drake, 1984, 1985; Zakay, 1984; Perloff and Fetzer, 1986) and applied settings (e.g., Svenson, 1981; DeJoy, 1987). Perceived controllability of an event was found to be an important determinant of UO. Weinstein (1980) found support for UO only with controllable events and not with uncontrollable ones. He suggested that the latter represent luck, either good or bad, whereas controllable events enable one to imagine that it is in one's power to change the course of events. Similarly, McKenna (1993) claims that the finding that people underestimate their personal probability of encountering negative events should be interpreted in terms of an illusion of control. The specificity of a comparison-target is an important determinant of UO (Weinstein, 1980; Zakay, 1983, 1984). Perloff and Fetzer (1986) found that UO is significantly reduced when a comparison-target is vague, relative to when the target is specific. Similarly, Alicke et al. (1995) found that people were less biased when they compared themselves with an individuated target than when they compared themselves with a nonindividuated target. Several explanations were offered for the UO phenomenon. Weinstein and Lachendro (1982) suggested that egocentric tendencies might lead people to think only about themselves even when asked to make comparative judgments and cause people to focus their attention on factors that might improve their own chances while ignoring factors which might improve others' chances. Weinstein (1980) further proposed that people tend to perceive others in terms of unrealistic stereotypes, namely, as people who tend to do little to improve their chances. When subjects received information about others, or were asked to identify with others via a role-playing procedure (Weinstein and Lachendro, 1982), the degree of UO was significantly reduced. It appears that lack of information contributes to the use of stereotypical images and to the operation of egocentrism. Therefore, the provision of information about others reduced either the tendency to ignore others or to negatively stereotype them, thereby leading to reduced UO. Perloff and Fetzer (1986) suggested that downward comparisons comprise another process leading to UO. Downward comparisons reflect the claim by Brown (1986) and Taylor and Brown (1988) that people are motivated to maintain and enhance a positive view of themselves. Consequently, they are differentiated from others in ways that show themselves in the most favorable light. Alicke et al. (1995) suggest that "the tendency for people to evaluate themselves more favorably than others may be viewed as a heuristic that serves a number of adaptive functions, the most important of which is to maintain a relatively high level of self-esteem" (p. 824). The reduction of UO regarding a vague comparison-target is explained, accordingly, by the facilitation of downward comparisons caused by the vagueness of a comparison-target. It is of interest to note, however, that in most of the UO studies the full range of interactions between valence and degree of perceived controllability of future events and the nature of a comparison-target was not examined. In many studies (e.g., Perloff and Fetzer, 1986; McKenna, 1993; Alicke et al., 1995), uncontrollable negative future events are in the focus of research. In the present paper it is suggested that UO should have a different pattern regarding positive events perceived as uncontrollable (e.g., to win first prize in the lottery) as
D. Zakay/Acta Psychologica 93 (1996) 121-131
123
compared with negative events perceived as uncontrollable and both negative and positive events perceived as controllable. More specifically, it is presently proposed that self-other judgments in the case of positive uncontrollable future events should yield a lower level of UO than that obtained for positive-controllable and negative future events. It is also possible that for some positive-uncontrollable events UO will be eliminated, even when making a comparison between oneself and a vague comparison-target. The rationale behind this hypothesis is that positive-uncontrollable events are not expected to activate the processes suggested as leading to UO. Downward social comparisons or the tendency to enhance one's self-perception, are motivated mainly by the wish to maintain one's high self-esteem or feeling of safety, and serve an ego-defense function. However, the outcome of an uncontrollable positive event does not imply anything about one's abilities, lower his/her self-esteem or make h i m / h e r vulnerable to victimization. Furthermore, it does not pose a threat to one's ego when it does not happen to oneself or even when it does materialize to a vague, unknown comparison-target. When a friend or someone I do not know wins the first prize in the lottery, I am not hurt, nor does this make the lucky winner better than me in any respect, except luck. Treating a vague comparison-target as an unrealistic stereotype also does not lower his/her perceived chances of winning the lottery. On the contrary, such events are mostly associated with unknown persons, and therefore the availability heuristic (Tversky and Kahneman, 1973) might support the assignment of higher occurrence probabilities to a comparison-target than to oneself. In the case of negativeuncontrollable events, different processes are implied. Though the availability heuristic might be activated in the negative case as well, it supports the generation of UO since the negative outcome is a threat to one's safety. Therefore, wishful thinking might lead to the assignment of lower occurrence probabilities to oneself, as in the classic "it won't happen to m e " case (Weinstein, 1984). To conclude, it is hypothesized that: (1) Likelihood ratings should be higher for controllable than for uncontrollable events. (2) In the case of positive-controllable events (PC), negative-controllable (NC), and negative-uncontrollable (NU) events, the 'better than average' effect will be found regarding a vague comparison-target. The degree of UO in these three events' categories will be reduced or eliminated when a close and specific comparison-target is used. (3) The pattern of UO will be different in the case of positive-uncontrollable (PU) events. Though occurrence probabilities assigned to PU events are expected to be higher than those assigned for NU events, the 'better than average effect' should not be found, regardless of the nature of the comparison-target.
2. Method 2.1. Participants
Sixty-eight female and 59 male high school students ranging in age between 17 and 18 years, agreed to participate in the experiment. All participants were students from four classes in a high school located in the northern part of Israel. Two classes with a total of 36 females and 29 males were randomly selected to participate in the first part of
124
D. Zakay/Acta Psychologica 93 (1996) 121-131
the study - the event generation part. Event generation was performed separately from assigning occurrence probabilities to events in order to eliminate possible influences of explicit rating of events' valence and perceived controllability on probabilities' rating. 2.2. Part 1 - Events generation 2.2.1. Materials and procedure
Participants in this part were asked to write down as many events as they could think of which were relevant for high school students of their own age. The four categories (PC, PU, NC, and NU) of events were defined and it was requested that their lists include events of all four types. It was also requested that each event be rated on the following 10-point scale: (1) Valence scale - the degree to which an event's outcomes are negative or positive, 1 standing for 'very negative' and 10 standing for 'very positive', and (2) Perceived controllability of an event - the degree to which a target has control over event's outcomes, 1 standing for 'completely uncontrollable' and 10 for 'completely controllable'. 2.2.2. Selection of events
Twelve events (see Appendix A) which met the following criteria were selected: (1) at least 50% of the participants (male and female) suggested the event, (2) the event was not sex-specific, and (3) the event clearly belonged to one of the four events' categories. A positive-controllable event (PC) should have valence and controllability ratings in the upper quartile of the distribution of each scale. A positive-uncontrollable event (PU) should have a valence rating in the upper quartile and a controllability rating in the lower quartile. A negative-controllable event (NC) should have a valence score in the lower quartile and a controllability rating in the upper quartile, and negative-uncontrollable events (NU) should have valence and controllability ratings in the lower quartiles. In order to validate the selection of events, the valence and controllability ratings were subjected to three-way ANOVA's (school classes × valence × perceived controllability) with repeated measures within class. No significant differences were found between the two classes to which participants belonged and therefore the ratings were collapsed across classes and two-way ANOVA's were used for the analyses. The internal consistencies of the ratings within each group ranged between 0.68 and 0.75 (alpha Cronbach's values). Means and standard deviations of the ratings are presented in Table 1.
Table 1 Means and standard deviations (in parentheses) of events' ratings of valence and controllability (n = 65) Event's controllability
Event's valence Positive
Controllable Uncontrollable
Negative
Valence ratings
Controllability ratings
Valence ratings
Controllability ratings
7.53 (1.10) 7.84 (1.75)
7.82 (1.55) 2.93 (1.42)
2.47 (1.10) 1.83 (1.20)
7.47 (1.49) 2.30 (0.92)
D. Zakay / Acta Psychologica 93 (1996) 121-131
125
For valence ratings a significant main effect of valence (F(1,64) = 501.11; p < 0.01) was obtained. As expected, positive events were rates as having a higher valence than negative events. The main effect of controllability (F(1,64) = 2.03) was not significant, but the interaction between valence and controllability (F(1,64) = 12.77; p < 0.01) was significant, because controllable negative events were perceived as more positive than uncontrollable negative events. For perceived controllability ratings the main effects of valence (F(1,64) = 16.06; p < 0.01) and of controllability (F(1,64) = 741.12; p < 0.01) were significant, but the interaction ( F ( 1 , 6 4 ) = 3.03; p = 0.08), was not significant. Controllable events were perceived as more controllable than uncontrollable events and positive events were perceived as more controllable than negative events. It can be concluded that the selection of events yielded four distinct groups in terms of valence and perceived controllability. The distinctiveness of each category is assured by post hoc comparisons (Duncan). The valence ratings of PU and PC do not differ significantly and each one of them differs significantly from valence ratings of NC and NU, but controllability ratings of PU and PC differ significantly. Similar findings were obtained for NC and NU regarding valence and controllability ratings. 2.3. Part 2 - Testing unrealistic optimism 2.3.1. Materials and procedure
Participants were told (as in Perloff and Fetzer, 1986) that they were participating in a study of the beliefs high school students of their own age have about themselves and others. The study was conducted in a class setting, participants were not required to write their names on the questionnaires and were assured that the study would not influence their grades in any way. The participants were then asked to think about two comparison-targets defined (after Perloff and Fetzer, 1986) as 'the average high school student of your sex and age in the northern part of Israel' and 'your closest friend in your class'. Following that, the 12 events, selected in the first part, were administered in random order and participants were asked to give three ratings regarding each one of the 12 events. Presentation order of comparison-targets was random. The ratings were made on a scale (a modification of a scale used by Alicke et al., 1995, study 5) ranging between - 100 and + 100 where - 100 stood for 'very unlikely' and + 100 for 'very likely'. Like in Alicke et al. (1995, study 5) the scales were prefaced with the question " H o w likely is this to happen to you (or to 'your closest friend in class', or to 'the average high school student of your own age and sex in the northern part of Israel') in the following 24 months".
3. Results Average likelihood ratings for each event and each comparison-target are presented in Appendix A. The likelihood ratings assigned for each comparison-target in each event were subjected to one-way ANOVA's with repeated measures. The F-values are a m presented in Appendix A. Analyses at events' level indicate that in all the belonging to the PC, NC and NU categories, the difference between compar"
126
D. Zakay /Acta Psychologica 93 (1996) 121-131
was significant and in the expected direction, namely, higher likelihood ratings for oneself than for the average comparison-target in PC events, and a reverse pattern in NC and NU events. In all these three categories the likelihood ratings assigned for the close comparison-target are much more closer to those assigned for oneself than for those assigned for the average comparison-target. The pattern is different in PU events. Regarding the event of winning a large prize in the lottery, the likelihood ratings assigned for the average comparison-target are closer to those assigned for the close comparison-target than to those assigned for oneself and both are higher than those assigned for oneself. Regarding the other two PU events, the differences between likelihood ratings assigned for the three comparison-targets are not significant. Averages of likelihood ratings in each event's category were calculated. The means and standard deviations of these averages are presented in Table 2. The likelihood ratings were subjected to four-way ANOVA (class X valence X comparison-target X perceived controllability), but since the effect of class was not found to be significant by itself or as an interaction with any one of the other independent variables, the ratings were collapsed across class and subjected to three-way ANOVA with repeated measures. The main effects of valence (F(1,61) = 110.10; p < 0.01), of controllability (F(I,61) = 32.94; p < 0.01), and of comparison-target (F(2,122) = 22.23; p < 0.01) were significant. Likelihood ratings were higher for positive than for negative events and for controllable than for uncontrollable events. The interaction between valence and controllability (F(1,61 = 2.92; p = 0.09) was not significant but the interactions between valence and comparison-target (F(2,122) = 37.70; p < 0.01), controllability and comparison-target (F(2,122) = 6.81; p < 0.01), and the triple interaction between valence, controllability and comparison-target (F(2,122)= 19.74; p <0.01) were significant. In order to better understand these interactions, simple effects of comparison-targets in each event's category were computed, and were found to be significant in all cases. In PC events (F(2,122)= 19.15; p < 0.01) likelihood ratings assigned for oneself were higher than those assigned for the average comparison-target. The opposite was the case for PU (F(2,122)= 7.18; p < 0.01); NC (F(2,122) = 37.01; p < 0.01); and NU (F(2,122) --- 26.19; p < 0.01). Next, simple effects for each comparison-target were calculated. In the case of oneself, significant effects were found for valence (F(1,61) = 86.50; p < 0.01), for controllability (F(1,61) = 30.80; p < 0.01), and for the interaction (F(I,61) = 19.87; p < 0.01). Likelihood ratings were similar for negative events and lower than those assigned for Table 2 Means and standard deviations (in parentheses) of likelihood ratings (n = 62) Event's controllability
Event's valence Negative comparison target
Positive comparison target Self Controllable Uncontrollable
49.48 (33.20) 8.79 (42.11)
Close
Average
41.18
23.86
(32.24) 22.97 (34.79)
(32.05) 23.66 (29.88)
Self - 22.03
(36.70) - 23.97 (43.71 )
Close
Average
- 8.55
18.48
(32.77) - 22.69 (45.28)
(28.13) 7.91 (32.37)
D. Zakay/Acta Psychologica 93 (1996) 121-131
127
positive events but were much higher for PC than for PU events. In the case of a close comparison-target, significant effects were obtained for valence ( F ( 1 , 6 1 ) = 102.27; p < 0 . 0 1 ) , and for controllability ( F ( 1 , 6 1 ) = 18.12; p < 0 . 0 1 ) , but the interaction (F(1,61) = 0.19) was not significant. Likelihood ratings were higher for positive than for negative events and for controllable than for uncontrollable events. In the case of average comparison-target the effects of valence (F(1,61) = 12.79; p < 0.01) and of controllability (F(1,61) = 3.85; p < 0.05) were significant and the interaction (F(1,61) = 2.88; p = 0.09) was not significant. Likelihood ratings assigned for PC and PU events were very similar and higher for NC than for NU events. The overall pattern of results indicates that the triple interaction between valence, controllability and comparison-target is the key for understanding UO. It is clear that PU events have a different impact on assigning likelihood ratings for each comparison-target than PC events. In order to make this distinction visible, a new score of optimism (OPT) was calculated by subtracting the likelihood rating assigned for a comparison-target from that assigned for oneself for positive events and by subtracting oneself rating from a comparison-target rating for negative events. Thus, a higher OPT score indicates higher level of UO. Two OPT scores were computed: Self-Close, between oneself and the close comparison-target, and Self-Average, between oneself and the average comparison-target. The CloseAverage OPT score was not computed since it is dependent on the other two scores. Means and standard deviations of OPT scores are presented in Table 3. OPT scores were analyzed by two-way ANOVA's (valence X controllability) with repeated measures. For Self-Close OPT scores, the effects of valence ( F ( 1 , 6 1 ) = 9 . 9 8 ; p < 0.01) and of controllability ( F ( 1 , 6 1 ) = 25.34; p < 0.01) were significant, indicating that UO was higher for positive than for negative events and also for controllable than for uncontrollable events. The interaction (F(1,61) = 1.25) was not significant. These findings indicate that whereas UO was induced by PC, NC and to a lower degree by NU events, UO was not induced by PU events. For Self-Average OPT the effects of valence (F(I,61) = 31.29; p < 0.01), controllability (F(1,61) = 29.00; p < 0.01) and the interaction (F(1,61) = 12.76; p < 0.01) were significant. In this case, UO was clearly induced by PC, NC and NU events, but not by PU events. Another three-way ANOVA with repeated measures (valence X controllability x OPT type) was conducted. The interesting effect yielded by this analysis is the triple interaction between
Table 3 Means and standard deviations (in parentheses) of OPT scores a (n = 62) Event's controllability
Event's valence Positive
Controllable Uncontrollable
Negative
Self-Close
Self-Average
Self-Close
Self-Average
7.85 (33.43) - 13.95 (32.39)
25.36 (32.57) - 14.11 (41.01 )
13.86 (33.80) 1.50 (30.94)
40.72 (43.66) 31.89 (41.93)
Higher scores indicate a higher level of UO.
D. Zakay /Acta Psychologica 93 (1996) 121-131
128
OPT 50 45
[]
Self-Close
40
[]
Self-Average
40.72 ~-.~
35
~N,"~ .\\\
31.89
30 25
25.36
55x
20
\\\
\\\
13.86 X,,"-,~
15
-
10 5 ,X\\
0
r- ,
~\",
-5 -10 -15
-13.95 -i4.11
-20
PC
PU
NC
NU
Fig. 1. OPT scores according to events' type and comparison-target.
valence, controllability and OPT type (F(I,61) = 63.35; p < 0.01). UO was obtained for both comparison-targets for PC and NC events. For NU events UO was obtained for the average comparison-target, but not for the close comparison-target. However, in the case of PU events, UO was not obtained for either of the two comparison-targets. The triple interaction is presented in Fig. 1.
4. Discussion The results obtained in the two experiments lend support to the hypotheses tested. Participants assigned higher likelihood ratings for controllable than for uncontrollable events regardless of which comparison-target was involved. The 'better than average' aspect of UO, however, was replicated only for negative events and for positive-controllable events, but not for positive-uncontrollable events. Thus, the major hypothesis of the present study was supported. This distinction of PU events is clearly manifested in the analyses of each event by itself and also by the analyses of the OPT scores. The PU category differs from the other three events' categories in terms of the comparison-target effect. The decrease in degree of UO when the comparison-target is close and familiar to the participant, as compared with a vague comparison-target (Perloff and Fetzer, 1986; Alicke et al., 1995) was replicated for PC, NC and NU events. This was not the case regarding PU events.
D. Zakay/Acta Psychologica 93 (1996) 121-131
129
UO is most plausibly resulting from the operation of motivational processes such as defensiveness and wishful thinking (Miller and Ross, 1975). Self-serving biases in the attribution process (e.g., Weary, 1979) might also play a role here. Egocentric tendencies (Weinstein and Lachendro, 1982) add their share by directing people's attention to focus only inward. The present findings, however, indicate that the interaction between event's valence and its degree of perceived controllability should also be taken into account in order to fully understand the processes underlying UO. Negative events differ from positive ones by being more ego-threatening (Duck and Mullin, 1995). Taylor (1991) claims that negative events evoke strong and rapid physiological, cognitive, emotional, and social responses and mobilize the organism much more intensively than neutral or positive events. Thus, when one is presented with a possible future negative event, whether or not perceived as controllable, ego-defense mechanisms are most plausibly activated. Similar defensive effects should be expected in the case of positive-controllable events since failing such an event or achieving worse results than an unknown vague comparison-target, can be ego-threatening. Positive future events which are not perceived as controllable, on the other hand, should not pose a real threat to one's ego and self-esteem. Achieving less than a remote or a close comparison-target in such an event, does not indicate incompetence on the one hand, and does not shake the status quo, since unlike in an uncontrollable negative outcome, one's life status is not threatened or worsened. Therefore, ego-defense mechanisms do not have to be activated. Consequently, for PU events likelihood ratings of oneself might be equal to or less than those assigned to a close or a remote comparison-target. In the present study each event's category was represented by three events only, though all three were highly relevant for the participants. Zakay (1995) found similar results to those obtained here in a study in which occurrence probabilities of 40 events (10 representing each category) were rated by Kibbutz members with ages ranging between 20 and 45 years. Nevertheless, further experimentation involving a variety of events and various population is required in order to identify the determinants of UO and define how they interact. The importance of this is both theoretical and applied, since UO might be an important factor in many personal, social, and political decisions.
Acknowledgements The author wishes to thank two anonymous reviewers for their helpful comments on an earlier draft of the paper. The help of Galit Askayo in the collection of data is highly appreciated.
Appendix A Table 4 presents the means of valence, controllability and likelihood ratings of events.
D. Zakay /Acta Psychologica 93 (1996) 121-131
130 Table 4 Event No.
Valence
Controllability
Likelihood rating Self
Close
F(comparison targets) Average
PC 1 2 3
8.60 7.55 6.44
6.62 8.76 8.09
50.44 35.84 62.18
56.88 31.12 35.54
26.12 22.00 24.09
F(2,120) = 10.10 * * F(2,120) = 3.00 * F(2,120) = 18.59 * '
7.49 7.60 8.43
3.12 1.61 4.06
-25.01 20.14 31.24
0.27 25.46 43.19
2.59 16.96 51.43
F(2,120) = 10.44 * * F(2,122) = 0.72 n.s. F(2,122) = 2.55; p = 0.08
2.79 1.90 2.78
6.56 8.32 7.53
- 12.79 -27.73 -25.59
10.68 - 18.15 - 17.46
17.42 26.10 13.43
F(2,120) = 8.57 * * F(2,118) = 20.88 * * F(2,122) = 14.42 ' *
1.82 2.29 2.29
1.75 3.40 3.40
- 13.66 - 23.32 -34.94
- 18.47 - 22.98 -26.52
13.69 5.72 4.33
F ( 2 , 1 1 6 ) = 12.42 * * F(2,116) = 8.20 * * F(2,108) = 16.03 * "
PU 4 5 6
NC 7 8 9
NU 10 11 12
Note: Participants who rated valence and controllability did not rate events' likelihood. p < 0.05. * * p < 0.01. '
Event's description: (1) to be selected for an officer's course in the army; (2) to get high grades in matriculation exams; (3) to succeed in achieving good social relations; (4) to win a large prize in the lottery; (5) 'love at first sight' in an unexpected accidental meeting; (6) to be chosen to participate in a popular TV show; (7) to fail in an important exam; (8) failure in maintaining an important social relation; (9) to cause a traffic accident as a driver; (10) severe illness of one of the family members; (11) severe illness of oneself; (12) being a victim of a terror attack.
References Alicke, M.D., M.L. Klatz, D.L. Breitenbecher, T.J. Yurak and D.S. Vredenburg, 1995. Personal contact, individuation, and the better-than-average effect. Journal of Personality and Social Psychology 65(5), 804-825. Brown, J.D., 1986. Evaluation of self and othrs: Self-enhancement biases in social judgments. Social Cognition 4, 353-376. DeJoy, D.M., 1987. The optimism bias and traffic safety. Proceedings of the Human Factors Society, 31st Annual M e e t i n g ( p p . 756-759). Drake, R.A., 1984. Lateral asymmetry of personal optimism. Journal of Research in personality 18, 497-507. Drake, R.A., 1985. Lateral asymmetry of risky recommendations. Personality and Social Psychology Bulletin 11(4), 4 0 9 - 4 1 7 . Duck, J.M. and B.A. Mullin, 1995. The perceived impact of the mass media: Reconsidering the third person effect. European Journal of Social Psychology 25, 7 7 - 9 3 . McKenna, F.P., 1993. It w o n ' t happen to me: Unrealistic optimism or illusion of control? British Journal of Psychology 84, 3 9 - 5 0 . Miller, D.T. and M. Ross, 1975. Self-serving biases in the attribution of causality: Fact or fiction? Psychological Bulletin 82, 213-225. Perloff, L.S., 1983. Perceptions of vulnerability to victimization. Journal of Social Issues 39, 4 1 - 6 1 .
D. Zakay / Acta Psychologica 93 (1996) 121-131
131
Perloff, L.S. and B.K. Fetzer, 1986. Self-other Judgments and Perceived Vulnerability to Victimization, Journal of Personality and Social Psychology 50, 502-510. Svenson, O., 1981. Are we all less risky and more skillful than our fellow drivers? Acta Psychologica 47, 143-148. Taylor, S.E., 1991. Assymetrical effects of positive and negative events: The mobilization-minimization hypothesis. Psychological Bulletin 110(1), 67-85. Taylor, S.E. and J.D. Brown, 1988. Illusion and well-being: A social psychological perspective on mental health. Psychological Bulletin 103, 193-210. Tversky, A. and D. Kahneman, 1973. Availability: A heuristic for judging frequency and probability. Cognitive Psychology 5, 207-232. Weary, G., 1979. Self-serving attributional biases: Perceptual or response distortions? Journal of Personality and Social Psychology 37, 1418-1420. Weinstein, N.D., 1980. Unrealistic optimism about future life events. Journal of Personality and Social Psychology 39, 806-820. Weinstein, N.D., 1984. Why it won't happen to me: Perceptions of risk factors and susceptibility. Health Psychology 3, 431-457. Weinstein, N.D., 1989. Optimistic biases about personal risks. Science 264, 1232-1233. Weinstein, N.D. and E. Lachendro, 1982. Egocentrism as a source of unrealistic optimism. Personality and Social Psychology Bulletin 8, 195-200. Zakay, D., 1983. The relationship between the probability assessor and the outcomes of an event as a determiner of subjective probability. Acta Psychologica 53, 271-280. Zakay, D., 1984. The influence of perceived event's controllability on its subjective occurrence probability. The Psychological Record 34, 233-240. Zakay, D., 1995. Unrealistic optimism in the case of positive-uncontrollable events. Unpublished manuscript. Tel-Aviv University.