The use of computer-mediated interaction in exploring affective influences on strategic interpersonal behaviours

The use of computer-mediated interaction in exploring affective influences on strategic interpersonal behaviours

Computers in Human Behavior Computers in Human Behavior 23 (2007) 901–919 www.elsevier.com/locate/comphumbeh The use of computer-mediated interaction...

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Computers in Human Behavior Computers in Human Behavior 23 (2007) 901–919 www.elsevier.com/locate/comphumbeh

The use of computer-mediated interaction in exploring affective influences on strategic interpersonal behaviours Joseph P. Forgas *, Rebekah East, Norman Y.M. Chan School of Psychology, University of New South Wales, Sydney 2052, Australia Available online 23 September 2005

Abstract What role can computers play in the study of strategic interpersonal behaviours, and research on affective influences on social behaviour in particular? Despite intense recent interest in affective phenomena, the role of affect in social interaction has rarely been studied. This paper reviews past work on affective influences on interpersonal behaviour, with special emphasis on Michael ArgyleÕs pioneering studies in this field. We then discuss historical and contemporary theories of affective influences on social behaviour. A series of experiments using computer-mediated interaction tasks are described, investigating affective influences on interpersonal behaviours such as self-disclosure strategies and the production of persuasive arguments. It is suggested that computer-mediated interaction offers a reliable and valid technique for studying the cognitive, information processing variables that facilitate or inhibit affective influences on interpersonal behaviour. These studies show that mild affective states produce significant differences in the way people perform in interpersonal situations, and can accentuate or attenuate (through affective priming) self-disclosure intimacy or persuasive argument quality. The implications of these studies for recent theories and affect-cognition models, and for our understanding of peopleÕs everyday interpersonal strategies are discussed.  2005 Elsevier Ltd. All rights reserved. Keywords: Affect; Interpersonal behavior; Computer-mediated interaction; Affect and cognition

*

Corresponding author. Tel.: +61 2 93853037; fax: +61 2 93853641. E-mail address: [email protected] (J.P. Forgas).

0747-5632/$ - see front matter  2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.chb.2005.08.010

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1. Introduction Since its origins in the late 19th century, experimental social psychology has undergone a number of profound paradigmatic shifts. Perhaps the most important organizational and institutional development came quite early in the 20th century, when empirical social psychologists chose to align themselves with psychology, then in ascendancy, as their reference discipline, rather than sociology. This development had profound consequences. For most of its history, social psychology studied individuals in their various social situations, instead of focusing on actual interpersonal behaviour as the main object of inquiry. This psychologizing of social psychology allowed us to benefit from the rapid development of psychology as an experimental discipline, and gave us access to powerful theories and methods derived from the mother discipline. However, we also had to pay a price. By sharing psychologyÕs focus on the individual as the unit of analysis, we have tended to ignore strategic interpersonal behaviour. It is interesting that the ÔpsychologizingÕ of social psychology occurred against the background of influential theories such as George Herbert MeadÕs symbolic interactionism that strongly argued that interpersonal behaviour ought to be the true focus of social psychology. This tendency has become even more marked in the last twenty years, since the almost universal acceptance of the cognitive approach in social psychology. Social psychology journals are now full of experiments analysing the mechanisms underlying the thoughts, feelings and judgments of isolated individuals sitting in front of a computer screen, often in contrived experimental situations. Real, dynamic interpersonal behaviour is rarely studied. The lack of interest in studying interpersonal behaviour is only partly due to the currently dominant cognitivist paradigm; the very difficulty of observing, collecting and analysing data from dynamic interactive situations is likely to be another reason. The purpose of this article is to argue that this long-standing juxtaposition of the ndividualistic and interactionist approaches to social psychology may come to be resolved with the adoption of computer-mediated interaction techniques that can capture the richness of ongoing interactive behaviours, while retaining the control and precision that is the hallmark of many contemporary experiments. In particular, this paper will describe a number of empirical experiments using a computer-mediated interaction method, exploring the influence of temporary affective states on such strategic interpersonal behaviours as self-disclosure and persuasive argumentation. 2. Studying strategic interaction in the past: the ÔconfederateÕ method Of course, the idea that two or more people can be placed in a controlled environment and their strategic interactive behaviours can be observed, recorded and analysed is not new. There was a flowering of this approach in the 1960s and 1970s, and many of the most illuminating experiments of this kind are associated with the name of Michael Argyle and his colleagues at Oxford University. In a series of interesting and innovative experiments, Argyle explored the way people use strategic nonverbal messages such as gaze, distance, posture and the like in realistic encounters. The typical method involved a ÔstoogeÕ technique: naı¨ve participants would interact with a confederate who has been ÔprogrammedÕ to perform various behaviours. For example, in the classic study by Argyle and Dean (1965) demonstrating the intimacy-equilibrium theory of nonverbal communication, confederates were instructed to occupy various interpersonal distances, and the participantsÕ

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gaze behaviour was recoded as a function of manipulated interpersonal distance. As far as the participants were concerned, this was a real, natural conversation with another student, lending an uncommon degree of external validity to this controlled laboratory experiment. The typical interaction experiments carried out by Argyle and others thus relied on skilled actors or stooges who were ÔprogrammedÕ to behave in certain ways, and the reactions of naı¨ve participants were the dependent variables measured (e.g., Argyle, Lefebvre, & Cook, 1974). However, the impressive external validity of these studies has to be evaluated against some serious internal validity problems. In a ÔrealÕ interaction, it is almost impossible to train confederates, even if they are experienced actors as they sometimes were in these studies, to such a level of perfection that their behaviour would remain entirely constant irrespective of the actions of their interaction partner. The consequence is that there may be unknown, and uncontrollable confounds in these experiments, to the extent that the confederateÕs behaviour may be influenced by the actions of their partner across trials. Another problem with this method is that it only allowed the study of explicit, observable behaviours as dependent variables. Yet social psychology in the past few decades has been characterized by a growing focus on the internal, cognitive and affective processes of individuals as they engage in interpersonal behaviours. It is perhaps not a coincidence that the spreading influence of cognitive theories in social psychology has coincided with the decreasing popularity of experiments involving ÔrealÕ interaction between people in general, and the trained confederate method in particular. 3. The use of computer-mediated interaction The Ôcognitive revolutionÕ in social psychology produced new emphasis on interactantsÕ cognitive and perceptual strategies, as distinct from manifest behaviour as investigated by Argyle. The problem contemporary researchers face is – how to study such variables in a realistic, interactive environment? The experiments to be described here rely on a variant of the ÔconfederateÕ method using a computer-mediated interaction procedure. In effect, participants in a dyadic interaction are required to interact via an interposed computer system, as if they were exchanging emails with another person. This technique also has its advantages and disadvantages. Its main disadvantage is that to some extent, it reduces the ÔrealismÕ and external validity of the bogus partner method as used by Argyle and his colleagues. However, this reduction in realism need not be serious. To the extent that a new generation of young people has already grown up with extensive exposure to computer-mediated interaction, and almost all participants in contemporary studies use email exchanges on a daily basis, interacting with a partner via computer keyboard need not be an unusual experience. On the positive side, using computer-mediated interactions can produce some important advantages. Such methods allow a high degree of standardization in the partnerÕs responses, something that would not be possible with real, live partners. Communicating with a ÔpartnerÕ through sending typed messages allows computers to be programmed to respond in controlled ways, effectively simulating the features of a real interaction in a highly controlled environment. In our experiments, the partnerÕs responses were completely controlled and standardized, as in fact the responses were always generated by a computer program rather than a real person. This deception was never detected by any of our participants; they all believed that the responses they saw on their screen were in fact written by a real person, rather than a pre-programmed computer. We took great care

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in making the responses seem realistic, even to the extent that the computer typed its responses in a slow, halting way, as a person would, and occasionally even mistyped and then corrected typographic mistakes. The second advantage of using a computer in an interaction experiment is that it allows the careful recording and analysis of important cognitive variables, such as the time taken to deal with a task, the time taken to produce a response, etc. Such processing latency measures allow us to gain real insight into the cognitive mechanisms that underlie interpersonal responses, something that could not be done in real interactions. Further, such computerized interaction experiments can be readily adapted for use on the internet, allowing access to a very large number of participants at relatively little cost. 4. Affect and strategic interpersonal behaviour Understanding how human beings use interpersonal strategies remains one of the key questions for psychology. Social living is only possible because human beings possess an elaborate capacity to employ and respond to complex interpersonal strategies. Modern industrial mass societies place great demands on us to coordinate our behaviours and achieve our interpersonal objectives. Most of our social interactions now involve strangers and superficially known others. As a result, the task of planning our interpersonal strategies has become far more complex and demanding compared to earlier times (Goffman, 1972; Heider, 1958). Effectively using social strategies thus requires ever-more sophisticated and elaborate cognitive processes. The experiments to be reviewed here will suggest that it is the very complexity and indeterminacy of many social encounters that makes it more likely that affective states will play a disproportionate role in how people use interpersonal strategies. The principle appears to be that the more complex and ambiguous a social situation, the more likely that people will need to engage in open, elaborate and constructive thinking in order to produce an appropriate response. A number of theories as well as empirical studies predict that open, elaborate processing strategies are more likely to influenced by affective states (Forgas, 1995a). How can we account for the relative absence of research on the role of affect in strategic interaction processes? The lack of interest in this issue is all the more surprising if we consider that most people are intuitively aware that their feelings often have a profound influence on their interpersonal behaviours. Philosophers and writers have also long been fascinated by the complex influence of affect on interpersonal relations. Many of these theorists saw affect as a potentially dangerous, invasive force that tends to subvert rational thinking, and impair the effective use of social power and influence (Machiavelli, 1961). Within psychology, FreudÕs psychodynamic theories played a key role in emphasizing the dangerous, invasive character of affective impulses, suggesting that controlling affective states requires considerable countervailing psychological resources. However, this view of affect as a disruptive force has been challenged during the last few decades as a result of important advances in neuroanatomy, psychophysiology and social cognition research. Instead, recent evidence suggests that affect is often a necessary and useful component of adequately responding to difficult social situations (Adolphs & Damasio, 2001; Damasio, 1994). However, a precise understanding of the mechanisms responsible for these effects has been slow to emerge. In fact, most of what we now know about the role of affect in social judgments and behaviour has probably been discovered since the early 1980s. A key objective of contemporary research, and these experiments

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in particular, is to understand how, when and why affective states will influence interpersonal behaviour and influence strategies. As a first step, some of the early research and theories illustrating affective influences on social behaviours will be reviewed. A recent multi-process theory, the affect infusion model (Forgas, 1995a) will be outlined as a comprehensive account of how, when and why affective states will or will not influence social influence processes. The second half of the paper will present empirical evidence demonstrating the role of affect in social influence processes. 5. Early work on affect and interpersonal behaviour One notable early attempt to investigate the role of affective variables in interpersonal behaviour is associated with the name of Michael Argyle at Oxford. His work on nonverbal communication represents an interesting approach to quantify the influence of nonverbal (affective) vs. verbal (cognitive) cues on perceptions of an individual. For example, Argyle, Alkema, and Gilmour (1971) and Argyle, Salter, and Nicholson (1970) asked trained communicators to deliver interpersonal messages indicating friendliness or unfriendliness, and superiority or inferiority to a partner in the nonverbal (affective) or verbal (semantic) modalities. Thus, a verbal message indicating friendliness (ÔI like youÕ) may be communicated in either a friendly (smiling, lively tone of voice, etc.), or in an unfriendly (unsmiling, dull tone of voice, etc.) nonverbal manner. This design allowed Argyle and his colleagues to precisely quantify the relative impact of the verbal and the nonverbal channels on perceived friendliness or superiority/inferiority of the communicator. These experiments demonstrated than nonverbal (affective) cues are several times more important that verbal cues in communicating friendliness and superiority. Over two decades ago, others such as Zajonc (1980, 2000) argued that affective reactions often constitute the primary and dominant influence on dealing with social situations, and function as an independent and often dominant force in determining peopleÕs social strategies and responses. According to this view, affect is not just one of the three faculties of the human mind – and a relatively neglected one at that – but one of the primary forces driving all interpersonal behaviour. Several lines of evidence seem to support such a view. Affective reactions play a primary role in determining how people evaluate everyday social situations, and how they categorize social stimuli (Forgas, 1979, 1982). In one early study, Razran (1940) found that affect had a significant mood-congruent effect on how people reacted to persuasion. In another experiment Feshbach and Singer (1957) predicted that attempts to suppress affect should increase the ÔpressureÕ for affect to infuse unrelated behaviours and judgments. In this study, electric shocks were used to induce fear. Fearful subjects were more likely to see ‘‘another person as fearful and anxious’’ (p. 286), and this effect was greater when subjects were instructed to suppress their fear. Feshbach and Singer (1957) argued that ‘‘suppression of fear facilitates the tendency to project fear onto another social object’’ (p. 286). Conditioning researchers, such as Byrne and Clore (1970) suggested that incidental association between affective states and other stimuli can significantly influence how we respond to people. Several studies showed that aversive environments typically produce an affective reaction, and this will in turn influence responses to previously neutral stimuli, such as people encountered in that environment (Griffitt, 1970). Although there have been various lines of evidence indicating a pattern of affect congruence in elaborately processed social judgments and behaviours, the theoretical explanation

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of these effects remained unsatisfactory. Neither the psychoanalytic, nor the conditioning theories could offer a convincing explanation of exactly how, why and when such affect infusion effects occur. It was not until the emergence of cognitive information processing theories in recent years that we gained a better understanding of the psychological mechanisms that link affect, cognition and behaviour. We suggest in this paper that affective states may also play a significant role in the way various interpersonal strategies are planned and executed. In particular, experiments will be described demonstrating that low-intensity moods significantly impact (a) on the quality of persuasive arguments produced by people, as well as (b) on their self-disclosure strategies. Further, it will be argued that these effects are largely mediated by the kind of cognitive information processing styles people adopt when thinking about and planning their social influence strategies. The findings will be discussed in terms of comprehensive theories such as the affect infusion model that predict process-dependent mood effects on social judgments and behaviours (Forgas, 1995a). 6. Contemporary theories linking affect and interpersonal behaviour There are several cognitive mechanisms that have been proposed to explain affective influences on social judgments and behaviour. This paper will first briefly consider theories accounting for the impact of mood on information processing strategies, and then discuss evidence for two theories that explain the influence of mood on the content of thinking. The affect-as-information model (Schwarz & Clore, 1988) argues that people sometimes directly use their prevailing affective state as information in inferring their responses to social situations. The alternative affect priming theory predicts that affect should indirectly influence the outcome of social judgments and behaviours through selectively priming and making more accessible affect-related constructs to be used in planning and executing social behaviours (Bower, 1981; Bower & Forgas, 2001). 6.1. Affect and information processing strategies Planning and responding to social influence typically involves some degree of elaborate information processing, as people need to plan their actions or responses. It turns out that affect may not only influence the content of cognition and thus subsequent behaviours, but may also impact on the process of cognition, that is, how people think about and evaluate social information (Clark & Isen, 1982). There have been a number of studies that suggest that people experiencing positive affect often tend to employ less effortful and more superficial processing strategies, reach decisions more quickly, use less information, avoid demanding, systematic thinking, and are more confident about their decisions. In contrast, negative affect frequently triggers a more effortful, systematic, analytic and vigilant processing style (Clark & Isen, 1982). Studies have also showed that positive affect can produce distinct processing advantages. People experiencing positive mood are more likely to adopt more creative, open, constructive and inclusive thinking styles, use broader categories and show greater cognitive and behavioural flexibility (Bless, 2000; Fiedler, 2000). These effects seem to be consistent with theories that emphasize the fundamental evolutionary significance of positive and negative affective states as triggering different processing styles. Thus, positive affect generally promotes a more assimilative, schema-based, top-down processing style, while negative affect produces a more accommodative, bottom-up and

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externally focussed processing strategy (Bless, 2000; Fiedler, 2000). The processing effects of positive or negative affect should have significant implications for the way people exercise social influence strategies, such as producing persuasive arguments, making requests or engaging in negotiations, as the research to be reviewed here will suggest. 6.2. Affect as information theory When faced with the necessity to respond to a social situation, ‘‘rather than computing a judgment on the basis of recalled features of a target, individuals may . . . ask themselves: ÔHow do I feel about it?/and/in doing so, they may mistake feelings due to a pre-existing state as a reaction to the target’’ (Schwarz, 1990, p. 529). This Ôhow-do-I-feel-about-itÕ heuristic suggests that affective states influence attitudes and behaviours because of an inferential error: people misread their prevailing affective state as if it was caused by the social situation they are trying to respond to. This strategy is most likely when people lack sufficient interest, motivation or resources to compute a more elaborate response. For example, when people who have just seen happy or sad films were asked to respond to a street survey, we found a significant pattern of affect congruence in their reactions (Forgas & Moylan, 1987). Similarly, responses to a telephone survey may show similar effects (Schwarz & Clore, 1988). These are situations where respondents presumably have little interest or time to engage in elaborate processing, and respond using a simple affectas-information heuristic. However, most situations involving social influence are likely to impose more involving and elaborate processing demands on social actors. We need a complementary theory, such as the affect priming model, to explain affect infusion effects into such elaborately processed interpersonal strategies. 6.3. The affect priming theory This model was first systematically outlined by Bower (1981). According to the model, the influence of affect on thinking and behaviour is neither motivationally based as psychodynamic theories suggest, nor is it due to incidental, blind associations, as conditioning theories imply. Instead, the associative network model argues that representations about the social world, including affective states, are integrally linked within an associative network of memory. An affective state should thus automatically prime associated ideas and memories to be used in constructive social and interpersonal tasks. Numerous studies support for these predictions (Bower, 1981; Clark & Isen, 1982; Forgas & Bower, 2001). However, there are also important boundary conditions to be considered (Eich & Macauley, 2000; Forgas, 1995a). Affect infusion into strategic behaviours is most likely in complex and demanding situations that require open, constructive processing that promote the incidental use of affectively primed information (Fiedler, 2000; Forgas, 1995a, 1995b, 2002; Sedikides, 1995). 6.4. The affect infusion model Recent integrative theories such as the affect infusion model (AIM; Forgas, 1995a, 2002) specifically argue that the nature and extent of affective influences on social behaviour should largely depend on the kind of information processing strategy people employ in a particular situation. The AIM seeks to specify the circumstances that promote or inhibit affect congruence, and predicts that affect infusion should only occur in circumstances that

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promote an open, constructive processing style. As this model has been adequately described elsewhere, only a brief overview will be included here (Forgas, 1995a, 2002). The AIM identifies four alternative processing strategies people may use in computing a response to a social situation: direct access, motivated, heuristic, and substantive processing. These four strategies differ in terms of two basic dimensions: the degree of effort exerted in seeking a solution, and the degree of openness of the information search strategy. The combination of these two processing dimensions, quantity (effort), and quality (openness) produces four distinct processing styles: substantive processing (high effort/open, constructive), motivated processing (high effort/closed), heuristic processing (low effort/open, constructive), and direct access processing (low effort/closed). Mood congruence and affect infusion is most likely when a constructive processing strategy is used, such as substantive or heuristic processing. In contrast, affect is unlikely to influence the outcome of closed, merely reconstructive tasks involving motivated or direct access processing (see also Fiedler, 2000, Fiedler, 2001). 7. Empirical evidence: affect and persuasive arguments As the previous discussion suggests, affect can play a significant and complex role in many kinds of strategic social behaviours and judgments. In the remainder of the paper empirical studies will be reviewed that illustrate the multiple roles that affect plays in strategic interaction. The underlying principle in all of these studies is that interpreting, planning and dealing with complex interpersonal events necessarily requires the use of elaborate, substantive processing strategies; such cognitive strategies in turn are likely to be open to affect infusion effects. We have seen that affective states can significantly influence peopleÕs information processing strategies. As previously argued, there is an emerging consensus that positive affect promotes a more schema-drive, top-down and flexible processing style. Negative mood in turn seems to facilitate a more bottom-up, externally oriented processing strategy that pays more attention to the available stimulus information (Bless, 2000; Fiedler, 2000). This processing effect was confirmed in several recent experiments. It was found, for example, that judgmental mistakes such as the fundamental attribution error tend to be reduced when people experience negative affect (Forgas, 1998c). This seems to occur because aversive mood makes people pay greater attention to the demands of the situation and process their responses in a more careful, piecemeal fashion. A more recent study by Hertel, Neuhof, Theuer, and Kerr (2000) provides further evidence for the idea that positive and negative moods are associated with different processing styles in a complex interpersonal bargaining task. Hertel et al. led participants to believe that they were interacting with three other people in a public good dilemma game, when in fact, the use of a computer-mediated interaction task enabled Hertel et al. to provide controlled standardized feedback about the other ÔplayersÕ strategic behaviour. Participants had to decide how much they wanted to invest in a common enterprise, at the expense of personal profit, or defect and free-ride off the other players. Results revealed that sad participants displayed more systematic and rational behaviour than happy participants, investing more in the common enterprise when othersÕ cooperation was low, but defecting when the other playersÕ cooperation was high. Happy participants on the other hand, were more likely to simply use the other playersÕ behaviour as a guideline and tended to heuristically imitate the other playersÕ behaviour, presumably relying on the reciprocity rule.

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Similarly, in a recent study Au, Chan, Wang, and Vertinsky (2003) used a computerized trading system to explore the effects of mood on the decision behaviours of traders in financial markets. They showed that traders in a positive mood made less accurate decisions and thus had an inferior trading performance compared to those in a neutral or a negative mood. The more externally focussed and prudent processing strategy associated with negative moods was shown to produce superior performance than the more optimistic and over-confident strategies linked to positive moods. These studies clearly demonstrate that positive and negative affective states can have significant and predictable effects on processing style, and on strategic behaviours. Extrapolating from such studies and existing affect-cognition theories, it may be that negative affect also has a corresponding beneficial influence on some social influence strategies such as the production of higher-quality persuasive messages. One of the most important social influence strategies people use in everyday life is verbal persuasion. In order to get what we want from others, we typically rely on the medium of language to present as a convincing a case as possible for a proposed action. Language represents a universal and highly flexible medium of social interaction (Mead, 1934), allowing almost unlimited scope for employing more or less effective persuasive strategies. Of course, there has been much work on the way persuasive messages are received. Our interest here is in the complementary problem: what is the role of affect in the way persuasive messages are produced and used? Amateur persuaders – and that means all of us – must think on their feet, plan and produce their persuasive strategies on-line, and be sensitive to the immediate feedback they receive from their interlocutors. What role does everyday mood play in the production of such everyday persuasive messages? 8. Experiment 1 The first experiment was designed as an initial investigation of the effects of positive and negative moods on the quality of persuasive messages. It was hypothesized that negative mood should improve, and positive mood impair the quality of persuasive communications. 8.1. Overview of method, design and participants In this experiment, students were induced into positive or negative moods using an audiovisual mood induction procedure, and were then asked to produce persuasive arguments seeking to convince a friend of the merits of their position on two public issues, student fees, and land rights. On each of these issues, there was a popular, widely preferred position in this group (for land rights, and against student fees), and an unpopular, disliked position (against land right and for student fees). Each participant produced persuasive arguments for the popular position on one issue, and the unpopular position on the other issue. Thus, the experiment comprised a 2 · 2 · (2) design, with mood (happy, sad), issue popularity (popular, unpopular) and issue content (student fees, land rights) as the independent variables. Participants were 59 volunteer students (34 female, 25 male) who participated in the experiment for course credit. Participants were induced into positive or negative mood by watching short videotapes, described as part of a separate experiment. The happy tape contained cca. 10 min excerpts from a popular comedy series, and the sad film dealt with death from cancer. These films

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have been used in previous studies and were found to be highly effective for inducing significantly different, positive and negative affective states (e.g., Forgas, 2002). After the mood induction, in an ostensibly unrelated experiment described as dealing with social communication, participants were asked to imagine that they were having a discussion with an acquaintance about current affairs, and their job was to try to persuade their partner of a particular point of view. The two issues discussed were (1) the proposition that student fees should be increased and (2) the issue of Aboriginal land rights in Australia. On both of these issues, the majority of students had a preferred view (against fees, and pro land rights). The persuasive arguments generated were thus clearly either in favour of a popular or an unpopular position in this milieu. Each participant produced persuasive arguments on both topics, arguing the popular position on one issue and the unpopular position on the other. They were instructed to write down their persuasive arguments using the words they would actually use when persuading their friend on a response form, as if preparing notes for an upcoming discussion. Persuasive arguments were written down and were subsequently rated by two judges who were blind to the experimental manipulations. The judges achieved an overall inter-rater reliability of 0.86, and rated each argument on 10-point scales, evaluating their overall quality, their persuasiveness, and their valence (positive–negative content). As the quality and persuasiveness measures were strongly correlated (r = .78), these two scales were combined to form a single measure of argument quality. 8.2. Results An analysis of self-rated mood confirmed that the mood induction was highly effective: those in the happy and sad conditions rated their mood as significantly different (F(1,58) = 135.07; p < 0.01; M = 2.83 vs. 6.65). Subsequent analyses showed that mood had a highly significant influence on argument quality, F(1,55) = 11.45; p < 0.01. Those in a negative mood produced arguments that were judged by two trained raters blind to the experimental manipulations as of significantly higher quality and more persuasive than the arguments produced by participants in a happy mood (M = 6.62 vs. 5.59; see Fig. 1). Issue popularity had no main or interactive effect on argument quality, indicating that sad mood increased the quality of arguments produced irrespective of the issues argued or the popularity of the position taken. An analysis of variance of the second dependent variable, argument valence, showed that there was a trend towards a mood-congruent effect, as happy persons produced more positive, and sad persons produced more negative arguments. However, this effect failed to reach significance (F(1,55) = 2.89; p < 0.32; M = 4.54 vs. 5.32). In a related, follow-up experiment we used a somewhat similar procedure, incorporating several improvements, such as the inclusion of a neutral group, and using a different, autobiographical mood induction method and different argument issues. The study also included an additional dependent measure: we decided to also investigate the extent to which the persuasive arguments produced included personal, self-referential material. Persuasive arguments were produced for or against Australia becoming a republic, and for or against a populist right-wing political party. Participants (N = 125) were asked to recall, re-experience and write about a positive and negative life experience in an ostensibly unrelated autobiographical memory task. Immediately after the mood induction, they were instructed to write down as many persuasive arguments as they could advocating a ÔforÕ

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Fig. 1. Mood effects on the quality and valence of persuasive messages: negative affect increases the rated persuasiveness of arguments for land rights and against fees (left columns). There is also a mood-congruent influence on the valence (right columns) of persuasive arguments (Experiment 1).

or ÔagainstÕ position on two topical issues: Australia becoming a republic, and attitudes towards a new right-wing party. The arguments produced were then rated on persuasiveness, quality, valence and self-relevance using ten-point ratings scales by two trained raters who achieved an inter-rater reliability of 0.91. Results showed that mood was effectively induced (F(2,122) = 38.78; p < 0.01), with happy participants feeling significantly better, and sad participants feeling significantly worse than controls. Mood again had a highly significant influence on the quality of persuasive arguments. Students in a sad mood produced arguments that were rated as of higher quality and more persuasive than were arguments produced by the neutral group, and happy students produced less persuasive and high quality arguments than the neutral group. This finding again confirms that even slight fluctuations in affective states can have a significant and reliable impact on the quality and perceived persuasiveness of the messages produced. This result is also broadly consistent with theoretical predictions derived from the affect infusion model and other theories (Bless, 2000; Fiedler, 2000; Forgas, 1995a) that predict that negative mood should promote a more accommodative, careful, systematic, bottom-up processing style that is more attuned to the requirements of a particular situation. It appears that this more situationally oriented processing style contributed to the higher quality arguments produced by subjects in a negative mood. 9. Experiment 2 Although these experiments produced strong and consistent results, the persuasive arguments were produced in a hypothetical, imagined situation and there was no real

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social interaction involved. Participants also did not receive any feedback about the effectiveness of their social influence strategies from their audience, as would be the case in reallife interactions involving persuasive arguments. Also, the motivation to produce effective persuasion strategies was not manipulated in the previous studies. It may well be that a strong motivation to do well may over-ride mood effects on the quality of persuasive arguments, as suggested by the AIM. To deal with these issues, Experiment 3 relied on a different procedure, asking participants to interact with a ÔpartnerÕ through a computer keyboard as if exchanging emails, and produce their persuasive arguments using this medium. In fact, there was no partner; instead, the computer was pre-programmed to ÔrespondÕ to persuasive messages in standard ways indicating agreement or disagreement with the communication. Experiment 3 also manipulated the motivation to be persuasive, by offering some participants a significant reward (the chance to win movie passes). 9.1. Overview of method, design and participants Participants believed that there were two unrelated experiments: a test of Ôverbal abilitiesÕ (in fact the false feedback mood induction procedure), and a study of interpersonal communication. In the verbal abilities test, participants performed a series of verbal tasks, and received manipulated feedback about their good or bad performance to induce positive or negative mood. A neutral group performed the same tasks, but received no feedback (see Forgas, 1998c). After the mood induction, participants engaged in a computer-mediated communication task, trying to persuade another student to participate in a boring experiment by sending emails, and receiving favourable or unfavourable responses. In fact, there was no real ÔpartnerÕ; rather, the computer was pre-programmed to respond as if the emails were typed in by a real person. Motivation to persuade was manipulated by half the participants being offered a significant reward (movie passes) if their persuasion efforts succeed. The experiment was based on a 3 · 2 · 2 between-subjects design, with mood (happy, neutral, sad), motivation (high, low) and partner response (accepting, rejecting) as the independent variables. Participants were 128 students (75 female, 53 male) who participated in the study for course credit. Manipulated feedback about performance was used to induce good and bad moods (Forgas, 1991). Participants were asked to complete what they believed was Ôa test of spatial-numerical abilitiesÕ and they were asked to look at each of the test pages, and then estimate (a) the surface area of the irregular diagram shown, and (b) the number of dots enclosed within each diagram. Given the complex and irregular shape of the diagrams, and the very large number of dots, these questions could not be answered accurately, allowing the experimenters to subsequently provide manipulated feedback about test performance designed to induce good or bad moods. In the positive mood condition, participants were told that their performance indicates ‘‘excellent visual-spatial ability . . . good numeric, rotational and other allied cognitive skills . . . in the top 5% of the adult population’’. In the control condition they were told that the test is still under development, and were thanked for their participation. In the negative condition participants were told that their results show ‘‘poor visual-spatial ability . . . poor numeric, rotational and other allied cognitive skills . . . placing them near the bottom of the population’’. A brief post-experimental questionnaire validated mood by asking participants to rate their mood valence as well as their level of arousal on four seven-point bipolar scales (happy–sad, good– bad, aroused–not aroused, tense–relaxed).

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Participants were then told that next, they will be exchanging messages with another student in an adjoining room, trying to persuade their partner to volunteer for another study immediately after this one. In effect, the persuasion task was conceptually similar to the persuasion task used by Festinger and Carlsmith (1959) in their classic experiment on dissonance induced attitude change. Further, half of the participants were promised a significant reward (movie passes) if they were successful. The communication task was described as a mediated interaction, and their partner could only use a very limited range of standard sentences in responding to their messages. The reply messages were in fact produced by the computer, typed one letter at the time to simulate a human partner, and communicated increasingly positive, accepting or increasingly negative rejecting reactions to the subjectÕs persuasive messages. The first ÔreplyÕ was always noncommittal, and progressed to increasing acceptance and rejection of the persuasive attempts in subsequent exchanges (e.g., ÔI am not sureÕ, ÔI may be interestedÕ, ÔI somewhat agreeÕ, ÔI agreeÕ, ÔOK, IÕll do the studyÕ). All students readily accepted this rationale, and the debriefing confirmed that none of them had any doubts about the genuineness of the procedure, the existence of a ÔpartnerÕ they attempted to persuade, or the reality of the persuasion task. In fact, each participant was allowed to produce eight arguments in total before the procedure was terminated. The eight arguments were divided into three categories: the initial three arguments, before any feedback was received, the middle two arguments, and the final three arguments. The overall design of the study is thus a 3 · 2 · 2 · (3) design, with mood, high/low reward, accepting/rejecting partner, and early, middle and late arguments as the independent variables. Two raters blind to the manipulations rated each argument for quality, complexity, persuasiveness, originality and valence and achieved an inter-rater reliability of 0.82 or higher on each of these measures. 9.2. Results The mood induction again had a highly significant influence on self-rated mood, F(2,65) = 21.11; p < 0.01, with the happy, neutral and sad groups rating their mood as significantly different (M = 2.84, 3.24, 4.7). There was a significant main effect of mood on argument quality, F(2,59) = 7.73, p < 0.01. The negative group (M = 4.33, SD = 0.137) generated significantly higher quality arguments than the neutral group (M = 3.878, SD = 0.146) who in turn did better than the positive group (M = 3.59, SD = 0.131). There was no significant effect of time, F(2,118) = 2.055, p > 0.1, reward, F(1,59) = 0.22, p > 0.1, or difficulty, F(1,59) = 0.3, p > 0.1. There were also no significant interaction effects. Thus, sad people generated higher quality arguments than neutral and happy people, and this effect was not qualified by how much reward was offered for participating or how difficult it was to persuade. This result is in line with earlier results obtained in hypothetical situations, and established that affective states indeed have a significant impact on the quality of persuasive messages produced even in a realistic interpersonal social influence task (see Fig. 2). There was no significant main effect of mood on ratings of argument originality. However, as originality ratings were correlated with quality ratings, r = 0.65, p < 0.01, to test the independent effects of mood on argument characteristics, a series of further analyses were carried out, evaluating the effects of mood on argument originality while controlling for argument quality. We also looked at the effect of mood on quality while controlling for

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Fig. 2. Affective influences on the production of persuasive messages: people in negative mood produce more persuasive and higher quality messages, but the expectation of a high reward reduces these mood effects (Experiment 2).

originality. The analysis of covariance again revealed a significant mood effect on the quality of arguments, F(2,58) = 8.29, p < 0.01; however, originality was also highly significant covariate, F(1,58) = 57.1, p < 0.001. In a highly interesting pattern, this mood effect was further qualified by a significant interaction with the reward condition, F(2,58) = 3.3, p < 0.05. Mood had a much greater effect on argument quality in the low reward condition than the high reward condition. It appears that in the low reward condition the negative mood group produced higher quality arguments than the neutral mood group who in turn produced higher quality arguments than the positive group. None of the groups were significantly different in the high reward condition. This finding confirms a key prediction of the affect infusion model, that mood effects on information processing – and subsequent social influence strategies – are strongest in the absence of motivated processing. An evaluation of mood, reward, and persuasibility effects on argument originality while controlling for argument quality produced a significant main effect of mood, F(2,58) = 1.96, p > 0.1. This was again qualified by a significant interaction between mood and reward, F(2,58) = 4.27, p < 0.019. Mood again had a significant effect on argument originality only in the low, but not the high reward condition. Those in a negative mood group produced less original arguments than the neutral mood group and the neutral mood group produced less original arguments that the positive mood group. This result is again consistent with theoretical predictions suggesting that positive affect promotes a more creative, flexible and internally driven processing style – hence greater argument

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originality- even though the overall quality and persuasiveness of arguments was higher in negative mood. These experiments provide convergent evidence that slight changes in incidental mood can produce profound differences in the quality and effectiveness of interpersonal strategies, such as the persuasive arguments people produce as part of their social influence attempts. The robustness of these mood effects is confirmed by the fact that similar results were obtained both in hypothetical situations and in realistic interactions, with a variety of attitude topics, using a range of different mood induction procedures and irrespective of the popularity and social desirability of the position argued. The third experiment also showed that mood effects on persuasive arguments can be reduced or eliminated when a strong external motivation is provided to participants. These results make sense in terms of our theoretical predictions, and the implications of the affect infusion model in particular, and suggest that computer-mediated interaction tasks offer a suitable method for investigating affective influences on interpersonal behaviours. As negative affect promotes a more careful, externally focussed information processing style, the present results show that this kind of processing also produces more persuasive and higher quality verbal arguments. 10. Affective influences on strategic self-disclosure In experiments currently under way, we also investigated the possibility that affective states may influence not only the production of persuasive messages, but also the way people disclose information about themselves. Self-disclosure is one of the most important interpersonal tasks people undertake in everyday life. The ability to disclose intimate information is an essential skill in the maintenance and development of rewarding intimate relationships, and is also critical to mental health and social adjustment (Forgas, 1985). Inappropriate self-disclosure can lead to adverse evaluations by others, and ultimately, relationship breakdown and social isolation. Michael ArgyleÕs work on social skills suggests that knowing when, how and what to disclose about oneself is an essential prerequisite for successful social interaction and the development and maintenance of rewarding personal relationships (Argyle, 1985; Argyle, Trower, & Bryant, 1974). Do temporary mood states influence peopleÕs self-disclosure strategies? Several lines of evidence suggest that the answer is likely to be ÔyesÕ (e.g., Argyle, Trimboli, & Forgas, 1988). Recent research suggests that affect has an influence on verbal communication in a variety of strategic interpersonal tasks that are characterized by psychological ambiguity. For example, we have found that positive mood tends to prime a more confident, direct requesting style, and negative mood leads to more cautious, polite requests (Forgas, 1999a, 1999b). Further, these mood effects on requesting seem to be much stronger when the request situation is more demanding and difficult, and thus requires more extensive, substantive processing. Affective states also influenced the latency of making a request in a realistic encounter: those in a negative mood were more hesitant, and delayed making their requests much longer than did control, or happy persons. Further, affective states were found to play an important role in elaborately planned interpersonal encounters such bargaining and negotiating encounters (Forgas, 1998a). People in a positive mood develop more positive and optimistic attitudes about the bargaining task, and formulate and use more optimistic, cooperative and integrative negotiating strategies. These findings suggest that even slight changes in affective state will influence the way people interpret communication situations, the goals they set for themselves, and the way they communicate information about themselves.

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In a series of recent experiments, we explored the effects of induced mood on selfdisclosure strategies (Forgas, 2001). In a pilot study, affective state was induced by exposing people to positively or negatively valenced videotapes. Subsequently, in an allegedly unrelated experiment, they were asked to indicate the order in which they would feel comfortable disclosing increasingly intimate information about themselves to a person they have just met, selected from a list of topics pre-rated for interpersonal intimacy. Results indicated a small but significant tendency for people in a positive mood to select more intimate disclosure topics than people in a negative mood. 11. Self-disclosure in computer-mediated interaction Of course, these effects occurred in a highly artificial, simulated context. In order to extend the ecological validity of the results, in a recent experiment participants (N = 90) were asked to interact with another person in a neighbouring room in a Ôgetting acquaintedÕ exercise through a computer keyboard, as if they were exchanging emails. In fact, there was no other person; the computer was pre-programmed to respond in ways that indicated either consistently high or low levels of self-disclosure, or showed a gradually increasing or decreasing patterns of self-disclosure intimacy. This procedure allowed us to investigate not only the overall intimacy of self-disclosure as a function of mood, but also the interactive effects of various partner disclosure patterns. Results again showed that mood had a significant influence on self-disclosure intimacy. We also found that these effects were significantly dependent on the behaviour of the partner. Individuals induced to feel good generally responded with more intimate disclosure, but only when the partner was also disclosing either consistently, or increasingly intimate information. Positive mood did not increase the intimacy of self-disclosure when the partner was not disclosing (see Fig. 3). People in a positive mood also disclosed significantly

Fig. 3. The effects of positive and negative mood on self-disclosure: positive mood increases, and negative mood decreases the intimacy of self-disclosure, and these effects are significantly greater when the partner is high disclosing rather than low disclosing (unpublished data).

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more positive rather than negative information about themselves, and formed more positive impressions of the ÔpartnerÕ than did people in a negative mood, consistent with the overall mood-congruent pattern also found in other interpersonal tasks (Forgas, 2001). Why do these effects occur? When people face an uncertain and unpredictable social encounter, such as a task involving self-disclosure, they need to rely on open, constructive processing in order to formulate their plans to guide their interpersonal behaviours. In other words, they must go beyond the information given, and rely on their available thoughts and memories to construct a response. Affect can selectively prime more affect-congruent thoughts and associations, and these ideas should ultimately influence the level of intimacy in self-disclosure. Happy persons seem to disclose more because they assess the likelihood of a positive, accepting response and reciprocal disclosure more optimistically. However, these mood effects rapidly disappear when the interaction partner does not appear to match disclosure intimacy. Self-disclosure is a risky interpersonal strategy, because revealing too much about ourselves may give away intimate information at too early a stage, and may also be seen as socially inappropriate. Whether we undertake such a risky move depends on a constructive assessment of the situation; it is at this stage that affect may play a role, influencing the way intrinsically ambiguous social situations are interpreted as either benign or dangerous. The very same mechanisms also seem to influence the way people formulate risky interpersonal requests, the way they respond to approaches by others, and the way they plan and execute negotiations (Forgas, 1998b, 1998c, 1999a, 1999b). 12. Summary and conclusions This paper argued that the experimental study of strategic interpersonal behaviours remains one of the core tasks for empirical social psychologists. This enterprise has been somewhat overshadowed in recent years by the growing popularity of individualistic, cognitive theories of social behaviour, and the general difficulty of studying interactive strategies in a controlled experimental setting. We proposed that computer-mediated interaction tasks might offer a suitable method for the rigorous study of realistic interpersonal tasks. Affective states in particular do seem to play a crucially important, yet still insufficiently understood role in the way people behave in interpersonal situations. We have reviewed recent theories and research on affect and social behaviour here, showing that even mild fluctuations in affective states can have a profound influence on how people perceive, interpret and behave in social situations (Forgas, 2002). The series of experiments discussed here examined how induced moods influence peopleÕs behaviours in computer-mediated interaction tasks investigating persuasive communication, and self-disclosure strategies. Both sets of studies showed that being in a good or bad mood impacts on the quality of persuasive messages, and the intimacy of self-disclosure strategies. Using a computer-mediated task, we were able to precisely control and manipulate the bogus Ôinteraction partnerÕsÕ communications (in fact, pre-programmed responses presented by the computer). This method also allows the careful measurement of important cognitive variables such as reading and response latencies, which are important in testing the cognitive processing theories responsible for promoting or inhibiting mood effects on behaviour. The experiments presented here clearly continue the classic experimental tradition of studying strategic interpersonal behaviours inaugurated by Michael Argyle and his colleagues at Oxford (Argyle & Dean, 1965; Argyle et al., 1971, 1974, 1970). As we argued in the introduction, the main drawback of traditional experimental

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research on interpersonal behaviour using the Ôbogus partnerÕ method was that it made it difficult to control variables precisely, and that it did not allow the careful step-by-step analysis of the moves made by participants. Substitution of a computer as the bogus ÔpartnerÕ in interaction tasks does solve these problems albeit at the cost of some loss of external validity and realism. However, to the extent that interacting with others via a keyboard, sending and receiving email messages is arguably a ÔnaturalÕ form of interaction for most of our participants, the loss of realism need not be great. It is perhaps regrettable that since Michael ArgyleÕs classic work in the 1960s and 1970s, there has been a gradual decline in experiments looking at strategic interpersonal behaviours. This decline seems to be neatly correlated with the growing dominance of the social cognitive paradigm in social psychology. Once again, the use of a computer-mediated interaction approach offers a resolution to this apparent dilemma. Using the methods described here, we can not only study interpersonal exchanges, we are also able to collect cognitive processing measurements, such as reaction and judgmental latencies on line. This way, we may gain unprecedented insights into the cognitive processes underlying various interpersonal moves and strategies. More generally, we hope that this discussion will contribute to the growing interest in the substantive question of how affective states influence everyday social thinking and behaviour, and in particular, the use of computer-mediated interaction tasks in investigating these phenomena. References Adolphs, R., & Damasio, A. (2001). The interaction of affect and cognition: A neurobiological perspective. In J. P. Forgas (Ed.), The handbook of affect and social cognition (pp. 27–49). Mahwah, N.J.: Erlbaum. Argyle, M. (1985). Social skills training. Bulletin of the British Psychological Society, 38, 340–341. Argyle, M., Alkema, F., & Gilmour, R. (1971). Communication of friendly and hostile attitudes by verbal and nonverbal signals. European Journal of Social Psychology, 1, 385–401. Argyle, M., & Dean, J. (1965). Eye contact, distance and affiliation. Sociometry, 28, 289–304. Argyle, M., Lefebvre, L., & Cook, M. (1974). Meaning of 5 patterns of gaze. European Journal of Social Psychology, 4, 125–136. Argyle, M., Salter, V., & Nicholson, H. (1970). Communication of inferior and superior attitudes by verbal and nonverbal signals. British Journal of Social and Clinical Psychology, 9, 222–229. Argyle, M., Trimboli, L., & Forgas, J. (1988). The bank manager-doctor effect: disclosure profiles in different relationships. Journal of Social Psychology, 128, 117–124. Argyle, M., Trower, P., & Bryant, B. (1974). Explorations in the treatment of personality disorders and neuroses by social skills training. British Journal of Medical Psychology, 47, 63–72. Au, K., Chan, F., Wang, D., & Vertinsky, I. (2003). Mood in foreign exchange trading: cognitive processes and performance. Organizational Behavior and Human Decision Processes, 91, 322–338. Bless, H. (2000). The interplay of affect and cognition: The mediating role of general knowledge structures. In J. P. Forgas (Ed.), Feeling and thinking: The role of affect in social cognition (pp. 201–222). New York: Cambridge University Press. Bower, G. H. (1981). Mood and memory. American Psychologist, 36, 129–148. Bower, G. H., & Forgas, J. P. (2001). Mood and social memory. In J. P. Forgas (Ed.), The handbook of affect and social cognition. Mahwah, N.J.: Erlbaum. Byrne, D., & Clore, G. L. (1970). A reinforcement model of evaluation responses. Personality: An International Journal, 1, 103–128. Clark, M. S., & Isen, A. M. (1982). Towards understanding the relationship between feeling states and social behavior. In A. H. Hastorf & A. M. Isen (Eds.), Cognitive social psychology (pp. 73–108). New York: ElsevierNorth Holland. Damasio, A. R. (1994). DescartesÕ error. New York: Grosste/Putnam. Eich, E. E., & Macauley, D. (2000). The informational role of affect. In J. P. Forgas (Ed.), Feeling and thinking: The role of affect in social cognition (pp. 109–130). New York: Cambridge University Press.

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