Timothy Ketelaar

Personality and susceptibility to positive and negative emotional states

Grays (1981) theory suggests that extraverts and neurotics are differentially sensitive to stimuli that generate positive and negative affect, respectively. From this theory it was hypothesized that efficacy of a standard positive-affect induction would be more strongly related to extraversion than to neuroticism scores, whereas efficacy of a standard negative-affect induction would be more strongly related to neuroticism scores. Positive and negative affect was manipulated in a controlled setting, and the effectiveness of the mood induction was assessed using standard mood adjective rating scales. Results are consistent with the hypothesis that neurotic Ss (compared with stable Ss) show heightened emotional reactivity to the negative-mood induction, whereas extraverts (compared with intraverts) show heightened emotional reactivity to the positive-mood induction. Results corroborate and extend previous findings.

EXTRAVERSION, NEUROTICISM AND SUSCEPTIBILITY TO POSITIVE AND NEGATIVE MOOD INDUCTION PROCEDURES

Recent correlational research suggests that Extraversion is associated witha predisposition to experience positive affect, whereas Neuroticism is associated with a predisposition to experience negative affect. Using Grays (A Model for Personality, pp. 246–276, 1981) terms, such results may be due to differential sensitivity to signals of reward and punishment on the part of Extraverts and Neurotics, respectively. Assuming that signals of reward generate positive affect and signals of punishment (or frustrative non-reward) generate negative affect, we hypothesized that the efficacy of a negative affect induction would be better predicted from Neuroticism than Extraversion scores, whereas the efficacy of a positive affect induction should be better predicted from Extraversion than Neuroticism scores. In the current study a laboratory mood induction technique (false feedback of success and failure) was used to induce positive and negative affect, and its effectiveness was assessed using standard mood adjective ratings. Results support the hypothesis that Extraverts (compared to Introverts) show heightened emotional reactivity to positive (but not negative) mood induction procedures, whereas Neurotics (compared to Stable individuals) show heightened emotional reactivity to negative (but not positive) mood induction procedures. Results are discussed in terms of an emotion-based approach to personality theory, and directions for future research are suggested.

Relations between Affect and Personality: Support for the Affect-Level and Affective-Reactivity Views

A consensus has emerged that neuroticism is associated with negative affect and extraversion is associated with positive affect. However, it is unclear whether these personality traits are associated with magnitude of affective reactions (Affective-Reactivity view), with levels of tonic affect (Affect-Level view), or with both. To assess these views, affective state was manipulated using film clips, measured at multiple time points and related to measures of neuroticism and extraversion (H. J. Esyenck) and dispositional negative affect and positive affect (Watson, Clark, & Tellegen). Results supported both Affective-Reactivity and Affect-Level views, and this support was more robust for neuroticism and extraversion than for dispositional negative affect and positive affect.

The effects of feelings of guilt on the behaviour of uncooperative individuals in repeated social bargaining games: An affect-as-information interpretation of the role of emotion in social interaction

In two studies we found that feelings of guilt provoke individuals to cooperate in repeated social bargaining games (a prisoners dilemma in Study 1 and an ultimatum game in Study 2). Feelings of guilt were either experimentally manipulated (Study 1) or assessed via self-report (Study 2) after participants had played one round of a social bargaining game. As predicted, individuals who experienced feelings of guilt (compared to individuals who felt no guilt) after pursuing a non-cooperative strategy in the first round of play, displayed higher levels of cooperation in the subsequent round of play (even one week later). Results are discussed in terms of an “affect-as-information” model, which suggests that non-cooperating individuals who experience the negative affective state associated with guilt in a social bargaining game may be using this feeling state as “information” about the future costs of pursuing an uncooperative strategy. Because in guilt the focus is on the specific, individuals are capable of ridding themselves of this emotional state through action (Lewis, 1993, p. 570)

The Role of Affect in Determining the Attributional Weight of Immoral Behaviors

Theories about why immoral behaviors carry a large amount of attributional weight tend to emphasize traditional cognitive variables. In contrast, the authors propose that the degree of negative affect that these behaviors induce in observers is largely responsible for their attributional weight. Studies 1 and 2 demonstrate an association between the amount of negative affect induced by immoral behaviors and their attributional weight. Studies 3 and 4 provide causal evidence for this idea by either “adding in” or “taking away” the negative affect associated with immoral behaviors to influence their attributional weight. Finally, Study 5 demonstrates that negative affect can be induced through a variety of negative emotions (disgust, sadness, and fear), with similar results. It is argued that it is difficult to account for these data solely on the basis of traditional cognitive variables, and so a theory that includes an emphasis on affect as a causal variable is desirable.

Framing Our Thoughts: Ecological Rationality as Evolutionary Psychology’s Answer to the Frame Problem

Decision makers challenged by real-world adaptive problems must often select a course of action quickly, despite two computational obstacles: There is usually a vast number of possible courses of action that can be explored, and a similarly vast number of possible consequences that must be considered when evaluating these options. Thus, decision makers routinely face the frame problem: how to focus attention on adaptively relevant information and how to keep this information set small enough that the mind can actually perform the computations necessary to generate adaptive behavior. By identifying simple, effective heuristics that work within the computational and informational constraints of an organism and still result in adaptively adequate behavior, the new ecological rationality perspective within evolutionary psychology suggests how intelligent agents can overcome this frame problem. In this chapter we show how ecologically rational psychological mechanisms can address two challenges derived from the frame problem: 1) Using the example of sequential mate choice, we demonstrate that a satisficing information search strategy can lead to good decisions using only a limited amount of information; and 2) We argue that emotions can guide information search, by focusing the computational mind on precisely that information which is most useful for making decisions that lead to good outcomes over the long run.

On the Natural Selection of Alternative Models: Evaluation of Explanations in Evolutionary Psychology

A central goal ofourtarget article was to evaluate the soundness of evolutionary psychologys epistemology in relation to the critical claim that evolutionary explanations are unfalsifiable. None of the 16 commentators challenge our central assertion-that the methods and strategies employed by evolutionary psychologists to generate and test hypotheses are scientifically defensible-and thus we consider our basic goal to have been achieved. However, the commentators raise a number of thoughtful and thought-provoking points. In our response to these commentaries we focus on a subset of philosophical and metatheoretical issues that we believe are most deserving of further discussion. The first part ofthis rejoinder addresses issues concerning evolutionary psychology and the philosophy of science; the second part addresses issues concerning the core assumptions of evolutionary psychology.

Clarifying the Foundations of Evolutionary Psychology: A Reply to Lloyd and Feldman

Department of PsychologyNew Mexico State UniversityLloyd and Feldman’s (this issue) continuing com-mentary on our recent target article and rejoinder (Ellis& Ketelaar, 2000; Ketelaar & Ellis, 2000) focuses ontwooverarchingissues.First,LloydandFeldmanclaimthatourdescriptionofthecoremetatheoreticalassump-tions of modern evolutionary theory overemphasizesthe role of inclusive fitness (i.e., the so-called selfishgeneapproach)attheexpenseofunderemphasizingim-portant alternative approaches (e.g., multilevel selec-tion models, gene–culture coevolution models). Sec-ond, Lloyd and Feldman criticize some of the methodsandassumptionsthatostensiblycharacterizetheevolu-tionarypsychologyresearchprogram.Thesecriticismsconcerntheconceptualizationoforganismsasinclusivefitness maximizers, the soundness of the epistemologyof evolutionary psychology, the modularity of psycho-logicalmechanisms,andtheuniversalityofpsychologi-calmechanisms.Inthefirstpartofthisrejoinder,weac-knowledge that different schools of thought existregarding the plausibility and importance of variousmetatheoretical assumptions in human evolutionarypsychology. We argue that to date, however, only thegene-centered adaptationist program (consistent withinclusive fitness theory) has demonstrated scientificprogressivitybygeneratingacoherent,integratedbodyofnewknowledgeandexplainingawayseveralapparentanomalies. In the second part of this rejoinder, wediscuss several misunderstandings that underlie Lloydand Feldman’s criticisms of human evolutionarypsychology.The Role of Inclusive Fitness Theory inEvolutionary PsychologyLloyd and Feldman (this issue) criticize our refer-ence to inclusive fitness theory as providing the foun-dation of modern evolutionary theory:

EMOTLAB: Software for studying emotional signaling in economic bargaining games

EMOTLAB software creates a virtual social environment in which individuals interact via computer with a virtual interaction partner in a series of economic bargaining games. The virtual partner appears on the participant’s computer screen as a digital image (e.g., video or picture file) during each trial. A key feature of EMOTLAB software is its ability to control both the strategic behavior and the emotion signaling behavior (e.g., anger vs. embarrassment) of the virtual interaction partner. By simply editing a series of text files that control the subroutines governing the different features of the experiment (payoff structure, number of trials, etc.), EMOTLAB can generate an essentially infinite number of different social bargaining situations in which participants earn monetary payoffs contingent upon their decisions. This paper provides an overview of this software and how one can edit various subroutines to generate a typical experimental session in which research participants encounter a virtual interaction partner who displays different emotional signals.

The Evaluation of Competing Approaches within Human Evolutionary Psychology

A central assumption of human evolutionary psychology is that the brain is comprised of many specialized psychological mechanisms that were shaped by natural selection over vast periods of time to solve the recurrent information-processing problems faced by our ancestors (Buss, 1995, 1999; Barkow, Cosmides, & Tooby, 1992; Gaulin & McBurney, 2000; Ketelaar & Ellis, 2000; Symons, 1995). Although this so-called “narrow” approach to evolutionary psychology1 shares many features with the broader meta-theoretical perspective of evolutionary biology, this approach can be considered just one application (among many) of the basic principles and knowledge of evolutionary biology, rather than the sine qua non of all “evolutionary psychology”. In this manner, the term “narrow” merely reflects a focus on a particular set of core assumptions (inclusive fitness, gene-centered selection, adaptationism), rather than a limited or necessarily myopic application of evolutionary biology. Paradoxically, some researchers have argued that what is referred to here as the “narrow” approach to evolutionary psychology actually represents the ascendent view in much of human evolutionary psychology (see Ketelaar & Ellis, 2000; Ellis & Ketelaar, in press). The aim of this chapter is to illustrate how researchers can evaluate competing evolutionary explanations at all levels of analysis ranging from the most basic assumptions lying at the hard core of the meta-theory to the strong and weak predictions lying in the protective belt of auxiliary hypotheses that surrounds the hard core.