When Less Is More: Evolutionary Origins of the Affect Heuristic (original) (raw)

Defining value through quantity and quality-Chimpanzees (Pan troglodytes) undervalue food quantities when items are broken

Behavioural processes, 2015

Decision-making largely is influenced by the relative value of choice options, and the value of such options can be determined by a combination of different factors (e.g., the quantity, size, or quality of a stimulus). In this study, we examined the competing influences of quantity (i.e., the number of food items in a set) and quality (i.e., the original state of a food item) of choice items on chimpanzees' food preferences in a two-option natural choice paradigm. In Experiment 1, chimpanzees chose between sets of food items that were either entirely whole or included items that were broken into pieces before being shown to the chimpanzees. Chimpanzees exhibited a bias for whole food items even when such choice options consisted of a smaller overall quantity of food than the sets containing broken items. In Experiment 2, chimpanzees chose between sets of entirely whole food items and sets of initially whole items that were subsequently broken in view of the chimpanzees just befo...

The Evolution of Our Preferences: Evidence from Capuchin-Monkey Trading Behavior

Cowles Foundation Discussion Papers, 2005

Behavioral economics has demonstrated systematic decision-making biases in both lab and field data. But are these biases learned or innate? We investigate this question using experiments on a novel set of subjects-capuchin monkeys. By introducing a fiat currency and trade to a capuchin colony, we are able to recover their preferences over a wide range of goods and risky choices. We show that standard price theory does a remarkably good job of describing capuchin purchasing behavior; capuchin monkeys react rationally to both price and wealth shocks. However, when capuchins are faced with more complex choices including risky gambles, they display many of the hallmark biases of human behavior, including reference-dependent choices and loss-aversion. Given that capuchins demonstrate little to no social learning and lack experience with abstract gambles, these results suggest that certain biases such as loss-aversion are an innate function of how our brains code experiences, rather than learned behavior or the result of misapplied heuristics. * We would like to acknowledge a very generous Whitebox Advisors' Research Grant, without which this research would not have been possible. Alisia Eckert provided invaluable research assistance throughout this project. Many people gave generously of their time on this and earlier drafts; we would especially like to thank

Natural choice in chimpanzees (Pan troglodytes): Perceptual and temporal effects on selective value

Learning and Motivation, 2009

In three experiments, four chimpanzees made choices between two visible food options to assess the validity of the selective value effect (the assignment of value to only the most preferred type of food presented in a comparison). In Experiment 1, we established that all chimpanzees preferred single banana pieces to single apple pieces before presenting the critical test. In this test two chimpanzees preferred a mix of one banana piece and one apple piece to a single banana piece when both banana piece were approximately the same size, but two chimpanzees were indifferent between the two options, exhibiting the selective value effect. In Experiment 2, when the banana pieces in both options were more closely equated in size the chimpanzees then were biased to choose the single banana piece over the mixed array even though this was the smaller total amount of food. However, in Experiment 3, when we introduced longer intervals between each trial, the chimpanzees preferred the mixed set and thus the larger total amount of food. The results demonstrate that only some chimpanzees exhibit the choice pattern indicative of the selective value effect, and they do so only when item size is not carefully controlled and trials are presented quickly in succession. Thus, the behavior pattern originally labeled the selective value effect may actually be explained by a combination of chimpanzees' sensitivity to small differences in preferred food amount and chimpanzees tendency to avoid less preferred foods that would delay the acquisition of further preferred food items.

Chimpanzees Predict the Hedonic Outcome of Novel Taste Combinations: The Evolutionary Origins of Affective Forecasting

Frontiers in Psychology, 2020

Affective forecasting-predicting the emotional outcome of never-before experienced situations-is pervasive in our lives. When facing novel situations, we can quickly integrate bits and pieces of prior experiences to envisage possible scenarios and their outcomes, and what these might feel like. Such affective glimpses of the future often steer the decisions we make. By enabling principled decision-making in novel situations, affective forecasting confers the important adaptive advantage of eluding the potentially costly consequences of tackling such situations by trial-and-error. Affective forecasting has been hypothesized as uniquely human, yet, in a recent study we found suggestive evidence of this ability in an orangutan. To test non-verbal subjects, we capitalized on culinary examples of affective forecasting and devised a behavioral test that required the subjects to make predictions about novel juice mixes produced from familiar ingredients. In the present study, we administered the same task to two chimpanzees and found that their performance was comparable to that of the previously tested orangutan and 10 humans, who served as a comparison group. To improve the comparability of human and animal performance, in the present study we also introduced a new approach to assessing if the subjects' performance was indicative of affective forecasting, which relies exclusively on behavioral data. The results of the study open for the possibility that affective forecasting has evolved in the common ancestor of the great apes, providing Hominids with the adaptive advantage of e.g., quickly evaluating heterogeneous food patches using hedonic prediction.

Utility maximization and melioration: Internalities in individual choice

Journal of Behavioral Decision Making, 1993

How do people go about choosing between alternatives in relatively simple settings? This study explores some of the variables that past work suggests may be relevant. Volunteer subjects worked for money in six procedures in which the probability of a payment from either of two alternatives was 1.0, but the rate of pay (i.e. the speed with which a payment was delivered or the size of the payment) interacted with the subjects' recent allocation of choices, which we define as the 'internalities'. Because of the internalities, choosing the currently more profitable alternative did not maximize total earnings. Subjects were more likely to fail to maximize when the interaction between present pay and past choices was spread over longer sequences of choices, or when the reward variable was the speed, rather than the value, of each payment. Subjects often disregarded the internalities and were instead guided by the current yields of the two alternatives, which is a frequently observed tendency, called 'melioration', in experiments on choices by animals. The tendency toward melioration was only partially counteracted by explicit instructions on how to maximize earnings. We discuss a theoretical framework for melioration that postulates both motivational and cognitive sources. KEY WORDS Choice Utility maximization Melioration Individual behavior Rational choice theory Some of the fundamental assumptions of rational choice theory have recently been challenged by controlled experiments on judgment and choice. For example, people make systematic errors in estimating probabilities (Camerer, 1987; Tversky and Kahneman, 1974), and they violate such fundamental choice axioms as transitivity (Tversky, 1969), regularity (Huber et al., 1982), or even dominance (Kahneman and Tversky, 1981). In this paper we illustrate and discuss a possibly related source of human suboptimality in decision making which has been most extensively documented in animal 0894-3257/93/030149-37S23.50 0 1993 by John Wiley 8~ Sons, Ltd.

(Ir)rational choices of humans, rhesus macaques, and capuchin monkeys in dynamic stochastic environments

Cognition

Human and animal decision-making is known to violate rational expectations in a variety of contexts. Previous models suggest that statistical structures of real-world environments can favor such seemingly irrational behavior, but this has not been tested empirically. We tested 16 capuchin monkeys, seven rhesus monkeys, and 30 humans in a computerized experiment that implemented such stochastic environments. Subjects chose from among up to three options of different value that disappeared and became available again with different probabilities. All species overwhelmingly chose transitively (A > B > C) in the control condition, where doing so maximized overall gain. Most subjects also adhered to transitivity in the test condition, where it was suboptimal, but ultimately led to negligible losses compared to the optimal, non-transitive strategy. We used a modelling approach to show that differences in temporal discounting may account for this pattern of choices on a proximate level. Specifically, when short-and long-term goals are valued similarly, near-optimal decision rules can map onto rational choice principles. Such cognitive shortcuts have been argued to have evolved to preserve mental resources without sacrificing good decision-making, and here we provide evidence that these heuristics can provide almost identical outcomes even in situations in which they lead to suboptimal choices.

The complementary role of affect-based and cognitive heuristics to make decisions under conditions of ambivalence and complexity

PLOS ONE, 2018

Little is known about the interplay between affective and cognitive processes of decision making within the bounded rationality perspective, in particular for the debate on adaptive decision making and strategy selection. This gap in the knowledge is particularly important as affect and deliberation may direct preferences in opposite directions. How do decision makers solve such dissonance? In this paper, we address this question by exploring the use of integral affect as a choice heuristic in comparison with and in conjunction to "take the best," and weighted addition of attributes (WADD). We operationalize theories of reliance on affect in choice through a "Take the emotionally best" algorithm. Its predictive power is experimentally tested against other models, including mixed-sequential cognitive/affective procedures. We find that individual decisions are better predicted by a sequential combination of "Take the emotionally best" and "Take the best" with a slight dominance of the former. Conditions of cognitive/affective ambivalence, low discrimination ability and high complexity provide the cognitive architecture where such blended choice strategies predict decisions more precisely. This implies that reliance on integral affect may precede the use of cognitive cues following an ecological rationality perspective rather than supporting a kind of competition between affect and cognition as implied in current literature.