(Ir)rational choices of humans, rhesus macaques, and capuchin monkeys in dynamic stochastic environments (original) (raw)
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Research Square (Research Square), 2023
The propensity of humans and non-human animals to discount future returns for short-term bene ts is well established. This contrasts with the ability of organisms to unfold complex developmental sequences over months or years. Research has focused on various descriptive and predictive parameters of 'temporal discounting' in behavior, and researchers have proposed models to explain temporal preference in terms of rational outcomes, but the underlying cause of this phenomenon has not been deeply explored. We propose that preference for short-term reward ('impulsivity') may not be rational when examined from the perspective of an omniscient observer, but may be the product of the way natural selection acts on events in a temporal framework in the context of future uncertainty. Using a simple Newtonian model for time across a tness landscape in which movement by organisms is only possible in one direction, we examine several factors that in uence the ability of an organism to choose a distant reward over a more temporally proximate reward: including the temporal distance of the far reward, the relative value of the distant reward, and the effect of uncertainty about the value and presence of the distant reward. Our results indicate that an organism may choose a more distant reward, but only if it is not too far into the future, and only if it has a substantially higher-value tness payoff relative to the short-term reward. Most notably, any uncertainty about the distant reward made it extremely unlikely for an organism to choose the delayed reward strategy compared to choosing a closer reward, even if the distant reward had a much higher payoff because events that are uncertain are only partially visible to natural selection pressures. We argue that these results explain why so many animals have di culty making 'better' long-term rational strategies for a distant reward over the lower-value short-term reward. Uncertainty is likely to be an especially important ecological factor in promoting and biasing short-term behavioral strategies. These results help illustrate why human and non-human animals have di culty making the more rational choice when faced with short-term and long-term rewards.
Rational decisions: The adaptive nature of context-dependent choice
2009
Although classical economic theory hinges on the assumption that rational actors should seek to maximize gains, psychologists and behavioral economists have recently collected a wealth of evidence challenging this premise. In violation of the principles of rational choice, context appears to dramatically influence human decision making. Like humans, numerous nonhuman animals, ranging from honeybees to primates, are sensitive to context, suggesting deep evolutionary roots for seemingly irrational decision-making. Many psychologists have suggested that such choices may stem from cognitive biases that result in errors. We contend, however, that labeling context-dependent choices as errors obscures the real issue. Natural selection does not create organisms that adhere to economic theory-it creates decision makers that maximize fitness. We review evidence that many species show context-dependence when making decisions and then present a framework for analyzing the adaptive consequences of these choices. We argue for an approach weaving psychological perspectives into an evolutionary framework to elucidate the nature of decision making.
Is a bird in the hand worth two in the future? The neuroeconomics of intertemporal decision-making
2008
When making intertemporal decisions, i.e., decisions between outcomes occurring at different instants in time, humans and animals prefer rewards with short-term availability over rewards that become available in the long run. Discounted utility theory (DUT) is an influential normative model for intertemporal decisions that attempts to capture preference over time. It prescribes which is the best decision to take with respect to consistent, coherent and optimal choice. Over the last few decades, DUT's descriptive validity has been critically challenged. Empirical studies found systematic violations of several of DUT's assumptions, including time-consistency of preferences, stationarity, constant discounting and utility maximisation. To account for these anomalies, alternative models have been devised invarious academic disciplines, including economics, psychology, biology, philosophy, and most lately, cognitive neuroscience. This article reviews the most recent literature on the behavioural and neural processes underlying intertemporal choices, and elucidates to which extent these findings can be used to explain violations of DUT's assumptions. In the first three sections, DUT is introduced, and behavioural anomalies are discussed. The fourth part focuses on the neuroscience of intertemporal choice, including its functional neuroanatomy, attempts to find a discounted value signal in the brain, and recent efforts to identify neural mechanisms producing time-inconsistencies. In the last section, the computational literature on neural learning mechanisms is reviewed. Then, a new, biologically plausible computational model of intertemporal choice is proposed that is able to explain many of the behavioural anomalies. The implications of these results help to understand why humans and animals frequently decide irrationally and to their long-term economic disadvantage, and which neural mechanisms underly such decisions. #
Philosophical Transactions of the Royal Society B: Biological Sciences
Principles of economics predict that the costs associated with obtaining rewards can influence choice. When individuals face choices between a smaller, immediate option and a larger, later option, they often experience opportunity costs associated with waiting for delayed rewards because they must forego the opportunity to make other choices. We evaluated how reducing opportunity costs affects delay tolerance in capuchin monkeys. After choosing the larger option, in the High cost condition, subjects had to wait for the delay to expire, whereas in the Low cost different and Low cost same conditions, they could perform a new choice during the delay. To control for the effect of intake rate on choices, the Low cost same condition had the same intake rate ratio as the High cost condition. We found that capuchins attended both to intake rates and to opportunity costs. They chose the larger option more often in the Low cost different and Low cost same conditions than in the High cost cond...
Journal of experimental psychology. Animal learning and cognition, 2014
Researchers are exploring whether animals share with humans something like a metacognitive capacity. Though some results point to human-animal continuities in this domain, they face the dominant criticism that animals' performances might be associative. A persistent problem is that animal-metacognition paradigms present static environments of risk and reward that may foster inflexible and conditioned responding. Those environments do not challenge animals to show the flexibility in their…
Rationality and intertemporal choice
Journal of Bioeconomics, 2009
The alleged problems associated with self-control, hyperbolic discounting and other examples of seemingly irrational intertemporal choice are examined in the context of an evolution-based neurobiological model that emphasizes the role of the biological evolution of big brains and language and the cultural evolution of institutions. There is no utility function in the brain; it has no central-planner, in fact, the brain is a self-organized complex system, a decentralized spontaneous order. This spontaneous order is coordinated, much like an economy, by a distributed network that maintains and makes available the discounted net value of various options to decentralized and specialized areas in the brain when making decisions. Further, that decision making is embodied and embedded in the decision making environment. For humans, an important part of that environment is the social environment consisting of institutions and other components of culture. It was, in part, the evolution of this environment that made long-range planning possible. Additionally, it is very often the lack of embedded experience with the environment that leads to what seems to be irrational intertemporal choices. In fact, under close examination the evidence for consistent irrational intertemporal choice is weak.
Humans and monkeys show similar skill in estimating uncertain outcomes
Psychonomic bulletin & review, 2012
When information is incomplete but a choice must be made, individuals sometimes can rely on past experiences to help them assess uncertain outcomes in terms of the probabilities of payoffs. Monkeys (Cebus apella) and humans (Homo sapiens) were presented with a test in which they first made quantity judgments between two clear options. Then they made choices in which only one option was visible, and they had to estimate the quantity for the other option. Both species were guided by the past outcomes, as they shifted from selecting the known option to selecting the unknown option at the point at which the known option went from being greater than the average rate of return to being less than the average rate of return. This comparability across species suggests that tallying ongoing average rates of return from repeated choices occurs spontaneously and likely serves an adaptive purpose when dealing with uncertainty in the environment.
Temporal Discounting Predicts Risk Sensitivity in Rhesus Macaques
Current Biology, 2007
Humans and animals tend to both avoid uncertainty and to prefer immediate over future rewards. The co-morbidity of psychiatric disorders such as impulsivity, problem gambling, and addiction suggests that a common mechanism may underlie risk sensitivity and temporal discounting .
Cognitive mechanisms of risky choice: Is there an evaluation cost
We contrast two classes of choice processes, those assuming time-consuming comparisons and those where stimuli for each option act independently, competing for expression by cross censorship. The Sequential Choice Model (SCM) belongs in the latter category, and has received empirical support in several procedures involving deterministic alternatives. Here we test this model in risky choices. In two treatments, each with five conditions, European starlings (Sturnus vulgaris) faced choices between options with unpredictable outcomes and risk-free alternatives. In the delay treatment the five conditions involved choices between a variable option offering two equiprobable delays to reward and a fixed option with delay differing between conditions. The amount treatment was structurally similar, but amount of reward rather than delay was manipulated. As assumed (and required) by the SCM, latency to respond in no-choice trials reflected each option's richness with respect to the background alternatives, and, crucially, preferences in simultaneous choices were predictable from latencies to each option in forced trials. However, we did not detect reliable differences in response times between forced and choice trials, neither the lengthening expected from evaluation models nor the shortening expected from the SCM.