Should Governments Invest More in Nudging?

Governments are increasingly adopting behavioral science techniques for changing individual behavior in pursuit of policy objectives. The types of "nudge" interventions that governments are now adopting alter people's decisions without coercion or significant changes to economic incentives. We calculated ratios of impact to cost for nudge interventions and for traditional policy tools, such as tax incentives and other financial inducements, and we found that nudge interventions often compare favorably with traditional interventions. We conclude that nudging is a valuable approach that should be used more often in conjunction with traditional policies, but more calculations are needed to determine the relative effectiveness of nudging.

Dissociating motivation from reward in human striatal activity.

Neural activity in the striatum has consistently been shown to scale with the value of anticipated rewards. As a result, it is common across a number of neuroscientific subdiscliplines to associate activation in the striatum with anticipation of a rewarding outcome or a positive emotional state. However, most studies have failed to dissociate expected value from the motivation associated with seeking a reward. Although motivation generally scales positively with increases in potential reward, there are circumstances in which this linkage does not apply. The current study dissociates value-related activation from that induced by motivation alone by employing a task in which motivation increased as anticipated reward decreased. This design reverses the typical relationship between motivation and reward, allowing us to differentially investigate fMRI BOLD responses that scale with each. We report that activity scaled differently with value and motivation across the striatum. Specifically, responses in the caudate and putamen increased with motivation, whereas nucleus accumbens activity increased with expected reward. Consistent with this, self-report ratings indicated a positive association between caudate and putamen activity and arousal, whereas activity in the nucleus accumbens was more associated with liking. We conclude that there exist regional limits on inferring reward expectation from striatal activation.

Essentialism in the absence of language? Evidence from rhesus monkeys (Macaca mulatta).

We explored whether rhesus monkeys (Macaca mulatta) share one important feature of human essentialist reasoning: the capacity to track category membership across radical featural transformations. Specifically, we examined whether monkeys--like children (Keil, 1989)--expect a transformed object to have the internal properties of its original category. In two experiments, monkeys watched as an experimenter visually transformed a familiar fruit (e.g. apple) into a new kind of fruit (e.g. coconut) either by placing a fruit exterior over the original, or by removing an exterior shell and revealing the inside kind of fruit. The experimenter then pretended to place an inside piece of the transformed fruit into a box which the monkey was allowed to search. Results indicated that monkeys searched the box longer when they found a piece of fruit inconsistent with the inside kind, suggesting that the monkeys expected that the inside of the transformed fruit would taste like the innermost kind they saw. These results suggest that monkeys may share at least one aspect of psychological essentialism: they maintain category-specific expectations about an object's internal properties even when that object's external properties change. These results therefore suggest that some essentialist expectations may emerge in the absence of language, and thus raise the possibility that such tendencies may emerge earlier in human development than has previously been considered.

Grape expectations: the role of cognitive influences in color-flavor interactions.

Color conveys critical information about the flavor of food and drink by providing clues as to edibility, flavor identity, and flavor intensity. Despite the fact that more than 100 published papers have investigated the influence of color on flavor perception in humans, surprisingly little research has considered how cognitive and contextual constraints may mediate color-flavor interactions. In this review, we argue that the discrepancies demonstrated in previously-published color-flavor studies may, at least in part, reflect differences in the sensory expectations that different people generate as a result of their prior associative experiences. We propose that color-flavor interactions in flavor perception cannot be understood solely in terms of the principles of multisensory integration (the currently dominant theoretical framework) but that the role of higher-level cognitive factors, such as expectations, must also be considered.

Do capuchin monkeys (Cebus apella) diagnose causal relations in the absence of a direct reward?

We adapted a method from developmental psychology to explore whether capuchin monkeys (Cebus apella) would place objects on a "blicket detector" machine to diagnose causal relations in the absence of a direct reward. Across five experiments, monkeys could place different objects on the machine and obtain evidence about the objects' causal properties based on whether each object "activated" the machine. In Experiments 1-3, monkeys received both audiovisual cues and a food reward whenever the machine activated. In these experiments, monkeys spontaneously placed objects on the machine and succeeded at discriminating various patterns of statistical evidence. In Experiments 4 and 5, we modified the procedure so that in the learning trials, monkeys received the audiovisual cues when the machine activated, but did not receive a food reward. In these experiments, monkeys failed to test novel objects in the absence of an immediate food reward, even when doing so could provide critical information about how to obtain a reward in future test trials in which the food reward delivery device was reattached. The present studies suggest that the gap between human and animal causal cognition may be in part a gap of motivation. Specifically, we propose that monkey causal learning is motivated by the desire to obtain a direct reward, and that unlike humans, monkeys do not engage in learning for learning's sake.

An expectations-based approach to explaining the cross-modal influence of color on orthonasal olfactory identification: the influence of the degree of discrepancy.

In the present study, we explored the conditions under which color-generated expectations influence participants' identification of flavored drinks. Four experiments were conducted in which the degree of discrepancy between the expected identity of a flavor (derived from the color of a drink) and the actual identity of the flavor (derived from orthonasal olfactory cues) was examined. Using a novel experimental approach that controlled for individual differences in color-flavor associations, we first measured the flavor expectations held by each individual and only then examined whether the same individual's identification responses were influenced by his or her own expectations. Under conditions of low discrepancy, the perceived disparity between the expected and the actual flavor identities was small. When a particular color--identified by participants as one that generated a strong flavor expectation--was added to these drinks (as compared with when no such color was added), a significantly greater proportion of identification responses were consistent with this expectation. This held true even when participants were explicitly told that color would be an uninformative cue and were given as much time as desired to complete the task. By contrast, under conditions of high discrepancy, adding the same colors to the drinks no longer had the same effect on participants' identification responses. Critically, there was a significant difference in the proportion of responses that were consistent with participants' color-based expectations in conditions of low as compared with high discrepancy, indicating that the degree of discrepancy between an individual's actual and expected experience can significantly affect the extent to which color influences judgments of flavor identity.