Economic Games Quantify Diminished Sense of Guilt in Patients with Damage to the Prefrontal Cortex

Damage to the ventromedial prefrontal cortex (VMPFC) impairs concern for other people, as reflected in the dysfunctional real-life social behavior of patients with such damage, as well as their abnormal performances on tasks ranging from moral judgment to economic games. Despite these convergent data, we lack a formal model of how, and to what degree, VMPFC lesions affect an individual's social decision-making. Here we provide a quantification of these effects using a formal economic model of choice that incorporates terms for the disutility of unequal payoffs, with parameters that index behaviors normally evoked by guilt and envy. Six patients with focal VMPFC lesions participated in a battery of economic games that measured concern about payoffs to themselves and to others: dictator, ultimatum, and trust games. We analyzed each task individually, but also derived estimates of the guilt and envy parameters from aggregate behavior across all of the tasks. Compared with control subjects, the patients donated significantly less and were less trustworthy, and overall our model found a significant insensitivity to guilt. Despite these abnormalities, the patients had normal expectations about what other people would do, and they also did not simply generate behavior that was more noisy. Instead, the findings argue for a specific insensitivity to guilt, an abnormality that we suggest characterizes a key contribution made by the VMPFC to social behavior

Exploring the scope of neurometrically informed mechanism design

A basic goal in mechanism design is to construct mechanisms that simultaneously satisfy efficiency, voluntary participation, and dominant strategy incentive compatibility. Previous work has shown that this is impossible, unless the agents and planner have sufficient information about each other and common knowledge. These results have remained largely theoretical because the required information is generally not available in practical applications. However, recent work has shown that these limitations can be overcome in simple settings, using neurometric technologies that provide noisy signals of subjects' preferences that can be used in the mechanism design problem. Here we build on this work by carrying out two new experiments designed to test the extent to which these Neurometrically Informed Mechanisms (NIMs) can be applied to more complicated and realistic environments. We find robustness to large type and action space and to the degrees of loss and risk-aversion observed in most of our sample

Uncovering the computational mechanisms underlying many-alternative choice

How do we choose when confronted with many alternatives? There is surprisingly little decision modelling work with large choice sets, despite their prevalence in everyday life. Even further, there is an apparent disconnect between research in small choice sets, supporting a process of gaze-driven evidence accumulation, and research in larger choice sets, arguing for models of optimal choice, satisficing, and hybrids of the two. Here, we bridge this divide by developing and comparing different versions of these models in a many-alternative value-based choice experiment with 9, 16, 25, or 36 alternatives. We find that human choices are best explained by models incorporating an active effect of gaze on subjective value. A gaze-driven, probabilistic version of satisficing generally provides slightly better fits to choices and response times, while the gaze-driven evidence accumulation and comparison model provides the best overall account of the data when also considering the empirical relation between gaze allocation and choice

Measuring utility with diffusion models

The diffusion model (DDM) is a prominent account of how people make decisions. Many of these decisions involve comparing two alternatives based on differences of perceived stimulus magnitudes, such as economic values. Here, we propose a consistent estimator for the parameters of a DDM in such cases. This estimator allows us to derive decision thresholds, drift rates, and subjective percepts (i.e., utilities in economic choice) directly from the experimental data. This eliminates the need to measure these values separately or to assume specific functional forms for them. Our method also allows one to predict drift rates for comparisons that did not occur in the dataset. We apply the method to two datasets, one comparing probabilities of earning a fixed reward and one comparing objects of variable reward value. Our analysis indicates that both datasets conform well to the DDM. Interestingly, we find that utilities are linear in probability and slightly convex in reward

Special Issue of the Journal of Behavioral Decision Making on “Applications and Innovations of Eye‐Movement Research in Judgment and Decision Making”

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/100158/1/bdm1798.pd

Different Attentional Patterns for Regret and Disappointment: An Eye-tracking Study.

The unfavorable comparison between the obtained and expected outcomes of our choices may elicit disappointment. When the comparison is made with the outcome of alternative actions, emotions like regret can serve as a learning signal. Previous work showed that both anticipated disappointment and regret influence decisions. In addition, experienced regret is associated with higher emotional responses than disappointment. Yet it is not clear whether this amplification is due to additive effects of disappointment and regret when the outcomes of alternative actions are available, or whether it reflects the learning feature of regret signals. In this perspective, we used eye-tracking to measure the visual pattern of information acquisition in a probabilistic lottery task. In the partial feedback condition, only the outcome of the chosen lottery was revealed, while in the complete feedback condition, participants could compare their outcome with that of the non-chosen lottery, giving them the opportunity to experience regret. During the decision phase, visual patterns of information acquisition were consistent with the assessment of anticipated regret, in addition to a clear assessment of lotteries' expected values. During the feedback phase, subjective ratings and eye-tracking results confirmed that participants compared their outcome with the outcome of the non-chosen lottery in the complete feedback condition, particularly after a loss, and ignored the non-realized outcome of the chosen option. Moreover, participants who made more visual saccades consistent with counterfactual comparisons during the feedback period anticipated regret more in their decisions. These results are consistent with the proposed adaptive function of regret