The tail of the caudate is sensitive to both gain and loss feedback during information integration categorization.

Although most category learning studies use feedback for training, little attention has been paid to how individuals utilize feedback implemented as gains or losses during categorization. We compared skilled categorization under three different conditions: Gain (earn points for correct answers), Gain and Loss (earn points for correct answers and lose points for wrong answers) and Correct or Wrong (accuracy feedback only). We also manipulated difficulty and point value, with near boundary stimuli having the highest number of points to win or lose, and stimuli far from the boundary having the lowest point value. We found that the tail of the caudate was sensitive to feedback condition, with highest activity when both Gain and Loss feedback were present and least activity when only Gain or accuracy feedback was present. We also found that activity across the caudate was affected by distance from the decision bound, with greatest activity for the near boundary high value stimuli, and lowest for far low value stimuli. Overall these results indicate that the tail of the caudate is sensitive not only to positive rewards but also to loss and punishment, consistent with recent animal research finding tail of the caudate activity in aversive learning.

Functional magnetic resonance imaging study on activity intensity of reward brain areas under uncertain decision-making in patients with depression / 中华行为医学与脑科学杂志

Objective:To explore the brain activation intensity changes of depressed patients in the phase of expected value (EV), positive prediction error (+ PE) and negative prediction error (-PE) under uncertain (risky, ambiguous) decision-making.Methods:From July 2018 to February 2021, a total of 48 depressed patients in the Affiliated Hospital of Qingdao University were collected (depression group), and 69 sex-, age-, and educational level-matched healthy people were recruited as the control group. All participants completed risky and ambiguous decision-making tasks under the E-Prime system.SA-9800 brain functional audio-visual stimulation system and GE3.0 T functional magnetic resonance imaging (fMRI) scanners were used to conduct synchronous scanning and data acquisition. Using Xjview software to analyze the activation intensity of related brain areas to compare the activity intensity of the two groups.SPSS 16.0 software was used for chi square test, independent sample t-test. Results:Under risky decision-making, compared with the control group, the brain areas with reduced activation during EV phase in depression group were bilateral prefrontal cortex (PFC)(MNI coordinate: left x=-45, y=21, z=-6; right x=0, y=69, z=-3), left para hippocampal gyrus(PHG)(MNI coordinate: x=-9, y=0, z=-22), bilateral occipital lobe(OL)(MNI coordinate: left x=-51, y=-81, z=-3; right x=48, y=-84, z=-9)( P<0.05). The brain areas with reduced activation during + PE phase were bilateral PFC, left hippocampus (HIP), bilateral temporal lobe (TL), left middle occipital gyrus( P<0.05). The brain areas with reduced activation were bilateral PFC, right putamen, bilateral TL( P<0.05) during -PE phase. Under ambiguous decision-making, compared with the control group, the brain areas with reduced activation during EV phase in depression group were bilateral PFC, right OL( P<0.05); the brain areas with reduced activation during + PE phase were bilateral PFC, right putamen and hippocampus, bilateral TL, bilateral OL( P<0.05); and the brain areas with reduced activation were bilateral PFC, bilateral TL( P<0.05) during -PE phase. Conclusion:The study shows that the activities of reward brain areas such as PFC, limbic system and OL system are reduced during EV and PE phase under uncertain decision-making in depressed patients.

Social distance modulates the process of uncertain decision-making: evidence from event-related potentials.

PURPOSE: Social distance affects risk perception in uncertain decision-making, but how this effect works and the mechanism of how social distance influences the early processing stages of uncertain decision-making are still unclear. This investigation aimed to explore how social distance influences risk-taking during uncertain decision-making using the Iowa Gambling Task with recording of event-related potentials. METHODS: A total of 57 healthy subjects (36 female) participated in the modified single-choice Iowa Gambling Task when they gambled based on three quantified social distances (self, friend, and stranger). The social distance between participant and beneficiary was quantified on a scale of 0-100 points, with 0 representing self, 5 representing a close friend, and 100 representing a stranger. RESULTS: Three stages of uncertain decision-making were analyzed. Behavioral results showed that social distance worked interactively with choice frame, and high social distance made people choose a more advantageous deck and a less disadvantageous deck than low social distance. The P300 in the choice-evaluation stage, which reflects stimulus discrimination, directly proved this result by showing that gambling for a stranger caused higher P300 when evaluating an advantageous deck and lower P300 when evaluating a disadvantageous deck than for others. Decision preceding negativity in the response-selection stage represents the anticipation of risky choices: this was larger with high social distance when choosing a disadvantageous deck. Feedback-related negativity and feedback-related P300 had motivational significance, showing smaller amplitudes when gambling for a stranger than for oneself. CONCLUSION: These results provide evidence that social distance works interactively with choice frames of uncertain decision-making. People at high social distance are more risk-taking in an advantageous frame and more risk-avoid ant in a disadvantageous frame.

A normative inference approach for optimal sample sizes in decisions from experience.

"Decisions from experience" (DFE) refers to a body of work that emerged in research on behavioral decision making over the last decade. One of the major experimental paradigms employed to study experience-based choice is the "sampling paradigm," which serves as a model of decision making under limited knowledge about the statistical structure of the world. In this paradigm respondents are presented with two payoff distributions, which, in contrast to standard approaches in behavioral economics, are specified not in terms of explicit outcome-probability information, but by the opportunity to sample outcomes from each distribution without economic consequences. Participants are encouraged to explore the distributions until they feel confident enough to decide from which they would prefer to draw from in a final trial involving real monetary payoffs. One commonly employed measure to characterize the behavior of participants in the sampling paradigm is the sample size, that is, the number of outcome draws which participants choose to obtain from each distribution prior to terminating sampling. A natural question that arises in this context concerns the "optimal" sample size, which could be used as a normative benchmark to evaluate human sampling behavior in DFE. In this theoretical study, we relate the DFE sampling paradigm to the classical statistical decision theoretic literature and, under a probabilistic inference assumption, evaluate optimal sample sizes for DFE. In our treatment we go beyond analytically established results by showing how the classical statistical decision theoretic framework can be used to derive optimal sample sizes under arbitrary, but numerically evaluable, constraints. Finally, we critically evaluate the value of deriving optimal sample sizes under this framework as testable predictions for the experimental study of sampling behavior in DFE.

Effects of working memory load on uncertain decision-making: evidence from the Iowa Gambling Task.

The Iowa Gambling Task (IGT) simulates uncertain gains and losses in real life situations and thus is a good measure of uncertain decision-making. The role of working memory (WM) in IGT performance still remains unclear. The present study aimed to examine the effect of WM on IGT performance. Three groups of participants matched on gender ratio were randomly assigned to no WM load, low WM load, and high WM load conditions. Initially the three groups did not show significant difference in WM capacity. They finished a modified version of IGT and then their implicit learning effect and explicit cognition on IGT were assessed. Results indicated a linear increasing trend of IGT performance among high WM load, low WM load and no WM load groups; participants in the no WM load and low WM load groups revealed implicit learning effect, while participants in the high WM load group did not; all participants showed explicit cognition on IGT to the same level. These results suggested that participants in the high WM load group showed good explicit cognition to IGT but showed poor performance. This pattern is similar to frontal patients. Further studies should be conducted to explore this issue.

Neural correlates of uncertain decision making: ERP evidence from the Iowa Gambling Task.

In our daily life, it is very common to make decisions in uncertain situations. The Iowa Gambling Task (IGT) has been widely used in laboratory studies because of its good simulation of uncertainty in real life activities. The present study aimed to examine the neural correlates of uncertain decision making with the IGT. Twenty-six university students completed this study. An adapted IGT was administered to them, and the EEG data were recorded. The adapted IGT we used allowed us to analyze the choice evaluation, response selection, and feedback evaluation stages of uncertain decision making within the same paradigm. In the choice evaluation stage, the advantageous decks evoked larger P3 amplitude in the left hemisphere, while the disadvantageous decks evoked larger P3 in the right hemisphere. In the response selection stage, the response of "pass" (the card was not turned over; the participants neither won nor lost money) evoked larger negativity preceding the response compared to that of "play" (the card was turned over; the participant either won or lost money). In the feedback evaluation stage, feedback-related negativity (FRN) was only sensitive to the valence (win/loss) but not the magnitude (large/small) of the outcome, and P3 was sensitive to both the valence and the magnitude of the outcome. These results were consistent with the notion that a positive somatic state was represented in the left hemisphere and a negative somatic state was represented in the right hemisphere. There were also anticipatory ERP effects that guided the participants' responses and provided evidence for the somatic marker hypothesis with more precise timing.