Age-group differences in trust-related decision-making and learning

Abstract

Facial impressions contribute to evaluations of trustworthiness. Older adults are especially vulnerable to trust violations, incurring risks for deception and exploitation. Using the newly developed social Iowa Gambling Task (S-IGT), we examined age-group differences in the impact of facial trustworthiness on decision-making and learning. In the congruent condition (CS-IGT), advantageous decks were paired with trustworthy faces and disadvantageous decks with untrustworthy faces. In the incongruent condition (IS-IGT), this pairing was reversed. Younger (n = 143) and older (n = 129) participants completed either the standard Iowa Gambling Task (IGT), CS-IGT, or IS-IGT. Both age groups preferred trustworthy faces in their initial choices. Older adults performed worse than younger adults across all tasks over time. Further, compared to younger adults, older adults performed worse on the IS-IGT, suggesting that incongruent facial cues interfered with older adults' performance, which aligns with reduced sensitivity to negative social reputations in aging. Multilevel modeling also indicated that age-group differences were most pronounced across all tasks in the last 40 trials. Together these findings suggest that differences between younger and older adults in experience-dependent decision-making are magnified in social contexts that involve a "wolf in sheep's clothing," which may reflect age-related difficulties in integrating incongruent information.

Figure 1

Task conditions and design features. There were three task conditions: Standard Iowa Gambling Task (IGT), Congruent Social Iowa Gambling Task (CS-IGT), and Incongruent Social Iowa Gambling Task (IS-IGT). In the CS-IGT, advantageous decks were paired with naturalistic photographs of trustworthy faces (placeholder depicted in green) and disadvantageous decks with untrustworthy faces (placeholder depicted in red). These photographs (not pictured here) were from the FACES database. In the IS-IGT, this pairing was reversed. In each task condition, participants started with 2000 points and drew a total of 100 cards from 4 decks. For every card drawn, participants received feedback on how many points they won (i.e., + 50 points for an advantageous deck draw (C or D) and + 100 points for a disadvantageous deck draw (A or B)). Occasionally (i.e., approximately every 10 cards), participants also received feedback of a penalty loss of points (i.e., between − 25 and − 250 points for advantageous deck draws and between − 150 and − 1250 points for disadvantageous deck draws). Performance was calculated as the total number of draws from advantageous decks minus the total number of draws from disadvantageous decks with larger, positive performance scores indicating better decision-making and smaller, negative performance scores indicating poorer decision-making. Only performance from the first four of the five blocks was examined due to task design, in which participants drew from non-replenishing card decks and due to a few participants running out of cards by the end of the fourth block (see Supplementary Information).

Figure 2

Task performance for (A) younger and (B) older adults in the standard Iowa Gambling Task (IGT; dotted red line), congruent social Iowa Gambling Task (CS-IGT; solid blue line), and incongruent social Iowa Gambling Task (IS-IGT; dashed green line). The x-axis indicates 4 blocks of 20 card draws each. The y-axis indicates performance score as the number of draws from advantageous decks minus the total number of draws from disadvantageous decks. Lines depict raw means and error bars depict 95% confidence intervals.