Aging is associated with maladaptive episodic memory-guided social decision-making

Abstract

Older adults are frequent targets and victims of financial fraud. They may be especially susceptible to revictimization because of age-related changes in both episodic memory and social motivation. Here we examined these factors in a context where adaptive social decision-making requires intact associative memory for previous social interactions. Older adults made more maladaptive episodic memory-guided social decisions but not only because of poorer associative memory. Older adults were biased toward remembering people as being fair, while young adults were biased toward remembering people as being unfair. Holding memory constant, older adults engaged more with people that were familiar (regardless of the nature of the previous interaction), whereas young adults were prone to avoiding others that they remembered as being unfair. Finally, older adults were more influenced by facial appearances, choosing to interact with social partners that looked more generous, even though those perceptions were inconsistent with prior experience.

Keywords: aging; decision-making; episodic memory; social; trust.

Fig. 1.

Task layout. The reward task involved learning about 32 faces and 32 houses in blocks (counterbalanced order), with half of the faces and houses resulting in $5 rewards (high-value stimuli) and half resulting in $0 (low-value stimuli). Then, after a 5-min anagrams task (included to create a delay between study and test), participants saw 96 decision trials in the decision task, with face trials and house trials intermixed. All stimuli from the reward task were shown again, along with 32 novel stimuli (16 faces and 16 houses). In face trials, participants had 5 s to decide if they wanted to interact with the face again, knowing they would have to accept the offer proposed by the person pictured. In house trials, subjects decided whether they wanted to play the lottery associated with the house again. Then a bracket appeared for 1 s around the option that they chose. Finally, in the self-paced memory task, participants saw intermixed face and house trials, in which they judged whether they had seen the stimuli before on a scale from definitely old (1) to definitely new (5). If they selected 1, 2, or 3, they then saw three additional questions probing the value of the stimulus, the confidence in that value, and whether they remembered playing with that stimulus in the decision phase. All stimuli from the reward task were shown in the memory task, along with 32 novel stimuli. See Materials and Methods for full details.

Fig. 2.

Relationships between associative memory measures and age for (A and B) face stimuli and (C and D) house stimuli. Age was negatively associated with associative memory performance, such that older adults were less accurate in remembering whether stimuli were high value (worth $5) or low value (worth $0). Age was also negatively associated with response bias in the social domain, such that older adults were more likely to report that the people they had learned about shared $5, while young adults were more likely to report that people shared $0. Dotted lines are linear best fit lines. **P < 0.01, ***P < 0.001.

Fig. 3.

Adaptive decision-making depends on associative memory. When participants (n = 165 with full data in each bin) had intact item memory but were guessing about the value of the stimulus, there was no difference in their decision-making about stimuli that were actually worth $5 or $0. When they were confident and correct about the associated values, they made adaptive choices, significantly approaching high-value stimuli and avoiding low-value stimuli. They made maladaptive choices when they were confident and incorrect about the associated values (item hits only pictured, data collapsed across social and nonsocial trials, dotted line indicates chance levels of choosing stimulus over schematic image). Estimated marginal means are plotted, and error bars represent SE. ***p < 0.001; n.s. = p > 0.05.

Fig. 4.

Aging is associated with less adaptive episodic memory-based decision-making in both the social (A) and nonsocial (B) domains. A correct or adaptive choice is one in which participants approached a high-value ($5) stimulus or avoided a low-value ($0) stimulus. The proportion is out of all trials that featured previously seen stimuli (from the reward task). When separating adaptive decisions into two subtypes—approaching high-value stimuli (C and D) and avoiding low-value stimuli (E and F)—age was positively associated with successfully approaching high-value stimuli in the social domain (C) but negatively associated with adaptive approach behavior in the nonsocial domain (D). Age was negatively associated with adaptive avoidance behavior in both the social (E) and nonsocial domains (F), although the effect is stronger for social stimuli. The dashed line corresponds to chance level (0.5), and the solid lines are linear best-fit lines. ***P < 0.001, *P < 0.05.

Fig. 5.

(A) Young (n = 71), but not (B) middle-aged (n = 62) or (C) older (n = 43), adults are biased toward avoiding low-value social stimuli more than nonsocial stimuli. When examining only trials that were confidently endorsed as being worth $5 or $0 (regardless of associative memory accuracy), participants were more likely to approach stimuli remembered as high value and avoid stimuli remembered as low value. Estimated marginal means are plotted, and error bars represent SE. (D) The tendency to approach faces that were remembered as being unfair was associated with age. This was driven by young adults being especially prone to avoiding faces they remembered as being unfair, while older adults chose to interact with faces more, even if the retrieved value was low. (E) This association with age did not extend to nonsocial stimuli. ***P < 0.001.

Fig. 6.

Age is associated with a reliance on perceived generosity of the face stimulus (based on facial appearance alone) in decision-making. In a mixed-effects logistic regression predicting whether the participant chose to interact with a previously seen face in the decision phase, independent ratings of perceived generosity of that face predicted participants’ choices to interact with those faces. The effects of value (i.e., whether that face gave $5 or $0 in the reward phase) and associative memory (i.e., whether the value of the face was accurately remembered), as well as the interaction between value and associative memory, were controlled for in the regression. Older adults relied on perceived generosity more in their decisions: the random slope for the effect of perceived generosity on choice was estimated separately for each subject, and this slope was positively associated with age. In the scatterplot, the y axis shows the sum of the overall fixed effect and subject-specific random effect of perceived generosity on choice. Although only perceived generosity is depicted here, other facial appearance ratings (warmth, trustworthiness, competence, and attractiveness) were also predictive of choice, and their influence on choice was also associated with age (Table 2).