Cumulative lifetime stressor exposure assessed by the STRAIN predicts economic ambiguity aversion

Abstract

Uncertainty is inherent in most decisions humans make. Economists distinguish between two types of decision-making under non-certain conditions: those involving risk (i.e., known outcome probabilities) and those that involve ambiguity (i.e., unknown outcome probabilities). Prior research has identified individual differences that explain risk preferences, but little is known about factors associated with ambiguity aversion. Here, we hypothesized that cumulative exposure to major psychosocial stressors over the lifespan might be one factor that predicts individuals' ambiguity aversion. Across two studies (Study 1: n = 58, M_age = 25.7; Study 2: n = 188, M_age = 39.81), we used a comprehensive lifetime stressor exposure inventory (i.e., the Stress and Adversity Inventory for Adults, or STRAIN) and a standard economic approach to quantify risk and ambiguity preferences. Greater lifetime stressor exposure as measured by the STRAIN, particularly in early life, was associated with higher aversion to ambiguity but not risk preferences.

Fig. 1. Task design.

a All risky (top) and ambiguous (bottom) lottery bags used in the experiment. b Example trial sequence. Here, the participant chose between receiving $5 for sure or a lottery with a 25% chance of winning $20 and a 75% of winning $0.

Fig. 2. Lottery Choice Results (Study 1).

Participants (n = 58) demonstrated risk (left, blue) and ambiguity aversion (left, red), even when accounting for risk (left, red/white diagonal). Further, participants chose the lottery option more as the probability of winning increased (blue, right) and less as the proportion of ambiguity increased (red, right). Overall, ambiguity was perceived as more aversive than risk. Errors bars indicate SE.

Fig. 3. Effect of lifetime stressor exposure on estimates of risk and ambiguity tolerance (Study 1).

Scatterplots depicting participants’ proportion of risky lottery choices (blue) plotted separately for total lifetime stressor a count and b severity, and proportion of ambiguous lottery choices (red) plotted separately for total lifetime stressor c count and d severity. A significant negative association emerged between both STRAIN indices and ambiguous lottery choices, indicating that greater lifetime stressor exposure was associated with less tolerance for ambiguity, while no such association was observed for risky lottery choices. Scatterplots depict non-parametric correlations (Spearman’s rho).

Fig. 4. Multiple regression results for ambiguous lottery choice, lifetime stressor exposure, age, and gender (Study 1).

Bars depicting B coefficients for proportion of (risk-corrected) ambiguous lottery choices controlling for age and gender. Lifetime stressor count and severity, but not age or gender, were significant predictors of ambiguous choice behavior. Data shown in bars are expressed as means; errors bars indicate SE. (N = 58).

Fig. 5. Stressor-specific effects on ambiguous lottery choice (Study 1).

Standardized beta coefficients derived from linear regressions depicting the relation between lifetime stressor count and proportion of (risk-corrected) ambiguous lottery choices controlling for age and gender. Stressors on the y-axis are categorized by stressor timing (early life vs. adulthood), type (acute vs. chronic), primary life domain, and core social-psychosocial characteristic. Acute stressors (p = 0.024) and those experienced in early life (p = 0.021) were both predictive of ambiguous choice behavior, especially those marked by Interpersonal Loss (p = 0.032) or Role Change/Disruption (p = 0.023). Errors bars indicate 95% CI. Tests are uncorrected for multiple comparisons. *p < .05, ^†p < .10. (N = 58).