Neurocomputational Dynamics of Cooperation

Participant-level Coaxing Score

Participant coaxing behavior will be measured during the primary social learning task. Coaxing will be operationalized as the difference in the participant's return rate between exchange and secrecy modes on trials in which the coplayer decides not to share. In exchange mode, the participant knows whether the coplayer chose to share or keep the monetary incentive before indicating whether they would return it. In secrecy mode, the participant must make the return decision before learning the coplayer's choice. The coaxing score is calculated as the exchange-mode return rate minus the secrecy-mode return rate. Scores range from -1 to 1, with positive values indicating greater strategic coaxing and 0 indicating no difference between modes.

Mean Informant-rated Momentary Manipulativeness

Manipulativeness will be assessed using the study-specific Interpersonal Dynamics EMA Battery. The informant-rated manipulativeness scale contains 3 items, each rated from 1 ("strongly disagree") to 5 ("strongly agree"). At each assessment, responses to the 3 items will be averaged to produce a momentary manipulativeness score that ranges from 1 to 5. Higher scores indicate greater informant-rated manipulativeness.

Latent Mentalizing Factor

A latent mentalizing factor will be derived using CFA, with participants' scores on three social cognition tasks serving as indicators. The latent factor will be standardized to a mean of 0 and standard deviation of 1 in the study sample and therefore has no fixed theoretical minimum or maximum. Higher factor scores indicate greater mentalizing ability.

Interpersonal Stress

Interpersonal stress will be assessed using the marital- or partner-relationship and other-relationship life domains of the Stress and Adversity Inventory for Adults. At each follow-up, the frequency scores for stressors in these two domains will be averaged to produce an interpersonal stress score. The score ranges from a minimum of 0 stressors, with no limit on reported stressor maximums. Higher scores indicate more frequent exposure to interpersonal relationship stressors.