The Effect of Ingroup vs. Outgroup Members' Behavior on Charity Preference: A Drift-Diffusion Model Approach

Abstract

Providing potential donors with information about the behavior of others (i.e., social information) is an increasingly used strategy to nudge prosocial decision-making. In the present study, we investigated the effect of ingroup vs. outgroup information on participants' charity preferences by applying a Drift Diffusion Model (DDM) approach. In a joint evaluation scenario, we manipulated different levels of ingroup/outgroup preference ratios for two charities within subjects. Every subject was presented with three stimulus types (i.e., high, medium, and low ingroup ratio) randomized in 294 trials divided into six blocks. We expected that for stimuli with a high ingroup/outgroup ratio, participants should more often and faster decide for the ingroup's most favored charity. We expected that the speed of evidence accumulation will be higher the larger the ingroup/outgroup ratio. Additionally, we investigated whether variations in model parameters can explain individual differences in participants' behaviors. Our results showed that people generally followed ingroup members' preferences when deciding for a charity. However, on finding an unexpected pattern in our results, we conducted post-hoc analyses which revealed two different behavioral strategies used by participants. Based on participants' decisions, we classified them into “equality driven” individuals who preferred stimuli with the least difference between ingroup and outgroup percentages or “ingroup driven” individuals who favored stimuli with the highest ingroup/outgroup ratio. Results are discussed in line with relevant literature, and implications for practitioners are given.

A novel electroencephalography-based paradigm to measure intergroup prosociality: An intergenerational study in the aftermath of the genocide against Tutsis in Rwanda.

“…They exhibited a higher intention for prosocial behavior toward members of their own in-group compared to members of the out-group. This finding aligns with previous research demonstrating in-group preference for prosociality (Hein et al, 2010; Rahal et al, 2020; Reich et al, 2022). It also suggests that intergroup prosociality biases can persist for decades after a genocide, even in a country that emphasizes reconciliation and peace among its citizens (Buckley-zistel, 2006), as shown in a previous study (Mironova & Whitt, 2016).…”

A novel EEG-based paradigm to measure intergroup prosociality. An intergenerational study in the aftermath of the genocide in Rwanda

“…We observed that participants from the group composed of survivors and their children displayed an intergroup prosociality bias, with an increased intended prosociality towards the member of their own ingroup compared to members of the outgroup. This is consistent with past literature showing an ingroup preference for prosociality (Hein et al, 2010;Rahal et al, 2020;Reich et al, 2022). It also indicates that, similar to a previous study (Mironova & Whitt, 2016), prosociality intergroup biases can remain decades after the conflict, even in a country emphasizing reconciliation and peace between its citizens (Buckley-zistel, 2006).…”