RESUMEN
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.
RESUMEN
BACKGROUND: There are case descriptions of pronounced peri-implant inflammatory reactions and necrosis in non-infectious knee joint replacements with metal-polyethylene pairing. OBJECTIVES: Due to the histopathological similarities to the dysfunctional metal-on-metal (MoM) hip joint replacement, MoM-like reactions in knee joint arthroplasty ("ARMD-KEP") are proposed and a histopathological comparison is made. MATERIALS AND METHODS: This analysis evaluates five cases of "ARMD-KEP" using: (1) the SLIM consensus classification, (2) the particle algorithm, (3) the CD3 focus score and (4) the AVAL score. The comparison groups consist of 11 adverse cases of MoM hip and 20 cases of knee joint arthroplasty without adverse reaction. RESULTS: The ARMD-KEP cases were identified as SLIM type VI. Their median ALVAL score was 10. The CD3 focus score confirmed an adverse reaction. Particle corrosion was found in two of five cases. CONCLUSIONS: This data indicates that, in rare cases, an adverse MoM-like reaction may be present in knee replacements, with inflammatory and immunological expression similar to that of the adverse MoM reaction in the hip. The pathomechanisms can be discussed as follows: (1) secondary metal-metal contact, (2) dysfunctional loading of the coupling mechanism and (3) corrosion of the metal components. Much like trunnionosis in the hip, the term "hingiosis" is proposed for corrosion phenomena in dysfunctional conditions of coupled knee endoprosthetic systems.
