“…Two competing hypotheses, the Mere Preferences Hypothesis and the Norms Focused Hypothesis (McAuliffe and Dunham, 2016;Zhang et al, 2020), were developed to explain the contradictory results. The Mere Preferences Hypothesis suggests that individuals' positive evaluation toward the ingroup would reduce TPP for ingroup perpetrators, supported by the majority of evidence based on adults (Yudkin et al, 2016;McAuliffe et al, 2017;Guo et al, 2020Guo et al, , 2022Yang et al, 2023) and children (Jordan et al, 2014), which supports the ingroup favoritism phenomenon (IGF). The Norms Focused Hypothesis emphasizes that individuals' concern for maintaining norms of group cooperation would enhance TPP for ingroup violators, as demonstrated by some evidence based on adults (Mendoza et al, 2014;Delton and Krasnow, 2017) and children (Gonzalez-Gadea et al, 2022), known as the black sheep effect (BSE).…”