Final answer:
Group members with low self-esteem are more likely to exhibit bias against an outgroup when their group identity is threatened, as a means to protect and enhance their self-image.
Step-by-step explanation:
According to social identity theory, group members with low self-esteem will most likely respond to a threat to their group identity by engaging in bias against the outgroup. This is because these individuals may feel a pressing need to bolster their self-worth through in-group favoritism, which often translates into biased behavior toward the outgroup.
High self-esteem members might not display the same level of bias since their sense of self-worth is less contingent on group identity.