 There are also biases in how subjects evaluate in-groups or out-groups; evaluating in-groups as more diverse and "better" in many respects, even when those groups are arbitrarily defined (ingroup bias, outgroup homogeneity bias).Some cognitive biases belong to the subgroup of attentional biases, which refers to paying increased attention to certain stimuli.It has been shown, for example, that people addicted to alcohol and other drugs pay more attention to drug-related stimuli.