We also examined the number

The pseudo category discrimination group was also divided into two subgroups. Each subgroup discriminated 16 randomly selected rewarded songs (eight male songs, eight female songs) from 16 unrewarded songs (eight male songs, eight female songs; subgroup 1: one male, two female subjects; subgroup 2: one male, one female subject).
This phase was identical to discrimination training, except that rewarded songs were reinforced with a reduced probability (i.e.