Introverts May Feel Anxious in Groups, but Probably Not Because They Overestimate Group Sizes

We examined whether higher levels of arousal (introversion or caffeine) cause individuals to overestimate the number of people within a group. Participants consumed caffeinated or decaffeinated coffee and estimated numbers of faces differing in emotionality. Larger sets were increasingly underestimated, but there were no significant interactions between personality and caffeine.