Is it a judgment of representativeness? Re-examining the birth sequence problem

Although all birth orders in the “birth sequence problem” are equiprobable, most participants judge the less representative order as less likely than the more representative order. But this well-known problem confounds representativeness with the direction in which birth orders are compared. We hypothesized and corroborated in three experiments (total N = 1,136) that participants pragmatically infer the birth orders’ relative prevalence from the direction of comparison. Experiment 1 found that participants judged the less representative sequence as more common when we reversed the comparison. Experiment 2 reproduced these results despite removing representativeness as a cue. In Experiment 3, participants preferred to place the relatively common sequence as the referent in an inverted “speaker” problem. Our results turn the iconic problem’s interpretation on its head: Rather than indicating flawed human cognition, the birth sequence problem illustrates people’s ability to adaptively extract subtle linguistic meaning beyond the literal content.