The Style of a Stranger: Identification Expertise Generalizes to Coarser Level Categories

Experience identifying visual objects and categories improves generalization within the same class (e.g., discriminating bird species improves transfer to new bird species), but does such perceptual expertise transfer to coarser category judgments? We tested whether fingerprint experts, who spend their days comparing pairs of prints and judging whether they were left by the same finger or two different fingers, can generalize their finger discrimination expertise to people more broadly. That is, can these experts identify prints from Jones's right thumb and prints from Jones's right index finger as instances of the same "Jones" category? Novices and experts were both sensitive to the style of a stranger's prints; despite lower levels of confidence, experts were significantly more sensitive to this style than novices. This expert advantage persisted even when we reduced the number of exemplars provided. Our results demonstrate that perceptual expertise can be flexible to upwards shifts in the level of specificity, suggesting a dynamic memory retrieval process.