A behavioral study on the impact of spatial frequency and age on cuteness perception

Cuteness acts as a key protective mechanism, enhancing the survival of fully dependent infants. Characteristic facial features trigger neural responses that promote caregiving behaviors. Therefore, understanding what kinds of facial features are perceived as 'cuteness' is of particular importance. This study investigates the role of spatial frequency (SF) in cuteness perception and examines whether this effect is influenced by age (young vs. old). We selected infant facial images and processed them into versions with different cuteness levels (by <i>baby schema</i>) and SF. Participants were invited to complete a two-alternative forced-choice task to measure their cuteness perception ability. They observed two infant faces for 2000 ms, then were asked to respond which face was cuter. The results revealed that broad SF faces were more effective for cuteness perception than filtered facial images. Additionally, young people demonstrated significantly higher cuteness perception ability compared to old people. Notably, young people showed a slightly higher accuracy for high SF images compared to low SF images, whereas no such difference was observed in old people. These findings suggest that cuteness perception relies on information from both low and high SF with the weighting of this information varying by age.