Differences in biological motion perception associated with hearing status and age of signed language exposure

This study investigates how American Sign Language (ASL) fluency and hearing status influence the perception of biological motion, using three point-light display (PLD) tasks. Prior research indicates that early exposure to ASL among deaf signers results in more rapid and effortless recognition of biological motion than hearing nonsigners, potentially due to the expertise in deciphering complex human movements or possibly due to neuroplasticity in deaf brains. However, it remains uncertain whether this advantage stems from signed language proficiency or the experience of being deaf. To explore this, we designed three PLD tasks involving viewing randomly moving dots, identifying a person from biological motion PLDs, and determining whether right-side up and inverted PLDs depict actions involving a ball. A diverse cohort of participants (N = 224) with varying ASL fluencies and hearing statuses completed the tasks online, providing us with reaction time and accuracy data. Our results demonstrate that earlier ASL exposure is associated with accuracy, especially on complex action identification tasks. Furthermore, we discovered robust evidence for a speed-accuracy trade-off in deaf participants, in which they performed more quickly but less accurately. The speed-accuracy trade-off was evident in the most difficult task, the action identification task. Further analysis of this deaf group revealed that earlier signed language acquisition led to higher accuracy in action identification task. We conclude that age of ASL exposure and hearing status both significantly contribute to variations in biological motion perception, with implications for understanding visual expertise and cognitive processing in both deaf and signing populations. (PsycInfo Database Record (c) 2024 APA, all rights reserved).