Perception of place‐of‐articulation information by monkeys versus humans

Abstract

Four monkeys and six humans representing five different native languages were compared in the ability to categorize natural CV tokens of /b/ vs /d/ produced by four talkers of American‐English (two male; two female) in four vowel contexts /i,e,a,u/. A two‐choice left/right procedure was used in which percent correct and response time data were compared between species. Both measures indicated striking vowel context effects for monkeys, but none for humans. Specifically, monkeys performed better for back vowels /a,u/ than front vowels /i,e/. Since back vowels have more distinctive F2 onset transitions differentiating /b/ vs /d/, these results imply that monkey perception is more dependent than human perception on the actual acoustic structure of the syllables. We conclude that humans do not use general mechanisms in place perception, rather they use some sort of special mechanism to eliminate vowel context effects. While monkeys do not provide accurate models of adult humans, they may be able to provide a model of the preverbal human infant before it learns a more speech‐specific adult strategy of place information extraction. [Work supported by NIH.]