What does that head-tilt mean? Brain Lateralization and Sex Differences in the Processing of Familiar Human Speech by Domestic Dogs

Abstract

Abstract Does the head-tilt observed in many domesticated dogs index lateralized language processing? To answer this question, the present study had dogs participate in four conditions in which owners provided an increasing amount of communicative cues. These ranged from no communicative/affective cues to rich affective cues coupled with dog-directed speech. In a sample of 103 dogs representing seven breed groups and mixed-breed dogs, we found significant differences in the number of head-tilts occurring between conditions, with the most communicative (last) condition eliciting the most head-tilts. There were also significant differences in the direction of the head-tilts and between sex groups. Dogs were more likely to tilt their heads to the right, and neutered male dogs were more likely to tilt their heads than spayed females. The right-tilt bias is consistent with left-hemisphere language processing, with males processing language in a more lateralized manner, and females processing language more bilaterally— a pattern also observed in humans.