Domestic dogs (Canis familiaris) recognise meaningful content in monotonous streams of read speech

Domestic dogs (Canis familiaris) can recognize basic phonemic information from human speech and respond to commands. Commands are typically presented in isolation with exaggerated prosody known as dog-directed speech (DDS) register. Here, we investigate whether dogs can spontaneously identify meaningful phonemic content in a stream of putatively irrelevant speech spoken in monotonous prosody, without congruent prosodic cues. To test this ability, dogs were played recordings of their owners reading a meaningless text in which we inserted a short meaningful or meaningless phrase, either read with unchanged reading prosody or with an exaggerated DDS prosody. We measured the occurrence and duration of dogs' gaze at their owners. We found that, while dogs were more likely to detect and respond to inserts that contained meaningful phrases spoken with DDS prosody, they were still able to detect these meaningful inserts spoken in a neutral reading prosody. Dogs detected and responded to meaningless control phrases in DDS as frequently as to meaningful content in neutral reading prosody, but less often than to meaningful content in DDS. This suggests that, while DDS prosody facilitates the detection of meaningful content in human speech by capturing dogs' attention, dogs are nevertheless capable of spontaneously recognizing meaningful phonemic content within an unexaggerated stream of speech.