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.