More than just a word: non-semantic command variables affect obedience in the domestic dog (Canis familiaris)

Dogs were initially trained to respond reliably to 'sit' and 'come' commands, when these were issued randomly in a variety of contexts. Then in a first experiment, the posture of the person giving the command, eye contact and the mode of delivery of the command were varied. Performance declined significantly when a tape-recorded version of the command was used and when the eyes of the experimental trainer were obscured with sunglasses when using the tape, but not when the sunglasses were used with the oral command. In a second experiment, the distance and position of the experimental trainer relative to an opaque screen were changed. Performance declined when the experimental trainer stood approximately 2.5 m away and was partially obscured by a screen. Response to the sit but not come command declined when the experimental trainer turned her back on the dog prior to issuing the command at this distance, but not when the experimental trainer subsequently stood behind the screen at this distance. The results suggest that non-verbal features moderate responsiveness to the command, and that this effect may depend partly on the dog's familiarity with the command possibly within a given context and the perceived proximity of the commander from the dog.