Exploring Burst Pulses as Indicators of Positive Affect in Bottlenose Dolphins (Tursiops truncatus) During Match-to-Sample Trials

The bottlenose dolphin (Tursiops truncatus) vocalizations called “burst pulses” exhibit distinct acoustic properties and can potentially be linked to affective states. This study aimed to determine if dolphins produce burst pulses during match-to-sample with both successful and unsuccessful outcomes and to explore any association with positive affect. We observed that burst pulses occurred in 74% of match-to-sample trials (in which the subject views a sample object and selects the match from a group of alternative objects), with a significantly higher frequency during correct responses. Additionally, there was a notable difference in the proportion of burst pulses occurring before versus after the trainer’s bridge, with more burst pulses occurring before the trainer’s bridge. The timing and characteristics of these burst pulses suggest they may be related to the dolphins’ interest and excitement rather than merely a response to reinforcement. These findings provide new insights into the complexity of dolphin vocalizations and their potential connection to affective states.