Chasing sounds

Prior work with Wright and others demonstrated that rhesus monkeys recognized the relative relationships of notes in common melodies. As an extension of tests of pattern similarities, tamarins were habituated to 3-sound unit patterns in an AAB or ABB form that were human phonemes, piano notes, or monkey calls. The subjects were tested with novel sounds in each category constructed either to match the prior pattern or to violate the prior habituated pattern. The monkeys attended significantly more to a violation of their habituated pattern to a new pattern when human phonemes were used, and there was a trend difference in attention toward pattern violations with melodies. Monkey call patterns generated a variety of behavioral responses, were less likely to show habituation, and did not generate a strong attention reaction to changes in the patterns. Monkeys can extract abstract rules and patterns from auditory stimuli but the stimuli, by their nature, may generate competing responses which block processing of abstract regularities.

► Tamarins were presented regular patterns of 3-sound sequences. ► When the pattern made of phonemes was violated, tamarins attended more. ► There was not a significant effect to changes in the patterns of melodies or monkey calls. ► Tamarins reacted overtly to individual monkey calls by barking or hooting back. ► Monkeys can extract rule-based patterns from auditory sequences of certain types.