The pool is getting bigger: “A California Sea Lion (Zalophus californianus) can keep the beat: motor entrainment to rhythmic auditory stimuli in a non vocal mimic”

J Comp Psychol 2013 Apr 1
A California Sea Lion (Zalophus californianus) can keep the beat: motor entrainment to rhythmic auditory stimuli in a non vocal mimic

Cook P, Rouse A, Wilson M, Reichmuth C
University of California Santa Cruz, USA

Is the ability to entrain motor activity to a rhythmic auditory stimulus, that is “keep a beat,” dependent on neural adaptations supporting vocal mimicry? That is the premise of the vocal learning and synchronization hypothesis, recently advanced to explain the basis of this behavior (A. Patel, 2006, Musical Rhythm, Linguistic Rhythm, and Human Evolution, Music Perception, 24, 99-104). Prior to the current study, only vocal mimics, including humans, cockatoos, and budgerigars, have been shown to be capable of motoric entrainment. Here we demonstrate that a less vocally flexible animal, a California sea lion (Zalophus californianus), can learn to entrain head bobbing to an auditory rhythm meeting three criteria: a behavioral response that does not reproduce the stimulus; performance transfer to a range of novel tempos; and entrainment to complex, musical stimuli. These findings show that the capacity for entrainment of movement to rhythmic sounds does not depend on a capacity for vocal mimicry, and may be more widespread in the animal kingdom than previously hypothesized. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

One thought on “The pool is getting bigger: “A California Sea Lion (Zalophus californianus) can keep the beat: motor entrainment to rhythmic auditory stimuli in a non vocal mimic”

  1. This study seems to clearly support the hypothesis that the ability to entrain in animals is not dependent on mechanisms supporting vocal mimicry. Of course, this hypothesis of Cook et al. assumes that sea lions do not demonstrate vocal mimicry, and these authors acknowledge that their arguments rest on that assumption. This point seems crucial in that there may not exist sufficient research to either support or disprove the idea that under appropriate conditions and with effective training, sea lions may have some vocal mimicry capacity. However, I would agree that the law of parsimony that does not require invoking neural innervations for vocal mimicry to explain entrainment behavior remains on the side of the authors. Likewise, it seems to make greater intuitive sense to suggest that a process as complex as flexible entrainment including the capability of transfering such entrainment is more related to neural mechanisms such as timing than to mere vocal mimicry. In addition, the authors argue that the capacity for entrainment may be greater in the animal kingdom than was previously thought. Again, this suggestion not only makes intuitive sense but is consistent with the observation that even frogs and insects demonstrate “constrained entrainment” behaviors. One might expect a continuum of entrainment capabilities and complexities from more primitive forms to the most advanced seen in humans.

    Although this article fails to support the hypothesis that entrainment in animals is completely dependent on vocal mimicry, the study does not address the question of whether such vocal mechanisms may play some role in entrainment. For example, vocal mimicry may allow for easier or more rapid learning of entrainment behavior, or such vocal mimicry may facilitate some kinds of advanced entrainment found more exclusively in humans. Other kinds of research would be needed to address this question. In this regard, one might evaluate the capabilities for entrainment in humans with vocal impairments to shed light on the more precise relationships, if any, between such vocal mechanisms and capacity to entrain. On the other hand, the study of people with various neural deficits and their capacity to entrain might illuminate the role of such neural timing factors in entrainment alluded to by the authors. Finally, regarding further research, it goes without saying that studying the entrainment behavior of other sea lions would be fruitful. With respect to the level of entrainment demonstrated, Ronan may place at the top of the class or may simply represent what nearly all sea lions can do with training.

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