Rhythmic abilities in humans and non-human animals: a review and recommendations from a methodological perspective

Abstract

Rhythmic behaviour is ubiquitous in both human and non-human animals, but it is unclear whether the cognitive mechanisms underlying the specific rhythmic behaviours observed in different species are related. Laboratory experiments combined with highly controlled stimuli and tasks can be very effective in probing the cognitive architecture underlying rhythmic abilities. Rhythmic abilities have been examined in the laboratory with explicit and implicit perception tasks, and with production tasks, such as sensorimotor synchronization, with stimuli ranging from isochronous sequences of artificial sounds to human music. Here, we provide an overview of experimental findings on rhythmic abilities in human and non-human animals, while critically considering the wide variety of paradigms used. We identify several gaps in what is known about rhythmic abilities. Many bird species have been tested on rhythm perception, but research on rhythm production abilities in the same birds is lacking. By contrast, research in mammals has primarily focused on rhythm production rather than perception. Many experiments also do not differentiate between possible components of rhythmic abilities, such as processing of single temporal intervals, rhythmic patterns, a regular beat or hierarchical metrical structures. For future research, we suggest a careful choice of paradigm to aid cross-species comparisons, and a critical consideration of the multifaceted abilities that underlie rhythmic behaviour. This article is part of the theme issue 'Synchrony and rhythm interaction: from the brain to behavioural ecology'.

Keywords: beat; cross-species; music; non-human animals; rhythm; temporal processing.

Figure 1.

Structure in rhythm. Colouring of events (black and white) indicates the perceived salience when a beat (dotted line) is present or when a hierarchical metrical structure (dotted tree structure) creates more and less salient beats (grey shades: darker indicates more salient, with black being the most salient beats, and white subdivisions of the beat).

Figure 2.

Rhythm perception tasks. (a) In implicit tasks, participants perform a task unrelated to the rhythm, such as detecting intensity changes. Performance is associated with the rhythmic structure, with better performance in more salient metrical positions. (b) In explicit tasks, participants may, for example, discriminate between different categories of rhythms (I and II), or may judge whether two rhythmic patterns are the same (III) or different (IV). (c) Variants of perceptual tasks have been done both in humans and non-human animals. For example, frogs' mating preferences, measured as approach to a stimulus, can be used as a proxy for discrimination performance, and birds can be trained in 2AFC tasks.

Figure 3.

Rhythm production tasks. (a) SMS involves synchronizing movement to a rhythm, and varies from 1 : 1 synchronization to an isochronous sequence (I), to tapping the beat to a non-isochronous pattern (II) and tapping the pattern itself (III). In unpaced tasks, tapping is continued after the input ceases. (b) Different movements can be used in SMS, such as finger taps in primates and humans, head bobs in sea lion and parrots, and chirps in katydids.