Associative sequence learning

Associative sequence learning (ASL) is a <a href="/facts/Neuroscience/o5RV8Cas">neuroscientific</a> theory that attempts to explain how <a href="/facts/Mirror_neuron/xfbp6k0S">mirror neurons</a> are able to match observed and performed actions, and how individuals (adults, children, animals) are able to imitate body movements. The theory was proposed by Cecilia Heyes in 2000. (For reviews see). A conceptually similar model proposed by <a href="/facts/Christian_Keysers/4E3pDggf">Christian Keysers</a> and David Perrett, based on what we know about the neural properties of mirror neurons and <a href="/facts/Spike-timing-dependent_plasticity/pfCGUP9Q">spike-timing-dependent plasticity</a> is the <a href="/facts/Hebbian_theory/Mmtd6Dzt">Hebbian learning account of mirror neurons</a>.
Its central principle is that associations between sensory and motor representations are acquired <a href="/facts/Ontogeny/ckqaQlL7">ontogenetically</a> (i.e. acquired during development), as a result of correlated <a href="/facts/Theory_of_cognitive_development/2BfVnk1s">sensorimotor experience</a>. Consider the example of an actor clenching their fist. In this situation the activation of the motor representation (the motor plan to clench fist) is often paired with the corresponding perceptual representation (the sight of a closed fist). Heyes proposes that, over time, a bidirectional associative link is formed such that activation of one representation excites the other. Put simply, as a consequence of paired 'doing' and 'seeing' links are established which allow action observation to prime action execution.
In the above example, correlated sensorimotor experience is provided by self-observation. However, this cannot explain the development of sensorimotor associations for so-called 'perceptually opaque' actions. These are actions which cannot be observed by the actor, and include <a href="/facts/Facial_expression/polSzUsf">facial expressions</a>, and whole body actions (e.g. a <a href="/facts/Serve_(tennis)/xKS5b2N8">tennis serve</a>). Heyes proposes two other sources of sensorimotor experience to account for the emergence of associations for opaque actions; experience mediated by mirror reflections, and the experience of being imitated by others. When an actor smiles in the mirror, his reflection smiles back. Consequently, a motor representation ("smile") is paired with the corresponding sensory representation (the sight of a smiling face). Similarly, there is considerable evidence that parents imitate young infants. Thus when an infant 'stumbles across' the motor plan to frown, this may be paired with the sight of a parent's frowning face.
Other sources of correlated sensorimotor experience may also include synchronous action (in dance and sports contexts where actors are executing and observing similar actions) and acquired equivalence experience (where an action excites a visual representation, via a shared auditory representation).
A further defining characteristic of the ASL model is its claim that the development of sensorimotor links is mediated by the same mechanisms of <a href="/facts/Classical_conditioning/ddtohoz3">associative learning</a> that produce <a href="/facts/Classical_conditioning/ddtohoz3">Pavlovian conditioning</a>. Crucially, Heyes therefore proposes that the development of sensorimotor associations is not only sensitive to temporal contiguity (the extent to which activation of sensory and motor representations are close together in time) but also to contingency (the extent to which activation of one representation is predictive of the other). This is a crucial feature of the ASL model as it explains why actors do not acquire spurious sensorimotor associations. Consider the example of two interactants, one of whom is scratching his ear when his colleague sneezes. Learning-based models which do not stipulate a sensitivity to contingency predict that the motor plan for ear-scratching ought to become associated with the visual representation of sneezing! However, ASL predicts that no association will develop because the act of ear-scratching is not predictive of the sight of sneezing – in other words there is no sensorimotor contingency. The Hebbian learning account of the emergence of mirror neurons also emphasizes the importance of contingency, as it is known that the synaptic plasticity that underlies Hebbian learning is known to depend on contingency.

Associative sequence learning open-in-new

Associative sequence learning