Time course analyses confirm independence of imitative and spatial compatibility.

Abstract

Imitative compatibility, or automatic imitation, has been used as a measure of imitative performance and as a behavioral index of the functioning of the human mirror system (e.g., Brass, Bekkering, Wohlschlager, & Prinz, 2000; Heyes, Bird, Johnson, & Haggard, 2005; Kilner, Paulignan, & Blakemore, 2003). However, the use of imitative compatibility as a measure of imitation has been criticized on the grounds that imitative compatibility has been confounded with simple spatial compatibility (Aicken, Wilson, Williams, & Mon-Williams, 2007; Bertenthal, Longo, & Kosobud, 2006; Jansson, Wilson, Williams, & Mon-Williams, 2007). Two experiments are reported in which, in contrast with previous studies, imitative compatibility was measured on both spatially compatible and spatially incompatible trials, and imitative compatibility was shown to be present regardless of spatial compatibility. Additional features of the experiments allowed measurement of the time courses of the imitative and spatial compatibility effects both within and across trials. It was found that imitative compatibility follows a different time course from spatial compatibility, providing further evidence for their independence and supporting the use of imitative compatibility as a measure of imitation

Associative (not Hebbian) learning and the mirror neuron system

“…The simulation results demonstrate firstly that the sensorimotor compatibility effects such as those found by Heyes et al [19], Cook et al [7] and Catmur and Heyes [3] can be accounted for in terms of weighted associations between sensory and motor units. The work therefore provides additional support for the model underlying the previous simulation of Cooper et al [8].…”

“…However, these apparently good fits are in some ways misleading. Figure 3 shows the compatibility effects obtained using each of the parameter settings from Table 1 is also not a major concern -this may be addressed by assuming that the strength of the imperative stimulus (the numerals 1 or 2) is slightly greater in this study than in the study of Catmur and Heyes [3] (an orange or purple dot), on which the earlier model (and the strength of imperative to motor associations) was based.…”

“…2 Full details of all model parameters are given in the supplementary materials. The complete model, which is written in the C programming language, is available for download from http://www.ccnl.bbk.ac.uk/models.html 3 Thus, if w ij (t) is the weight of the association to node j from node i at time t, then for each learning trial w ij (t+1) = w ij (t) + λ.∆w ji 4 The one parameter that was not held at its value from previous work was the habituation threshold of sensory nodes. In the previously reported work, sensory nodes were assumed to habituate to an input and decay once their activation exceeded a value of 0.80.…”

Interference of action perception on action production increases across the adult life-span

“…However, prior findings suggest a dissociation between imitative and spatial compatibilities, implying that they are driven by different underlying processes (Boyer, Longo, & Bertenthal, 2012;Wiggett, Hudson, Tipper, & Downing, 2011). Moreover, studies using similar paradigms have shown automatic movement imitation such as the one reported in our study independent of stimulus salience or spatial compatibility (Bertenthal et al, 2006;Catmur & Heyes, 2011;Heyes, Bird, Johnson, & Haggard, 2005). Furthermore, the suppression of an incongruent movement during action perception is shown to be accompanied by increased activity of sensorimotor areas (Koski et al, 2002).…”

Priming of hand and foot response: is spatial attention to the body site enough?

“…A number of studies looking at automatic imitation have explicitly tested for effects of spatial compatibility and whether automatic imitation effects can be explained simply by an alignment of body and spatial frames. These studies show that automatic imitation is not reducible to spatial compatibility (Brass, Bekkering & Prinz, 2001;Catmur & Heyes, 2011;Press et al, 2008;Wiggett et al, 2013). However, Bach et al's study did not control or test for this.…”