Do manufactured and natural objects evoke similar motor information? The case of action priming

There is considerable evidence that visually presented manipulable objects evoke motor information, supporting the existence of affordance effects during object perception. However, most arguments come from stimulus–response compatibility paradigms, raising the issue of the automaticity of affordance effects. Action priming paradigms overcome this issue but show less reliable results, possibly because affordance effects are moderated by additional factors. The present study aimed to assess whether affordance effects highlighted in action priming paradigms could be affected by object category (manufactured or natural). A total of 24 young adults performed a semantic categorisation task on natural and manufactured target objects presented after neutral (non-grasping hand postures) or action (congruent power or precision grips) primes. Results revealed a modulation of action priming effects as a function of object category. Object semantic categorisation was faster after action than neutral primes, but only for manufactured objects. Results suggest that natural and manufactured objects evoke distinct types of affordances and that action priming paradigms favour the evocation of functional affordances during object semantic categorisation. This finding fuels the debate on the nature of the motor information evoked by visual objects.

Top-down attentional factors modulate action priming in reach-to-grasp action

Previous studies report that viewing exaggerated, high-lifting reaches (versus direct reaches) primes higher vertical deviation in wrist trajectory in the observer’s subsequent reaches (trajectory priming), but it is unclear to what extent this effect depends upon task instructions relevant to top-down attention. In two experiments, participants were instructed to gaze at a dot presented on a large monitor for a colour-change go signal that cued them to execute a direct reach to a target. In the background, the monitor also displayed life-sized films of a human model. The films were of the model either remaining still or reaching to grasp a target with either a direct trajectory or an exaggerated, high-lifting trajectory. When the dot traced the human model’s wrist throughout her movement, a robust trajectory priming effect emerged. When the dot remained stationary in a central location but the human model reached in the background, the human model’s trajectory did not alter the participants’ trajectories. Finally, when the dot traced exaggerated and direct trajectories and the human model remained stationary, the dot’s movement produced an attenuated, non-significant trajectory priming effect. These findings show that top-down attentional factors modulate trajectory priming. In addition, a moving non-human stimulus does not produce the same degree of action priming when contextual factors make salient its independence of human agency and/or intention.

How Visual and Motor Experience Shapes the Development of Infants’ Perception of Actions Performed by Social Partners

This review focuses on three different processes: action priming, action prediction, and outcome evaluation. Together, these processes form a foundation for social perception early in life. Priming and prediction is argued to be separable processes with different degrees of plasticity, based in part on unique neural structures. These two future-oriented processes are assumed to operate in a sequential manner. A third set of processes, outcome evaluations, follows the completion of observed events and compare the actual events with the assumptions postulated by the preceding future-oriented processes. Together, these processes are argued to provide good grounds for learning via internal models that detect error signals that arise from the potential mismatch between priming and prediction and actual events as they unfold in the external world and use this information to update the accuracy of future-oriented processes.