Visual Hand Primes and Manipulable Objects (original) (raw)
Related papers
2005
In three experiments we assessed whether priming a hand shape activated motor information. Primes consisted of photographs of hands displaying one of three postures (precision, power, open hand). Targets consisted of photographs (Experiment 1 and 3) or words (Experiment 2) of objects, artifacts and natural kinds, manipulable with a precision (pencil) or with a power grip (bottle). Participants had to categorize objects into artifacts or natural kinds by pressing a different key. They had to respond to target-objects only when the targets followed the precision and the power primes, while they didn't have to respond when the targets followed the open hand (catch-trial). In Experiments 1 and 2, artifacts were processed slower than natural kinds, and natural kinds graspable with a power grip were processed faster than those graspable with a precision grip. These results confirm that visual primes activate general motor information on objects. However, only in Experiment 3, in which...
Viewing objects and planning actions: On the potentiation of grasping behaviours by visual objects
Brain and cognition, 2011
How do humans interact with tools? Gibson (1979) suggested that humans perceive directly what tools afford in terms of meaningful actions. This “affordances” hypothesis implies that visual objects can potentiate motor responses even in the absence of an intention to act. Here we explore the temporal evolution of motor plans afforded by common objects. We presented objects that have a strong significance for action (pinching and grasping) and objects with no such significance. Two experimental tasks involved participants viewing objects presented on a computer screen. For the first task, they were instructed to respond rapidly to changes in background colour by using an apparatus mimicking precision and power grip responses. For the second task, they received stimulation of their primary motor cortex using transcranial magnetic stimulation (TMS) while passively viewing the objects. Muscular responses (motor evoked potentials: MEPs) were recorded from two intrinsic hand muscles (associated with either a precision or power grip). The data showed an interaction between type of response (or muscle) and type of object, with both reaction time and MEP measures implying the generation of a congruent motor plan in the period immediately after object presentation. The results provide further support for the notion that the physical properties of objects automatically activate specific motor codes, but also demonstrate that this influence is rapid and relatively short lived.► How do objects automatically activate specific motor plans known as “affordances”? ► Task-irrelevant pictures shown to activate congruent grip actions. ► Affordance effect evident in both RTs and motor evoked potentials. ► Affordance effect arises rapidly and also dissipates quickly. ► Affordance effect evident for separate hand actions generated in the same hemisphere.
Manual asymmetries in visually primed grasping
Experimental Brain Research, 2006
Previous research has shown that the task irrelevant size of familiar objects facilitates compatible precision and power grip responses. The present study examined whether the task irrelevant size of novel objects produces the same compatibility effect. However, the main objective of the study was to investigate whether visually primed precision and power grips are manually asymmetric. Experiment 1 showed that the size of a novel prime object does facilitate compatible precision and power grips, even when both the object itself and the grasp type are irrelevant to the current task. However, this effect was only found when the precision grip was made with the right hand (RH) and the power grip was made with the left hand (LH). When these grips were made with the opposite hands, the effect was absent. Experiment 2 replicated the LH bias for large objects and the RH bias for small objects when power and precision grip responses were replaced with simple LH and RH button-press responses. It appears that the two hemispheres are specialised with regard to precision and power compatible objects.