Abnormalities of embodiment of the self and of self-object relations are recently described as a possible common component in schizophrenia. For these patients, the world can then appear as being deprived of practical meaning, which lays its foundation through sensory-motor experiences. Here, we investigate the hypothesis that schizophrenic patients could have a deficit in sensory-motor simulation. To investigate this question, we used two Stimulus Response Compatibility tasks, in schizophrenic and control subjects. When the stimuli and the responses share the same properties, it is well known that response times are shorter than when they do not (« SRC effect »). In experiment 1, we replicate a study from Tucker & Ellis (1998) in order to explore the hypothesis that schizophrenic patients could have a deficit in sensory-motor simulation during perception of graspable objects in contrast to healthy subjects (“Object-Affordance”). In experiment 2, we hypothesize that during a Simon task, the SRC effect would be efficient in both groups.
Our results show that, in a schizophrenic group, the SRC effect appears only when stimuli and responses share a spatial localization but does not when they share motor characteristics.
These results allow us to conclude that the visual asymmetry does not influence the implementation of the motor potentiation, as certain authors suggest in healthy subjects.
Moreover, in schizophrenia, the sensory-motor simulation impairments could emerge from a lack of relation between the object and the subject's environment more than from a difficulty in orienting attention.