Is there any Influence of Variations in Context on Object-Affordance Effects in Schizophrenia? Perception of Property and Goals of Action

Abstract

The simple perception of an object can potentiate an associated action. This affordance effect depends heavily on the action context in which the object is presented. In recent years, psychologists, psychiatrists, and phenomenologists have agreed that subjects with schizophrenia may not perceive the affordances of people or objects that could lead to a loss of ease in their actions. We examined whether the addition of contextually congruent elements, during the perception of everyday objects, could promote the emergence of object-affordance effects in subjects with schizophrenia and controls. Participants performed two Stimulus–Response-Compatibility tasks in which they were presented with semantic primes related to sense of property (Experiment 1) or goal of action (Experiment 2) prior to viewing each graspable object. Controls responded faster when their response hand and the graspable part of the object were compatibly oriented, but only when the context was congruent with the individual’s needs and goals. When the context operated as a constraint, the affordance-effect was disrupted. These results support the understanding that object-affordance is flexible and not just intrinsic to an object. However, the absence of this object-affordance effect in subjects with schizophrenia suggests the possible impairment of their ability to experience the internal simulation of motor action potentialities. In such case, all activities of daily life would require the involvement of higher cognitive processes rather than lower level sensorimotor processes. The study of schizophrenia requires the consideration of concepts and methods that arise from the theories of embodied and situated cognition.

Using Bayes factors to assess object-affordance effects: A comment on Sevos et al. (2016)

“…As the Bayes factor and posterior probability are directly related via Equation 3, they both tell the same story; that is, the null effect of name prime reported in Sevos et al (2016) is not well supported.…”

“…Now, let us compute Bayes factors for the reported null effects in Experiment 1 and 2 of Sevos et al (2016). In Experiment 1, the authors reported that for the n = 18 patients with schizophrenia, the critical interaction of response and orientation did not differ as a function of name prime (present versus absent), F(1, 17) = 2.584, p = 0.126, η This means that, given the data, a null interaction is only 1.21 times more likely than a true interaction between response and orientation.…”

“…The claim that patients with schizophrenia lack this sensorimotor facilitation is based upon two nonsignificant effects reported in Experiments 1 and 2 of Sevos et al (2016). This is problematic, though, since the traditional null-hypothesis testing approach does not allow one to "accept" a null hypothesis.…”

“…In their recent article, Sevos, Grosselin, Brouillet, Pellet, and Massoubre (2016) present data indicating that subjects with schizophrenia "have an impaired ability to experience an internal simulation of motor action potentialities when they perceived graspable objects" (p. 12). This lack of sensorimotor facilitation in patients with schizophrenia aligns broadly with other patient studies, and indicates that such individuals would require extensive use of higher cognitive processes even for the simplest routine activities in their daily life.…”

“…To this end, we will describe how to compute BF 01 and the posterior probabilities for the null effects reported in Experiments 1 and 2 of Sevos et al (2016 …”