Is a letterbox always a letterbox? The role of affordances in guiding perceptual categorization.

Classically investigated in the context of judgment tasks about achievable actions, affordances have also been investigated in the context of the stimulus-response compatibility paradigm. Earlier work showed that perceptual categorization performance is significantly faster and more accurate when the orientation of the graspable part of a presented object, and the orientation of the participant's response are compatible, suggesting that the main function of affordances is restricted to action preparation. Here, we investigate the potential role of affordances in the categorization of ambiguous stimuli through a stimulus-response compatibility paradigm. In other words, we investigate if in ambiguous situations, such as ones in which a stimulus may give rise to two percepts, affordances would stabilize perception on one of these two and, therefore, helps in the subsequent categorizations. Two experiments were run, based on the forced-choice stimulus-response compatibility (SRC) paradigm, with a progressive series of ambiguous (bistable) lateral-graspable objects. In Experiment 1, subjects responded by pressing horizontally opposite keyboard keys, while in Experiment 2, the keyboard keys were vertically separated. Experiment 1 found that subjects perceived the initial object in a bistable series for longer, and exhibited greater response stability in compatible than incompatible situations. In Experiment 2, none of these modulations were significant. Overall, our results show that affordances operationalized through a SRC paradigm modulated how subjects categorized ambiguous stimuli. We argue that affordances may play a substantial role in ambiguous contexts by reducing the uncertainty of such situations.

The Action Constraints of an Object Increase Distance Estimation in Extrapersonal Space.

This study investigated the role of action constraints related to an object as regards allocentric distance estimation in extrapersonal space. In two experiments conducted in both real and virtual environments, participants intending to push a trolley had to estimate its distance from a target situated in front of them. The trolley was either empty (i.e., light) or loaded with books (i.e., heavy). The results showed that the estimated distances were larger for the heavy trolley than for the light one, and that the actual distance between the participants and the trolley moderated this effect. This data suggests that the potential mobility of an object used as a reference affects distance estimation in extrapersonal space. According to embodied perception theories, our results show that people perceive space in terms of constraints related to their potential actions.

How movement direction shapes the spatial representation of its effects: About the consequence of the ideomotor bidirectional association.

Ideomotor theories assume that action and perception share a common representational system in which a movement and its effect are equally represented and integrated by a bidirectional association. However, there is no mention of how this association leads to influence the representational content of each part. In this article, we investigated the influence of movement properties on the spatial representation of auditory effects. In line with the Action Constrains Theory of space perception, we suggest that changes in the movement direction leads to correlative changes in the spatial representation of the effect. In a pre-experiment, we replicated traditional ideomotor results with a response-effect (R-E) compatibility procedure. In two experiments, we used one condition of this procedure (i.e., the corresponding R-E mapping) to manipulate the movement properties associated to a non-spatialised effect. In the first experiment, the effect was associated with horizontal outward movements or with forward-backward movements. In the second experiment, we tested some alternative explanations for the results obtained in the first experiment. Globally, we showed that rightward movements led to localised auditory effect more on the right space than leftward movements and that backward movements led to localisation of the effect closer from the subjects than forward movements. In accordance with the Action Constrains Theory of space perception, these data suggest that movement shapes the spatial organisation of the effect representation.

From anticipation to integration: the role of integrated action-effects in building sensorimotor contingencies.

Ideomotor approaches to action control have provided evidence that the activation of an anticipatory image of previously learned action-effects plays a decisive role in action selection. This study sought for converging evidence by combining three previous experimental paradigms: the response-effect compatibility protocol introduced by Kunde (Journal of Experimental Psychology: Human Perception and Performance, 27(2), 387-394, 2001), the acquisition-test paradigm developed by Elsner and Hommel (Journal of Experimental Psychology: Human Perception and Performance, 27(1), 229, 2001), and the object-action compatibility manipulation of Tucker and Ellis (Visual Cognition, 8(6), 769-800, 2001). Three groups of participants first performed a response-effect compatibility task, in which they carried out power and precision grasps that produced either grasp-compatible or grasp-incompatible pictures, or no action effects. Performance was better in the compatible than in the incompatible group, which replicates previous observations and extends them to relationships between grasps and objects. Then, participants were to categorize object pictures by carrying out grasp responses. Apart from replicating previous findings of better performance in trials in which object size and grasp type was compatible, we found that this stimulus-response compatibility effect depended on previous response-effect learning. Taken together, these findings support the assumption that the experience of action-effect contingencies establishes durable event files that integrate representations of actions and their effects.

Integration of Action and Size Perception Through Practice.

Size perception is known to influence our usual interactions with environment. Numerous studies highlighted that during the visual presentation of an object, the properties of manual actions vary as a function of this object's size. In order to better understand the dynamic variations of relationships between size perception and action, we used an experimental paradigm consisting in two phases. During a previous implicit learning phase, a manual response (right or left) was specifically associated with the appearance of a large or small stimulus. During further test phase, participants were required to prepare a response while discriminating the color of a stimulus (GO/No GO task). We observed that the response execution was faster when the size of the stimulus was congruent with the size that had been associated to this response (during implicit learning phase). These results suggest that when a response usually co-occurs with visual stimuli characterized by a specific size pattern, the response and the size pattern become integrated. Any subsequent preparation and execution of this action are therefore influenced by the reactivation of this visual pattern. This result brings out new insights on how sensorimotor interactions may modulate the ability to anticipate perceptive size variations in the environment.

Assessing the functional role of motor response during the integration process.

The aim of this study was to provide evidence that actions performed by an individual influence the sensorimotor memory processing and, in particular, the integration process. We conducted 3 experiments that highlighted the multimodal aspect of memory traces. The 1st experiment consisted of a short-term priming paradigm based on 2 phases: a learning phase, consisting of the association between a shape and a sound, and a test phase, examining the priming effect of the shape seen in the learning phase on the processing of target tones. The participants' motor response became a factor in Experiments 2 and 3, allowing us to observe its influence on the integration between the shape and the sound. In Experiment 1, we showed that (a) the prime associated with the sound in the learning phase had an effect on target processing and (b) the component reactivated by the prime was perceptual in nature (i.e., auditory). Experiment 2 showed that the participants' responses were faster when the association of a shape and a sound had been learned with a motor response rather than without. Experiment 3 showed that the integration process required the individual to act while learning the association between the shape and the sound; otherwise no integration effect was observed. Our results highlight the role of motor responses as a necessary criterion for the integration process to take place. (PsycINFO Database Record