Heath E. Matheson

A test of the embodied simulation theory of object perception: potentiation of responses to artifacts and animals

Theories of embodied object representation predict a tight association between sensorimotor processes and visual processing of manipulable objects. Previous research has shown that object handles can ‘potentiate’ a manual response (i.e., button press) to a congruent location. This potentiation effect is taken as evidence that objects automatically evoke sensorimotor simulations in response to the visual presentation of manipulable objects. In the present series of experiments, we investigated a critical prediction of the theory of embodied object representations that potentiation effects should be observed with manipulable artifacts but not non-manipulable animals. In four experiments we show that (a) potentiation effects are observed with animals and artifacts; (b) potentiation effects depend on the absolute size of the objects and (c) task context influences the presence/absence of potentiation effects. We conclude that potentiation effects do not provide evidence for embodied object representations, but are suggestive of a more general stimulus–response compatibility effect that may depend on the distribution of attention to different object features.

A computer-generated face database with ratings on realism, masculinity, race, and stereotypy

Ratings of realism, masculinity, race, and racial stereotypy were collected on a set of computer-generated faces representing European, South East Asian, and African American ethnicities. To determine if these faces are processed in the same way as photographs of real faces, we demonstrated with these faces superior memory performance for upright faces over inverted faces (the face inversion effect). Further, in observers of European decent, we found both superior memory for European faces and a larger inversion effect for European than African American faces. Based on these results, we believe that this set of faces may be of use in perceptual investigations in which race is a critical manipulation.

Slow categorization but fast naming for photographs of manipulable objects

Previous research investigating the influence of object manipulability (the properties of objects that make them appropriate for manual action) on object identification has not tightly controlled for effects of both object familiarity and age of acquisition of objects. The current research carefully controlled these two variables on a balanced set of 120 photographs and showed significant effects of object manipulability during object categorization (Experiment 1) and object naming (Experiment 2). Critically, the effects showed a manipulability-effect reversal, with faster categorization of non-manipulable objects, but faster naming of manipulable objects, suggesting that task moderates the direction of the manipulability effect. Exposure duration (the amount of time the object was visible to participants) was also investigated, but no interactions between exposure duration and manipulability were found. These results indicate that not only can manipulability influence object identification, but the way in which it does depends on the task.

Handles of manipulable objects attract covert visual attention: ERP evidence

Previous research has demonstrated that people are faster at making a manual response with the hand that is aligned with the handle of a manipulable object compared to its functional end. According to theories of embodied cognition (ETC), the presentation of a manipulable object automatically elicits sensorimotor simulations of the respective hand and these simulations facilitate the response. However, an alternative interpretation of these data is that handles preferentially attract visual attention, since attended stimuli and locations typically elicit faster responses. We investigated attentional biases elicited by manipulable and non-manipulable objects using event-related-potentials (ERPs). On each trial, a picture of a manipulable object was followed by a target dot that participants had to make a button-press to. The dot was located at either the handle or functional end of the object. Consistent with previous attentional cuing paradigms, we showed that the P1 ERP component was greater in response to targets cued by handles than by functional ends. These results suggest that object handles automatically bias covert attentional processes. These attentional biases may account for earlier behavioural findings, without any recourse to ETC.

Neuropsychological dissociations between motion and form perception suggest functional organization in extrastriate cortical regions in the human brain

In this review of neuropsychological case studies, a number of dissociations are shown between different visual abilities including low-level motion perception, static form perception, form-from-motion perception and biological motion perception. These dissociations reveal counter-intuitive results. Specifically, higher level form-from-motion perception can persist despite deficits in low-level motion perception and static form perception. To account for these dissociations, we present a model of functional organization and identify future directions for investigations of higher order form-from-motion perception.

Photographs of manipulable objects are named more quickly than the same objects depicted as line-drawings: Evidence that photographs engage embodiment more than line-drawings.

Previous research has shown that photographs of manipulable objects (i.e., those that can be grasped for use with one hand) are named more quickly than non-manipulable objects when they have been matched for object familiarity and age of acquisition. The current study tested the hypothesis that the amount of visual detail present in object depictions moderates these “manipulability” effects on object naming. The same objects were presented as photographs and line-drawings during a speeded naming task. Forty-six participants named 222 objects depicted in both formats. A significant object depiction (photographs versus line drawing) by manipulability interaction confirmed our hypothesis that manipulable objects are identified more quickly when shown as photographs; whereas, non-manipulable objects are identified equally quickly when shown as photographs versus line-drawings. These results indicate that factors such as surface detail and texture moderate the role of “action” and/or “manipulability” effects during object identification tasks, and suggest that photographs of manipulable objects are associated with more embodied representations of those objects than when they are depicted as line-drawings.

Accessing Embodied Object Representations From Vision: A Review

Theories of embodied cognition (EC) propose that object concepts are represented by reactivations of sensorimotor experiences of different objects. Abundant research from linguistic paradigms provides support for the notion that sensorimotor simulations are involved in cognitive tasks like comprehension. However, it is unclear whether object concepts, as accessed from the visual presentation of objects, are embodied. In the present article we review a large body of visual cognitive research that addresses 5 main predictions of the theory of EC. First, EC accounts predict that visual presentation of manipulable objects, but not nonmanipulable objects, should activate motor representations. Second, EC predicts that sensorimotor activity is necessary to perform visual-cognitive tasks such as object naming. Third, EC posits the existence of distinct neural ensembles that integrate information from action and vision. Fourth, EC predicts that relationships between visual and motor activity change throughout development. Fifth, EC predicts that the visual presentation of objects or actions should prime performance cross-modally. We summarize findings from neuroimaging, neuropsychology, neurophysiology, development, and behavioral paradigms. We show that while much of the research published so far demonstrates that there is a relationship between visual and motoric representations, there is no evidence supporting a strong form of EC. We conclude that sensorimotor simulations may not be required to perform visual cognitive tasks and highlight a number of directions for future research that could provide strong support for EC in visual cognitive paradigms.

Second-order relational face processing is applied to faces of different race and photographic contrast.

A large body of research suggests that faces are processed by a specialized mechanism within the human visual system. This specialized mechanism is made up of subprocesses (Maurer, LeGrand, & Mondloch, 2002). One subprocess, called second- order relational processing, analyzes the metric distances between face parts. Importantly, it is well established that other-race faces and contrast-reversed faces are associated with impaired performance on numerous face processing tasks. Here, we investigated the specificity of second-order relational processing by testing how this process is applied to faces of different race and photographic contrast. Participants completed a feature displacement discrimination task, directly measuring the sensitivity to second-order relations between face parts. Across three experiments we show that, despite absolute differences in sensitivity in some conditions, inversion impaired performance in all conditions. The presence of robust inversion effects for all faces suggests that second-order relational processing can be applied to faces of different race and photographic contrast.

A Contextual Effect of 2nd-Order Configural Processing of Non-Face Objects by Non-Experts

We investigated here the detection of 2nd-order configural relations both in faces and in non-face objects. In experiment 1 it was shown that observers were more sensitive to feature displacements in upright faces and houses than in inverted faces and houses. The presence of an inversion effect in the house stimuli suggested that 2nd-order relational processing was applied to the non-face stimuli. In experiment 2, the inversion effect for houses was absent when only houses were presented. In experiment 3, face and house stimuli were once again presented in the same task and inversion effects were again seen for both types of stimuli. Together, these results suggest that 2nd-order relational processing can be flexibly applied to non-face objects when they are presented in the context of faces.

Embodied object concepts: The contribution of structural and functional manipulability depends on available visual information.

Object identification is driven, in part, by the extent to which we have sensorimotor experience with the object. Importantly, the activation of embodied object representations depends on contextual information. In the present study, we use a visual masking paradigm to investigate how the availability of visual information modulates the role of manipulability in the representation of object concepts. Using both an object naming task (i.e., linguistic response) and a picture-word matching task (i.e., manual response), we provide evidence that structural manipulability (the ability to pick up an object with one hand) and functional manipulability (the action information that pertains to the ultimate use of the object) have dissociable effects on object identification. In both tasks, the effects of structural manipulability were greater when structural information was available in the image (i.e., when the objects were unmasked); in contrast, the effects of functional manipulability were greater when the objects were masked. Importantly, these effects were not due to object familiarity or the age at which the name of the objects was acquired. Our results are consistent with the activation of the two pathways within the dorsal visual stream that are part of a distributed neural network that represents embodied action information. We extend previous research by showing that visual information determines which type of embodied information drives object identification. L’identification d’un objet s’effectue, en partie, par le degré d’expérience sensorimotrice que nous avons avec l’objet en question. Fait important, l’activation de représentations d’objet incarnées dépend de l’information contextuelle. Dans la présente étude, nous utilisons un modèle de masquage visuel pour examiner comment la disponibilité de l’information visuelle module le rôle de la manipulabilité dans la représentation de concepts d’objets. L’utilisation combinée d’une tâche de dénomination (c.-à-d. une réponse linguistique) et d’une tâche d’association mot-image (c.-à-d. une réponse manuelle) nous permet de fournir la preuve que la manipulabilité structurelle (la capacité à saisir un objet avec une main) et la manipulabilité fonctionnelle (l’information de l’action ayant trait à l’utilisation finale de l’objet) ont des effets indissociables sur l’identification d’objets. Dans les deux tâches, les effets de la manipulabilité structurelle étaient supérieurs lorsque l’information structurelle était fournie avec l’image (c.-à-d. lorsque les objets étaient visibles); en revanche, les effets de la manipulabilité fonctionnelle étaient supérieurs lorsque les objets étaient masqués. Fait important, ces effets n’étaient pas associés à une familiarité de l’objet ou à l’âge auquel le nom de l’objet a été appris. Nos résultats concordent avec l’activation des deux voies du parcours visuel dorsal qui fait partie d’un réseau de neurones distribués, lequel représente une information d’action incarnée. Nous approfondissons les recherches précédentes en montrant que l’information visuelle détermine quel type d’information incarnée favorise l’identification d’objets.