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. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The DalHouses: 100 new photographs of houses with ratings of typicality, familiarity, and degree of similarity to faces.

Houses have often been used as comparison stimuli in face-processing studies because of the many attributes they share with faces (e.g., distinct members of a basic category, consistent internal features, mono-orientation, and relative familiarity). Despite this, no large, well-controlled databases of photographs of houses that have been developed for research use currently exist. To address this gap, we photographed 100 houses and carefully edited these images. We then asked 41 undergraduate students (18 to 31 years of age) to rate each house on three dimensions: typicality, likeability, and face-likeness. The ratings had a high degree of face validity, and analyses revealed a significant positive correlation between typicality and likeability. We anticipate that this stimulus set (i.e., the DalHouses) and the associated ratings will prove useful to face-processing researchers by minimizing the effort required to acquire stimuli and allowing for easier replication and extension of studies. The photographs of all 100 houses and their ratings data can be obtained at http://dx.doi.org/10.6084/m9.figshare.1279430.

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.

Testing the embodied account of object naming: a concurrent motor task affects naming artifacts and animals.

Embodied theories of object representation propose that the same neural networks are involved in encoding and retrieving object knowledge. In the present study, we investigated whether motor programs play a causal role in the retrieval of object names. Participants performed an object-naming task while squeezing a sponge with either their right or left hand. The objects were artifacts (e.g. hammer) or animals (e.g. giraffe) and were presented in an orientation that favored a grasp or not. We hypothesized that, if activation of motor programs is necessary to retrieve object knowledge, then concurrent motor activity would interfere with naming manipulable artifacts but not non-manipulable animals. In Experiment 1, we observed naming interference for all objects oriented towards the occupied hand. In Experiment 2, we presented the objects in more 'canonical orientations'. Participants named all objects more quickly when they were oriented towards the occupied hand. Together, these interference/facilitation effects suggest that concurrent motor activity affects naming for both categories. These results also suggest that picture-plane orientation interacts with an attentional bias that is elicited by the objects and their relationship to the occupied hand. These results may be more parsimoniously accounted for by a domain-general attentional effect, constraining the embodied theory of object representations. We suggest that researchers should scrutinize attentional accounts of other embodied cognitive effects.

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.

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.

A significant bilateral field advantage for shapes defined by static and motion cues.

Matching performance is better when pairs of visual stimuli are presented in bilateral conditions--in which one stimulus is presented to each side of the visual field--than in unilateral presentations-when both stimuli are presented to one side of the field. This is called the bilateral field advantage (BFA). The processing of visual motion has also been found to be more strongly integrated across the cerebral hemispheres than is processing of static cues. However, in these studies higher-order motion tasks, such as processing motion-defined form, have not been examined. To determine if the BFA generalises to such tasks, we measured the magnitude of the effect using a shape-matching task in which the stimuli were random polygons that were either in motion, motion-defined, or static. The polygon pairs were presented either: (i) bilaterally, one to either side of the vertical meridian; (ii) unilaterally, both to one side of the vertical meridian (left or right visual fields); or (iii) centrally, vertically separated across the horizontal meridian (a control condition). An equal advantage of bilateral conditions over unilateral ones was found for all three types of polygon shape cues, showing that the BFA generalises to conditions where shapes are in motion and where shape is defined by motion. These findings are compatible with the notion that motion processing is strongly integrated across the cerebral hemispheres, and with the idea that this integration manifests itself with simple motion information, rather than with higher-order motion processing such as matching shapes defined by motion.

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.

Behavioral effects of visual field location on processing motion- and luminance-defined form.

Traditional theories posit a ventral cortical visual pathway subserving object recognition regardless of the information defining the contour. However, functional magnetic resonance imaging (fMRI) studies have shown dorsal cortical activity during visual processing of static luminance-defined (SL) and motion-defined form (MDF). It is unknown if this activity is supported behaviorally, or if it depends on central or peripheral vision. The present study compared behavioral performance with two types of MDF [one without translational motion (MDF) and another with (TM)] and SL shapes in a shape matching task where shape pairs appeared in the upper or lower visual fields or along the horizontal meridian of central or peripheral vision. MDF matching was superior to the other contour types regardless of location in central vision. Both MDF and TM matching was superior to SL matching for presentations in peripheral vision. Importantly, there was an advantage for MDF and TM matching in the lower peripheral visual field that was not present for SL forms. These results are consistent with previous behavioral findings that show no field advantage for static form processing and a lower field advantage for motion processing. They are also suggestive of more dorsal cortical involvement in the processing of shapes defined by motion than luminance.

Perceptual biases in processing facial identity and emotion.

Normal observers demonstrate a bias to process the left sides of faces during perceptual judgments about identity or emotion. This effect suggests a right cerebral hemisphere processing bias. To test the role of the right hemisphere and the involvement of configural processing underlying this effect, young and older control observers and patients with right hemisphere damage completed two chimeric faces tasks (emotion judgment and face identity matching) with both upright and inverted faces. For control observers, the emotion judgment task elicited a strong left-sided perceptual bias that was reduced in young controls and eliminated in older controls by face inversion. Right hemisphere damage reversed the bias, suggesting the right hemisphere was dominant for this task, but that the left hemisphere could be flexibly recruited when right hemisphere mechanisms are not available or dominant. In contrast, face identity judgments were associated most clearly with a vertical bias favouring the uppermost stimuli that was eliminated by face inversion and right hemisphere lesions. The results suggest these tasks involve different neurocognitive mechanisms. The role of the right hemisphere and ventral cortical stream involvement with configural processes in face processing is discussed.

Hierarchical attention in discriminating objects at different levels of specificity.

An implicit assumption of studies in the attentional literature has been that global and local levels of attention are involved in object recognition. To investigate this assumption, a divided attention task was used in which hierarchical figures were presented to prime the subsequent discrimination of target objects at different levels of category identity (basic and subordinate). Target objects were identified among distractor objects that varied in their degree of visual similarity to the targets. Hierarchical figures were also presented at different sizes and as individual global and local elements in order to investigate whether attention-priming effects on object discrimination were due to grouping/parsing operations or spatial extent. The results showed that local processing primed subordinate object discriminations when the objects were visually similar. Global processing primed basic object discriminations, regardless of the similarity of the distractors, and subordinate object discriminations when the objects were visually dissimilar. It was proposed that global and local processing aids the selection of perceptual attributes of objects that are diagnostic for recognition and that selection is based on two mechanisms: spatial extent and grouping/parsing operations.

Category-specific effects on the identification of non-manipulable objects.

Theories of category-specific effects on visual object identification predict easier identification of non-living than living objects. The Sensory-Functional theory credits greater representational weighting of the visual properties of living objects independent of greater weighting of the functional properties of non-living objects. It predicts a lost or reversed non-living advantage for non-manipulable objects. Normal participants matched pictures of non-manipulable objects with words describing three levels of identity while visual object similarity, and concept familiarity were controlled. Consistent with the Sensory-Functional theory, living objects were matched faster than non-living objects. Concept familiarity facilitated subordinate matches. Visual similarity hampered subordinate matches and facilitated basic matches.

Subordinate-level categorization relies on high spatial frequencies to a greater degree than basic-level categorization.

In two experiments, category verification of images of common objects at subordinate, basic, and superordinate levels was performed after low-pass spatial filtering, high-pass spatial filtering, 50% phase randomization, or no image manipulation. Both experiments demonstrated the same pattern of results: Low-pass filtering selectively impaired subordinate-level category verification, while having little to no effect on basic-level category verification. Subordinate categorization consequently relies to a greater degree on high spatial frequencies of images. This vulnerability of subordinate-level processing was specific to a lack of high spatial frequency information, as opposed to other visual information, since neither high-pass filtering nor the addition of phase noise produced a comparable reduction in performance. These results are consistent with the notion that object recognition at basic levels relies on the general shapes of objects, whereas recognition at subordinate levels relies on finer visual details.

Manipulability and living/non-living category effects on object identification.

Object naming studies have generally observed that both normal and brain damaged individuals are faster and more accurate at identifying non-living objects than living objects (). However, a potential confounding variable, manipulability, has been present in past studies that may mediate this effect. Previous studies that have observed a non-living advantage have often used manipulable and non-manipulable exemplars to represent the non-living and living groups, respectively. Under conditions which controlled for object manipulability and familiarity, results demonstrated advantages for the identification of non-manipulable and for living objects.

Face recognition is affected by similarity in spatial frequency range to a greater degree than within-category object recognition.

Previous studies have suggested that face identification is more sensitive to variations in spatial frequency content than object recognition, but none have compared how sensitive the 2 processes are to variations in spatial frequency overlap (SFO). The authors tested face and object matching accuracy under varying SFO conditions. Their results showed that object recognition was more robust to SFO variations than face recognition and that the vulnerability of faces was not due to reliance on configural processing. They suggest that variations in sensitivity to SFO help explain the vulnerability of face recognition to changes in image format and the lack of a middle-frequency advantage in object recognition.

Electrophysiological correlates of object categorization: back to basics.

The time course of visual object categorization as a function of electrophysiological activity in the brain was investigated using a variant of the "oddball" design. Category level was manipulated by sequentially presenting subordinate, basic or superordinate target objects among a variety of non-target objects. It was found that superordinate categorizations were performed more quickly and differentiated from basic level categorizations in amplitude early in visual processing (320-420 ms). In contrast, subordinate categorizations took longer to perform and differentiated from basic level categorizations in amplitude and latency at later stages (450-550 ms). Notably, these effects were observed using the same objects categorized at different levels suggesting that visually categorizing objects at varying levels of abstraction engaged specific cognitive processes. These results are consistent with research on rapid visual categorization that challenges the generality of basic category level superiority effects.

The role of axes of elongation and symmetry in rotated object naming.

Many theorists have postulated that axes of elongation and/or symmetry play an important role in the recognition of objects. In this paper, evidence is presented that mitigates this claim from independent assessments of the effects of axes of elongation or symmetry on the time to name rotated line drawings of common objects. This conclusion was further supported in a stronger test in which both of these variables were orthogonally controlled, the aspect ratio of elongation was manipulated,and only objects that were completely geometrically symmetrical or asymmetrical were used. In all the experiments, objects were named for several blocks to determine the influence of these variables on effects of orientation with practice. Symmetry was found to diminish the effects of orientation after practice in naming the object set, and the effects of the most extreme orientation tested (120 degrees from upright) were diminished when both axes defined the same orientation, relative to when they defined different orientations. Contrary to many theories, these findings relegate the axes of symmetry and elongation to relatively minor roles during object identification.

Using Matlab to generate families of similar Attneave shapes.

We present a program for Matlab that quickly generates Attneave-style random polygons and families of similar polygons. The function allows a great deal of user control over various aspects of the shape generation process. It also has the ability to detect and eliminate shapes that do not match a variety of user-entered parameters regarding the lengths of the shapes' sides, vertex angles, and topological form. The function eliminates the time-consuming task of generating such shapes by hand and should allow their broader use in behavioral research. The Matlab script function can be downloaded at www.dal.ca/~mcmullen/downloads.html.