Biomedical subjects

Fiona N Newell

Publications and source records attributed to Fiona N Newell.

12 recordsLinked to original sources

PubMed2006

Are representations of unfamiliar faces independent of encoding modality?

It is well documented that both featural and configural information are important in visual face recognition. Less is known, however, about the nature of the information underlying haptic face recognition and whether or not this information is the same as in vision. In our experiments we found better within modal than crossmodal face recognition performance suggesting that face representations are largely specific to each modality. Moreover, this cost in crossmodal performance was found to be independent of differences in exploratory procedures across the modalities during encoding. We found that crossmodal face perception was most efficient when configural information of the facial features was preserved suggesting that configural information is shared across modalities. Our findings suggest that face information is processed in a similar manner across vision and touch but that qualitative differences in the nature of the information encoded underlies efficient within modal relative to crossmodal recognition.

Adult↗

PubMed2006

The role of familiarity in the recognition of static and dynamic objects.

Although the perception of our world is experienced as effortless, the processes that underlie object recognition in the brain are often difficult to determine. In this chapter, we review the effects of familiarity on the recognition of moving or static objects. In particular, we concentrate on exemplar-level stimuli such as walking humans, unfamiliar objects and faces. We found that the perception of these objects can be affected by their familiarity; for example the learned view of an object or the learned dynamic pattern can influence object perception. Deviations in the viewpoint from the familiar viewpoint, or changes in the temporal pattern of the objects can result in some reduction of efficiency in the perception of the object. Furthermore, more efficient sex categorization and crossmodal matching were found for familiar than for unfamiliar faces. In sum, we find that our perceptual system is organized around familiar events and that perception is most efficient with these learned events.

Discrimination, Psychological↗

PubMed2005

Visual and haptic representations of scenes are updated with observer movement.

Scene recognition has been found to be sensitive to the orientation of the scene with respect to the stationary observer. Recent studies have shown, however, that observer movement can compensate for changes in visual scene orientation, through a process of spatial updating. Here we investigated whether spatial updating in scene recognition is affected by the encoding or learning modality by examining whether observer movement can also compensate for orientation changes in haptic scene recognition. In experiment 1, we replicated previously reported effects of observer movement on visual scene recognition. In experiment 2, we used the same apparatus as in experiment 1 but here participants were required to learn and recognize the scenes using touch alone. We found a cost in recognition performance with changes in scene orientation relative to the stationary observer. However, when participants could move around the scene to recognize the new orientation, then this cost in recognition performance disappeared. Thus, we found that spatial updating applies to recognition in both the visual and haptic modalities, both of which intrinsically encode the spatial properties of a scene.

Adolescent↗

PubMed2005

The role of long-term and short-term familiarity in visual and haptic face recognition.

Recent studies have suggested that the familiarity of a face leads to more robust recognition, at least within the visual domain. The aim of our study was to investigate whether face familiarity resulted in a representation of faces that was easily shared across the sensory modalities. In Experiment 1, we tested whether haptic recognition of a highly familiar face (one's own face) was as efficient as visual recognition. Our observers were unable to recognise their own face models from tactile memory alone but were able to recognise their faces visually. However, haptic recognition improved when participants were primed by their own live face. In Experiment 2, we found that short-term familiarisation with a set of previously unfamiliar face stimuli improved crossmodal recognition relative to the recognition of unfamiliar faces. Our findings suggest that familiarisation provides a strong representation of faces but that the nature of the information encoded during learning is critical for efficient crossmodal recognition.

Adult↗

PubMed2005

The interaction of shape- and location-based priming in object categorisation: evidence for a hybrid "what + where" representation stage.

The relationship between part shape and location is not well elucidated in current theories of object recognition. Here we investigated the role of shape and location of object parts on recognition, using a classification priming paradigm with novel 3D objects. In Experiment 1, the relative displacement of two parts comprising the prime gradually reduced the priming effect. In Experiment 2, presenting single-part primes in locations progressively different from those in the composite target had no effect on priming. In Experiment 3, manipulating the relative position of composite prime and target strongly affected priming. Finally, in Experiment 4 the relative displacement of single-part primes and composite targets did influence response time. Together, these findings are best interpreted in terms of a hybrid theory, according to which conjunctions of shape and location are explicitly represented at some stage of visual object processing.

Adolescent↗

PubMed2004

Visual, haptic and crossmodal recognition of scenes.

Real-world scene perception can often involve more than one sensory modality. Here we investigated the visual, haptic and crossmodal recognition of scenes of familiar objects. In three experiments participants first learned a scene of objects arranged in random positions on a platform. After learning, the experimenter swapped the position of two objects in the scene and the task for the participant was to identify the two swapped objects. In experiment 1, we found a cost in scene recognition performance when there was a change in sensory modality and scene orientation between learning and test. The cost in crossmodal performance was not due to the participants verbally encoding the objects (experiment 2) or by differences between serial and parallel encoding of the objects during haptic and visual learning, respectively (experiment 3). Instead, our findings suggest that differences between visual and haptic representations of space may affect the recognition of scenes of objects across these modalities.

Adult↗

PubMed2004

The role of characteristic motion in object categorization.

We report three experiments where we investigated the role of movement in object recognition. Previous studies have suggested a distinct and separate mechanism for object motion encoding, related to the action or motor-based system. To date, however, the role of an object's motion in long-term memory representations has not been explicitly tested. Here we were specifically interested in whether an object's characteristic motion patterns are integrated with static properties in an object's representation in memory. To that end, we used a simple categorization task where novel objects were categorized on the basis of two static (color and shape) and two dynamic (action and path) properties. The "action" of an object referred to its intrinsic motion pattern, whereas "path" referred to an object's extrinsic motion pattern (i.e., the route an object took). In Experiment 1, we found that all properties were relevant for categorization with the exception of path. This result was not due to path being less salient than other properties (Experiment 2). In Experiment 3, we found that when the action property was redundant that path was now used for categorization, suggesting that path was not used with action in Experiment 1 because of temporal order effects. Our findings argue for a cue-integrated model of object representation in memory.

Adolescent↗

PubMed2004

Familiarity breeds attraction: effects of exposure on the attractiveness of typical and distinctive faces.

Several studies have shown that facial attractiveness is positively correlated with both familiarity and typicality. Here we manipulated the familiarity of typical and distinctive faces to measure the effect on attractiveness. In our first experiment, we collected ratings of attractiveness, distinctiveness, and familiarity using three different groups of participants. Our stimuli included 84 images of female faces, presented in a full-face view. We replicated the finding that attractiveness ratings negatively correlate with distinctiveness ratings. In addition, we showed that attractiveness ratings were positively correlated with familiarity ratings. In our second experiment, we demonstrated that increasing exposure to faces increases their attractiveness, although there was no differential effect of exposure on typical and distinctive faces. Our results suggest that episodic familiarity affects attractiveness ratings independently of general or structural familiarity. The implications of our findings for the 'face-space' model are discussed.

Adaptation, Psychological↗

PubMed2004

Is object search mediated by object-based or image-based representations?

Recent research suggests that visually specific memory representations for previously fixated objects are maintained during scene perception. Here we investigate the degree of visual specificity by asking whether the memory representations are image-based or object-based. To that end we measured the effects of object orientation on the time to search for a familiar object from amongst a set of 7 familiar distractors arranged in a circular array. Search times were found to depend on the relative orientations of the target object and the probe object for both familiar and novel objects. This effect was found to be partly an image matching effect but there was also an advantage shown for the object's canonical view for familiar objects. Orientation effects were maintained even when the target object was specified as having unique or similar shape properties relative to the distractors. Participants' eye movements were monitored during two of the experiments. Eye movement patterns revealed selection for object shape and object orientation during the search process. Our findings provide evidence for object representations during search that are detailed and share image-based characteristics with more high-level characteristics from object memory.

Adult↗

PubMed2004

The effect of temporal delay and spatial differences on cross-modal object recognition.

In a series of experiments, we investigated the matching of objects across visual and haptic modalities across different time delays and spatial dimensions. In all of the experiments, we used simple L-shaped figures as stimuli that varied in either the x or the y dimension or in both dimensions. In Experiment 1, we found that cross-modal matching performance decreased as a function of the time delay between the presentation of the objects. We found no difference in performance between the visual-haptic (VH) and haptic-visual (HV) conditions. Cross-modal performance was better when objects differed in both the x and y dimensions rather than in one dimension alone. In Experiment 2, we investigated the relative contribution of each modality to performance across different interstimulus delays. We found no differential effect of delay between the HH and VV conditions, although general performance was better for the VV condition than for the HH condition. Again, responses to xy changes were better than changes in the x or y dimensions alone. Finally, in Experiment 3, we examined performance in a matching task with simultaneous and successive presentation conditions. We failed to find any difference between simultaneous and successive presentation conditions. Our findings suggest that the short-term retention of object representations is similar in both the visual and haptic modalities. Moreover, these results suggest that recognition is best within a temporal window that includes simultaneous or rapidly successive presentation of stimuli across the modalities and is also best when objects are more discriminable from each other.

Adolescent↗

PubMed2002

Categorical perception of familiar objects.

We report three experiments where the categorical perception of familiar, three-dimensional objects was investigated. A continuum of shape change between 15 pairs of objects was created and the images along the continuum were used as stimuli. In Experiment 1 participants were first required to discriminate pairs of images of objects that lay along the shape continuum. Then participants were asked to classify each morph-image into one of two pre-specified classes. We found evidence for categorical perception in some but not all of our object pairs. In Experiment 2 we varied the viewpoint of the objects in the discrimination task and found that effects of categorical perception generalized across changes in view. In Experiment 3 similarity ratings for each object pair were collected. These similarity scores correlated with the degree of perceptual categorization found for the object pairs. Our findings suggest that some familiar objects are perceived categorically and that categorical perception is closely tied to inter-object perceptual similarity.

Adolescent↗

PubMedDate not supplied

Visual, haptic and cross-modal recognition of objects and scenes.

In this article we review current literature on cross-modal recognition and present new findings from our studies on object and scene recognition. Specifically, we address the questions of what is the nature of the representation underlying each sensory system that facilitates convergence across the senses and how perception is modified by the interaction of the senses. In the first set of our experiments, the recognition of unfamiliar objects within and across the visual and haptic modalities was investigated under conditions of changes in orientation (0 degrees or 180 degrees ). An orientation change increased recognition errors within each modality but this effect was reduced across modalities. Our results suggest that cross-modal object representations of objects are mediated by surface-dependent representations. In a second series of experiments, we investigated how spatial information is integrated across modalities and viewpoint using scenes of familiar, 3D objects as stimuli. We found that scene recognition performance was less efficient when there was either a change in modality, or in orientation, between learning and test. Furthermore, haptic learning was selectively disrupted by a verbal interpolation task. Our findings are discussed with reference to separate spatial encoding of visual and haptic scenes. We conclude by discussing a number of constraints under which cross-modal integration is optimal for object recognition. These constraints include the nature of the task, and the amount of spatial and temporal congruency of information across the modalities.

Animals↗