Rebecca Lawson

What's in a name ? Access to information from people's names

Abstract The processing of peoples names is contrasted with face recognition and word recognition. The effects of the familiarity of initial and surnames and frequency of surnames (the number of people with the same surname) were investigated in several tasks. It was found that the effects of name familiarity and surname frequency were analogous to the effects of word frequency in tasks which did not require access to memory for individuals (a nationality decision and naming latency). In tasks which do require access to memory for individuals (familiarity decision and a semantic classification), the effect of surname frequency was analogous to the effect of distinctive-ness in face recognition. The results are discussed in terms of a functional model of name processing in which name recognition units mediate between the output of word recognition units and access to identity-specific semantics.

Achieving visual object constancy across plane rotation and depth rotation

Visual object constancy is the ability to recognise an object from its image despite variation in the image when the object is viewed from different angles. I describe research which probes the human visual systems ability to achieve object constancy across plane rotation and depth rotation. I focus on the ecologically important case of recognising familiar objects, although the recognition of novel objects is also discussed. Cognitive neuropsychological studies of patients with specific deficits in achieving object constancy are reviewed, in addition to studies which test neurally intact subjects. In certain cases, the recognition of invariant features allows objects to be recognised irrespective of the view depicted, particularly if small, distinctive sets of objects are presented repeatedly. In contrast, in most situations, recognition is sensitive to both the view in-plane and in-depth from which an object is depicted. This result suggests that multiple, view-specific, stored representations of familiar objects are accessed in everyday, entry-level visual recognition, or that transformations such as mental rotation or interpolation are used to transform between retinal images of objects and view-specific, stored representations.

VIEW SPECIFICITY IN OBJECT PROCESSING : EVIDENCE FROM PICTURE MATCHING

Four experiments investigated the types of representations mediating sequential visual matching of objects depicted at different depth rotations. Matching performance was affected by the similarity between depicted views of the objects. Effects of view similarity were not influenced by the presence of a meaningless mask in the interstimulus interval (ISI), but they were reduced by long ISis and by familiarity with the stimuli. It is suggested that with longer ISis or increased stimulus familiarity, a number of object representations are activated that, although abstracted from some image characteristics, remain view specific. Under these conditions, matching is less reliant on representations closely tied to the view of the initial stimulus presented. The results are consistent with both the derivation and the long-term representation of view-specific rather than view-invariant descriptions of objects. Models of human visual object recognition must account for the generally rapid and accurate achievement of object constancy: that is, the relative immunity of object recognition to changes in the retinal image projected by an object, dependent on the position of the object with respect to the viewer. Transformations of position, scale, and distance and rotations in plane and in depth can profoundly alter the retinal image projected by the same object from one viewing occasion to another. Despite this, human visual object recognition generally proceeds efficiently and shows remarkably little sensitivity to changes in the viewpoint of the observer. The precise procedures by which object constancy is achieved remain poorly understood. Several accounts assume that a series of different representations are computed en route to a relatively abstract, view-invariant representation. The derivation of a single, abstract, view-invariant representation is held to be necessary to minimize long-term storage requirements and to allow semantic and associative information specific to a given object to be retrieved from a range of retinal projections (e.g., Hinton, 1981; Lowe, 1987; Marr, 1982). Contrasting approaches suggest the existence of a small number of view-specific representations of each object, perhaps invariant over certain properties such as retinal position and scale but not invariant over rotation in depth (Edelman & Weinshall, 1991; Perrett, Benson, Oram,

Object Recognition under Sequential Viewing Conditions: Evidence for Viewpoint-Specific Recognition Procedures:

In many computational approaches to vision it has been emphasised that object recognition involves the encoding of view-independent descriptions prior to matching to a stored object model, thus enabling objects to be identified across different retinal projections. In contrast, neurophysiological studies suggest that image descriptions are matched to less abstract, view-specific representations, resulting in more efficient access to stored object knowledge for objects presented from a view similar to a stored viewpoint. Evidence favouring a primary role for view-specific object descriptions in object recognition is reported. In a series of experiments employing line drawings of familiar objects, the effects of depth rotation upon the efficiency of object recognition were investigated. Subjects were required to identify an object from a sequence of very briefly presented pictures. The results suggested that object recognition is based upon the matching of image descriptions to view-specific stored representations, and that priming effects under sequential viewing conditions are strongly influenced by the visual similarity of different views of objects.

View-specific effects of depth rotation and foreshortening on the initial recognition and priming of familiar objects

In a series of three experiments, we examined, first, the effects of viewpoint in depth on the efficiency of initial picture naming and, second, the effects of priming on subsequent naming. On initial presentation, foreshortened views were harder to name than were more typical (nonforeshortened) views. In addition, priming increased as a function of the similarity of the prime and target. Indeed, if a foreshortened view of an object had already been named, the subjects named a subsequent foreshortened view of that object as fast as or faster than they named a subsequent, more typical view. These results provide evidence against theories that predict full view-invariant object recognition and view-invariant priming of object recognition. Instead, the results support theories that suggest that object recognition is mediated by stored representations that are both view- and object-specific.

Repetition priming and the haptic recognition of familiar and unfamiliar objects

In four experiments, we examined the haptic recognition of 3-D objects. In Experiment 1, blindfolded participants named everyday objects presented haptically in two blocks. There was significant priming of naming, but no cost of an object changing orientation between blocks. However, typical orientations of objects were recognized more quickly than nonstandard orientations. In Experiment 2, participants accurately performed an unannounced test of memory for orientation. The lack of orientation-specific priming in Experiment 1, therefore, was not because participants could not remember the orientation at which they had first felt an object. In Experiment 3, we examined haptic naming of objects that were primed either haptically or visually. Haptic priming was greater than visual priming, although significant cross-modal priming was also observed. In Experiment 4, we tested recognition memory for familiar and unfamiliar objects using an old-new recognition task. Objects were recognized best when they were presented in the same orientation in both blocks, suggesting that haptic object recognition is orientation sensitive. Photographs of the unfamiliar objects may be downloaded from www.psychonomic.org/archive.

Recognition thresholds for plane-rotated pictures of familiar objects

We investigated picture plane rotation effects on the minimum stimulus duration required to recognise pictures of familiar objects in a picture-word verification task. Participants made unspeeded responses, selecting from 126 written alternatives. Longer stimulus durations were needed to identify plane-misoriented views. These orientation effects were non-linear, arguing against a simple mental rotation account of compensation for plane misorientation in identification tasks. Orientation effects were found for almost all items, in particular including those labelled at the basic level (cf. Hamm, McMullen, 1998, Journal of Experimental Psychology: Human Perception and Performance 24, 413-426). We suggest that plane misorientation increases the difficulty of basic level as well as subordinate level identification unless only a small, visually dissimilar set of stimuli are presented. Errors in the task were analysed to provide an alternative, objective measure of perceived visual similarity, by assessing the number and nature of mistaken identifications made to a given target object. We propose that misorientation effects are best understood in terms of the effects of the perceived visual similarity of a target to its set of response alternatives rather than in terms of the level (basic or subordinate) at which the target is to be identified.

A Comparison of the Effects of Depth Rotation on Visual and Haptic Three-Dimensional Object Recognition.

A sequential matching task was used to compare how the difficulty of shape discrimination influences the achievement of object constancy for depth rotations across haptic and visual object recognition. Stimuli were nameable, 3-dimensional plastic models of familiar objects (e.g., bed, chair) and morphs midway between these endpoint shapes (e.g., a bed-chair morph). The 2 objects presented on a trial were either both placed at the same orientation or were rotated by 90 degrees relative to each other. Discrimination difficulty was increased by presenting more similarly shaped objects on mismatch trials (easy: bed, then lizard; medium: bed, then chair; hard: bed, then bed-chair morph). For within-modal visual matching, orientation changes were most disruptive when shape discrimination was hardest. This interaction for 3-dimensional objects replicated the interaction reported in earlier studies presenting 2-dimensional pictures of the same objects (Lawson & Bülthoff, 2008). In contrast, orientation changes and discrimination difficulty had additive effects on within-modal haptic and cross-modal visual-to-haptic matching, whereas cross-modal haptic-to-visual matching was orientation invariant. These results suggest that the cause of orientation sensitivity may differ for visual and haptic object recognition.

The Effects of View in Depth on the Identification of Line Drawings and Silhouettes of Familiar Objects: Normality and Pathology

Three experiments are reported into the effects of viewpoint in depth, and of stimulus type (line drawings vs silhouettes) on picture identification. Clear effects of both factors were observed. Strongly foreshortened views were harder to identify than more canonical views, and silhouettes were harder to identify than line drawings. Furthermore, there was a strong interaction. The foreshortening disadvantag e was greatly increased if silhouettes rather than line drawings were presented. Our results suggest that the internal information available in line drawings (but not silhouettes) is critical for identifying foreshortened views of objects. Additional results from an agnosic patient, HJA, suggest that certain forms of brain damage can disrupt the use of internal information for identification, reducing differences between performance with line drawings and silhouettes.

The effects of plane rotation on the recognition of brief masked pictures of familiar objects

Two experiments examined the effects of plane rotation on the recognition of briefly displayed pictures of familiar objects, using a picture—word verification task. Mirroring the results of earlier picture naming studies (Jolicoeur, 1985; Jolicoeur & Milliken, 1989), plane rotation away from a canonical upright orientation reduced the efficiency of recognition, although in contrast to the results from picture naming studies, the rotation effects were not reduced with experience with the stimuli. However, the rotation effects were influenced by the visual similarity of the distractor objects to the picture of the object presented, with greater orientation sensitivity being observed when visually similar distractors were presented. We suggest that subjects use orientation-sensitive representations to recognize objects in both the present unspeeded verification and in the earlier speeded naming tests of picture identification.