Coordinate transformations in object recognition.

A basic problem of visual perception is how human beings recognize objects after spatial transformations. Three central classes of findings have to be accounted for: (a) Recognition performance varies systematically with orientation, size, and position; (b) recognition latencies are sequentially additive, suggesting analogue transformation processes; and (c) orientation and size congruency effects indicate that recognition involves the adjustment of a reference frame. All 3 classes of findings can be explained by a transformational framework of recognition: Recognition is achieved by an analogue transformation of a perceptual coordinate system that aligns memory and input representations. Coordinate transformations can be implemented neurocomputationally by gain (amplitude) modulation and may be regarded as a general processing principle of the visual cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Object recognition and object orientation in Alzheimer's disease.

There are a wide variety of neuropsychological deficits in Alzheimer's disease (AD), among which are disorders of visual perception and spatial cognition. The present study investigated the ability of 20 mildly to moderately deteriorated patients with AD (and 174 age- and education-matched controls) on tasks that required them to visually identify, provide the canonical orientation of, and mentally rotate common objects. Some 85% of the AD patients performed poorly on all tasks. The authors were able to identify a small number of individual patients whose pattern of performance represented double dissociations between recognizing objects and knowing their canonical orientation. These findings are interpreted in the context of previous findings, especially as to whether information relating to an object's orientation and identity is independently coded. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of perceptual load in object recognition.

Predictions from perceptual load theory (Lavie, 1995, 2005) regarding object recognition across the same or different viewpoints were tested. Results showed that high perceptual load reduces distracter recognition levels despite always presenting distracter objects from the same view. They also showed that the levels of distracter recognition were unaffected by a change in the distracter object view under conditions of low perceptual load. These results were found both with repetition priming measures of distracter recognition and with performance on a surprise recognition memory test. The results support load theory proposals that distracter recognition critically depends on the level of perceptual load. The implications for the role of attention in object recognition theories are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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° 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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of varying stimulus size on object recognition in pigeons.

The authors investigated the pigeon's ability to generalize object discrimination performance to smaller and larger versions of trained objects. In Experiment 1, they taught pigeons with line drawings of multipart objects and later tested the birds with both larger and smaller drawings. The pigeons exhibited significant generalization to new sizes, although they did show systematic performance decrements as the new size deviated from the original. In Experiment 2, the authors tested both linear and exponential size changes of computer-rendered basic shapes to determine which size transformation produced equivalent performance for size increases and decreases. Performance was more consistent with logarithmic than with linear scaling of size. This finding was supported in Experiment 3. Overall, the experiments suggest that the pigeon encodes size as a feature of objects and that the representation of size is most likely logarithmic. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unraveling mechanisms for expert object recognition: Bridging brain activity and behavior.

Behavioral sensitivity to object transformations and the response to novel objects (Greebles) in the fusiform face area (FFA) was measured several times during expertise training. Sensitivity to 3 transformations increased with expertise: (a) configural changes in which halves of objects were misaligned, (b) configural changes in which some of the object parts were moved, and (c) the substitution of an object part with a part from a different object. The authors found that holistic-configural effects can arise from object representations that are differentiated in terms of features or parts. Moreover, a holistic-inclusive effect was correlated with changes in the right FFA. Face recognition may not be unique in its reliance on holistic processing, measured in terms of both behavior and brain activation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Similarities and differences in spatial learning and object recognition between young male C57Bl/6J mice and Sprague-Dawley rats.

Mice and rats are often used interchangeably in neuroscience research. However, species differences in brain structure and connectivity exist within the medial temporal lobe circuits that contribute to learning and memory. The hippocampus in particular contributes to both spatial learning and recognition memory, but the extent to which rats and mice are comparable in these two cognitive domains remains unclear. To evaluate potential species differences in spatial memory and object recognition, young adult male Sprague–Dawley rats and male C57Bl/6J mice were tested in the water maze and novel object recognition tasks. Following six days of training, with four trials per day, there was no difference in the ability of rats and mice to learn the location of a hidden platform. However, rats performed better than mice on the probe trial, indicative of superior retention. In the novel object preference test, no species differences in recognition memory were detected, although rats spent more time exploring the arena and took longer to approach the objects. These observations suggest that while species differences in spatial memory retention are present, they do not correlate with differences in object recognition memory. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Semantic interference from visual object recognition on visual imagery.

A new technique for examining the interaction between visual object recognition and visual imagery is reported. The "image-picture interference" paradigm requires participants to generate and make a response to a mental image of a previously memorized object, while ignoring a simultaneously presented picture distractor. Responses in 2 imagery tasks (making left-right higher spatial judgments and making taller-wider judgments) were longer when the simultaneous picture distractor was categorically related to the target distractor relative to unrelated and neutral target-distractor combinations. In contrast, performance was not influenced in this way when the distractor was a related word, when a semantic categorization decision was made to the target, or when distractor and target were visually but not categorically related to one another. The authors discuss these findings in terms of the semantic representations shared by visual object recognition and visual imagery that mediate performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanisms and neural basis of object and pattern recognition: A study with chess experts.

Comparing experts with novices offers unique insights into the functioning of cognition, based on the maximization of individual differences. Here we used this expertise approach to disentangle the mechanisms and neural basis behind two processes that contribute to everyday expertise: object and pattern recognition. We compared chess experts and novices performing chess-related and -unrelated (visual) search tasks. As expected, the superiority of experts was limited to the chess-specific task, as there were no differences in a control task that used the same chess stimuli but did not require chess-specific recognition. The analysis of eye movements showed that experts immediately and exclusively focused on the relevant aspects in the chess task, whereas novices also examined irrelevant aspects. With random chess positions, when pattern knowledge could not be used to guide perception, experts nevertheless maintained an advantage. Experts' superior domain-specific parafoveal vision, a consequence of their knowledge about individual domain-specific symbols, enabled improved object recognition. Functional magnetic resonance imaging corroborated this differentiation between object and pattern recognition and showed that chess-specific object recognition was accompanied by bilateral activation of the occipitotemporal junction, whereas chess-specific pattern recognition was related to bilateral activations in the middle part of the collateral sulci. Using the expertise approach together with carefully chosen controls and multiple dependent measures, we identified object and pattern recognition as two essential cognitive processes in expert visual cognition, which may also help to explain the mechanisms of everyday perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Personality variables and recognition response level.

The relationships between amount of cue accumulation prior to recognition response and MMPI variables were examined. The Ss were 33 male college students. They were shown stimulus object-name pairs to a criterion level and were then shown sequences of test figures containing an increasing amount of cue information. The S was required to name the object upon recognition. The only significant finding predicted was an r of .49 between Pa score and recognition score. 16 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Magnitude of the object recognition deficit associated with perirhinal cortex damage in rats: Effects of varying the lesion extent and the duration of the sample period.

The present study examines 2 factors that might moderate the object-recognition deficit seen after perirhinal cortex damage. Object recognition by normal rats was improved by extending (from 4 to 8 min) the sample period during which an object was first explored. Furthermore, there was a significant positive correlation between time spent in close exploration of the sample object and degree of successful novelty discrimination. In contrast, rats with perirhinal cortex lesions failed to benefit from increased close exploration and did not discriminate the novel object after even the longest sample period. Nevertheless, the lesions did not disrupt habituation across repeated exposure to the same object. The second factor was extent of perirhinal cortex damage. A significant correlation was found between total perirhinal cortex loss and degree of recognition impairment. Within the perirhinal cortex, only damage to the caudal perirhinal cortex correlated significantly with recognition memory deficits. This study highlights the critical importance of the perirhinal cortex within the temporal lobe for recognition memory and shows that the lesion-induced deficit occurs despite seemingly normal levels of close object exploration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rhinal cortex lesions and object recognition in rats.

Tested 11 male rats with bilateral lesions of lateral entorhinal cortex and perirhinal cortex on a nonrecurring-items delayed nonmatching-to-sample (DNMS) task resembling the one that is commonly used to study object recognition (OR) in monkeys. The rats were tested at retention delays of 4, 15, 60, 120, and 600 sec before and after surgery. After surgery, they displayed a delay-dependent deficit: They performed normally at the 4-sec delay but were impaired at delays of 15 sec or longer. The addition of bilateral amygdala lesions did not increase their DNMS deficits. The present finding of a severe DNMS deficit following rhinal cortex damage is consistent with the authors' previous finding that bilateral lesions of the hippocampus cause only mild DNMS deficits in rats unless there is also damage to rhinal cortex (D. G. Mumby et al, 1992). These findings add to accumulating evidence that the rhinal cortex, but not the amygdala, plays a critical role in OR. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The time course of object-feature retrieval in recognition.

The time course of perception and retrieval of object features was investigated. Participants completed a perceptual matching task and 2 recognition tasks under time pressure. The recognition tasks imposed different retention loads. A stochastic model of feature sampling with a Bayesian decision component was used to estimate the rate of feature perception and the rate of retrieval of feature information. The results demonstrated that retrieval rates did not differ among object features if only a single object was held in memory. If 2 objects were retained in memory, differences among retrieval rates of features emerged, indicating that features that were quickly perceived were also quickly retrieved. The results from the 2-object retention condition are compatible with process reinstatement models of retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of selective neonatal hippocampal lesions on tests of object and spatial recognition memory in monkeys.

Earlier studies in monkeys have reported mild impairment in recognition memory after nonselective neonatal hippocampal lesions. To assess whether the memory impairment could have resulted from damage to cortical areas adjacent to the hippocampus, we tested adult monkeys with neonatal focal hippocampal lesions and sham-operated controls in three recognition tasks: delayed nonmatching-to-sample, object memory span, and spatial memory span. Further, to rule out that normal performance on these tasks may relate to functional sparing following neonatal hippocampal lesions, we tested adult monkeys that had received the same focal hippocampal lesions in adulthood and their controls in the same three memory tasks. Both early and late onset focal hippocampal damage did not alter performance on any of the three tasks, suggesting that damage to cortical areas adjacent to the hippocampus was likely responsible for the recognition impairment reported by the earlier studies. In addition, given that animals with early and late onset hippocampal lesions showed object and spatial recognition impairment when tested in a visual paired comparison task, the data suggest that not all object and spatial recognition tasks are solved by hippocampal-dependent memory processes. The current data may not only help explain the neural substrate for the partial recognition memory impairment reported in cases of developmental amnesia, but they are also clinically relevant given that the object and spatial memory tasks used in monkeys are often translated to investigate memory functions in several populations of human infants and children in which dysfunction of the hippocampus is suspected. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Context- but not familiarity-dependent forms of object recognition are impaired following excitotoxic hippocampal lesions in rats.

Dual-process models of recognition memory in animals propose that recognition memory is supported by two independent processes that reflect the operation of distinct brain structures: a familiarity process that operates independently of the hippocampus and a context-dependent (episodic) memory process that is dependent on the hippocampus. A novel variant of an object recognition procedure was used to examine this proposal. Healthy rats showed a preference for exploring a novel object rather than a familiar object: a familiarity-dependent recognition effect. They also showed a preference for exploring a familiar object that was presented in a different spatiotemporal context rather than a familiar object that was presented either in a different spatial or temporal context: a context-dependent form of recognition that is sensitive to "what" object has been presented "where" and "when." Rats with excitotoxic hippocampal lesions showed the familiarity-dependent but not the context-dependent form of recognition. The results provide support for dual-process theories of recognition memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Seeing two sides at once: Effects of viewpoint and object structure on recognizing three-dimensional objects.

Five experiments demonstrated that adults can identify certain novel views of 3-dimensional model objects on the basis of knowledge of a single perspective. Geometrically irregular contour (wire) and surface (clay) objects and geometrically regular surface (pipe) objects were accurately recognized when rotated 180° about the vertical (y) axis. However, recognition accuracy was poor for all types of objects when rotated around the y-axis by 90°. Likewise, more subtle rotations in depth (i.e., 30° and 60°) induced decreases in recognition of both contour and surface objects. These results suggest that accurate recognition of objects rotated in depth by 180° may be achieved through use of information in objects' 2-dimensional bounding contours, the shapes of which remain invariant over flips in depth. Consistent with this interpretation, a final study showed that even slight rotations away from 180° cause precipitous drops in recognition accuracy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contrasting the edge- and surface-based theories of object recognition: Behavioral evidence from macaques (Macaca mulatta).

This study assessed the contribution of edge and surface cues on object representation in macaques (Macaca mulatta). In Experiments 1 and 2, 5 macaques were trained to discriminate 4 simple volumetric objects (geons) and were subsequently tested for their ability to recognize line drawings, silhouettes, and light changes of these geons. Performance was above chance in all test conditions and was similarly high for the line drawings and silhouettes of geons, suggesting the use of the outline shape to recognize the original objects. In addition, transfer for the geons seen under new lighting was greater than for the other stimuli, stressing the importance of the shading information. Experiment 3, using geons filled with new textures, showed that a radical change in the surface cues does not prevent object recognition. It is concluded that these findings support a surface-based theory of object recognition in macaques, although it does not exclude the contribution of edge cues, especially when surface details are not available. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time-course contingencies in perceptual organization and identification of fragmented object outlines.

To study the dynamic interplay between different component processes involved in the identification of fragmented object outlines, the authors used a discrete-identification paradigm in which the masked presentation duration of fragmented object outlines was repeatedly increased until correct naming occurred. Survival analysis was used to investigate whether and when different types of information—such as contour integration cues (proximity, collinearity, and fragment density), fragment properties (low vs. high curvature), stimulus complexity (global symmetry, number and saliency of the parts), and memory factors (natural vs. artifactual)—influenced the timing of identification. The results show that the importance of these different types of information can change over the time course of object identification, indicating so-called time-course contingencies. Most important, the straight segments of a contour played a larger role for complex outlines with high part saliency during early (bottom-up) grouping processes, whereas the curved segments of object outlines were more important during later (top-down) matching processes for simpler outlines with lower part saliency. This new insight can explain why different studies on shape-based object identification have produced seemingly contradictory results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Face and emotion recognition deficits in Turner syndrome: A possible role for X-linked genes in amygdala development.

Face recognition is thought to rely on configural visual processing, Where face recognition impairments have been identified, qualitatively delayed or anomalous configural processing has also been found. A group of women with Turner syndrome (TS) with monosomy for a single maternal X chromosome (45, Xm) showed an impairment in face recognition skills compared with normally developing women. However, normal configural face-processing abilities were apparent. The ability to recognize facial expressions of emotion, particularly fear, was also impaired in this TS subgroup. Face recognition and fear recognition accuracy were significantly correlated in the female control group but not in women with TS. The authors therefore suggest that anomalies in amygdala function may be a neurological feature of TS of this karyotype. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensorimotor prediction and memory in object manipulation.

Notes that when people lift objects of different size but equal weight, they initially employ too much force for the large object and too little force for the small object. However, over repeated lifts of the two objects, they learn to suppress the size–weight association used to estimate force requirements and appropriately scale their lifting forces to the true and equal weights of the objects. Thus, sensorimotor memory from previous lifts comes to dominate visual size information in terms of force prediction. Here the authors ask whether this sensorimotor memory is transient, preserved only long enough to perform the task, or more stable. After completing an initial lift series in which they lifted equally weighted large and small objects in alternation, 24 18–28 yr olds then repeated the lift series after delays of 15 min or 24 hrs. In both cases, participants retained information about the weights of the objects and used this information to predict the appropriate fingertip forces. This preserved sensorimotor memory suggests that participants acquired internal models of the size–weight stimuli that could be used for later prediction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)