Preattentive and attentive visual search in individuals with hemispatial neglect.

Preattentive and attentive visual processing was examined in patients with hemispatial neglect, hemispatial neglect with hemianopia, and control participants. In the preattentive search task, targets possessed a unique feature that was not shared by distractors. In the attentive search task, targets lacked a feature that was present in the distractors. Preattentive search was normal in 3 neglect patients with cortical lesions but not in 2 neglect patients with hemianopia. A 4th neglect patient without hemianopia with a subcortical infarct abnormally used serial search mechanisms in the preattentive task. Neglect patients were characteristically impaired in the contralesional field in the attentive search task. This study demonstrates preserved explicit detection of visual features in cases of hemispatial neglect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Robust representations for faces: Evidence from visual search.

We report evidence from visual search that people can develop robust representations for highly overlearned faces. When observers searched for their own face versus the face of an unfamiliar observer, search slopes and intercepts revealed consistently faster processing of self than stranger. These processing advantages persisted even after hundreds of presentations of the unfamiliar face and even for atypical profile and upside-down views. Observers not only showed rapid asymptotic recognition of their own face as the target, but could reject their own face more quickly as the distractor. These findings suggest that robust representations for a highly overlearned face may (a) mediate rapid asymptotic visual processing, (b) require extensive experience to develop, (c) contain abstract or view-invariant information, (d) facilitate a variety of processes such as target recognition and distractor rejection, and (e) demand less attentional resources. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Types of visual–spatial representations and mathematical problem solving.

Although visual-spatial representations are used extensively in mathematics and spatial ability is highly correlated with success in mathematics education, research to date has not demonstrated a clear relationship between use of visual-spatial representations and success in mathematical problem solving. The authors distinguished 2 types of visual-spatial representations: schematic representations that encode the spatial relations described in a problem and pictorial representations that encode the visual appearance of the objects described in the problem. Participants solved mathematical problems and reported on their solution strategies. The authors were able to reliably classify their visual-spatial representations as primarily schematic or primarily pictorial. Use of schematic spatial representations was associated with success in mathematical problem solving, whereas use of pictorial representations was negatively correlated with success. Use of schematic representations was also significantly correlated with one measure of spatial ability. The research therefore helps clarify the relationship between visual imagery, spatial ability, and mathematical problem solving. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pip and pop: Nonspatial auditory signals improve spatial visual search.

Searching for an object within a cluttered, continuously changing environment can be a very time-consuming process. The authors show that a simple auditory pip drastically decreases search times for a synchronized visual object that is normally very difficult to find. This effect occurs even though the pip contains no information on the location or identity of the visual object. The experiments also show that the effect is not due to general alerting (because it does not occur with visual cues), nor is it due to top-down cuing of the visual change (because it still occurs when the pip is synchronized with distractors on the majority of trials). Instead, we propose that the temporal information of the auditory signal is integrated with the visual signal, generating a relatively salient emergent feature that automatically draws attention. Phenomenally, the synchronous pip makes the visual object pop out from its complex environment, providing a direct demonstration of spatially nonspecific sounds affecting competition in spatial visual processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implications of visual search deficits for cognitive theory.

Neuropsychological evidence was presented and found to be consistent with Treisman's Feature Integration Theory (FIT). Several studies were reported using groups of patients with unilateral visual neglect, stable patients with known lesion loci, and a single patient with bilateral parietal-occipital lesions. Collectively, the data support a distinction between feature and conjunction search. They also support arguments for the primary role of spatial representation in forming correct conjunctions between features and for individuating objects. Nevertheless, the data do call for some refinements in FIT. The spatial maps involved in feature integration for serial visual search and for the experience of an accurately conjoined object appear to be relatively late. Features are likely to be integrated in the nervous system at sub-threshold levels in early vision (e.g., vl or v2), but it requires supra-threshold spatial knowledge to successfully conjoin features in visual experience (Wojciulik, Robertson & Kanwisher, 1994). The evidence as a whole, however, is consistent with FIT in that spatial information is necessary for controlled visual search and for the accurate conjunction of features in multi-item arrays. In addition, it suggests that explicit access to relatively late spatial information is necessary to correctly conjoin features in the experiences percept. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A validity study of two projective object representations measures.

Two projective measures of object representations, the Concept of the Object on the Rorschach (H. Rorchach, 1942) and the Social Cognition and Object Relations Scales (D. Westen, 1993) were compared with each other, with measures of intelligence (Wechsler Adult Intelligence Scale—Revised; D. Wechsler, 1981), and measures of pathology (Millon Clinical Multiaxial Inventory [T. Millon, 1983], Minnesota Multiphasic Personality Inventory [S. R. Hathaway & J. McKinley, 1983] Axis 11 diagnoses). Analyses focused on the construct validity of object representations and the implications of structural and affective aspects of object representations for psychopathology. Results support the construct validity of object representations and an affective, but not a cognitive–structural, linkage between object representations and pathology. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Feature integration theory revisited: Dissociating feature detection and attentional guidance in visual search.

In feature integration theory (FIT; A. Treisman & S. Sato, 1990), feature detection is driven by independent dimensional modules, and other searches are driven by a master map of locations that integrates dimensional information into salience signals. Although recent theoretical models have largely abandoned this distinction, some observed results are difficult to explain in its absence. The present study measured dimension-specific performance during detection and localization, tasks that require operation of dimensional modules and the master map, respectively. Results showed a dissociation between tasks in terms of both dimension-switching costs and cross-dimension attentional capture, reflecting a dimension-specific nature for detection tasks and a dimension-general nature for localization tasks. In a feature-discrimination task, results precluded an explanation based on response mode. These results are interpreted to support FIT's postulation that different mechanisms are involved in parallel and focal attention searches. This indicates that the FIT architecture should be adopted to explain the current results and that a variety of visual attention findings can be addressed within this framework. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Association, inhibition, and object permanence in dogs' (Canis familiaris) spatial search.

The relative role of associative processes and the use of explicit cues about object location in search behavior in dogs (Canis familiaris) was assessed by using a spatial binary discrimination reversal paradigm in which reversal conditions featured: (1) a previously rewarded location and a novel location, (2) a previously nonrewarded location and a novel location, or (3) a previously rewarded location and a previously nonrewarded location. Rule mediated learning predicts a similar performance in these different reversal conditions whereas associative learning predicts the worst performance in Condition 3. Evidence for an associative control of search emerged when no explicit cues about food location were provided (Experiment 1) but also when dogs witnessed the hiding of food in the reversal trials (Experiment 2) and when they did so in both the prereversal and the reversal trials (Experiment 3). Nevertheless, dogs performed better in the prereversal phase of Experiment 3 indicating that their search could be informed by the knowledge of the food location. Experiment 4 confirmed the results of Experiments 1 and 2, under a different arrangement of search locations. We conclude that knowledge about object location guides search behavior in dogs but it cannot override associative processes. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Feature asymmetries in visual search: effects of display duration, target eccentricity, orientation and spatial frequency

In Experiments 1-3, we monitored search performance as a function of target eccentricity under display durations that either allowed or precluded eye movements. The display was present either until observers responded, for 104 msec, or for 62 msec. In all three experiments an orientation asymmetry emerged: observers detected a tilted target among vertical distracters more efficiently than a vertical target among vertical distracters. As target eccentricity increased, reaction times and errors augmented, and the set size effect became more pronounced, more so for vertical than tilted targets. In Experiments 4-7, the stimulus spatial properties were manipulated: spatial frequency; size; and orientation. The eccentricity effect was more pronounced for vertical than tilted targets and for high- than low-spatial frequency targets. This effect was eliminated when either the size, the size and orientation, or the size and spatial frequency were magnified (M-cortical factor). By increasing the signal-to-noise ratio, magnification reduced the extent of both asymmetries; it aided more the detection of tilted than vertical and of high- than low-spatial frequency targets. Experiments 4-7 indicate that performance improvement in the magnified conditions was due to the specific pairing of stimulus size with retinal eccentricity and not to the larger stimulus size of the magnified conditions. We conclude that stimulus size, orientation and spatial frequency influence the extent of the eccentricity effect and the efficiency of search performance.     

Measuring the search image: Expectation, detection and recognition in pigeon visual search.

Pigeons searched computer screens for a grating target that varied in spatial frequency and orientation. In Experiment 1, a pretrial cue signaled that a particular target would appear. The cue speeded response to this primed target and to targets of the same orientation and similar spatial frequency to the primed target. However, the cue slowed search for targets differing from the primed target in orientation. In Experiment 2, pecks to a single target were reinforced. Responding generalized somewhat to targets of spatial frequency similar to the primed target and to targets of either orientation. Thus, stimulus aspects that affect detection may differ from those that affect recognition; if a common representation serves both, it functions differently in the 2 cases. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of surface medium on visual search for orientation and size features.

By using a visual search task, this study examined the encoding of orientation and size for stimuli defined in five different surface media: luminance, color, texture, relative motion, and binocular disparity. Results indicated a spatially parallel analysis of size and orientation features for all surface media, with the possible exception of binocular disparity. The data also revealed a search rate asymmetry in the orientation task for all media: Parallel or shallow search functions were obtained for oblique targets in vertical distractors, whereas steeper serial search functions were obtained for vertical targets in oblique distractors. No consistent asymmetry was found for the large and small targets in the size task. There seemed to be common principles of coding in all these different media, suggesting either a single analysis of shape features applied to a common representation or multiple analyses, one for each surface medium, with each extracting a similar set of features. The shared coding principles may facilitate the use of redundancy across media to reduce ambiguities in the locations and shapes of contours in the visual scene. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A theory of visual attention.

A unified theory of visual recognition and attentional selection is developed by integrating the biased-choice model for single-stimulus recognition (R. D. Luce, 1963; R. N. Shepard, 1957) with a choice model for selection from multielement displays (C. Bundesen et al; see record 1985-05669-001) in a race model framework. Mathematically, the theory is tractable, and it specifies the computations necessary for selection. The theory is applied to extant findings from a broad range of experimental paradigms. The findings include effects of object integrality in selective report, number and spatial position of targets in divided-attention paradigms, selection criterion and number of distracters in focused-attention paradigms, delay of selection cue in partial report, and consistent practice in search. On the whole, the quantitative fits are encouraging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distributed representations of structure: A theory of analogical access and mapping.

This article describes an integrated theory of analogical access and mapping, instantiated in a computational model called LISA (Learning and Inference with Schemas and Analogies). LISA represents predicates and objects as distributed patterns of activation that are dynamically bound into propositional structures, thereby achieving both the flexibility of a connectionist system and the structure sensitivity of a symbolic system. The model treats access and mapping as types of guided pattern classification, differing only in that mapping is augmented by a capacity to learn new correspondences. The resulting model simulates a wide range of empirical findings concerning human analogical access and mapping. LISA also has a number of inherent limitations, including capacity limits, that arise in human reasoning and suggests a specific computational account of these limitations. Extensions of this approach also account for analogical inference and schema induction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attachment representations in mothers, fathers, adolescents, and clinical groups: A meta-analytic search for normative data.

This meta-analysis on 33 studies, including more than 2,000 Adult Attachment Interview (AAI) classifications, presents distributions of AAI classifications in samples of nonclinical fathers and mothers, in adolescents, in samples from different cultures, and in clinical groups. Fathers, adolescents, and participants from different countries show about the same distribution of AAI classifications as nonclinical mothers do. The distribution of nonclinical mothers is as follows: 24% dismissing, 58% autonomous, and 18% preoccupied mothers. About 19% of the nonclinical mothers are unresolved with respect to loss or trauma of other kinds. Mothers from low socioeconomic status show more often dismissing attachment representations and unresolved loss or trauma. Autonomous women and autonomous men are more often married to each other than can be expected by chance, and the same goes for unresolved men and women. Clinical participants show highly deviating distributions of AAI classifications, with a strong overrepresentation of insecure attachment representations, but systematic relations between clinical diagnosis and type of insecurity are absent. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Controlling the focus of spatial attention during visual search: Effects of advanced aging and Alzheimer disease.

It was hypothesized that slowed visual search in healthy adult aging arises from reduced ability to adjust the size of the attentional focus. A novel, cued-visual search task manipulated the scale of spatial attention in a complex field in healthy elderly individuals and patients with dementia of the Alzheimer type (DAT). Precues indicated with varying validity the size and location of the area to be searched. Location precues exerted the strongest effects on conjunction search and the weakest effects on feature search. As the size of valid location cues decreased, conjunction search was facilitated. These effects declined progressively with advanced age and the onset of DAT. As the size of invalid cues increased, conjunction search was first facilitated, then slowed, but neither age nor DAT altered this effect. These results indicate that both Alzheimer's disease and, to a lesser degree, advanced aging, reduce control of the spatial focus of attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Teaching with concrete and abstract visual representations: Effects on students' problem solving, problem representations, and learning perceptions.

In 3 experiments, we examined the effects of using concrete and/or abstract visual problem representations during instruction on students' problem-solving practice, near transfer, problem representations, and learning perceptions. In Experiments 1 and 2, novice students learned about electrical circuit analysis with an instructional program that included worked-out and practice problems represented with abstract (Group A), concrete (Group C), or abstract and concrete diagrams (Group AC), whereby the cover stories were abstract in Group A and concrete in Groups C and AC. Experiment 3 added a 4th condition (C-A) with a concrete cover story and abstract diagrams. Group AC outperformed Groups A and C on problem-solving practice in Experiments 1 and 2 and outperformed Group C on transfer across the 3 experiments; Group AC also outperformed Group C-A in Experiment 3. Further, Group A outperformed Group C on transfer in Experiments 2 and 3 and outperformed Group C-A in Experiment 3. Transfer scores were positively associated with the quality of the diagrams and the number of abstract representations drawn during the transfer test. Data on students' learning perceptions suggest that the advantage of Group AC relies on the combined cognitive support of both representations. Our studies indicate that problem solving is fostered when learners experience concrete visual representations that connect to their prior knowledge and are enabled to use abstract visual representations. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Serial and parallel attentive visual searches: Evidence from cumulative distribution functions of response times.

Participants searched a visual display for a target among distractors. Each of 3 experiments tested a condition proposed to require attention and for which certain models propose a serial search. Serial versus parallel processing was tested by examining effects on response time means and cumulative distribution functions. In 2 conditions, the results suggested parallel rather than serial processing, even though the tasks produced significant set-size effects. Serial processing was produced only in a condition with a difficult discrimination and a very large set-size effect. The results support C. Bundesen's (1990) claim that an extreme set-size effect leads to serial processing. Implications for parallel models of visual selection are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A theory of dynamic occluded and illusory object perception.

Humans see whole objects from input fragmented in space and time, yet spatiotemporal object perception is poorly understood. The authors propose the theory of spatiotemporal relatability (STR), which describes the visual information and processes that allow visible fragments revealed at different times and places, due to motion and occlusion, to be assembled into unitary perceived objects. They present a formalization of STR that specifies spatial and temporal relations for object formation. Predictions from the theory regarding conditions that lead to unit formation were tested and confirmed in experiments with dynamic and static, occluded and illusory objects. Moreover, the results support the identity hypothesis of a common process for amodal and modal contour interpolation and provide new evidence regarding the relative efficiency of static and dynamic object formation. STR postulates a mental representation, the dynamic visual icon, that briefly maintains shapes and updates positions of occluded fragments to connect them with visible regions. The theory offers a unified account of interpolation processes for static, dynamic, occluded, and illusory objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Beyond the search surface: Visual search and attentional engagement.

A. Treisman (1991) described a series of visual search studies testing feature integration theory against an alternative (J. Duncan and G. Humphreys, 1989) in which feature and conjunction search are basically similar. Here, the latter account is noted to have 2 distinct levels: (1) a summary of search findings in terms of stimulus similarities and (2) a theory of how visual attention is brought to bear on relevant objects. Working at the 1st level, Treisman found that even when similarities were calibrated and controlled, conjunction search was much harder than feature search. The theory, however, can only really be tested at the 2nd level, because the 1st is an approximation. An account of the findings is developed at the 2nd level, based on the 2 processes of input-template matching and spreading suppression. New data show that, when both of these factors are controlled, feature and conjunction search are equally difficult. Possibilities for unification of the alternative views are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Textons, visual pop-out effects, and object recognition in infancy.

Five experiments were conducted to determine whether primitive perceptual features, or textons, which B. Julesz (1984) identified in studies of texture segregation with adults, also affect object recognition early in development. Three-month-old infants discriminated Ts and Ls composed of overlapping line segments from +s but not from each other in a delayed-recognition test after 24 hrs; however, Ts and Ls were discriminated from each other after only 1 hr. In a priming paradigm, Ts, Ls, and +s were discriminated from one another after 2 wks. In succeeding experiments, infants exhibited adultlike visual pop-out effects in both delayed recognition and priming paradigms, detecting an L in the midst of 6 +s and vice versa; these effects were symmetrical. The pop-out effects apparently resulted from parallel search: Infants failed to detect 3 Ls among 4 +s. Clearly, some of the same primitive units that have been identified as the building blocks of adult visual perception underlie object recognition early in infancy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)