Distinguished Scientific Awards for an Early Career Contribution to Psychology.

Discusses contributions of Phillip L. Ackerman, Martha J. Farah, Daniel T. Gilbert, and Martin F. Sarter, the 1992 recipients of the Distinguished Scientific Awards for an Early Career Contribution to Psychology awarded by the American Psychological Association. Ackerman is awarded for research on individual differences. Farah is recognized for her empirical and theoretical analysis of visual cognition. Gilbert is recognized for research on interpersonal inference. Sarter is awarded for research on the neuronal mechanisms underlying attention, learning, and memory. Biographies of the recipients are given. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Object-based attentional selection—Grouped arrays or spatially invariant representations?: Comment on Vecera and Farah (1994).

S. P. Vecera and M. J. Farah (see record 1994-32352-001) have addressed the issue of whether visual attention selects objects or locations. They obtained data that they interpreted as evidence for attentional selection of objects from an internal spatially invariant representation. A. F. Kramer, T. A. Weber, and S. E. Watson question this interpretation on both theoretical and empirical grounds. First, the authors suggest that there are other interpretation of the Vecera and Farah data that are consistent with location-mediated selection of objects. Second, they provide data, using the displays employed by Vecera and Farah in conjunction with a postdisplay probe technique, that suggests that attention is directed to the locations of the target objects. The implications of the results for space and object-based attentional selection are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Information-limited parallel processing in difficult heterogeneous covert visual search.

Difficult visual search is often attributed to time-limited serial attention operations, although neural computations in the early visual system are parallel. Using probabilistic search models (Dosher, Han, & Lu, 2004) and a full time-course analysis of the dynamics of covert visual search, we distinguish unlimited capacity parallel versus serial search mechanisms. Performance is measured for difficult and error-prone searches among heterogeneous background elements and for easy and accurate searches among homogeneous background elements. Contrary to the claims of time-limited serial attention, searches in heterogeneous backgrounds instead exhibited nearly identical search dynamics for display sizes up to 12 items. A review and new analyses indicate that most difficult as well as easy visual searches operate as an unlimited-capacity parallel analysis over the visual field within a single eye fixation, which suggests limitations in the availability of information, not temporal bottlenecks in analysis or comparison. Serial properties likely reflect overt attention expressed in eye movements. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Superadditive effects of multiple lesions in a connectionist architecture: Implications for the neuropsychology of optic aphasia.

Neuropsychological disorders have traditionally been understood in terms of a focal lesion to a single component of a cognitive architecture. Optic aphasia (OA) defies explanation in this way. In OA, naming of visual stimuli is impaired in the absence of general visual agnosia or anomia. OA has been explained by positing multiple semantic systems or multiple functional pathways to visual naming. M. J. Farah (1990) instead sketched a parsimonious account based on multiple lesions—to pathways mapping visual input to semantics and semantics to naming responses—and the assumption that the effects of the lesions are superadditive. The authors demonstrate superadditive effects of damage in a connectionist architecture and model other phenomena associated with OA. Multiple lesions with superadditivity provide a novel class of explanations for neuropsychological deficits that previously seemed to imply the existence of highly specialized processing components. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the speed of pop-out in feature search.

When something unique is present in a scene, this element may become immediately visible and one has the impression that it pops out from the scene. This phenomenon, known as pop-out in the visual search literature, is thought to produce the fastest search possible, and response times for the detection of the pop-out target do not vary as a function of the number of nontargets. In this study, we challenge this notion and show that the detection of a given visual feature is faster for multiple targets than for a single pop-out target. However, when the task requires a detailed target analysis, the pop-out condition can be faster than the multiple-target condition. Current models of visual search are discussed in light of the findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Michael Turvey.

Announces Michael Turvey as a recipient of the 1974 Early Career Award, and presents his biography and list of scientific publications. His most important research contribution to date is his information-processing analysis of peripheral and central visual mechanisms. Turvey elucidated the processes involved in forward and backward masking by cleanly designed experiments utilizing noise and pattern masks presented either monoptically or dichoptically. Further, in his 1973 Psychological Review paper he integrated his results with a large body of literature on both visual theory and psychological experiments in terms of a model for the concurrent-contingent relationships between peripheral and central processes in the sequence of events leading from the onset of a visual display to recognition of a stimulus. In addition, he has been responsible for an extensive series of studies analyzing the function of release from proactive inhibition in short-term memory. He and his associates have contributed methods for studying primary or iconic memory, including an auditory analogue of Sperling's partial report procedure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pointing accuracy of a joy stick without visual feedback.

To determine how accurately man can point a joy stick at visual targets without visual feedback as to the position of the stick, 7 Ss were given four experimental trials, each consisting of one presentation of each of 24 targets to which the S pointed. "1. Pointing errors ranged from1° to 52°, with a mean of 13.4°. 90% of the pointing errors were 25° or less in magnitude. 2. There was a correspondence between magnitude of errors and locus of the visual target… . 3. There was a tendency for Ss to undershoot targets located around the periphery of the target space and to overshoot targets located around the center of the space." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A decisional component of holistic encoding.

It has been proposed (see, specifically, M. J. Farah, K. D. Wilson, M. Drain, & J. N. Tanaka, 1998) that human faces are used in cognition as undifferentiated wholes. General recognition theory (GRT; F. G. Ashby & J. T. Townsend, 1986) is used to represent hypotheses regarding the possible sources for the behavioral evidence supporting holistic representation. Specifically, it is suggested that holism can be understood in terms of violations of informational independence, informational separability, or decisional separability, as these constructs are defined in GRT. Stimuli were presented upright, inverted, and in an encoding task that emphasized the meaningful nature of the stimuli. Patterns of performance (recognition hit rates) were consistent with prior studies. However, there were only a handful of violations of informational separability. Instead, consistent violations of decisional separability suggested a decisional basis for holistic effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Role of Perirhinal Cortex in Visual Discrimination Learning for Visual Secondary Reinforcement in Rats.

Perirhinal cortex in monkeys has been thought to be involved in visual associative learning. The authors examined rats' ability to make associations between visual stimuli in a visual secondary reinforcement task. Rats learned 2-choice visual discriminations for secondary visual reinforcement. They showed significant learning of discriminations before any primary reinforcement. Following bilateral perirhinal cortex lesions, rats continued to learn visual discriminations for visual secondary reinforcement at the same rate as before surgery. Thus, this study does not support a critical role of perirhinal cortex in learning for visual secondary reinforcement. Contrasting this result with other positive results, the authors suggest that the role of perirhinal cortex is in "within-object" associations and that it plays a much lesser role in stimulus-stimulus associations between objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parallel Processing in Visual Search Asymmetry.

The difficulty of visual search may depend on assignment of the same visual elements as targets and distractors-search asymmetry. Easy C-in-O searches and difficult O-in-C searches are often associated with parallel and serial search, respectively. Here, the time course of visual search was measured for both tasks with speed-accuracy methods. The time courses of the 2 tasks were similar and independent of display size. New probabilistic parallel and serial search models and sophisticated-guessing variants made predictions about time course and accuracy of visual search. The probabilistic parallel model provided an excellent account of the data, but the serial model did not. Asymptotic search accuracies and display size effects were consistent with a signal-detection analysis, with lower variance encoding of Cs than Os. In the absence of eye movements, asymmetric visual search, long considered an example of serial deployment of covert attention, is qualitatively and quantitatively consistent with parallel search processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Signal detection theory and modularity: On being sensitive to the power of bias models of semantic priming.

G. Rhodes, A. J. Parkin, and T. Tremewan (1993) have shown that semantic priming influences signal detection theory measures of sensitivity in visual word recognition. Following an argument presented by M. Farah (1989), they suggested that this is evidence that semantic information influences perceptual encoding, and that such an influence represents a violation of modularity. This article shows that, contrary to Farah's claim, measures of sensitivity cannot be assumed to reflect the operation of perceptual encoding. Simulations are presented to demonstrate that modular criterion-bias models of priming in which priming has no effect on perceptual encoding predict the same sensitivity effects that Rhodes et al take as evidence against modularity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrophysiological evidence for a shared representational medium for visual images and visual percepts.

Systematic effects of imagery on visual signal detection performance have been used to argue that imagery and the perceptual processing of stimuli interact at some common locus of activity (Farah, 1985). However, such a result is neutral with respect to the question of whether the interaction occurs during modality-specific visual processing of the stimulus. If imagery affects stimulus processing at early, modality-specific stages of stimulus representation, this implies that the shared stimulus representations are visual, whereas if imagery affects stimulus processing only at later, amodal stages of stimulus representation, this implies that imagery involves more abstract, postvisual stimulus representations. To distinguish between these 2 possibilities, we repeated the earlier imagery-perception interaction experiment while recording event-related potentials (ERPs) to stimuli from 16 scalp electrodes. By observing the time course and scalp distribution of the effect of imagery on the ERP to stimuli, we can put constraints on the locus of the shared representations for imagery and perception. An effect of imagery was seen within 200 ms following stimulus presentation, at the latency of the 1st negative component of the visual ERP, localized at the occipital and posterior temporal regions of the scalp, that is, directly over visual cortex. This finding supports the claim that mental images interact with percepts in the visual system proper and hence that mental images are themselves visual representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual search performance among persons with schizophrenia as a function of target eccentricity.

The current study investigated one possible mechanism of impaired visual attention among patients with schizophrenia: a reduced visual span. Visual span is the region of the visual field from which one can extract information during a single eye fixation. This study hypothesized that schizophrenia-related visual search impairment is mediated, in part, by a smaller visual span. To test this hypothesis, 23 patients with schizophrenia and 22 healthy controls completed a visual search task where the target was pseudorandomly presented at different distances from the center of the display. Response times were analyzed as a function of search condition (feature vs. conjunctive), display size, and target eccentricity. Consistent with previous reports, patient search times were more adversely affected as the number of search items increased in the conjunctive search condition. It was important however, that patients’ conjunctive search times were also impacted to a greater degree by target eccentricity. Moreover, a significant impairment in patients’ visual search performance was only evident when targets were more eccentric and their performance was more similar to healthy controls when the target was located closer to the center of the search display. These results support the hypothesis that a narrower visual span may underlie impaired visual search performance among patients with schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automatic guidance of visual attention from verbal working memory.

Previous studies have shown that visual attention can be captured by stimuli matching the contents of working memory (WM). Here, the authors assessed the nature of the representation that mediates the guidance of visual attention from WM. Observers were presented with either verbal or visual primes (to hold in memory, Experiment 1; to verbalize, Experiment 2; or merely to attend, Experiment 3) and subsequently were required to search for a target among different distractors, each embedded within a colored shape. In half of the trials, an object in the search array matched the prime, but this object never contained the target. Despite this, search was impaired relative to a neutral baseline in which the prime and search displays did not match. An interesting finding is that verbal primes were effective in generating the effects, and verbalization of visual primes elicited similar effects to those elicited when primes were held in WM. However, the effects were absent when primes were only attended. The data suggest that there is automatic encoding into WM when items are verbalized and that verbal as well as visual WM can guide visual attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of Visual Speed While Moving.

During self-motion, the world normally appears stationary. In part, this may be due to reductions in visual motion signals during self-motion. In 8 experiments, the authors used magnitude estimation to characterize changes in visual speed perception as a result of biomechanical self-motion alone (treadmill walking), physical translation alone (passive transport), and both biomechanical self-motion and physical translation together (walking). Their results show that each factor alone produces subtractive reductions in visual speed but that subtraction is greatest with both factors together, approximating the sum of the 2 separately. The similarity of results for biomechanical and passive self-motion support H. B. Barlow's (1990) inhibition theory of sensory correlation as a mechanism for implementing H. Wallach's (1987) compensation for self-motion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inversion superiority in visual agnosia may be common to a variety of orientation polarised objects besides faces

Selective impairment in recognition of faces (prosopagnosia) resulting from certain localized cortical lesions has been advanced as an argument for a face specific brain module. The argument is claimed to be strengthened by the discovery of an inversion superiority effect in the recognition of faces by a prosopagnosic patient (Farah et al., Vis Res 1995b;35:2089-2093). The present paper reports an inversion superiority effect in the recognition of faces and shoes in a visual agnosic patient. The finding raises the possibility that several classes of orientationally polarized objects, of which shoes and faces are examples, will exhibit inversion superiority.     

Selective attention in the primate visual system.

A series of single unit PET and behavioural studies is described addressing the functions and neurophysiology of visual attention. Beyond striale cortex, visual information is processed in a network of separate cortical areas, specialized in part for analysis of different visual attributes. Issues arising in such a modular system include the nature of the attentional state in extrastriate cortex, its flexible control by the requirements of current behaviour, and the coordination between areas implied by attention to whole objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and visual marking: Selective deficits for moving stimuli.

The selective processing of new visual information can be facilitated by the top-down inhibition of old stimuli already in the visual field, a capacity-limited process termed visual marking (D. G. Watson & G. W. Humphreys, 1997). Three experiments assessed the effects of aging on visual marking using stationary (Experiment 1) and moving (Experiments 2 and 3) items. For young participants, visual marking was observed in all experiments. For older participants, visual marking was observed only with stationary items. The results are not consistent with any simple account of general age-related decrements and provide further support for the deployment of different methods of visual marking depending on the properties of the old items and the current task demands. (PsycINFO Database Record (c) 2010 APA, all rights reserved)