How shape constancy relates to drawing accuracy.

There is increasing evidence that the major source of drawing errors lies in the initial perception of the to-be-drawn object. In four experiments, the authors explore the relation between an artist's susceptibility to perceptual transformations, as measured by a simple shape constancy task, and drawing accuracy. The data reveal a robust negative relation between errors on the shape constancy task and drawing accuracy in general, and specifically the accuracy of the rendering of spatial relations. The data further suggest that the perceptual processes that lead to errors on the shape constancy task occur during the initial encoding of the stimuli. The authors conclude that the shape constancy task likely measures one's ability to overcome constructive perception processes that transform the retinal image into a final percept, and that this ability is necessary for the accurate rendering of objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Low and high spatial frequencies are most useful for drawing.

What perceptual information do artists use to accurately render what they see? To answer this question, we investigated the utility of low, middle, and high spatial frequency bands for drawing. Untrained artists drew portraits from four spatial frequency bands (unfiltered, low, middle, and high). Raters judged the accuracy of those drawings compared to images of either the same or an unfiltered version of the face. Contrary to predictions based on the useful spatial frequencies for face recognition, which favor middle spatial frequencies (MSFs), the results showed that low spatial frequencies (LSFs) and high spatial frequencies (HSFs) were more useful for drawing, and the unfiltered condition produced the best drawings. Thus, the information most useful for drawing faces is not the same as that for recognizing faces. Specifically, artists may utilize the global configuration information carried in LSFs and the edge and detail information carried in HSFs to render accurate drawings. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Shifts in perceived position following adaptation to visual motion

Where do we perceive an object to be when it is moving? Nijhawan [1] has reported that if a stationary test pattern is briefly flashed in spatial alignment with a moving one, the moving element actually appears displaced in the direction in which it is moving. Nijhawan postulates that this may be the result of a mechanism that predicts the future position of the moving element so as to compensate for the fact that the element will have moved position from the time at which the light left it to the time at which the observer becomes aware of it (as a result of the finite time taken for neural transmission). There is an alternative explanation of this effect, however. Changes in the stimulus presentation could affect perceptual latency [2], and therefore the perceived position if in motion (as suggested for the Pulfrich pendulum effect [3] [4]). In other words, if the flashed probe of the Nijhawan demonstration takes longer to reach perceptual awareness than the moving stimulus, the latter will appear to be ahead of the probe. Here, I demonstrate an alternative way of testing this hypothesis. When an illusory movement is induced (via the motion aftereffect) within a stationary pattern, it can be shown that this also produces a change in its perceived spatial position. As the pattern is stationary, one cannot account for this result via the notion of perceptual lags.     

Attention: Reaction Time and Accuracy Reveal Different Mechanisms.

The authors propose that there are 2 different mechanisms whereby spatial cues capture attention. The voluntary mechanism is the strategic allocation of perceptual resources to the location most likely to contain the target. The involuntary mechanism is a reflexive orienting response that occurs even when the spatial cue does not indicate the probable target location. Voluntary attention enhances the perceptual representation of the stimulus in the cued location relative to other locations. Hence, voluntary attention affects performance in experiments designed around both accuracy and reaction time. Involuntary attention affects a decision as to which location should be responded to. Because involuntary attention does not change the perceptual representation, it affects performance in reaction time experiments but not accuracy experiments. The authors obtained this pattern of results in 4 different versions of the spatial cuing paradigm. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Speed mediation of adult age differences in cognition.

Previous research has established that a large proportion of the adult age-related variance in various measures of fluid or process cognition is reduced when statistical control procedures such as hierarchical regression are used to eliminate variation in measures of perceptual speed. This finding was confirmed in the present study and was extended to include paired-associate and free-recall measures of memory in addition to measures of reasoning and spatial abilities. Most of the speed mediation was associated with speed measures requiring cognitive operations such as comparison or substitution instead of merely motor responses such as copying symbols or drawing lines. These results suggest that the rate of performing elementary cognitive operations is an important proximal mediator of the adult age differences in several types of cognitive tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simian scribbles: A reappraisal of drawing in the chimpanzee (Pan troglodytes).

Three chimpanzees (Pan troglodytes) were provided with 18 different stimulus pages for drawing. The resulting 618 drawings were coded for drawn marks, and results were compared with early reports on ape drawing (Morris, 1962; Schiller, 1951) and with more recent systematic studies (Smith, 1973). The findings of the present study confirm Smith's observations of a tendency for the animals to draw closer to the center and toward the bottom of the page. No evidence for perceptual balancing was observed in drawings produced on pages with lateral figures, nor was any evidence for closure apparent with complex figures. The present results agree with earlier findings that chimpanzees will engage in drawing activities without training or reinforcement, and this behavior may reflect their intrinsic interest in exploratory and manipulative play. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stroop theory, memory, and prefrontal cortical functioning: Reply to Cohen et al. (1997).

In this article, the authors respond to J. D. Cohen, K. O. Dunbar, D. M. Barch and T. S. Braver's (see record 1997-02838-005) comment on their target article (see record 1997-02838-004). The present article (a) takes issue with the characterization given by Cohen et al. of the authors' approach as a classical speed-of-processing account of Stroop effects, (b) discusses the value and relevance of other theoretical concepts, such as traditional accounts of working memory and parallel distributed processing (PDP) approaches to Stroop effects, (c) further examines the possibility that the differences the authors observed in Experiment 2 between normal participants' performance and that of participants with schizophrenia may have been due to distractor stimulus degradation, particularly for participants with schizophrenia, and (d) argues for the relevance of the prefrontal cortex, as well as other brain areas, in accounting for their results. The authors conclude with a final theoretical question. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

“Neurally constrained modeling of perceptual decision making”: Correction.

Reports an error in "Neurally constrained modeling of perceptual decision making" by Braden A. Purcell, Richard P. Heitz, Jeremiah Y. Cohen, Jeffrey D. Schall, Gordon D. Logan and Thomas J. Palmeri (Psychological Review, 2010[Oct], Vol 117[4], 1113-1143). Two grant numbers were incorrectly cited in the author note, and one correct grant number was omitted. The author note incorrectly indicated that research was supported by grants RO1-MH55806 and RO1-EY13358. In addition, grant R01-EY08890 should have been listed. (The following abstract of the original article appeared in record 2010-18180-001.) Stochastic accumulator models account for response time in perceptual decision-making tasks by assuming that perceptual evidence accumulates to a threshold. The present investigation mapped the firing rate of frontal eye field (FEF) visual neurons onto perceptual evidence and the firing rate of FEF movement neurons onto evidence accumulation to test alternative models of how evidence is combined in the accumulation process. The models were evaluated on their ability to predict both response time distributions and movement neuron activity observed in monkeys performing a visual search task. Models that assume gating of perceptual evidence to the accumulating units provide the best account of both behavioral and neural data. These results identify discrete stages of processing with anatomically distinct neural populations and rule out several alternative architectures. The results also illustrate the use of neurophysiological data as a model selection tool and establish a novel framework to bridge computational and neural levels of explanation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Converging operations for perceptual defense.

Discusses some recent experimental attempts to provide converging operations for a concept of perceptual defense. For present purposes, perceptual defense is defined as a relative failure of perception per se due to the emotional character of the stimulus. Experiments are evaluated and discussed mainly in terms of their ability to eliminate as an explanation the response-bias hypothesis for differential accuracy between neutral and emotional words. In addition, following Blum, a stimulus-effect hypothesis is described and applied; all the experiments discussed require, if differences in accuracy of recognition are to be attributed to perceptual variation, converging operations to eliminate this hypothesis. It is argued as well that the search for converging operations for perceptual defense has implications for methodology in other areas of perception. (20 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional theory of illusory conjunctions and neon colors.

Illusory conjunctions are the incorrect perceptual combination of briefly presented colors and shapes. In the neon colors illusion, achromatic figures take on the color of an overlaid grid of colored lines. Both illusions are explained by a theory that assumes (a) poor location information or poor spatial resolution for some aspects of visual information and (b) that the spatial location of features is constrained by perceptual organization. Computer simulations demonstrate that the mechanisms suggested by the theory are useful in veridical perception and they are sufficient to produce illusory conjunctions. The theory suggests mechanisms that economically encode visual information in a way that filters noise and fills in missing data. Issues related to neural implementation are discussed. Four experiments illustrate the theory. Illusory conjunctions are shown to be affected by objective stimulus organization, by subjective organization, and by the linguistic structure of ambiguous Hebrew words. Neon colors are constrained by linguistic structure in the same way as illusory conjunctions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual reactions to threat under varying conditions of measurement.

This study investigated the perceptual recognition behavior for threat and nonthreat words under 3 conditions of measurement, stimulus absent, stimulus present, and forced choice. The results indicated that the probability of using threat words as recognition guesses in the stimulus-absent condition is predictive of (a) probability of usage in stimulus present and (b) differential accuracy for threat and nonthreat words in stimulus present. However, stimulus-absent data failed to predict forced-choice accuracy for threat. Further, stimulus present accuracy data failed totally to predict forced-choice accuracy data. The pattern of results emphasizes the vital contribution of response factors in producing the perceptual defense effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

“Neurally Constrained Modeling of Perceptual Decision Making": Erratum.

Reports an error in "Neurally constrained modeling of perceptual decision making" by Braden A. Purcell, Richard P. Heitz, Jeremiah Y. Cohen, Jeffrey D. Schall, Gordon D. Logan and Thomas J. Palmeri (Psychological Review, 2010[Oct], Vol 117[4], 1113-1143). The presentation of the colors in Figure 3, Panel A was incorrect due to an error in the production process. (The following abstract of the original article appeared in record 2010-18180-001.) [Correction Notice: An erratum for this article was reported in Vol 118(1) of Psychological Review (see record 2010-23057-001). Two grant numbers were incorrectly cited in the author note, and one correct grant number was omitted. The author note incorrectly indicated that research was supported by grants RO1-MH55806 and RO1-EY13358. In addition, grant R01-EY08890 should have been listed.] Stochastic accumulator models account for response time in perceptual decision-making tasks by assuming that perceptual evidence accumulates to a threshold. The present investigation mapped the firing rate of frontal eye field (FEF) visual neurons onto perceptual evidence and the firing rate of FEF movement neurons onto evidence accumulation to test alternative models of how evidence is combined in the accumulation process. The models were evaluated on their ability to predict both response time distributions and movement neuron activity observed in monkeys performing a visual search task. Models that assume gating of perceptual evidence to the accumulating units provide the best account of both behavioral and neural data. These results identify discrete stages of processing with anatomically distinct neural populations and rule out several alternative architectures. The results also illustrate the use of neurophysiological data as a model selection tool and establish a novel framework to bridge computational and neural levels of explanation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Are McCollough effects conditioned responses?

McCollough effects (MEs), first described by C. McCollough (1965), are perceptual aftereffects of color that depend on the spatial configuration of line patterns. Several investigators have suggested that MEs may be the product of an associative learning mechanism, and G. M. Murch (see record 1976-20108-001) developed a formal model attributing MEs to classical conditioning. In the present article, Murch's conception is evaluated by comparing the basic characteristics of conditioning with those of MEs. Although some similarities are noted, MEs differ from CRs in that they fail to display relative permanence, be disrupted by reduction of the correlation between the CS and UCS during acquisition, and show accumulative effects of practice. It is concluded that MEs are not classically conditioned responses; the question of whether they can be regarded as any form of learned behavior is debated. (74 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of mental abilities: An investigation of the "differentiation hypothesis."

Attempted to determine the extent to which verbal, numerical, spatial, and perceptual speed abilities will be differentiated as a function of differing amounts of classroom learning. The hypothesis was tested that verbal and numerical abilities will be differentiated earlier than perceptual speed and spatial scanning, because learning requiring the former types of abilities is emphasized quite early in the school program. 3 groups (111 7th graders, 95 9th graders, and 75 11th graders) were given the tests measuring verbal, numerical, perceptual, and spatial-scanning abilities from the Kit of Reference Tests. The factor analyses of the correlation matrices yielded 4 factors for each sample associated with eigenvalues greater than 1. The verbal and number factors were identifiable at the Grade-7 level but neither of the other 2 was easily interpretable. The spatial-scanning factor emerged at the Grade-9 level and all 4 factors were distinctly defined at the Grade-11 level. Results support the hypothesis that mental abilities become differentiated as a function of increased learning experiences. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibition of return is not detected using illusory line motion

Inhibition of return (IOR) is the name that has been assigned to a response time (RT) delay to a stimulus presented at a recently stimulated spatial location. A commonly held explanation for the origins of IOR is that perceptual processing in inhibited and that this inhibition translates into slower RT. Three experiments with 10 subjects were used to directly test this perceptual explanation. The first two experiments assessed the level of perceptual facilitation present in the IOR paradigm using the frequency and latency of illusory line motion judgments. Contrary to the predictions of the perceptual view, the line motion and RT measures revealed only speeded processing at previously stimulated spatial locations. Experiment 3 required a simple detection response and used the same stimulus and timing parameters as those in Experiments 1 and 2. IOR was present, replicating the recent finding that judgments based on perceptual qualities of the stimulus do not demonstrate a RT delay, whereas simple detection tasks do show RT inhibition at previously stimulated locations. These findings are discussed in relation to a number of hypotheses about the origin of the RT delay.     

How Perception Impacts on Drawings.

In 3 experiments the authors investigate how errors in perception produce errors in drawings. In Experiment 1, when Shepard stimuli were shown as a pair of tables, participants made severe errors in trying to adjust 1 part of the stimulus to match the other. When the table legs were removed, revealing a pair of parallelograms with minimal perspective cues, the illusion was weaker. The authors predicted that participants would err when drawing the table but not the parallelogram stimuli. The results of Experiment 2 support the prediction and establish a direct link between degree of perceptual distortion of the table stimuli and the severity of error in drawing. When drawing only the right-hand part of the figure, participants also erred to a greater degree in drawing the table than the parallelogram (Experiment 3). Collectively, the results suggest that perceptual distortion is linked with errors in drawing the table stimuli. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Perceptual conflict between vision and touch

Although most of the studies support the conclusion that a perceptual conflict may be resolved in the visual dominance, a few suggest its prematurity and methodological problems. In the present study, the conflict was made by the instruction and the trick in order to keep the S's naivety, and the degree of conflict was varied. wthe visual comparison (vision), the haptic comparison (touch), the visual-haptic comparison (drawing by a pencil), and the haptic-visual comparison (production by the plasticine) were used as the comparison procedures. The result was that the perceptual conflict was resolved in a compromise between vision and touch. However, as the degree of conflict became greater, the judgements in the conflict tended to depend upon the comparison procedures. And in such a conflict taht the visual size was smaller than the tactual, the vision dominance tended to occur, and vice versa.     

Age differences in using source-relevant cues.

Ss heard words originating from 2 speakers and later decided which of the 2 speakers said the words. Older adults had difficulty with source monitoring when perceptual cues from 2 sources were similar (2 female speakers), but this difficulty was overcome when perceptual cues were distinctive (a male and a female speaker) and were the only salient cues to source. Older adults also benefited from distinctive spatial cues when these were the only salient cues to source. Older adults, however, experienced difficulties in using multiple cues (both perceptual and spatial) to source effectively, whereas younger adults were able to use multiple cues to enhance their source-monitoring performance. It is suggested that age differences in source monitoring result from differential cue utilization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On gradients and texture "gradients."

Comments on J. E. Cutting and R. T. Millard's article (see record 1985-08483-001) on the extent to which texture gradients, systematic variations in image texture due to perspective projection of surface texture, provide information about the shape and disposition of surfaces relative to a viewer. The present author suggests that it is difficult to conclude that the perception of flatness or curvature derives from processes that capitalize on these gradient relationships, per se. The difficulty becomes most apparent when attempting to formalize the perceptual computations and the spatial information that is made explicit. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How object-specific are object files? Evidence for integration by location.

Given the distributed representation of visual features in the human brain, binding mechanisms are necessary to integrate visual information about the same perceptual event. It has been assumed that feature codes are bound into object files—pointers to the neural codes of the features of a given event. The present study investigated the perceptual criteria underlying integration into an object file. Previous studies confounded the sharing of spatial location with belongingness to the same perceptual object, 2 factors we tried to disentangle. Our findings suggest that orientation and color features appearing in a task-irrelevant preview display were integrated irrespective of whether they appeared as part of the same object or of different objects (e.g., 1 stationary and the other moving continuously, or a banana in a particular orientation overlaying an apple of a particular color). In contrast, integration was markedly reduced when the 2 objects were separated in space. Taken together, these findings suggest that spatial overlap of visual features is a sufficient criterion for integrating them into the same object file. (PsycINFO Database Record (c) 2010 APA, all rights reserved)