Integrating pictorial information across eye movements.

Six experiments are reported dealing with the types of information integrated across eye movements (EMs) in picture perception. A line drawing of an object was presented in peripheral vision, and the 12 Ss (members of the university community) made an EM to it. During the saccade, the initially presented picture was replaced by another that the S was instructed to name as quickly as possible. The relation between the stimulus on the 1st fixation and the stimulus on the 2nd fixation was varied. Across experiments, there was about 100–230 msec facilitation when the pictures were identical compared with a control condition in which only the target location was specified on the 1st fixation. This finding implies that information about the 1st picture facilitated naming the 2nd picture. When the pictures represented the same concept (e.g., 2 pictures of a horse), there was a 90-msec facilitation effect that could have been the result of either the visual or conceptual similarity of the pictures. However, when the pictures had different names, only visual similarity produced facilitation; there appeared to be inhibition from the competing names. Results of all experiments are consistent with a model in which the activation of both the visual features and the name of the picture seen on the 1st fixation survive the saccade and combine with the information extracted on the 2nd fixation to produce identification and naming of the 2nd picture. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal and content variations as determinants of infants' visual control of verbal stimulations.

20 93–119 day old infants were presented with utterances varying in content or temporal structure that were contingent on fixation on a visual target. Treatment A consisted of utterances of equal duration and continually varying content. Treatment B consisted of utterances of slightly variable duration (temporal runs) and continually varying content. Treatment C included utterances organized in temporal runs and was composed of partial content variations (content runs). For Group AB, each A trial alternated with a B trial 4 times. For Group AC, each A trial alternated with a C trial 4 times. Half of the Ss in each group received Treatment A as their 1st trial; half of the Ss in Group AB received Treatment B; and half of the Ss in Group AC received Treatment C as their 1st trial. Group AB Ss showed a longer total fixation time than those of Group AC, with a more homogeneous distribution of number of fixations across treatments. Mean length of fixations was longer for Treatment A than B in Group AB, whereas Group AC showed a longer mean length of fixation for Treatment C relative to Treatment A. Those with Treatment B or C as their 1st trial looked more frequently at the target, and their decrease in looking time over trials showed a linear trend, whereas Ss with Treatment A at first displayed irregular decreases. These differences between groups and presentation orders suggest that 3-mo-old infants are sensitive to differences in linguistic material. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bilateral interactions in saccade programming. A saccade-latency study

Subjects were required to make a saccade to a target appearing randomly 4 degree to the left or right of the current fixation position (1280 trials per experiment). Location cues were used to direct visual attention and start saccade preparation to one of the two locations before target onset. When the cue indicated the target location (valid trials), the generation of express saccades (visually guided saccades with latencies around 100 ms) was strongly facilitated. When the opposite location was cued (invalid trials), express saccades were abolished and replaced by a population of mainly fast-regular saccades (latencies around 150 ms). This was found with a peripheral cue independently of whether the fixation point was removed before target onset (gap condition; experiment 1) or remained on throughout the trial (overlap condition; experiment 2). The same pattern also was observed with a central cue that did not involve any visual stimulation at a peripheral location (experiment 3). In the case where the primary saccade was executed in response to the cue and the target appeared at the opposite location, continuous amplitude transition functions were observed: starting at about 60-70 ms from target onset onward, the amplitude of the cue-elicited saccades continuously decreased from 4 degree to values below 1 degree. The results are explained by a fixation-gating model, according to which the antagonism between fixation and saccade activity gives rise to multimodal distributions of saccade latencies. It is argued that allocation of visual attention and saccade preparation to one location entails a successive disengagement of the fixation system controlling saccade preparation within the hemifield to which the saccade is prepared and a partial engagement of the opposite fixation system.     

Development of preferences and processes of visual scanning in the human infant during the first 3 months of life.

Used corneal infrared photography to record the visual fixations of 24 infants (4-6 wks and 10-12 wks) exposed to simple geometric figures. Results indicate that Ss in both age groups showed decreasing fixation time to the feature that initially attracted most fixations. Young Ss limited their fixations to a smaller area of the visual field than did older Ss. This developmental change in dispersed scanning might be an essential factor in later figure preferences. There was no preference for specific features, closed figures, or any particular figure. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Suppression of visible persistence.

Five experiments with the 1st author and 3 college students examined the duration of visible persistence in sequences of stimuli. In Exps I and II, the basic display consisted of a point that stepped around a circular path on the face of an oscilloscope. Ss estimated the number of points seen simultaneously. Results were compared with a control condition (Exp III), in which the points were plotted in random order rather than sequentially. Exp IV replicated Exps I and III at 4 additional eccentricities; Exp V examined whether reasonable fixation could be maintained with the larger displays and how a tendency to track the moving point would affect the number of points seen simultaneously. It was found that visible persistence of a point was suppressed if other points were shown nearby and after an appropriate delay. The degree of suppression depended on the spatial proximity of successive points. It was also found that both duration of visible persistence and degree of suppression increased with eccentricity in the visual field. Results are discussed in terms of 2 independent processes, persistence and suppression, that operate in a hierarchically antithetical relation. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Information integration across eye movements.

The visual world contains more information than can be perceived in a single glance. Consequently, humans make eye and head movements and somehow construct a stable and continuous representation of the visual environment from these successive views. How this is accomplished has puzzled psychologists for over a century. The present research investigated the properties of transsaccadic integration, the integration of information across saccadic eye movements. The results of several experiments suggest that the mental representation of the environment that is constructed across eye movements is surprisingly schematic and undetailed, and based more on the contents of the current fixation than on one's memory for the contents of previous fixations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Subjective landmarks in perception and memory for spatial location.

Four experiments involving 125 undergraduates investigated the use of cognitive strategies for encoding spatial location in visual figures. Ss reproduced the position of a dot in a square figure that had distance markers placed along 2 sides. Ss' responses were biased toward imaginary points of intersection formed by the distance markers when Ss responded from memory (Exp 1) or while viewing the figures (Exp 2). Findings demonstrate that empty regions of a figure can serve as subjective landmarks for spatial localization. In Exp 3, dot relocation was similarly distorted toward physical cross marks placed at the intersections of distance markers. The attraction of dots to intersection points depended on the viewer employing a strategy of mentally projecting from distance markers to form imaginary intersections. In Exp 4, attraction toward intersection points was observed only when Ss employed the projection strategy. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Picture perception: Effects of luminance on available information and information-extraction rate.

Three experiments with 255 undergraduates and a 4th in which the author and 2 colleagues served as Ss showed that complex visual stimuli—pictures and digit arrays—were remembered better when shown at high luminance (LM) than at low LM. Evidence was found for the possibilities that lowering LM reduced the amount of available information in the stimulus and that lowering LM reduced the rate at which the information was extracted from the stimulus. When stimuli were presented at durations short enough to permit only a single eye fixation, LM affected only the rate at which information was extracted. Decreasing LM by a factor of 100 caused information to be extracted more slowly by a factor that ranged, over experiments, from 1.4 to 2.0. When pictures were presented at durations long enough to permit multiple fixations, however, LM affected the total amount of extractable information. In a 5th experiment, with 4 undergraduates, converging evidence was sought for the proposition that within the 1st eye fixation on a picture, LM affects the rate of information extraction. If this proposition is correct and the 1st eye fixation lasts until some criterion amount of information is extracted, then fixation duration should increase with decreasing LM. This prediction was confirmed. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional limits on the perception and memory of visual information.

Attentional limits on perception and memory were measured by the decline in performance with increasing numbers of objects in a display. Multiple objects were presented to Ss who discriminated visual attributes. In a representative condition, 4 lines were briefly presented followed by a single line in 1 of the same locations. Ss were required to judge if the single line in the 2nd display was longer or shorter than the line in the corresponding location of the 1st display. The length difference threshold was calculated as a function of the number of objects. The difference thresholds doubled when the number of objects was increased from 1 to 4. This effect was generalized in several ways, and nonattentional explanations were ruled out. Further analyses showed that the attentional processes must share information from at least 4 objects and can be described by a simple model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coordinate frame for symmetry detection and object recognition.

Ss were required to determine whether dot patterns were symmetric. Cuing the Ss in advance about the orientation of the axis of symmetry produced a substantial speedup in performance (Exps 1 and 3) and an increase in accuracy with brief displays (Exp 2). The effects appeared roughly additive, with an overall advantage for vertical symmetry; thus, the vertical axis effect is not due to a tendency to prepare for the vertical axis. The cuing advantage was found to depend upon the S's knowing in advance the spatial location as well as orientation of the frame of reference (Exp 4). Exp 5 provided evidence that the frame of reference responsible for these effects is the same as the one that determines shape perception: Ss viewed displays containing a letter (at an unpredictable orientation) and a dot pattern, rapidly naming the letter and then determining whether the dots were symmetric about a prespecific axis. When the top–bottom axis of the letter was oriented the same way as the axis of symmetry for the dots, symmetry judgments were significantly more accurate. Results suggest a single frame of reference for both types of judgment. A theory of visual symmetry is proposed to account for the phenomena and characterize their relation to "mental rotation" effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coupling of the human Y2 receptor for neuropeptide Y and peptide YY to guanine nucleotide inhibitory proteins in permeabilized SMS-KAN cells

This study of location information involved in information persistence used the partial-report paradigm. Six subjects were asked on 144 trials to recall positions of dots presented in a display. The subjects were instructed to maintain only information on location (but not on identity information) of the presented dots until a partial-report cue was introduced. The effects of display duration (50, 200, and 350 msec.) and cue delay (interval between the display offset and the onset of the partial-report cue: 50, 250, and 500 msec.) were examined. Analysis showed effect of cue delay on partial-report performance decreased as the duration of display increased so performance was negatively affected by the cue delay only when the subject was exposed to the presented dots for 50 msec. Contrarily, partial-report performance did not decline much for a 200-msec. duration and showed little variation in a 350-msec. duration, even though the cue delay increased. Consequently, the decay of the information on location mediating partial-report performance about dots varies with duration of display.     

Capturing visual attention and the curve tracing operation.

The hypothesis that orienting visual attention is an important component of visual curve tracing was investigated. Ss examined a visual display and decided as quickly as possible whether 2 dots were on the same or different curves. The rate of tracing was determined by measuring the effects of curve distance on response time. Attention was directed to a curve by momentarily presenting it at a higher luminance. Directing attention to a curve that had 2 dots on it resulted in faster tracing rates with large benefits in overall response time. Directing attention to a distractor curve resulted in slower tracing rates and sizable costs in overall response times. Two alternative nonattentional explanations (eye movements and visible persistence) were examined and rejected. The role of attention in curve tracing is discussed in terms of the selective nature of curve tracing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of spatial location in integration of pictorial information across saccades.

Identification of a fixated object in a visual display is facilitated by integrating information from a preview of that object in the periphery with information extracted on the subsequent foveal fixation (A. Pollatsek et al; see record 1985-16415-001). These experiments investigated the extent to which this integration is dependent on the spatial location of the information remaining constant. Two preview objects were presented in the periphery; Ss fixated that region and named a single target object that appeared in the same spatial location in which one of the two preview objects had been presented. Of primary interest was the facilitative effect when a preview object was identical to the target object as a function of whether they were in the same spatial location. Although there was a small effect of switching, there was still a substantial preview benefit even when the location of the identical object switched. There was also a preview benefit in conditions in which there were no eye movements and the preview and target objects were at least 5° apart. The process of object identification may be relatively insensitive to location information. Object information and location information coded fairly independently. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hemispheric differences in sizes of receptive fields or attentional biases?

Ss judged whether 2 successive line segments had the same orientation. The pairs were lateralized, and the location on the screen and the distance between the segments in a pair were varied. When stimuli were relatively close to the center of the screen, Ss evaluated segments that were relatively far apart more quickly when they were presented in the left visual field and tended to judge segments that were close together more quickly when they were presented in the right visual field. In contrast, when the line segments were moved into the periphery, the previous pattern of results was reversed. In addition, results in a second block of trials depended on how attention had been set in the 1st set of trials. The observed hemispheric differences were due to attentional effects, not stable physiological properties of the brain. Previously observed hemispheric differences in spatial frequency analysis could reflect attentional biases. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceived numerosity: An information processing analysis.

Presented 3 university students with matrices of from 1 to 16 dots and asked them to count the dots they could see. In Condition 1 a visual noise pattern followed the display of dots by one of several intervals in order to control the time available to process them. In Condition 2 no mask was used, but the exposure duration was varied. In the processing time condition, dots were counted at a rate of 4 msec/dot when less than 6 dots were presented, and at a rate of 60 msec/dot for all dots in excess of 6. If enough time was given to process all the dots presented, virtually all were reported, whereas, if enough time was given to count only some of the dots, virtually none of the excess were counted. In the duration condition, in which processing time was not restricted, counting appeared to be a function of the visibility of the dots, as shown by a family of more linear functions between number of dots presented and number counted, with the slope determined by the duration of exposure. Data are consistent with a serial processing interpretation of dot counting occurring at a very early stage of information extraction, in which there is a serial scanning mechanism which extracts information from an initial brief store and transfers it to a 2nd store for actual counting. (French summary) (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial localization in left and right visual fields.

Presented a series of single dots tachistoscopically in either the left or the right visual field, Ss task being to locate the dot on a spatial map depicting all of the lot locations presented. 7 experiments were carried out with 232 right-handed male and female undergraduates. For men, localization of the dot was more accurate in the left than in the right visual field, under all testing conditions. Women showed the left-field superiority under some testing conditions; under others they showed no difference between fields. There was no sex difference in over-all accuracy of performance, and simple detection of a dot was not more accurate in 1 field than another for either sex. Results are discussed in terms of a probable "spatial coordinate" system in the right hemisphere of the brain. (French summary) (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The microstructure of attentional deployment on a dual task in loud noise.

Investigated the effects of loud white noise (100 db) on the temporal and spatial properties of the integration of 2-concurrent visual motor tasks by 32 Ss (aged 18–27 yrs). The main task was a 4-choice, self-paced, continuous response task presented by means of a display unit of an Apple microcomputer. The secondary task was a dot-detection task, in which a blue dot appeared occasionally in 1 of 6 possible unbiased spatial locations at the same horizontal reference above the main task on the same display unit. The 2 tasks were presented in both single and dual task conditions. Task order was counterbalanced, creating 4 subgroups for the quiet condition and 4 for the noise condition. Results show that in noise and quiet there was a single-to-dual task decrement on the main and secondary tasks. The slowness was more pronounced on the detection task in noise. Comparisons within the central task showed evidence that slowness in noise was created by the moments of actual concurrence of central task responses and secondary task signals; in the intervals between, there was evidence of compensatory speeding of response rates in both quiet and noise, but the effect was more pronounced in noise. In noise, Ss were more likely to interrupt the central task to respond to the dot, but this did not favor the dot-detection response. Findings are discussed in terms of a reduced-capacity model in noise that may cause changes in attentional parameters. (French abstract) (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Saccadic system functioning among schizophrenia patients and their first-degree biological relatives.

In Study 1, 30 schizophrenia Ss and 27 nonpsychiatric comparison Ss were presented with a fixation task, a visually guided reflexive saccade (prosaccade) task, a predictive tracking task (0.4-Hz square wave), and an antisaccade task. The 2 groups did not differ on either the fixation or prosaccade tasks. Schizophrenia Ss had an increased number of errors on the antisaccade task and had decreased rightward visually guided saccade amplitudes during the predictive tracking task. In Study 2, 13 psychiatric comparison Ss and 32 1st-degree biological relatives of the schizophrenia Ss were compared with the schizophrenia Ss and a larger and older sample of nonpsychiatric Ss (n?=?33) on the predictive tracking and antisaccade tasks. The groups did not differ on predictive saccadic tracking. The schizophrenia Ss and their 1st-degree biological relatives made more errors on the antisaccade task than both the nonpsychiatric and psychiatric comparison groups (who did not significantly differ). Results are consistent with the notion that dysfunction of dorsolateral prefrontal cortex, caudate nucleus, or both is related to liability for schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Roles of object-file review and type priming in visual identification within and across eye fixations.

Dynamic visual identification was investigated in 4 experiments. In Exps 1 and 2, 2 perceptual objects (2 frames, each containing a letter or 1 containing a letter and the other a plus sign) were previewed in the periphery. A saccade brought these objects to central vision. During the saccade the display was changed so that 1 frame contained a letter and the other a plus sign, and the S identified the letter by naming it aloud as rapidly as possible. In Exp 3, the retinal events of Exps 1 and 2 were simulated. In Exp 4, both the preview and the target were presented centrally within a single fixation. In all experiments both object specific and nonspecific preview benefits were observed. These results support a theory in which the preview benefits observed during visual identification arise from 2 processes, object file review and type priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)