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Biomedical subjects

A Pollatsek

Publications and source records attributed to A Pollatsek.

At least 19 recordsLinked to original sources
PubMed1992

Phonological codes are used in integrating information across saccades in word identification and reading.

A major issue in reading is the extent to which phonological information is used in visual word perception. The present experiments demonstrated that phonological information acquired on 1 fixation from a word in the parafovea is used to help identify that word when it is later fixated. A homophone of a target word, when presented as a preview in the parafovea, facilitated processing of the target word seen on the next fixation more than a preview of a word matched with the homophone in visual similarity to the target word. This facilitation was observed both in the time to name an isolated target word and in the fixation time on the target word while silently reading a sentence; the preview was virtually never consciously identified in either task. Because the visual similarity of the preview to the target also plays a part in the facilitative effect on the preview, however, codes other than phonological codes are preserved across saccades.

Humans↗
PubMed1992

Identification of objects in scenes: the role of scene background in object naming.

Research with brief presentations of scenes has indicated that scene context facilitates object identification. In the present experiments we used a paradigm in which an object in a scene is "wiggled"--drawing both attention and an eye fixation to itself--and then named. Thus the effect of scene context on object identification can be examined in a situation in which the target object is fixated and hence is fully visible. Experiment 1 indicated that a scene background that was episodically consistent with a target object facilitated the speed of naming. In Experiments 2 and 3, we investigated the time course of scene background information acquisition using display changes contingent on eye movements to the target object. The results from Experiment 2 were inconclusive; however, Experiment 3 demonstrated that scene background information present only on either the first or second fixation on a scene significantly affected naming time. Thus background information appears to be both extracted and able to affect object identification continuously during scene viewing.

Adult↗
PubMed1992

Eye movements and scene perception.

Research on eye movements and scene perception is reviewed. Following an initial discussion of some basic facts about eye movements and perception, the following topics are discussed: (I) the span of effective vision during scene perception, (2) the role of eye movements in scene perception, (3) integration of information across saccades, (4) scene context, object identification and eye movements, and (5) the control of eye movements. The relationship of eye movements during reading to eye movements during scene perception is considered. A preliminary model of eye movement control in scene perception is described and directions for future research are suggested.

Attention↗
PubMed1991

Word identification in isolation and in context by college dyslexic students.

College dyslexic students (DYS) were compared to chronological age (CA)-matched and to reading age (RA)-matched control groups on tasks assessing naming of words and nonwords, regular and irregular words, and the use of context in word identification. The DYS group had the slowest naming latency for words in all tasks. In addition, they had extreme difficulty in naming nonwords, which in terms of the dual-route model for word recognition indicates impairment in the indirect route to the lexicon. However, they displayed a regularity effect in reading regular and irregular words and thus apparently utilized the indirect route in reading words. Correlational data supported the conclusion that the data are in conflict with the traditional dual-route model, and an alternative conceptualization is suggested. The use of context is discussed in terms of the interactive-compensatory model (Stanovich, 1980) and findings were generally supportive of the model. The DYS subjects of the present study appeared to be different from the RA controls and their performance did not support a developmental-lag model for explaining their reading problems.

Adult↗
PubMed1990

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 (Pollatsek, Rayner, & Collins, 1984). 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. The major finding was that although there was a small effect of switching, there was still a substantial preview benefit even when the location of the identical object switched. In addition, the switching effect did not interact with the level of identity between the preview and target. 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 degrees apart. Thus, the data indicate that the process object identification is relatively insensitive to location information and that object information and location information are coded fairly independently.

Adult↗
PubMed1990

Eye movement guidance in reading: the role of parafoveal letter and space information.

The relation between parafoveal letter and space information in eye movement guidance during reading was investigated in 2 experiments. Contingent upon the reader's fixation, the type of parafoveal information available to the right of fixation was varied by (a) space information only, (b) space information with letter information added at some delay, or (c) letter and space information simultaneously. In addition, the onset of the relevant parafoveal information was delayed between 0 and 250 ms into the fixation. The time course of processing the 2 types of information (letters or spaces) differed, as did the nature of their impact on the eye movement record. Although both letter and space information influenced saccade length and initial landing positions within words, only letter information had an effect on fixation duration. In addition, fixation duration was affected only by information entering within the first 50 ms of the fixation, whereas saccade length was affected by information arriving at any time during the fixation. The results are consistent with a model of eye movement control in which 2 independent processes are operating in tandem to determine when and where to move the eyes during reading.

Adult↗
PubMed1989

Effect of background information on object identification.

Previous research using briefly presented displays has indicated that objects in a coherent scene are easier to identify than are objects in incoherent backgrounds. Of interest is whether the identification of the target object depends on the identification of the scene or the identification of other diagnostic objects in the scene. Experiment 1 indicated objects are more difficult to identify when located in an "episodically" inconsistent background even when the same diagnostic objects are present in both inconsistent and consistent backgrounds. Experiment 2 demonstrated that the degree to which noncued (cohort) objects are consistent with the target object has no effect on the object identification task. Experiment 3 showed consistent episodic background information facilitated object identification and inconsistent episodic background information did not interfere relative to "nonsense" backgrounds roughly equated on visual characteristics. Implications for models of scene perception are discussed.

Adult↗
PubMed1989

Covert attention and eye movements during reading.

Eye movements were monitored during the reading of spatially transformed text in order to examine covert attentional processes in reading. In some conditions, the sequence of letters within a word was congruent with (i.e. in the same direction as) the sequence of words in the sentence; in other conditions the direction of letters within words and the direction of words in the sentence were incongruent. In addition, the window of visible text was varied so that in some conditions only the fixated word (and all preceding words) were visible, whereas in other conditions the fixated word and the succeeding word were both visible. Readers were able to extract more parafoveal information from text when the words themselves were normal than when the letters within the words were transformed. However, with practice, readers were able to use some parafoveal information even when the words were transformed. The most important finding was that the congruity of the word and letter order had no reliable effect on the ability to extract parafoveal information and influenced reading performance only when the words themselves were normal. We conclude that covert attention in reading is not a letter-by-letter scan that sweeps across the page, but either an asymmetric spotlight held constant on each fixation or a shifting of an attentional spotlight extending across multiletter units (possibly words) with the direction of shifts of attention closely coupled to the direction of eye movements.

Attention↗
PubMed1989

The acquisition of parafoveal word information in reading.

A somewhat counterintuitive finding has emerged from experiments that restrict the "window" of visual information available on a fixation during reading: fixation duration increases even though there is less information to process on a fixation. The two most likely explanations for this phenomenon are: (1) that the reader extracts abnormal information outside the window and this slows down processing; (2) that a restricted window does not allow a preview of a word before it is fixated, and hence identification of the word is slower when the word subsequently is fixated. In the present experiments, these two alternatives were tested. Conditions in which the size of the window alternated between fixations were compared with conditions in which the size of the window remained constant from fixation to fixation. This manipulation allowed us to separate effects due to restriction of the size of the window on the current fixation from preview benefits (which would be due to restriction of the size of the window on the prior fixation). Two experiments demonstrated clear beneficial effects on fixation duration due to receiving a preview of a word on the fixation prior to when it was fixated. In contrast, restriction of the size of the window had only marginal effects on the fixation on which that restriction occurred. In addition, a subsidiary analysis suggested that the benefit of previewing a word was influenced by its length; for short words, a preview primarily allowed the reader to skip the word more frequently, whereas for longer words, a preview primarily shortened the fixation time on the word when it was later fixated.

Adult↗
PubMed1989

Covert visual attention and extrafoveal information use during object identification.

Three experiments are reported that examined the relationship between covert visual attention and a viewer's ability to use extrafoveal visual information during object identification. Subjects looked at arrays of four objects while their eye movements were recorded. Their task was to identify the objects in the array for an immediate probe memory test. During viewing, the number and location of objects visible during given fixations were manipulated. In Experiments 1 and 2, we found that multiple extrafoveal previews of an object did not afford any more benefit than a single extrafoveal preview, as assessed by means of time of fixation on the objects. In Experiment 3, we found evidence for a model in which extrafoveal information acquired during a fixation derives primarily from the location toward which the eyes will move next. The results are discussed in terms of their implications for the relationship between covert visual attention and extrafoveal information use, and a sequential attention model is proposed.

Attention↗
PubMed1988

Developmental dyslexia and word retrieval deficits.

Developmental dyslexics, selected on the basis of very slow naming rates on the Rapid Automatic Naming Tasks (RAN), were compared to normal readers on oral language, picture categorization, and reading tasks. Findings indicated that the dyslexics' word retrieval deficits were one symptom of a more generalized, however subtle, oral language deficit which involved both receptive and expressive oral language functioning. The dyslexics' word retrieval problem also seemed chiefly related to language processing and not to deficits in semantic memory as there were no significant differences between dyslexics and controls on a nonverbal semantic memory task (picture categorization). In naming and identifying printed words, the dyslexics appeared to rely considerably upon the "indirect" or "assembly-of-phonology" route; they were slower in naming irregularly spelled words compared to regularly spelled words and on a lexical decision task, the dyslexics were slower in making negative decisions for "pseudohomophones" (e.g., "braik") than for other matched nonwords. Results are discussed in terms of the logogen model with some consideration of a developmental model as well.

Anomia↗
PubMed1988

Understanding the central processing limit in consistent-mapping visual search tasks.

Effects of load (i.e., the number of stimuli in the display) have been observed in multiple-frame studies using a consistent mapping of stimuli to responses (e.g., Fisher, 1982, 1984). In a series of four experiments, it is shown that these effects are not the consequence of differences across the high- and low-load conditions in either decision noise or peripheral masking. Additionally, it is shown that of two modes of limited capacity (a limited-channel and divided-capacity model) considered as possible explanations of load effects in tasks where subjects are required to locate a target, only one--the limited-channel model--is consistent with the results from all three location tasks. Finally, it is argued that the limited-channel model predicts not only the behavior observed in the four consistent-mapping experiments reported in this article but also the behavior observed in several related consistent-mapping tasks (Kleiss & Lane, 1986; Shiffrin & Gardner, 1972).

Attention↗
PubMed1987

Effects of foveal priming and extrafoveal preview on object identification.

The results of three different experiments suggested that the relation between an object in the fovea on fixation n and an object subsequently brought into the fovea on fixation n + 1 affects the time to identify the second object. In Experiment 1 we extended previous work by demonstrating that a previously seen related priming object speeded the time to name a target object even when a saccade intervened between the two objects. In Experiment 2 we replicated this result and further showed that the benefit on naming time was due to facilitation from the related object rather than inhibition from the unrelated object. In addition, naming of the target object was much slower in both experiments when there was not a peripheral preview of the target object on fixation n. However, because the effect of the foveal priming object was greater when the target was not present than when it was present, priming did not appear to make extraction of the extrafoveal information more efficient. In Experiment 3, fixation times were recorded while subjects looked at four objects in order to identify them. Fixation time on an object was shorter when a related object was fixated immediately before it, even though the four objects did not form a scene. The size of the facilitation was roughly comparable to that in several analogous experiments where scenes were used. The results suggest that the effects of a predictive scene context on object identification may be explainable in terms of an object-to-object or "intralevel" priming mechanism.

Cues↗
PubMed1979

Orthography and familiarity effects in word processing.

Both orthographic regularity and visual familiarity have been implicated as contributors to the efficiency of processing visually presented words. Our studies sought to determine which of the internal codes representing words in the nervous system are facilitated by these two variables. To do this, sets of letter strings in which orthography and familiarity were factorially combined were used as the basis for physical, phonetic, semantic, and lexical judgments. The data indicated consistent effects of orthography on the activation of all codes. These effects were seen in same-different matching and in judgments of stimulus orientation, which are based on visual codes; in judgments of pronounceability based on phonetic codes; in judgments of meaningfulness based on semantic codes; and in lexical decisions, which are based on phonetic and semantic codes together. Familiarity, on the other hand, had a clear influence on the activation of semantic codes and to a lesser extent affected phonetic codes. Despite previous positive results found in matching letter strings, however, no influence of familiarity occurred in judgments based on visual codes once evidence for criterion shifting was eliminated. Our negative results included direct tests of facilitation in matching acronyms (e.g., FBI) and in matching both regular and irregular strings familiarized by specific training. It now appears that earlier findings of visual familiarity effects may be attributed to response biases resulting from the activation of higher level codes sensitive to familiarity, and to the use of small sets of training stimuli that allowed subjects to induce orthographic-like rules. The results obtained so far with our methods seem to reconcile an inconsistent literature by showing that speeded decisions based on visual codes are most strongly influenced by rule-governed processing mechanisms sensitive to orthographic structure, whereas decisions based on phonetic and semantic codes are affected about equally by rule-governed mechanisms and by stimulus-specific mechanisms sensitive to familiarity. This conclusion may lead to changes in notions of how effective various kinds of visual training are likely to be at different stages in the acquisition of reading skill.

Discrimination Learning↗
PubMed1975

Familiarity affects visual processing of words.

While previous research has demonstrated that words can be processed more rapidly and/or more accurately than random strings of letters, it has not been convincingly demonstrated that the superior processing of words is a visual effect. In the present experiment, the cases of letters were manipulated in letter strings that were to be compared on the basis of physical identity. Mean response time was shorter for words than for nonwords even for pairs of letter strings that differed only in case (e.g., site-site). This finding implies that the advantage of words over nonwords (the familiarity effect) typically observed in the simultaneous matching task is not due solely to comparison of either the word names or the letter names and, thus, that at least part of the familiarity effect must be due to more rapid formation and/or comparison of visual representations of the two letter strings when they are words. Further analysis failed to reveal a significant involvement of phonemic or lexical codes in the comparison judgments.

Adolescent↗