Order of processing in visual perception.

Three experiments tested predictions derived from 3 cognitive scanning hypotheses proposing respectively a left-to-right, ends-first, and peripheral-foveal order of scanning. In Exps I and II configurations of letters and/or digits were presented to 11 Ss around a central fixation point, and the stimulus was followed by a 1-sec presentation of a patterned mask or a blank white field. Backward masking selectively impaired the identification of stimuli in foveal positions whether or not these stimuli occupied middle-of-row positions. In Exp III 4 Ss made a manual same-different response to the presence or absence of a critical letter presented 3Deg. to the left or right of fixation. Noise letters appeared on either side or both sides of the critical letter. Identification response times were faster when the critical letter appeared in the left-most position in left field arrays and the right-most position in right field arrays. Principal conclusions drawn from the 3 experiments were: (a) Alphanumeric stimuli are scanned from the peripheral visual field inward towards fixation. (b) Any left-to-right scanning occurs relatively late in iconic processing. (c) An ends-first scanning strategy is a particular case of a more general peripheral-foveal strategy. (French summary) (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Positional differences in performance on members of confusable and nonconfusable letter pairs.

Previous experiments by the present author (see PA, Vols 67:6977 and 70:7125) showed that a parafoveally presented letter is more accurately identified when flanked by a letter to its foveal side than when flanked by one to its peripheral side, but only if the 2 letters are nonconfusable. The present 4 experiments, with 65 undergraduates, indicated that the basis for this confusability–asymmetry interaction is not criterion or response bias, but rather that it occurs earlier in visual processing. In Exp I, the interaction was found when only 1 pair member was reported, thus eliminating response bias requiring the report of both letters as the source of the effect. In Exp II, the data were subjected to signal detection analysis, and the interaction persisted. In Exp III, pair members were presented simultaneously or in rapid sequence, and the interaction was found only with simultaneous presentations. In Exp IV, letters were used with upper- and lowercase counterparts that were quite different in shape. Uppercase letters that were most and least confusable for each S were paired for presentation in their uppercase or in mixed-case forms. The interaction occurred only with uppercase pairs. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parafoveal identification asymmetry: interactive effects of shape and color

If two adjacent letters project to the parafoveal region of the retina, both accuracy and discriminability measures have revealed that a letter flanked to its foveal side is identified more accurately than a letter the same distance from the fovea that is flanked to its peripheral side. This parafoveal identification asymmetry is greater if the letters are dissimilar in shape than if they are similar. Color and brightness were introduced as variables in the present experiments. The identification asymmetry was greatest for dissimilar letters in different (complementary) colors. Although those colors differed also in brightness, two letters that were achromatic but merely different in brightness did not produce an asymmetry interaction with shape. Interletter separation was varied between .15 and 1.95 deg, and the pattern of results just described persisted across both distances. The synergistic interaction of shape relation and color relation in determining the amount of identification asymmetry suggests that color and shape affect perceptual processing at the same level.     

Re-evaluating split-fovea processing in word recognition: Effects of retinal eccentricity on hemispheric dominance.

Several studies have claimed that hemispheric asymmetries affect word recognition right up to the point of fixation because each fovea is split precisely at its vertical midline and information presented either side of this midline projects unilaterally to different, contralateral hemispheres. To investigate this claim, four-letter words were presented to the left or right of fixation, either close to fixation entirely in foveal vision (0.15, 0.25, and 0.35 degrees from fixation) or further from fixation entirely in extrafoveal vision (2.00, 2.10, and 2.20 degrees from fixation). Fixation location and stimulus presentation were controlled using an eye-tracker linked to a fixation-contingent display and performance was assessed using a forced-choice task to suppress confounding effects of guesswork. A left hemisphere advantage was observed for words presented in extrafoveal locations but no hemisphere advantage (left or right) was observed for words presented in any foveal location. These findings support the well-established view that words encountered outside foveal vision project to different, contralateral hemispheres but indicate that this division for word recognition occurs only outside the fovea and provide no support for the claim that a functional split in hemispheric processing exists at the point of fixation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence against the computation of abstract letter identities in visual processing.

Conducted 2 studies conceptually similar to the study of D. Besner et al (see record 1985-05766-001) in which letter strings were reorganized into sets where the single letters that were different were phonologically similar (e.g., G vs C) or dissimilar (e.g., G vs K). Latencies for same–different decisions about mixed-case letter strings were faster when the different letters were phonologically dissimilar. Results suggested skilled readers access name codes of individual letters in making their speeded classifications. In the present studies with 16 undergraduates, phonological similarity was manipulated in either the 1st or 4th letter of a mixed-case 4-letter string. A similarity effect was found when the 1st letter was varied. Results are not consistent with the view that abstract letter identities are computed in the course of same–different decisions about simultaneously presented mixed-case displays. (French abstract) (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Look Here but Ignore What You See: Effects of Distractors at Fixation.

Distractor interference effects were compared between distractors in the periphery and those placed at fixation. In 6 experiments, the authors show that fixation distractors produce larger interference effects than peripheral distractors. However, the fixation distractor effects are modulated by perceptual load to the same extent as are peripheral distractor effects (Experiments 1 and 2). Experiment 3 showed that fixation distractors are harder to filter out than peripheral distractors. The larger distractor effects at fixation are not due to the cortical magnification of foveal stimuli (Experiments 4 and 5), nor can they be attributed to cuing by the fixation point (Experiment 2), the lower predictability or greater location certainty of fixation distractors (Experiment 5), or their being in a central position (Experiment 6). The authors suggest that preferential access to attention renders fixation distractors harder to ignore than peripheral distractors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Repetition blindness for locations: Evidence for automatic spatial coding in an RSVP task.

The authors report a new phenomenon called repetition blindness (RB) for locations: When 3 or 4 letters are presented rapidly and sequentially at random locations within a spatial array, experimental participants have difficulty reporting pairs of letters appearing in the same location within 250 ms of each other. This deficit occurs both during report of letter identities and during report of the locations in which the letters appear; it can also be found using a partial report task. During letter report, the deficit is found for 4-location arrays bit not for 8-location arrays. In contrast, letter RB is not found during location report even when the letters are always chosen from a set of 4. These results indicate that a small number of locations-but not letters-can be encoded automatically even when they are not explicitly reported. The authors argue that RB for locations results from a difficulty individuating 2 tokens at the same spatial location. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the recognition of words with inverted letters.

Conducted 2 experiments in which 24 Ss were asked to identify words with all or some of their letters inverted. The experiments differed only in the explicitness of the instructions given to Ss. In some cases the letters appearing upside down were inverted as 1 unit, and in other cases they were inverted by letter. It was found that when all the letters were inverted, recognition time was faster for unit inversion. When just a few of the letters in the words were inverted, recognition time was shorter when the inversion was letter by letter rather than by unit. Data are consistent with a model that assumes that when the stimulus is homogeneously misoriented unit correction is applied, and when such homogeneity does not exist piecemeal correction is applied. (French abstract) (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related deficits in component processes of working memory.

Working memory deficits in normal aging have been well documented, and studies suggest that high memory load plus the presence of distraction negatively impacts successful memory performance to a greater degree in older individuals. However, characterization of the component processes that are impaired by these task manipulations is not clear. In this behavioral study, younger and older subjects were tested with a delayed-recognition and recall task in which the encoding and delay period were both manipulated. During the encoding period, the subjects were presented with either a single letter or multiple letters at their predetermined forward letter span, and the delay period was either uninterrupted or interrupted with a visual distraction. There was an age-related impairment of working memory recognition accuracy only in the combination of high memory load and distraction. These results suggest that when working memory maintenance systems are taxed, faulty recognition processes may underlie cognitive aging deficits in healthy older individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye movements when reading transposed text: The importance of word-beginning letters.

Participants' eye movements were recorded as they read sentences with words containing transposed adjacent letters. Transpositions were either external (e.g., problme, rpoblem) or internal (e.g., porblem, probelm) and at either the beginning (e.g., rpoblem, porblem) or end (e.g., problme, probelm) of words. The results showed disruption for words with transposed letters compared to the normal baseline condition, and the greatest disruption was observed for word-initial transpositions. In Experiment 1, transpositions within low frequency words led to longer reading times than when letters were transposed within high frequency words. Experiment 2 demonstrated that the position of word-initial letters is most critical even when parafoveal preview of words to the right of fixation is unavailable. The findings have important implications for the roles of different letter positions in word recognition and the effects of parafoveal preview on word recognition processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A hemispheric division of labor aids mental rotation.

In the present study, we investigated whether a hemispheric division of labor is most advantageous to performance when lateralized inputs place unequal resource demands on the left and right cerebral hemispheres. In each trial, participants decided whether 2 rotated letters, presented either in the same visual field (within-field trials) or in opposite visual fields (across-field trials), were both of normal orientation, or whether one was normal and the other was mirror-reversed. To discriminate a letter's orientation, one must rotate the letter to the upright position. Therefore, we manipulated whether the two letters imposed similar or dissimilar demands on cognitive resources by varying the number of degrees that each letter needed to be rotated to reach the upright position. As predicted, in 2 experiments we found that the across-field advantage increased as the number of degrees each letter needed to be rotated became more dissimilar. These findings support a current model of hemispheric interactions, which posits that an unequal hemispheric distribution of cognitive load allows the cerebral hemispheres to take the lead for different aspects of cognitive processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Why is word recognition impaired by disorientation while the identification of single letters is not?

Past research has shown that speed of identifying single letters or digits is largely indifferent to orientation, whereas the recognition of single words or connected text is markedly disrupted by disorientation. In a series of four experiments, we attempted to reconcile these findings. The results suggest that disorientation does not impair the identification of the characters but disrupts the perception of their spatial arrangement. When spatial order information is critical for distinguishing between different stimuli, disorientation is disruptive because some rectification process is required to restore order information. Utilizing the similarity between the letter B and the number 13, we found strong effects of orientation when a stimulus was interpreted as the two-digit number 13 but not when interpreted as the single letter B. This, however, occurred only when the set of numbers to be classified included permutations of the same digits. Odd–even decisions on single-digit and two-digit numbers (Experiment 3) yielded strong effects of stimulus orientation for order-dependent numbers (e.g., 32), weaker effects for order-independent numbers (e.g., 24), and none for repeated-digit (e.g., 22) or single-digit numbers. Classification time for two-letter Hebrew words evidenced strong effects of orientation for words that differed only in letter order but much weaker effects for words that had no letters in common, even when these were embedded within some words that did (Experiment 4). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attending to color with proper fixation

In contemporary theorizing, there is a controversy about the role of spatial location in the selection of visual information; some theories postulate that position plays a unique role, whereas other theories hold that position is just one selection dimension that is not different from other dimensions, such as color and shape. In this context, a paradigm introduced by Tsal and Lavie (1988) promised to be of fundamental importance. With that paradigm, Tsal and Lavie found that, after reporting a first letter of a prespecified color, subjects preferred to switch their reporting to letters from array positions adjacent to that letter over continuing to report letters of the same color as that of the first letter. This switch from color to position provided firm evidence in favor of the "position-special" views as opposed to the "all-attributes-are-equal" views. In the present study, six experiments, employing Tsal and Lavie's paradigm and variations of that paradigm, are reported. Experiments 1,2,4, and 5 show that evidence for a switch from selection on the basis of color to selection on the basis of position is not obtained when subjects are forced to fixate the fixation point and possibly also not under normal contrast conditions without fixation controls. Experiment 3 shows that switching from color to position is difficult. Experiments 2, 5, and 6 show that evidence for a switch is obtained only under low-contrast conditions when subjects are not forced to fixate the fixation point. It is concluded that the Tsal and Lavie paradigm is an asymmetric paradigm. The results reported by Tsal and Lavie constituted a major threat for the "all-attributes-are-equal" theories and provided firm support for the "position-special" theories. The results reported in the present study are compatible with the all-attributes-are-equal theories, but, at the same time, do not constitute a major threat for the contemporary position-special theories.     

Evidence of preliminary response preparation from a divided attention task.

In a divided attention situation, preliminary response activations produced by stimuli on one channel were revealed through their effects on responses to stimuli on a secondary probe channel. Subjects performed concurrent but independent four-choice reaction-time tasks using the same four response fingers (middle and index fingers on both hands). In the main task, targets were large and small Ss and Ts, and medium-sized Ss and Ts sometimes appeared as distractors. Targets in the probe task were squares differing in location. A response to a probe square was faster if a distractor letter presented just before it had the same name as the target letter corresponding to that square (i.e., assigned to the same response key) than if the distractor letter had a different name—a result indicating that distractor letters cause partial response preparation. The timecourse of the effect demonstrated that preparation was based on preliminary information about distractor name that was available before distractor size had been determined. The results support models in which response preparation can sometimes begin before stimulus recognition has finished. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of structural and naming factors of letters upon the recognition of tachistoscopic letters (author''s transl)

To determine the nature of effects of a preceding letter stimulus upon the recognition of a following letter stimulus, 20 subjects were sequentially and tachistoscopically presented pairs of letters of pairs of random patterns, which consist of the same number of elements, and asked to judge whether they were "same" or "different" in form. Four variable interstimulus intervals (ISI) between the 1st stimuli and the 2nd stimuli were employed as parameters. Results obtained were as follows: (a) percentages of correct responses for the letters were not significantly different from those for the random patterns, and (b) percentages of correct responses for the "same" matching tasks were significantly higher than those for the "different" matching tasks, but, differences in number of correct responses between the two tasks diminished as ISI increased. These results reveal structural, rather than naming, effects of preceding letters in the information processing of matching single letters.     

Recognition without identification.

The ability of people to recognize words that they could not identify was examined. After studying a list of 15 words, participants completed a word fragment test consisting of 4-letter fragments of both studied and nonstudied words. Whether they were able to solve a particular fragment or not, participants then made an episodic recognition judgment. Even when participants were unable to solve a fragment, their recognition accuracy was significantly higher than chance. This effect was significant when list length was increased, when 2-letter fragments were used, when first letters were excluded from fragments, and when the letter casing and the presentation modality were changed from study to test. It also occurred when participants attempted to identify fragments at study and rated words at test. Recognition without identification is attributed to the use of orthographic information when determining the familiarity of a test item. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye Movements and Word Skipping During Reading Revisited.

The authors examined word skipping in reading in 2 experiments. In Experiment 1, skipping rates were higher for a preview of a predictable word than for a visually similar nonword, indicating there is full recognition in parafoveal vision. In Experiment 2, foveal load was manipulated by varying the frequency of the word preceding either a 3-letter target word or a misspelled preview. There was again a higher skipping rate for a correct preview and a lower skipping rate when there was a high foveal load, but there was no interaction, and the pattern of effects in fixation times was the same as in the skipping data. Experiment 2 also showed significant skipping of nonwords similar to the target word, indicating skipping based on partial information. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Parafoveal Semantic Processing of Emotional Visual Scenes.

The authors investigated whether emotional pictorial stimuli are especially likely to be processed in parafoveal vision. Pairs of emotional and neutral visual scenes were presented parafoveally (2.1° or 2.5° of visual angle from a central fixation point) for 150-3,000 ms, followed by an immediate recognition test (500-ms delay). Results indicated that (a) the first fixation was more likely to be placed onto the emotional than the neutral scene; (b) recognition sensitivity (A') was generally higher for the emotional than for the neutral scene when the scenes were paired, but there were no differences when presented individually; and (c) the superior sensitivity for emotional scenes survived changes in size, color, and spatial orientation, but not in meaning. The data suggest that semantic analysis of emotional scenes can begin in parafoveal vision in advance of foveal fixation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simon-Type Effects: Chronometric Evidence for Keypress Schemata in Typewriting.

In 4 experiments, chronometric evidence for keypress schemata in typing was sought by presenting stimuli to be typed in positions that were displaced from a central fixation point. Reaction times were shorter when stimulus positions corresponded to keyboard locations of the letters to be typed, suggesting that position was an important part of the internal representation of the response. Experiment 1 presented single letters left and right of fixation. Experiment 2 presented single letters above and below fixation. Experiment 3 presented words left and right of fixation and found evidence of parallel activation of keypress schemata. Experiment 4 found no effect of the eccentricity of the keyboard locations and responding fingers, suggesting that response-location codes are categorical, not metric. The results are consistent with D. E. Rumelhart and D. A. Norman's (1982) theory of typewriting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parafoveal and foveal processing of abbreviations during eye fixations in reading: Making a case for case.

The processing of abbreviations in reading was examined with an eye movement experiment. Abbreviations were of 2 distinct types: acronyms (abbreviations that can be read with the normal grapheme-phoneme correspondence [GPC] rules, such as NASA) and initialisms (abbreviations in which the GPCs are letter names, such as NCAA). Parafoveal and foveal processing of these abbreviations was assessed with the use of the boundary change paradigm (K. Rayner, 1975). Using this paradigm, previews of the abbreviations were either identical to the abbreviation (NASA or NCAA), orthographically legal (NUSO or NOBA), or illegal (NRSB or NRBA). The abbreviations were presented as capital letter strings within normal, predominantly lowercase sentences and also sentences in all capital letters such that the abbreviations would not be visually distinct. The results indicate that acronyms and initialisms undergo different processing during reading and that readers can modulate their processing based on low-level visual cues (distinct capitalization) in parafoveal vision. In particular, readers may be biased to process capitalized letter strings as initialisms in parafoveal vision when the rest of the sentence is normal, lowercase letters. (PsycINFO Database Record (c) 2011 APA, all rights reserved)