Priming and response selection processes in letter classification and identification tasks.

The processing of isolated visual letters was studied by means of a priming paradigm. In alphabetic (letter vs nonletter) classification, any letter prime reduced response times to letter targets. Additional facilitation occurred only with primes physically identical to the target. In letter naming, facilitation was seen with primes nominally identical to the target even when they were physically different. This result is not due to phonological priming because phonologically similar primes had no effect on naming times. Primes nominally different from the target but physically similar to it increased naming times. The classification task seems to be performed through the global monitoring of stored visual knowledge of letters. In contrast, the absolute identification of letters appears to rest on a signal-to-noise statistic derived from an abstract encoding of letter identities. Connectionist simulations provide support for these proposals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Letter encoding in visual word identification: More evidence for a word-integration explanation for parafoveal preview effects in reading.

A letter string presented briefly in the parafovea facilitates naming a foveally presented word provided that the two stimuli are orthographically similar. The facilitation is asymmetrical in that to obtain it, both letter strings must have the first letters in common. One possible explanation, a letter-integration hypothesis, proposes that readers only identify the letters at the beginning of the parafoveal stimulus, an action that facilitates processing the target. Another explanation, a word-integration hypothesis, postulates that all the letters of the parafoveal stimulus are identified and that the asymmetry occurs because the first letters of the parafoveal stimulus are weighted more heavily than the later ones. The two accounts differ in the way the position of the first letter is determined. To distinguish the views, English and Hebrew stimuli were presented to 7 bilingual readers. 12 normal students participated as controls. Readers could not anticipate the position of the first letters; hence, if the letter-integration explanation is correct, the asymmetry in the priming should be attenuated. Consistent with the word-integration explanation, however, priming occurred when the target shared the beginning letters with the prime in both languages. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Kinetics of AMPA-type glutamate receptor channels in rat caudate-putamen neurones show a wide range of desensitization but distinct recovery characteristics

In 5 experiments the authors examine the role of object-based grouping on negative priming. The experiments used a letter-matching task with multiple letters presented in temporally separated prime and probe displays. On mismatch trials, distractor letters in primes were repeated as targets in probes, or distractor and target letters were completely different. Negative priming was shown by slowed responses when distractors were repeated as targets relative to when the stimuli differed. This occurred both when only letters were presented (Experiments 1 and 4) and when letters were surrounded by boxes (Experiment 5). Experiments 2, 3, and 4 showed that negative priming was affected by the grouping of target and distractor letters in prime displays. Negative priming was reduced when 1 of the distractor letters was placed in the target box and 1 was left outside the box; facilitatory priming was observed when both distractor letters appeared in the target box. The data were accounted for in terms of there being (a) object-based competition for visual selection, (b) inhibition of distractor objects that compete for selection with target objects, and (c) activation or inhibition of the identities of all component elements within target or distractor objects.     

Object-based perceptual grouping affects negative priming.

In 5 experiments the authors examine the role of object-based grouping on negative priming. The experiments used a letter-matching task with multiple letters presented in temporally separated prime and probe displays. On mismatch trials, distractor letters in primes were repeated as targets in probes, or distractor and target letters were completely different. Negative priming was shown by slowed responses when distractors were repeated as targets relative to when the stimuli differed. This occurred both when only letters were presented (Experiments 1 and 4) and when letters were surrounded by boxes (Experiment 5). Experiments 2, 3, and 4 showed that negative priming was affected by the grouping of target and distractor letters in prime displays. Negative priming was reduced when 1 of the distractor letters was placed in the target box and 1 was left outside the box; facilitatory priming was observed when both distractor letters appeared in the target box. The data were accounted for in terms of there being (a) object-based competition for visual selection, (b) inhibition of distractor objects that compete for selection with target objects, and (c) activation or inhibition of the identities of all component elements within target or distractor objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual span in schizophrenia.

Administered a forced-choice letter recognition task to assess the span of apprehension of 30 schizophrenics (good premorbid paranoids, good premorbid nonparanoids, and poor premorbid nonparanoids) and 20 controls (hospitalized nonschizophrenics and penitentiary inmates). When the task required only that 1 target letter be detected, there were no significant differences between groups. When the target was presented in conjunction with varying numbers of irrelevant "noise" letters, however, the span of schizophrenics was significantly less than that of either control group. The span of schizophrenics reached an upper limit at a small display size (4 letters) and showed no further increase. The constructs of premorbid adjustment and paranoid status bore no relationship to the deficit. Measures of the trial-to-trial variability in number of elements processed and consistency of scanning path did not differentiate schizophrenics and controls. The number of irrelevant noise letters surrounding a target was found to have no influence on detection in either group. (23 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognition memory and attentional selection: Serial scanning is not enough.

In 2 experiments with a total of 54 graduate or undergraduate students, using memory sets of up to 10 letters, the response competition paradigm was employed to investigate the extent to which extraneous visual stimuli interfere with or affect the process of memory search. It was assumed that if selective attention could exclude the effect of noise letters from a Sternberg-type (S. Sternberg; see record 1966-10810-001) memory comparison process, then there would be an increase in intercept for the reaction time (RT)–set size functions but no increase in slope. This result was obtained. However, a large difference in response times to both positive and negative set targets were found when the accompanying noise letters indicated a competing response, as opposed to when they indicated the same response as the target. It is suggested that this implies rapid identification of the nature of both target and noise, independent of a serial comparison process. A modification of a dual process model (J. F. Juola et al; see record 1972-00186-001) in which stimuli activate a familiarity value independent of memory search was suggested to account for these results. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does unattended information facilitate change detection?

Changes between alternating visual displays are difficult to detect when the successive presentations of the displays are separated by a brief temporal interval. To assess whether unattended changes attract attention, observers searched for the location of a change involving either a large or a small number of features, in pairs of displays consisting of 4, 7, 10, 13, or 16 letters (Experiment 1) or digits (Experiments 2 and 3). Each display in a pair of displays was presented for 200 ms, and either a blank screen (Experiments 1 and 2) or a screen of equal luminance to the letters and digits (Experiment 3) was presented for 80 ms between the alternating displays. In all experiments, the search function for locating the larger change was shallower than the search function for locating the smaller change. These results indicate that unattended changes play a functional role in guiding focal attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship of rapid naming ability and language analysis skills to kindergarten and first-grade reading achievement.

34 kindergartners and 34 1st graders completed a series of measures including the McCarthy Scales of Children's Abilities and the WRAT. Language analysis tasks (segmentation and rhyming) and rapid automatized naming tasks (objects, colors, and letters) were found to tap different components of linguistic processing in both kindergarten and 1st-grade Ss. In kindergarten, rapid naming of colors was significantly related to 5 of 6 reading measures, whereas rapid naming of objects, syllable segmentation, and rhyming were related to at least 3 of the 6. In the 1st grade, rapid naming of letters and phoneme segmentation were significantly related to all 3 measures of 1st-grade reading achievement. Ss who could analyze letter names (as indicated by speed on the letter naming task) were more likely to be among the better readers at the end of the 1st grade. (66 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integrating information across fixations during reading: The use of orthographic bodies and of exterior letters.

Eye movements were recorded to determine whether the parafoveally visible orthographic body of a bisyllabic target word facilitated recognition during the next target fixation. Eye-movement-contingent display changes revealed part of the target, including its orthographic body, or its beginning letters, when it was parafoveally available, but the full target was visible after it was fixated. Target viewing durations showed no benefit from parafoveal preview of orthographic bodies. Instead, preview benefits derived primarily from the preview of word-initial letters. Examination of oculomotor activity revealed that single target fixations were common when the pretarget word received more than one fixation; conversely, more than one target fixation was common when the pretarget word had received a single fixation. Interword fixation strategies thus affected target viewing, but use of parafoveal target previews was unaffected by these strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Capturing Attention When Attention "Blinks".

Four experiments addressed the question of whether attention may be captured when the visual system is in the midst of an attentional blink (AB). Participants identified 2 target letters embedded among distractor letters in a rapid serial visual presentation sequence. In some trials, a square frame was inserted between the targets; as the only geometric object in the sequence, it constituted a singleton. Capture effects obtained when the AB was most severe and when it was over were compared. There were 3 main results. First, capture occurred even when the AB was crippling, suggesting that a singleton exogenously engaged attention even when processing of a previous target was continuing apace. Second, when the singleton contained the key target feature, capture effects were clearly manifest. Third, even when the singleton did not possess the key target feature, it still succeeded in capturing attention, although the effects were both feeble and fleeting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neon colors illuminate reading units.

The effect of syllable-size reading units on neon color was investigated in 6 experiments. The stimuli consisted of 5- or 7-letter words or pseudowords with a syllable break either just before or just after the middle (target) letter. The target letter was overlaid with a plaid of red and green lines that gave it an ambiguous neon color. The letters preceding the target were overlaid with a monochromatic grid (red or green), and the letters following the target were overlaid with the other color. Ss were significantly more likely to judge the target as more similar to the color of other letters within its syllable than colors of letters outside that unit. The effect was shown not to be an artifact of guessing strategy or eye movements. Word structure determined by orthography and morphology affected neon colors, but no effect was found for purely phonological units. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Why do non-color words interfere with color naming?

In the non-color-word Stroop task, university students' response latencies were longer for low-frequency than for higher frequency target words. Visual identity primes facilitated color naming in groups reading the prime silently or processing it semantically (Experiment 1) but did not when participants generated a rhyme of the prime (Experiment 3). With auditory identity primes, generating an associate or a rhyme of the prime produced interference (Experiments 2 and 3). Color-naming latencies were longer for nonwords than for words (Experiment 4). There was a small long-term repetition benefit in color naming for low-frequency words that had been presented in the lexical decision task (Experiment 5). Facilitation of word recognition speeds color naming except when phonological activation of the base word increases response competition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of global and local context on lexical processing during language comprehension.

Nine experiments involving young adults (N?=?525) tested the roles of local (sentence) and global (discourse) contexts on lexical processing. Contextual material was presented auditorily, and naming times for the last (visually presented) word were collected. Experiment 1 tested the local contexts alone and found facilitation of naming latencies when local contexts were related to the target word. Subsequent experiments, using varying baseline conditions, found that globally related material affected naming latency in all cases, whereas the same locally related material that was used in the first study now had no facilitation effect. The globally related material had an immediate effect on naming times. The authors argue that the results are inconsistent with associatively based models and with various hybrid models of context effects and that a discourse-based model best accounts for the data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of signal-noise similarity on visual information processing of schizophrenics.

Performed 2 studies with a total of 34 schizophrenic and 34 nonschizophrenic male inpatients to examine the effect of target-noise similarity on the span of apprehension performance of schizophrenics. Ss were required to search a briefly presented display of letters for a target letter which was presented along with noise letters of varying degrees of physical similarity to the target. In both studies the schizophrenics' performance was significantly poorer than that of controls, and the target-noise similarity manipulation affected both groups equally. Results indicate that the information-processing operations of both groups were similar but that schizophrenics performed them at a slower rate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Illusory words: The roles of attention and of top–down constraints in conjoining letters to form words.

Conducted 3 experiments with 40 undergraduates to confirm that illusory recombinations of letters can be seen when several words or letter-strings are presented too briefly to allow focused attention to each item in turn and to explore the role of lexical entries in promoting or preventing these preceptual errors. Overall findings indicate that when attention was divided among 4 briefly exposed syllables, Ss mistakenly detected targets whose letters were present in the display but in the wrong combinations. These illusory conjunctions were somewhat more frequent when the target was a word and when the distractors were nonwords, but the effects of lexical status were small and did not reach significance in free report of the same displays. Search performance was further impaired if the nonwords were unpronouncable consonant strings rather than increased conjunction errors. Results are discussed in relation to feature-integration theory and to current models of word perception. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing nominal information during visual search.

Conducted 3 experiments to examine the processing of nominal information during a visual search. In Exp I, 6 experienced and 2 naive Ss searched for a single pre-specified target letter, and the stimulus exposure-time needed to yield a 50% (corrected for chance) level of accuracy was estimated using the parameter estimation by sequential testing procedure. Results show that the exposure-time was not influenced by the presence (in the irrelevant items) of the target's other case; this suggested that there was no obligatory accessing of nominal information during preattentive processing. In Exp II, 6 experienced Ss searched in Condition 1 for a single target which was specified as being one of a same-name pair of letters, and in Condition 2 for a target specified as one of a same-shape pair of letters. The exposure-time required for the same-name search was greater than that required for the same-shape search. In Exp III, accuracy of search was compared in the same-shape and same-name conditions with a control condition. The target in this control condition was specified as one of a pair of letters not sharing a name or any special shape. 12 Ss searched 6-item displays and 12 Ss searched 12-item displays for a pre-specified target letter. Results confirm the difference detected in Exp II, but they do not show any difference between performance in the same-name condition and in the control condition. It is suggested that some focal processing is required for the development of a sufficiently detailed level of visual representation to allow for naming. (French summary) (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Specificity of pattern-analyzing skills in reading.

12 right-dominant male undergraduates in 2 groups named letters or read text as training for naming letters or reading text. The main findings are as follows: Naming letters was good practice for further letter-naming and also quickened speed of reading text, but not as much as reading itself did. Reading text was good practice for further reading, did not quicken naming letters, but did increase accuracy. The results show why neither the analytical nor the whole word approach to visual pattern training in literacy is dominant; the 2 methods teach different skills whose components are only partially correlated. The transfer of training method seems to be useful in studying some of the component skills of reading. (French summary) (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic interference in a delayed naming task: Evidence for the response exclusion hypothesis.

In 2 experiments participants named pictures of common objects with superimposed distractor words. In one naming condition, the pictures and words were presented simultaneously on every trial, and participants produced the target response immediately. In the other naming condition, the presentation of the picture preceded the presentation of the distractor by 1,000 ms, and participants delayed production of their naming response until distractor word presentation. Within each naming condition, the distractor words were either semantic category coordinates of the target pictures or unrelated. Orthogonal to this manipulation of semantic relatedness, the frequency of the pictures' names was manipulated. The authors observed semantic interference effects in both the immediate and delayed naming conditions but a frequency effect only in the immediate naming condition. These data indicate that semantic interference can be observed when target picture naming latencies do not reflect the bottleneck at the level of lexical selection. In the context of other findings from the picture-word interference paradigm, the authors interpret these data as supporting the view that the semantic interference effect arises at a postlexical level of processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Position-specific masking and the word-letter phenomenon: Reexamining the evidence from the Reicher-Wheeler paradigm.

When choosing which of 2 equally plausible "critical" letters (e.g., n or h) was present in a briefly presented backward-pattern-masked target (the Reicher-Wheeler task), people are more accurate with words (e.g., show) than isolated letters (h). Contemporary accounts argue that pattern masks induce this word-letter phenomenon (WLP) because critical letters in words are more resistant to replacement from masking letter fragments occupying the same serial positions. The authors tested this notion by directly examining the effect of position-specific masking on critical-letter report using backward-pattern masks that occupied only each critical-letter position. Under these conditions, no WLP was observed, even though all noncritical letters in words were unmasked. However, a strong WLP was obtained when masks occupied all possible serial positions, including those of noncritical letters. Further experiments indicated that these masking effects were not confounded by attentional factors. Implications for contemporary accounts of the WLP and the structure of the word recognition system are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Span of apprehension in schizophrenic patients as a function of distractor masking and laterality.

Compared 20 schizophrenic patients, 10 depressed control patients, and 20 normal control Ss in a forced-choice, target-detection method for assessing the span of apprehension. The detection task required the S to report which of 2 target letters was presented among 7 other (distractor) letters. Performance accuracy was examined as a function of target location and whether the distractor letters were masked after their presentation. The backward masking of the distractors improved target-detection accuracy of both control groups but reduced accuracy of the schizophrenic group. In addition, schizophrenics performed particularly poorly on targets located in the left half or lower half of the display. Results suggest that response to the masking of distractors may be a new index of attentional shortcoming in schizophrenia. Various theoretical explanations for the target location findings are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)