A theory of order relations in perceptual matching.

Relates order relations to research on retrieval processes and the representation of order information in memory. In 2 experimental tests, presentation of a study string of letters was followed by a test string to which the 6 undergraduate Ss responded "same" or "different." When adjacent letters were switched, RT was long and accuracy low, suggesting that a test letter is not simply compared to the letter in the same position in the study string; rather, the comparison is distributed across positions. The memory model assumes that the representation of a letter is distributed over position and that the comparison process assesses the amount of overlap between the test string and the memory representation. The diffusion retrieval model and overlap memory model are fitted to the data and goodness-of-fit is assessed. Shortcomings of alternative models are considered and applications of the model to related matching tasks, such as D. Taylor's (1976) converse of the perceptual matching task, and Angiolillo-Bent and L. Rips's (1981) multiple-element comparison task, are described. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serial position effects in the identification of letters, digits, and symbols.

In 6 experiments, the authors investigated the form of serial position functions for identification of letters, digits, and symbols presented in strings. The results replicated findings obtained with the target search paradigm, showing an interaction between the effects of serial position and type of stimulus, with symbols generating a distinct serial position function compared with letters and digits. When the task was 2-alternative forced choice, this interaction was driven almost exclusively by performance at the first position in the string, with letters and digits showing much higher levels of accuracy than symbols at this position. A final-position advantage was reinstated in Experiment 6 by placing the two alternative responses below the target string. The end-position (first and last positions) advantage for letters and digits compared with symbol stimuli was further confirmed with the bar-probe technique (postcued partial report) in Experiments 5 and 6. Overall, the results further support the existence of a specialized mechanism designed to optimize processing of strings of letters and digits by modifying the size and shape of retinotopic character detectors' receptive fields. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transposed-letter effects in reading: Evidence from eye movements and parafoveal preview.

Three eye movement experiments were conducted to examine the role of letter identity and letter position during reading. Before fixating on a target word within each sentence, readers were provided with a parafoveal preview that differed in the amount of useful letter identity and letter position information it provided. In Experiments 1 and 2, previews fell into 1 of 5 conditions: (a) identical to the target word, (b) a transposition of 2 internal letters, (c) a substitution of 2 internal letters, (d) a transposition of the 2 final letters, or (e) a substitution of the 2 final letters. In Experiment 3, the authors used a further set of conditions to explore the importance of external letter positions. The findings extend previous work and demonstrate that transposed-letter effects exist in silent reading. These experiments also indicate that letter identity information can be extracted from the parafovea outside of absolute letter position from the first 5 letters of the word to the right of fixation. Finally, the results support the notion that exterior letters play important roles in visual word recognition. (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)     

Memory for position and identity across eye movements.

Used a "transsaccadic" partial report procedure to measure memory for position and identity information across saccades. Delaying the partial-report cue after the eye movement had little effect on report accuracy. Mask presentation hindered recall only at the shortest delay. Accuracy was much higher when the letter array contained 6 letters than when it contained 10 letters. Intra-array errors were much more frequent than extra-array errors. These results suggest that memory across eye movements decays slowly, has a limited capacity, is maskable for a brief time, and retains identity information better than position information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Order of report and order of scanning in tachistoscopic recognition.

Presented horizontal rows of 8 letters across fixation to 6 university students. An instruction cue told Ss to report the letters either in a left-to-right or in a right-to-left sequence. There were 5 different temporal intervals between test stimulus and instruction cue and an ad lib condition, where the instruction cue was triggered by the Ss. With increasing interstimulus interval, the serial position curve for right-to-left report showed a significant transition from an initial superiority for letters to the right of fixation to a superiority for letters to the left of fixation. It is concluded that the asymmetry of the tachistoscopic serial position curve is due to the order of scanning the fading contents of a visual information store. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reading ability and single-letter orthographic redundancy.

Two experiments investigated the role of one form of intraword orthographic redundancy: the characteristic asymmetric spatial distributions of letters of the alphabet across serial positions within words. In Exp I, 81 college students demonstrated recognition knowledge of these distributions when given only the letter name, word length, and serial position information with no other context. Ss were correct more often for those letters which are least variable across serial positions. In Exp II, 28 5th graders who were skilled readers demonstrated a sensitivity to letter positional distributions similar to that of the adults; 20 poor readers did not. However, performance was equivalent for both good and poor readers on a subset of letters relatively unpredictable with respect to serial position. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory representation of alphabetic position and interval information.

The authors conducted 3 sets of experiments. In the 1st set of experiments, participants made alphabetic position estimations. In the 2nd set, participants made interletter distance estimations. In the 3rd set, they made comparative judgments of the alphabetic order of a pair of letters. The results showed that participants had highly accurate ordinal level information about the alphabet in memory but that interval level information was systematically distorted. In addition, alphabetic serial information was found to be used in 2 distinct modes in memory, depending on whether the representation could be contained within the span of immediate memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Letter position information and printed word perception: The relative-position priming constraint.

Six experiments apply the masked priming paradigm to investigate how letter position information is computed during printed word perception. Primes formed by a subset of the target's letters facilitated target recognition as long as the relative position of letters was respected across prime and target (e.g., "arict" vs. "acirt" as primes for the target "apricot"). Priming effects were not influenced by whether or not absolute, length-dependent position was respected (e.g., "a-ric-t" vs. "arict"/"ar-i-ct"). Position of overlap of relative-position primes (e.g., apric-apricot; ricot-apricot; arict-apricot) was found to have little influence on the size of priming effects, particularly in conditions (i.e., 33 ms prime durations) where there was no evidence for phonological priming. The results constrain possible schemes for letter position coding. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Font regularity constraints on the process of letter recognition.

Strings of four unrelated letters were presented for subjects to identify, followed by a patterned mask and then a forced choice test of each letter position. In Experiment 1, the type style in the regular conditions was consistent—all of the letters were of a single type font—whereas in the mixed condition, each string contained letters from two type fonts. Compared with the mixed condition, accuracy in the regular conditions was higher overall and increased at a faster rate as a function of processing time. This held across four sessions. In Experiment 2, the font in the mixed condition was varied either between or within letter strings; sizeable advantages for the regular conditions were found with both mix-methods. The results are consistent with the idea of a schemalike perceptual system that becomes tuned to the regularities of a particular font in order to process visual information efficiently. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development and initial validation of a new procedure for evaluating adequacy of effort given during neuropsychological testing: The letter memory test.

The authors report on results from a new procedure for evaluating adequacy of effort given during neuropsychological testing. The letter memory test (LMT) is a computer-administered, 45-item, forced-choice recognition task that uses consonant letters as stimuli and manipulates face difficulty level along 2 dimensions: number of letters to be remembered and number of choices amongst which the target stimulus must be identified. In 3 studies that included either analogue or known groups designs, the LMT discriminated poorly motivated from well-motivated groups at a moderately high level of accuracy, which was comparable to that of the Digit Memory Test and superior to that of the 21-item Test. The internal consistency reliability of the LMT was also high. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serial position and set size in short-term memory: The time course of recognition.

Subjects viewed sequentially presented lists of 3–6 words, which were followed by a recognition probe. Memory retrieval speed (dynamics) and strength were measured in an interruption speed–accuracy trade-off (SAT) procedure and a collateral reaction time (RT) procedure. In SAT, item strengths depended on serial position, but only two retrieval speeds were observed: a fast rate for the last item in the study list (a case of immediate repetition between study and test) and a slow rate for all other items that was independent of serial position and set size. Serial-position-dependent strengths and set-size-dependent criterion shifts accounted for standard RT patterns that have been taken as evidence for serial scanning in short-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Short-term memory for serial order in schizophrenia: A detailed examination of error types.

Cognitive deficits in schizophrenia have been associated with working memory problems. Schizophrenic patients (n?=?24) and controls (n?=?29) participated in simple short-term memory tasks, recalling a list of letters from the first to last item in the order of presentation. The authors hypothesized that deficient sequential representations would increase movement errors (e.g., ABCD being recalled as ABDC) or intrusion errors (e.g., ABCD being recalled as ABCX), whereas simple trace decay would lead to omission errors (e.g., ABCD being recalled as ABC_). Patients made disproportionately more omissions toward the end of 6-item lists. There were no group differences in movements or intrusions as a function of serial position. Schizophrenic patients' limited short-term memory span may be due to greater forgetting during recall and not to a selective deficit in the mechanisms responsible for maintaining serial order information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Oscillator-based memory for serial order.

A computational model of human memory for serial order is described (OSCillator-based Associative Recall [OSCAR]). In the model, successive list items become associated to successive states of a dynamic learning-context signal. Retrieval involves reinstatement of the learning context, successive states of which cue successive recalls. The model provides an integrated account of both item memory and order memory and allows the hierarchical representation of temporal order information. The model accounts for a wide range of serial order memory data, including differential item and order memory, transposition gradients, item similarity effects, the effects of item lag and separation in judgments of relative and absolute recency, probed serial recall data, distinctiveness effects, grouping effects at various temporal resolutions, longer term memory for serial order, list length effects, and the effects of vocabulary size on serial recall. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serial order in spatial immediate memory

Serial order effects in spatial memory are investigated in three experiments. In the first an analysis of errors in recall data suggested that immediate transpositions were the most common error and that order errors over 2 or 3 adjacent items accounted for the majority of errors in recall. The first and last serial positions are less error-prone than is the middle position in sets of six and seven items. A second experiment investigated recognition of transpositions and found that immediate transpositions were hardest to recognize but that a traditional serial position effect was not found. This may be due to the difficulty of maintaining one set of spatial items when another set is presented for comparison. A probe experiment, in which subjects were asked to recognize whether a single item came from a memory set and then to assign it to its position in the set indicated that the first and last positions were remembered more accurately than were central positions. The combination of serial order data in recall and position data suggests that there are similarities between serial order and position effects in the verbal and spatial domains and that serial order in spatial sequences is position-based.     

Emotion-attention interactions in recognition memory for distractor faces.

Effective filtering of distractor information has been shown to be dependent on perceptual load. Given the salience of emotional information and the presence of emotion-attention interactions, we wanted to explore the recognition memory for emotional distractors especially as a function of focused attention and distributed attention by manipulating load and the spatial spread of attention. We performed two experiments to study emotion-attention interactions by measuring recognition memory performance for distractor neutral and emotional faces. Participants performed a color discrimination task (low-load) or letter identification task (high-load) with a letter string display in Experiment 1 and a high-load letter identification task with letters presented in a circular array in Experiment 2. The stimuli were presented against a distractor face background. The recognition memory results show that happy faces were recognized better than sad faces under conditions of less focused or distributed attention. When attention is more spatially focused, sad faces were recognized better than happy faces. The study provides evidence for emotion-attention interactions in which specific emotional information like sad or happy is associated with focused or distributed attention respectively. Distractor processing with emotional information also has implications for theories of attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serial retrieval processes in the recovery of order information.

The retrieval of temporal order and item information from short-term memory (STM) are examined with the cued-response speed–accuracy trade-off (CR-SAT) procedure and a complementary reaction time (RT) task. The retrieval of order information was examined with a 2-alternative forced-choice (2AFC), relative judgment of recency (JOR) task. Analyses of the pattern of mean RT, RT accuracy, and the overall shape of the RT distribution for correct JORs suggest that order information is retrieved by a serial retrieval mechanism. Analyses of SAT retrieval functions confirm that order information is retrieved by a recency-based, serial retrieval process. These results contrast with previous SAT analyses of STM item recognition (B. McElree and B. A. Dosher, see record 1990-09049-001), which indicate that item information is retrieved by a parallel or direct-access mechanism. The dissociation between item and order information retrieval was further documented in a 2AFC item recognition SAT study. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention gating in short-term visual memory.

Investigated attention shift to a stream of numerals, in rapid serial visual presentation, using 3 graduate students with normal or corrected-to-normal vision. Ss detected a target embedded in a stream of letters presented at the left of fixation and, as quickly as possible, shifted their attention to a stream of numerals at the right of fixation. They attempted to report, in order, the 4 earliest occurring numerals after the target. Numerals appeared at rates of 4.6, 6.9, 9.2, and 13.4 sec. Analyses demonstrated that, for all Ss, targets, and numeral rates, the relative position of numerals in the response sequence showed clustering, disorder, and folding. Reported numerals tended to cluster around a stimulus position 400 msec after the target. Numerals were reported in an apparently haphazard order. The actual order of report resulted from a mixture of correctly ordered numerals with numerals ordered in the direction opposite to their order of presentation. Results are quantitatively described by a strength theory of order and are efficiently predicted by a computational attention gating model (AGM). The AGM may be derived from a more general attention model that assumes that (a) after detection of the target, an attention gate opens briefly to allow numerals to enter a visual short-term memory and (b) subsequent order of report depends on both item strength (how wide the gate was open during the numeral's entry) and on order information (item strength times cumulative strength of prior numerals). (78 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibition et mémoire de travail : effet d'une privation aigu? de sommeil sur une tache de génération aléatoire.

The literature contains inconsistent data on the effects of acute sleep deprivation on the superior cognitive functions. The primary purpose of this study is to determine the effectiveness of inhibition, one of the functions of the working memory executive centre (EC), over an extended, 36-hour waking period. Inhibition is a cognitive mechanism whereby individuals ignore non-relevant information recorded in their working memory. We also tested the effects of a 36- hour period of acute sleep deprivation on simple reaction time. Twelve young, healthy volunteers (M=21.5 years, ?=2.3) performed a random generation task involving letters and a simple reaction time psychomotor test over four sessions held at 10-hour intervals. Each participant was assigned a "constant routine." Participants were kept awake in a prone position within a room whose environment was held strictly constant (light, noise, temperature, meals, etc.). This control procedure provided assurance that any variation in participant performance was solely caused by sleep deprivation. The random generation task, nearly two minutes in length, consisted in verbally producing a sequence of 100 letters in a random fashion (i.e. by inhibiting, for example, alphabetical order) and by keeping to a set rhythm... (PsycINFO Database Record (c) 2010 APA, all rights reserved)