Short-term memory in autism spectrum disorder.

Three experiments examined verbal short-term memory in comparison and autism spectrum disorder (ASD) participants. Experiment 1 involved forward and backward digit recall. Experiment 2 used a standard immediate serial recall task where, contrary to the digit-span task, items (words) were not repeated from list to list. Hence, this task called more heavily on item memory. Experiment 3 tested short-term order memory with an order recognition test: Each word list was repeated with or without the position of 2 adjacent items swapped. The ASD group showed poorer performance in all 3 experiments. Experiments 1 and 2 showed that group differences were due to memory for the order of the items, not to memory for the items themselves. Confirming these findings, the results of Experiment 3 showed that the ASD group had more difficulty detecting a change in the temporal sequence of the items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phonotactic influences on short-term memory

The impact of phonotactic probabilities on serial recall was investigated in a series of experiments. In Experiments 1A and 1B, 7 and 8 year olds were tested on their serial recall of monosyllabic words and of nonwords varying in phonotactic frequencies. A recall advantage to words over nonwords remained when stimuli were balanced for phonotactic probability, but nonword recall showed superior accuracy for high over low probability nonwords, as in Experiment 2. The nonword frequency effect appears to reflect the frequency of constituent syllables rather than biphones. Both lexicality and high phonotactic frequency led to increased proportions of full over partial recall of the memory stimuli. These findings indicate that decayed memory traces in phonological short-term memory can be reconstructed using either lexical or phonotactic knowledge.     

Concrete words are easier to recall than abstract words: Evidence for a semantic contribution to short-term serial recall.

Immediate serial recall and maximal speech rate were assessed for concrete and abstract words differing in length. Experiment 1 showed large advantages for spoken recall of concrete words that were independent of speech rate. Experiment 2 showed an equivalent effect with written, rather than spoken, recall. Experiment 3 showed that the concreteness effect was still present when recall was backward rather than forward. In all 3 experiments, concrete words enjoyed an advantage that was roughly constant across all serial positions (with the possible exception of the 1st and last items). Experiment 4 used a matching-span procedure and showed that when there was no requirement for linguistic output, the effect of concreteness (but not the effect of word length) was eliminated. It is argued that semantic coding exerts powerful effects in verbal short-term memory tasks that have generally been underestimated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using overt rehearsals to explain word frequency effects in free recall.

Three experiments examined the word frequency effect in free recall using the overt rehearsal methodology. Experiment 1 showed that lists of exclusively high-frequency (HF) words were better recalled, were rehearsed more, and were rehearsed to more recent serial positions than low-frequency (LF) words. A small HF advantage remained even when these 2 variables were equated. Experiment 2 showed that all these effect, were much reduced with mixed lists containing both HF and LF words. Experiment 3 compared pure and mixed lists in a within-subject design and confirmed the findings of Experiments 1 and 2. It is argued that number of rehearsals, recency of rehearsals, and strength of interitem association cause the word frequency effect in free recall. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multiple roles for time in short-term memory: Evidence from serial recall of order and timing.

Three experiments are reported that examine the relationship between short-term memory for time and order information, and the more specific claim that order memory is driven by a timing signal. Participants were presented with digits spaced irregularly in time and postcued (Experiments 1 and 2) or precued (Experiment 3) to recall the order or timing of the digits. The primary results of interest were as follows: (a) Instructing participants to group lists had similar effects on serial and timing recall in inducing a pause in recall between suggested groups; (b) the timing of recall was predicted by the timing of the input lists in both serial recall and timing recall; and (c) when the recall task was precued, there was a tendency for temporally isolated items to be more accurately recalled than temporally crowded items. The results place constraints on models of serial recall that assume a timing signal generates positional representations and suggest an additional role for information about individual durations in short-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Examining the relationship between free recall and immediate serial recall: The effect of concurrent task performance.

In 3 experiments, participants saw lists of 16 words for free recall with or without a 6-digit immediate serial recall (ISR) task after each word. Free recall was performed under standard visual silent and spoken-aloud conditions (Experiment 1), overt rehearsal conditions (Experiment 2), and fixed rehearsal conditions (Experiment 3). The authors found that in each experiment, there was no effect of ISR on the magnitude of the recency effect, but interleaved ISR disrupted free recall of those words that would otherwise be rehearsed. The authors conclude that ISR and recency cannot both be outputs from a unitary limited-capacity short-term memory store and discuss the possibility that the process of rehearsal may be common to both tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparing the effects of aging and background noise of short-term memory performance.

Paired associate recall was tested as a function of serial position for younger and older adults for five word pairs presented aurally in quiet and in noise. In Experiment 1, the addition of noise adversely affected recall in young adults, but only in the early serial positions. Experiments 2 and 3 suggested that the recall of older adults listening to the words in quiet was nearly equivalent to that of younger adults listening in noise. In Experiment 4, we determined the signal-to-noise ratio (S/N) such that, on average, younger and older adults were able to correctly hear the same percentage of words when words were presented one at a time in noise. In Experiment 5, younger adults were tested under this S/N. Compared with older adults from Experiment 3, younger adults in this experiment recalled more words at all serial positions. The results are interpreted as showing that encoding in secondary memory is impaired by aging and noise either as a function of degraded sensory representations, or as a function of reduced processing resources. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissimilar items benefit from phonological similarity in serial recall.

In short-term serial recall, similar sounding items are remembered less well than items that do not sound alike. This phonological similarity effect has been observed with lists composed only of similar items, and also with lists that mix together similar and dissimilar items. An additional consistent finding has been what the authors call dissimilar immunity, the finding that ordered recall of dissimilar items is the same whether these items occur in pure dissimilar or mixed lists. The authors present 3 experiments that disconfirm these previous findings by showing that dissimilar items on mixed lists are recalled better than their counterparts on pure lists if order errors are considered separately from intrusion errors (Experiment 1), or if intrusion errors are experimentally controlled (Experiments 2 and 3). The memory benefit for dissimilar items on mixed lists poses a challenge for current models of short-term serial recall. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of word co-occurance on short-term memory: Associative links in long-term memory affect short-term memory performance.

In immediate serial recall tasks, high-frequency words are recalled better than low-frequency words. This has been attributed to high-frequency words' being better represented and providing more effective support to a redintegration process at retrieval (C. Hulme et al., 1997). In studies of free recall, there is evidence that frequency of word co-occurrence, rather than word frequency per se, may explain the recall advantage enjoyed by high-frequency words (J. Deese, 1960). The authors present evidence that preexposing pairs of low-frequency words, so as to create associative links between them, has substantial beneficial effects on immediate serial recall performance. These benefits, which are not attributable to simple familiarization with the words per se, do not occur for high-frequency words. These findings indicate that associative links between items in long-term memory have important effects on short-term memory performance and suggest that the effects of word frequency in short-term memory tasks are related to differences in interitern associations in long-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Irrelevant speech and irrelevant tones: The relative importance of speech to the irrelevant speech effect.

Irrelevant auditory stimuli disrupt immediate serial recall. In the equipotentiality hypothesis, D. M. Jones and W. J. Macken (see record 1993-20312-001) made the controversial prediction that speech and tones have an equivalent disruptive effect. In the present study, 5 experiments tested their hypothesis. Experiments 1–4 showed that meaningful speech disrupts recall more than do tones. Experiments 3 and 4 provided some evidence that meaningful speech disrupts recall more than does meaningless speech, and Experiment 4 showed that even meaningless speech disrupts recall more than do tones. Using slightly different experimental procedures, Experiment 5 showed that letters disrupt recall more than do tones. Implications of these results for a number of theories of primary memory and the irrelevant speech effect are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Phonotactic influences on short-term memory": Correction.

Reports an error in the original article by S. E. Gathercole et al (Journal of Experimental Psychology: Learning, Memory, & Cognition, 1999[Jan], 25[1], 84–95). On page 87, the mean proportions of correct item recall and standard deviations for the high vocabulary group in Experiment 1B were incorrect in Table 2. The analyses of variance reported for data arising from Experiment 1B were correct. A corrected table is given. (The following abstract of this article originally appeared in record 1998-11970-006.) The impact of phonotactic probabilities on serial recall was investigated in a series of experiments. In Experiments 1A and 1B, 7 and 8 year olds were tested on their serial recall of monosyllabic words and of nonwords varying in phonotactic frequencies. A recall advantage to words over nonwords remained when stimuli were balanced for phonotactic probability, but nonword recall showed superior accuracy for high over low probability nonwords, as in Experiment 2. The nonword frequency effect appears to reflect the frequency of constituent syllables rather than biphones. Both lexicality and high phonotactic frequency led to increased proportions of full over partial recall of the memory stimuli. These findings indicate that decayed memory traces in phonological… (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of concurrent semantic categorization on delayed serial recall.

The influence of semantic processing on the serial ordering of items in short-term memory was explored using a novel dual-task paradigm. Participants engaged in 2 picture-judgment tasks while simultaneously performing delayed serial recall. List material varied in the presence of phonological overlap (Experiments 1 and 2) and in semantic content (concrete words in Experiment 1 and 3; nonwords in Experiments 2 and 3). Picture judgments varied in the extent to which they required accessing visual semantic information (i.e., semantic categorization and line orientation judgments). Results showed that, relative to line-orientation judgments, engaging in semantic categorization judgments increased the proportion of item-ordering errors for concrete lists but did not affect error proportions for nonword lists. Furthermore, although more ordering errors were observed for phonologically similar relative to dissimilar lists, no interactions were observed between the phonological overlap and picture-judgment task manipulations. These results demonstrate that lexical-semantic representations can affect the serial ordering of items in short-term memory. Furthermore, the dual-task paradigm provides a new method for examining when and how semantic representations affect memory performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Item repetition in short-term memory: Ranschburg repeated

In serial recall from short-term memory, repeated items are recalled well when close together (repetition facilitation), but not when far apart (repetition inhibition; the Ranschburg effect). These effects were re-examined with a new scoring scheme that addresses the possibility that repetitions are distinct tokens in memory. Repetition facilitation and repetition inhibition proved robust, and were shown to interact with the temporal grouping of items (Experiment 1), which affected the probability of detecting repetition (Experiments 2A and 2B). It is argued that detection of a repetition is necessary for repetition facilitation, attributable to the tagging of immediate repetition, whereas the failure to detect or remember a repetition results in repetition inhibition, attributable to an automatic suppression of previous responses and a bias against guessing repeated items (Experiment 3). The findings are discussed in relation to models of short-term memory and the phenomenon of repetition blindness.     

Effects of Orthographic and Phonological Word Length on Memory for Lists Shown at RSVP and STM Rates.

This article reports 3 experiments in which effects of orthographic and phonological word length on memory were examined for short lists shown at rapid serial visual presentation (RSVP) and short-term memory (STM) rates. Only visual-orthographic length reduced RSVP serial recall, whereas both orthographic and phonological length lowered recall for STM lists in Experiment 1. Word-length effects may arise from output processes or from the temporal duration of output in recall. In 2 further experiments, output demands were reduced through the use of a recognition test. Recognition accuracy was impaired only by orthographic length for RSVP lists and by phonological length for STM lists in both experiments. The results demonstrate 2 item length effects not simply attributable to increased output time in recall, and implications for theories of STM are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evolution on a volcanic conveyor belt: using phylogeographic reconstructions and K-Ar-based ages of the Hawaiian Islands to estimate molecular evolutionary rates

This article reports dissociations between verbal span and the recency portion of the serial position curve in immediate free recall, in 2 neuropsychological case studies and in 3 experiments with normal participants. Patient A. N. presented with an impaired serial verbal span while showing an intact recency effect. The opposite pattern was observed in patient G. C., who despite a poor recency showed normal span in verbal serial recall tasks. Experiments 1 and 2 showed a recency effect with visually and auditory presented lists and written recall was resistant to the effects of articulatory suppression and of irrelevant speech, but was disrupted by the suffix effect. Experiment 3 showed that in contrast with recency, memory span was affected by articulatory suppression and irrelevant speech during presentation but not by a suffix. These findings are not consistent with the idea that span and recency measure aspects of the same memory system. Moreover, in clinical practice, they should not be used as equivalent alternatives.     

Dissociation between recency and span: Neuropsychological and experimental evidence.

This article reports dissociations between verbal span and the recency portion of the serial position curve in immediate free recall, in 2 neuropsychological case studies and in 3 experiments with normal participants. Patient A. N. presented with an impaired serial verbal span while showing an intact recency effect. The opposite pattern was observed in patient G. C., who despite a poor recency showed normal span in verbal serial recall tasks. Experiments 1 and 2 showed a recency effect with visually and auditory presented lists and written recall was resistant to the effects of articulatory suppression and of irrelevant speech, but was disrupted by the suffix effect. Experiment 3 showed that in contrast with recency, memory span was affected by articulatory suppression and irrelevant speech during presentation but not by a suffix. These findings are not consistent with the idea that span and recency measure aspects of the same memory system. Moreover, in clinical practice, they should not be used as equivalent alternatives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A common basis for recency effects in immediate and delayed recall.

Examined the effects of word frequency and list length on the long-term serial position curve in 2 experiments, using a total of 68 undergraduates. In Exp I, the object was to find a distractor activity that would be sufficient to eliminate the recency effect in conventional free recall. In Exp II, whether list length would show a similar pattern of effects in a continuous-distractor paradigm was examined. Results demonstrate that word frequency and list length had the same effects on the serial-position curve in the continuous-distractor paradigm of delayed recall that they had previously been shown to have in immediate recall. High word frequency and shorter lists led to improved recall of preterminal items but did not influence recall of terminal items. Results suggest that the same processes underlie recency effects in the 2 paradigms and that accounts that attribute recency effects to primary (or short-term) memory are inadequate. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Disruption of short-term memory by changing and deviant sounds: Support for a duplex-mechanism account of auditory distraction.

The disruption of short-term memory by to-be-ignored auditory sequences (the changing-state effect) has often been characterized as attentional capture by deviant events (deviation effect). However, the present study demonstrates that changing-state and deviation effects are functionally distinct forms of auditory distraction: The disruption of visual-verbal serial recall by changing-state speech was independent of the effect of a single deviant voice embedded within the speech (Experiment 1); a voice-deviation effect, but not a changing-state effect, was found on a missing-item task (Experiment 2); and a deviant voice repetition within the context of an alternating-voice irrelevant speech sequence disrupted serial recall (Experiment 3). The authors conclude that the changing-state effect is the result of a conflict between 2 seriation processes being applied concurrently to relevant and irrelevant material, whereas the deviation effect reflects a more general attention-capture process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Separate effects of word frequency and age of acquisition in recognition and recall.

Three experiments investigated word frequency and age of acquisition (AoA) effects in recognition and recall. Experiments 1 and 2 used the "remember-know" procedure developed by J. M. Gardiner (1988). In Experiment 1, recognition performance was higher for low-frequency words than for high-frequency words and higher for late-acquired words than for early-acquired words, but only in "remember" responses. Experiment 2 replicated the AoA effect by using a different set of early- and late-acquired words. Experiment 3 found advantages for low-frequency and late-acquired words in recall, but only when words were presented in mixed lists. The frequency effect was reversed, and the AoA effect was eliminated, when participants studied pure lists. Findings were attributed to the more distinctive encoding of low-frequency and late-acquired words. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of manipulation and irrelevant noise on working memory capacity of patients with Alzheimer's dementia.

The effect of manipulation and distracting noise on immediate serial recall was measured in patients with dementia of the Alzheimer type (DAT), neurologically healthy elderly individuals, and young adults. In Experiment 1, the authors compared serial word recall with word recall in alphabetical order. Alphabetical recall requires the active manipulation of the contents of working memory. Findings indicated that DAT patients were severely impaired in the alphabetical recall task, whereas the performance of neurologically healthy elderly participants was comparable with the performance of young adult participants. In Experiment 2, the authors investigated the effect of different irrelevant auditory backgrounds on immediate digit recall. In this task, both elderly participants and DAT patients performed similarly to the group of young adult participants, indicating comparable efficacy to resist auditory distraction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)