Cognitive categories and memory span: I. Shifting between categories

Broadbent and Gregory's hypothesis that shifting selection between cognitive classes is at least inefficient is tested by varying the number of transitions from consonants to digits and back in a mixed list memory span situation. No orderly decrease is found as a function of the number of transitions, which renders the attention hypothesis unlikely. An alternative position in terms of interference theory could explain the data qualitatively. Tests of further predictions of this theory need first an estimate of the degree of difference between cognitive classes.     

Developmental differences in short-lived auditory memory for various classes of speech sounds

Spoken serial recall by second-grade children of aurally presented lists of digits, synthetic stop consonants, and synthetic vowels showed a significant suffix effect (selective debilitation of recall at the final position under the stimulus suffix condition) only for the lists of digits and not for either consonants or vowels. Making the synthetic syllables more distinctive by simultaneously covarying the consonant and vowel failed to produce a suffix effect under a strict scoring criterion which required both consonant and vowel to be recalled correctly; however, when subjects were given credit for partially correct answers the suffix effect emerged. Adults given the redundant consonant-vowel syllables showed a significant suffix effect with the strict scoring criterion. However, when consonants and vowels varied orthogonally, the adults' performance showed the suffix effect only under the lenient scoring criterion. An argument is made for equivalence of basic memorial processing between children and adults, the difference being in the number of features needed to disambiguate the target items and in the ability to integrate these features to exploit interstimulus redundancy.     

Adult counting is resource demanding

Several recent studies on both the development of counting and working‐memory span tasks have provided results that could be interpreted as ruling out any cognitive resource model for counting. The aim of this study was to test the hypothesis that, even in adults, counting is a demanding task that requires the allocation of cognitive resources. In a first experiment, we asked adults to count arrays of dots while maintaining 5 items in memory (either digits or letters). As we predicted, the concurrent memory load did not increase the rate of errors but induced longer counting times. In a second experiment, we asked adults to count using either the numeric chain or the alphabet while they maintained 1, 3 or 5 items in memory (digits or letters). First, we replicated the load effect observed in Experiment 1. Second, though both types of counting required similar amounts of time, counting with the less automatized chain (i.e. the alphabet) resulted in a poorer recall performance. Finally, this detrimental effect in recall was all the more pronounced the greater the number of items to be recalled. These results are interpreted within theoretical frameworks that consider cognitive resources as attentional capacities.     

Synesthetic color experiences influence memory

We describe the extraordinary memory of C, a 21–year–old student who experiences synesthetic colors (i.e., photisms) when she sees, hears, or thinks of digits. Using three matrices of 50 digits, we tested C and 7 nonsynesthetes to evaluate whether C's synesthetic photisms influence her memory for digits. One matrix consisted of black digits, whereas the other two matrices consisted of digits that were either incongruent or congruent with the colors of C's photisms. C's recall of the incongruently colored digits was considerably poorer than her recall of either the black or the congruently colored digits. The 7 nonsynesthetes did not show such differences in their recall of the matrices. In addition, when immediate recall of the black digits was compared with delayed recall of those digits (48 hr), C showed no decrease in performance, whereas each of the nonsynesthetes showed a significant decrease. These findings both demonstrate C's extraordinary memory and show that her synesthetic photisms can influence her memory for digits.     

The impact of order incongruence between a task-irrelevant auditory sequence and a task-relevant visual sequence

A novel effect is reported in which serial recall of visual digits was disrupted to a greater degree by the presence of the same set of digits presented as an irrelevant auditory sequence than by the presence of irrelevant auditory consonants, but only when the order of the irrelevant digits was incongruent with that of the to-be-remembered digits (Experiment 1). Experiment 2 replicated this order-incongruence effect and showed also that disruption was dictated by the number of order-incongruent transitions but not by the number of novel tokens contained within the irrelevant sequence. The results favor an interference-by- process approach to the disruption of serial memory by irrelevant sound over approaches based on notions of interference by content and/or interference by depletion of attentional resources.     

Mechanisms of aural encoding: VII. Differences in consonant and vowel recall in a Peterson and Peterson short-term memory paradigm

Ss either saw or heard lists of three syllables which differed by their initial consonant phoneme or their final vowel phoneme. After 5 or 15 sec of mental arithmetic, Ss were required to recall the syllables. Following auditory presentation, vowels were recalled more accurately than consonants in all serial positions and at both delays. In addition, spoken consonants and vowels showed primacy and recency effects. Following visual presentation, consonants and vowels were recalled with equal accuracy at both delays, and no recency effects were observed. These data suggest that superior recall of vowels over consonants results from differential decay of these stimuli in an acoustic storage. These data are consistent with previous experiments showing that, during serial recall, the final vowels in a sequence are recalled more accurately than the final consonants.     

Consonants and vowels: different roles in early language acquisition

Language acquisition involves both acquiring a set of words (i.e. the lexicon) and learning the rules that combine them to form sentences (i.e. syntax). Here, we show that consonants are mainly involved in word processing, whereas vowels are favored for extracting and generalizing structural relations. We demonstrate that such a division of labor between consonants and vowels plays a role in language acquisition. In two very similar experimental paradigms, we show that 12-month-old infants rely more on the consonantal tier when identifying words (Experiment 1), but are better at extracting and generalizing repetition-based srtuctures over the vocalic tier (Experiment 2). These results indicate that infants are able to exploit the functional differences between consonants and vowels at an age when they start acquiring the lexicon, and suggest that basic speech categories are assigned to different learning mechanisms that sustain early language acquisition.     

Precategorical acoustic storage for vowels of short and long duration

Ss gave immediate ordered recall for series of seven isolated vowel sounds from a vocabulary of three-/a, u, i/. In a 2 by 2 design, the stimulus vowels were either 50 or 300 msec in duration (though always presented at a 2/sec rate), and the seven-item series was followed by either a nonverbal recall cue or a verbal recall cue that is a stimulus suffix. There was an interaction such that the recall impairment caused by the verbal suffix was larger when the stimulus items were vowels of long duration than when they were vowels of short duration. Since short vowels tend to be more categorically perceived than long vowels, this result reinforces the view that vowels and stop consonants are differently represented in auditory short-term memory for reasons that have to do with the way m winch they are perceived or vice versa.     

Recall of digits projected to temporal and nasal hemi-retinas

Fourteen right-handed, right eye dominant subjects recalled digits when different ones were projected simultaneously to either temporal or nasal retinas. The principal findings were: (a) Recall of digits projected to nasal retinas was significantly better than when projected to temporal retinas; (b) information projected to the right eye was recalled significantly better than that projected to the left eye. It is shown that the relative ineffectiveness of the recall of input from the non-dominant eye can be attributed almost wholly to the relative inefficient recall of digits projected to the left temporal retina.     

Person memory and person judgments based on categorically organized information

Free recall, cued recall, and rating-like judgments — conceived as alternative modes of expressing memorized information — were assessed in a person memory task. The target person had been described with respect to the presence or absence of 48 different interests (e.g., Mozart, sonatas, tennis, boxing) in 12 interest categories (e.g., music, sports). The number of interests (vs non-interests) per category was manipulated as well as the order of the three sub-tasks. The pattern of results can be explained within a categorical coding framework which suggests two functionally independent stages of recall: (a) access to a higher-order memory code on the category level, and (b0 reconstruction of specific items within categories. In particular, judgments of the degree of interest in the abstract categories were only related to selective free recall on the categorical level but not specific level free recall. Cued recall of the degree of interest in specific items was only related to free recall on the specific level. Making the category judgments before the free recall task, rather than afterwards, increased the availability of categories but not specific items. And inconsistent patterns of interests impaired the cued recall of specific patterns within categories but did not affect the categorical level. A strong positivity effect (i.e., more interests recalled than non-interests) was also found, resembling the often noted advantage of positive information in other domains of cognitive psychology.     

Mechanisms of aural encoding: I. Distinctive features for consonants

To examine the importance of distinctive features that are used to encode consonants (following Wickelgren’s analysis) in an immediate recall task, sequences of 5 consonants, all paired with the vowel /a/ were constructed and presented aurally for recall. The middle three items in each sequence all had either the same place of articulation (front, middle, or back of the vocal apparatus), orthe same manner of articulation (voiced, unvoiced, or nasal), or were unrelated in either place or manner (control). It was shown that, in comparison with the control sequences, consonants imbedded among others articulated similarly were recalled less accurately, suggesting that these distinctive features are important in encoding and memory maintenance. A comparison of the 3 manner and 3 place features showed that the greatest difficulty in recall occurred for the similar manner sequences (especially voiced and unvoiced, implicating manner of articulation as the critical distinctive feature in aural encoding. Some discussion is also presented of a distinction between articulation and acoustic factors in encoding processes.     

Recalling taboo and nontaboo words

People remember emotional and taboo words better than neutral words. It is well known that words that are processed at a deep (i.e., semantic) level are recalled better than words processed at a shallow (i.e., purely visual) level. To determine how depth of processing influences recall of emotional and taboo words, a levels of processing paradigm was used. Whether this effect holds for emotional and taboo words has not been previously investigated. Two experiments demonstrated that taboo and emotional words benefit less from deep processing than do neutral words. This is consistent with the proposal that memories for taboo and emotional words are a function of the arousal level they evoke, even under shallow encoding conditions. Recall was higher for taboo words, even when taboo words were cued to be recalled after neutral and emotional words. The superiority of taboo word recall is consistent with cognitive neuroscience and brain imaging research.     

Lexical coherence in short-term memory: Strategic reconstruction or “semantic glue”?

This study explores the foundation of lexical/semantic phoneme binding effects in verbal short-term memory (STM). The immediate serial recall of pure lists of words and nonwords was compared with the recall of mixed lists that had either a predictable, alternating structure (e.g., wnwnwn) or an unpredictable structure (i.e., the serial positions of the words/nonwords could not be known in advance). The study provides evidence for two separate mechanisms by which long-term linguistic knowledge contributes to STM. First, there was evidence for automatic lexical/semantic binding effects that were independent of knowledge of lexical status. The nonwords in both types of mixed list damaged word recall and encouraged the phonological elements of words to migrate. In both alternating and unpredictable mixed lists, the phonemes of words were more likely than the phonemes of nonwords to be recalled together as a coherent item, suggesting that lexical/semantic knowledge encourages the phonological elements of words to emerge together in immediate serial recall, even when lexical status is unknown. Secondly, there was evidence for “strategic redintegration”, which was dependent on prior knowledge of the lexical status of the items in mixed lists. When participants recalled items that they knew to be words in advance, they were able to use this knowledge to constrain their responses so that they were more likely to be lexically appropriate. These findings motivate modifications to current theories of the interaction between linguistic knowledge and verbal short-term memory.     

数量加工单方向干扰时间知觉的认知与神经机制

近年来,数量加工对时间知觉的单方向干扰效应受到广泛关注,然而关于该效应的认知和神经机制的研究却缺乏深度的文献梳理和理论分析。本文从抽象数量、数字符号等认知加工如何干扰时间知觉的角度,系统总结了近期数量加工单方向影响时间知觉的研究进展;并在对相关文献加以梳理的基础上,详细分析了该效应可能的认知和神经机制,并提出若干未来研究的设想。     

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.     

Category-level contributions to the alphanumeric category effect in visual search

Do letter and digit recognition depend on the same or different cognitive mechanisms? Letters are detected more quickly among digits than among letters; likewise, digit search is facilitated when distractors are letters, as opposed to digits. This effect suggests that different mechanisms underlie recognition of these two categories. There are, however, systematic physical differences between letters and digits that might account for the effect. We used target and distractor stimuli that facilitated within-category search when inverted, and category identity was, thereby, attenuated. However, in conditions of upright search, in which category identity was more salient, between-category search was more efficient for the same stimuli. These findings suggest that letter and digit recognition are, at least to a degree, functionally independent.     

The influence of phoneme position overlap on the phonemic similarity effect in nonword recall

The current research examined the predictions that short-term memory models generate for the phonological similarity effect, when similarity was defined in different ways. Three serial recall experiments with consonant-vowel-consonant (CVC) nonwords are reported, where the position of the phonemes that list items shared was manipulated (i.e., shared vowel and final consonant [_VC; Experiment 1], initial consonant and vowel [CV_; Experiment 2], or the two consonants [C_C; Experiment 3]. The results show that the position of common phonemes in nonwords has differential effects on order and item information. The findings are discussed in relation to previous research into the effect of phonemic similarity on nonword recall, and modifications to current short-term memory models are proposed.     

Do we access meaning when we name Arabic digits? Electrophysiological evidence

In this study, we evaluated whether the naming of Arabic digits required access to semantic information. Participants named pictures and Arabic digits blocked by category or intermixed with exemplars of other categories while behavioural and electrophysiological measures were gathered. Pictures were named slower and Arabic digits faster in the blocked context relative to the mixed context. Around 350–450 ms after the presentation of pictures and Arabic digits, brain waves were more positive in anterior regions and more negative in posterior regions when the blocked context was compared with the mixed context. The pattern of electrophysiological results suggests that pictures and Arabic digits are both processed semantically and they are subject to repetition effects during the naming task.     

Some evidence for 'speech' as an acoustic feature.

Under conditions of serial recall of auditorily presented lists of digits, recall of the last item has been shown to be adversely affected by the presence of a redundant item following the list. This is known as 'the suffix effect' (Crowder & Morton, 1969). In a series of experiments it is shown that the size of this effect is not influenced by the phonological complexity of the suffix. Non-speech sounds, on the other hand, produce no suffix effect even when the subjects are forced to process them. Certain speech sounds were also found to produce no effect. It is concluded that these sounds lacked properties which are characteristic of speech sounds and so were classified as 'non-speech' and that as a result, these sounds are processed by a separate system from the speech sounds.     

Testing the exclusivity effect in location memory

There is growing literature exploring the possibility of parallel retrieval of location memories, although this literature focuses primarily on the speed of retrieval with little attention to the accuracy of location memory recall. Baguley, Lansdale, Lines, and Parkin (2006) found that when a person has two or more memories for an object's location, their recall accuracy suggests that only one representation can be retrieved at a time (exclusivity). This finding is counterintuitive given evidence of non-exclusive recall in the wider memory literature. The current experiment explored the exclusivity effect further and aimed to promote an alternative outcome (i.e., independence or superadditivity) by encouraging the participants to combine multiple representations of space at encoding or retrieval. This was encouraged by using anchor (points of reference) labels that could be combined to form a single strongly associated combination. It was hypothesised that the ability to combine the anchor labels would allow the two representations to be retrieved concurrently, generating higher levels of recall accuracy. The results demonstrate further support for the exclusivity hypothesis, showing no significant improvement in recall accuracy when there are multiple representations of a target object's location as compared to a single representation.