Reversed memory coding and symbol reversal in children

The present study examined an hypothesized mirror-reversed memory-coding phenomenon whereby aligned and mirror-reversed memory records in opposite cerebral hemispheres are confused. Two groups of 7-yr.-old boys were chosen on the basis of tendency to confuse mirror and aligned written symbols. The experimental task required discrimination as same or different of letter pairs which were either same or different and either aligned or mirror-reversed. The pairs were simultaneously presented to right, left, or both cerebral hemispheres. The reversing group had slower reaction times than the normal group in all conditions. Evidence was insufficient to conclude that mirror-same bilateral presentation facilitated responses of either group over aligned-same or peripheral conditions. This result would have been necessary to indicate the presence of a mirror-reversed code across the hemispheres. Research utilizing delayed as well as simultaneous presentation of stimuli to children of various ages would clarify this ambiguity. Bilateral processing across conditions proved easier for both groups, indicating adequate hemispheric integration on a visual-perceptual task even in children who tended to confuse mirror images.     

Working memory training improves reading processes in typically developing children

The goal of this study was to investigate whether a brief cognitive training intervention results in a specific performance increase in the trained task, and whether there are transfer effects to other nontrained measures. A computerized, adaptive working memory intervention was conducted with 9- to 11-year-old typically developing children. The children considerably improved their performance in the trained working memory task. Additionally, compared to a matched control group, the experimental group significantly enhanced their reading performance after training, providing further evidence for shared processes between working memory and reading.     

Speech perception and memory coding in relation to reading ability

Previous work has demonstrated that children who are poor readers have short-term memory deficits in tasks in which the stimuli lend themselves to phonetic coding. The aim of the present study was to explore whether the poor readers' memory dificit may have its origin in perception with the encoding of the stimuli. Three experiments were conducted with third grade good and poor readers. As in earlier experiments, the poor readers were found to perform less well on recall of random word strings and to be less affected by the phonetic characteristics (rhyming or not rhyming) of the items (Experiment 1). In addition, the poor readers produced more errors of transposition (in the nonrhyming strings) than did the good readers, a further indication of the poor readers' problems with memory for order. The subjects were tested on two auditory perception tasks, one employing words (Experiment 2) and the other nonspeech environmental sounds (Experiment 3). Each was presented under two conditions: with a favorable signal-to-noise ratio and with masking. The poor readers made significantly more errors than the good readers when listening to speech in noise, but did not differ in perception of speech without noise or in perception of nonspeech environmental sounds, whether noise-masked or not. Together, the results of the perception studies suggest that poor readers have a perceptual difficulty that is specific to speech. It is suggested that the short-term memory deficits characteristic of poor readers may stem from material-specific problems of perceptual processing.     

The use of visual and verbal memory processes by three-year-old children

Nonverbal (imagery) materials become more effective than verbal materials in aiding memory as age increases; indeed, children under five years have shown superior memory for verbal over nonverbal materials. The present study points out and changes four commonalities in the design of studies finding this latter relationship in an attempt to determine if nonverbal materials would prove superior to verbal ones. Four six-item paired-associate lists were presented individually using a study-test procedure. Presentation of the lists involved either pictures, words, or both. Recognition was tested either verbally or visually.Results indicated that the combined visual-verbal study materials produced performance superior to visual materials alone, which in turn were superior to verbal materials alone. Recognition of pictures was superior to recognition of words, regardless of mode of input. The relationship of these results to the procedural changes made are discussed, along with implications for current hypotheses of children's use of imagery.     

Experimental analysis of coding processes

The first part of the paper reports an investigation of the effects of the concreteness-imagery (C-I) value of stimuli and responses on the long-term retention of paired-associate lists. With degree of learning equated, the measures of retention after a 1-week interval showed a significant interaction of Stimulus by Response C-I: When the responses had a high value, recall was substantially better with low than with high stimuli; when the responses were low, there was no reliable difference as a function of stimulus value. Recall was best when abstract stimuli were paired with concrete responses. The second part of the paper is addressed to some current issues in the analysis of coding processes. Major emphasis is placed on the experimental and theoretical differentiation of encoding and decoding processes.     

Evidence of acoustic coding in long-term memory

Contrary to previous indications, retroactive interference in long-term paired associate learning was found to be a function of acoustic similarity. Experimental groups were exposed to the A-B, A'-C paradigm where corresponding stimuli were homophones. Their retention scores were substantially and significantly lower than control groups run with an A-B, C-D paradigm. The failure of previous studies to reveal effects of acoustic similarity in this way is attributed to the use of an insufficiently high degree of similarity.     

Speech-like coding of pictures in short-term memory

Memory span for pictures of common objects and for the names of these objects was examined as a function of three speech-related variables. Both picture span and name span were found to be influenced by the phonological similarity (Experiment 1) and the length (Experiment 2) of the names, as well as by the subject’s engaging in “irrelevant” vocalization during item presentation (Experiment 3). Moreover, for each variable the effect was in the same direction and of comparable magnitude for the two types of items. Experiments 4-6 replicated these findings with the procedure modified such that the retention of order information was not required. It is concluded that under the present conditions, there is a substantial functional equivalence between short-term memory for readily nameable pictures and for words and that this equivalence may be thought of as due to mediation by a common, “speech-like” code.     

Acoustic and associative coding in short-term memory

Short lists of word-digit pairs were presented to 456 college student subjects. One of the words was repeated as a memory probe either immediately after list presentation or after a short rehearsal interval. The stimulus words were either acoustically identical or associatively related (UP, DOWN). Both acoustic identity and associative relatedness produced a memory decrement which decreased with rehearsal. One interpretation of these results is that the primary memory trace is a multiple-dimension one and that, given time, subjects can recover non-acoustic information from it. The data also indicate that the “fate” over time is different for acoustically similar and associatively related items.     

Development of reference and working spatial memory in preschool children

Three groups of preschool children (aged 18 to 28, 33 to 42, and 47 to 58 months) were given a radial search test similar to the radial arm maze used with nonhuman subjects. The children searched for chocolate sweets among 10 labeled locations in a room, 5 of which were baited with a sweet. Older children outperformed the intermediate group, who in turn outperformed the youngest group in requiring fewer choices to retrieve all of the sweets. Working memory and reference memory aspects of performance were then separated: Reference memory (restriction of choices to the baited subset) in older children was superior to that in the youngest group but not to that in the intermediate group. In terms of working memory (avoidance of repeat responses to already visited locations), the older group made fewer errors than the intermediate group, who, in turn, made fewer errors than the youngest group. We concluded that working and reference components of spatial memory in children may share common elements, perhaps the ability to recognize places as familiar, although reference memory may develop earlier than working memory.     

Asymptotic learning of alphanumeric coding in autobiographical memory

Studies of autobiographical memory have shown that observed levels of incidental learning are often relatively low. Do low levels of retention result simply from a low learning rate, or is learning also asymptotic? To address this question, it is necessary to trace performance over a large number of learning opportunities, and this was carried out in the context of the recent development of widespread texting behaviour. It was found that memory for the alphanumeric layout of a phone improved as a function of sending approximately the first 500 texts, but then the improvement stopped. The incidence of memory error was incompatible with a simple power-law relation but was modelled closely by an asymptotic relation. It is suggested that this pattern reflects a movement towards automaticity in the primary task which progressively closes down the possibility that incidental learning can occur.     

Revisiting distinctive processes in memory

In three experiments, we examined the relationship between orthographic and phonological distinctiveness and incidental recall. In each experiment, participants were given a surprise free recall test after they read words aloud as quickly and accurately as possible. The pattern of results replicated those reported in Cortese, Watson, Wang, and Fugett (2004) for intentional and explicit free recall and recognition memory tasks in which items were read silently. Specifically, we found that phonological-to-orthographic neighborhood size influenced recall performance, whereas orthographic-to-phonological consistency and phonological-to-orthographic consistency did not. Also, we failed to replicate the orthographic-tophonological consistency effect reported by Hirshman and Jackson (1997), and argue that their results were due to a confounding of consistency with phonological neighborhood size. Our results suggest that the processing of words sharing both orthography and phonology with a large number of words produces interference that reduces one’s ability to remember them.     

A structural analysis of working memory and related cognitive skills in young children

The aim of this study was to investigate the functional organisation of working memory and related cognitive abilities in young children. A sample of 633 children aged between 4 and 6 years were tested on measures of verbal short-term memory, complex memory span, sentence repetition, phonological awareness, and nonverbal ability. The measurement model that provided the best fit of the data incorporates constructs that correspond to the central executive, phonological loop, and episodic buffer subcomponents of working memory, plus distinct but associated constructs associated with phonological awareness and nonverbal ability.     

Short-term memory processes in counting

Four experiments examined the memory processes used to maintain location in a counting sequence. In Experiment 1, subjects who rapidly counted forward omitted many repeated-digit numbers (e.g., 77), as found previously with backward counting. Subjects in Experiment 2 counted backward with normal auditory feedback or with headphones through which white noise was channeled. In both cases, repeated-digit errors predominated, suggesting that the contents of short-term memory, rather than auditory sensory memory, are checked during counting. In Experiment 3, subjects silently wrote counting responses, and the omission errors resembled those in vocal counting. Repetition errors were also found and attributed to phonological recoding failures. Articulatory suppression in Experiment 4 greatly increased the number of repetition errors in the written counting task. A model of the counting process was proposed according to which subjects keep track of their location in the counting sequence by monitoring phonologically coded short-term memory representations of the numbers.     

Logical and memory processes in a unidimensional concept identification task by children and adults

Behavior of 12-year-old children and of adults was studied in a unidimensional concept identification task. Data have been analyzed within the framework of a hypothesis testing model involving a testing process and a memory process. The data show that testing strategy, as it is described in the model, is very close in children and adults. In children, however, who exhibit lesser retention of information preceding the last trial, the memory process suffers from more limitations than in adults.     

The effects of word length on memory for pictures: Evidence for speech coding in young children

In a series of three experiments children aged from 4 to 10 years old were presented with a serial recall task with pictures of common objects which had short or long names. Children of all ages showed consistently better recall of pictures with short names. This effect occurred without the pictures being named at presentation and was abolished by articulatory suppression. It is concluded, in contrast to some earlier studies, that children as young as 4 years are able to use a speech code as a means of memorizing pictures.     

Dissociative experiences are related to commissions in emotional memory

Two rival hypotheses of the link between dissociative experiences and emotional memory were tested: 1) the defence mechanism hypothesis that assumes that dissociation promotes fragmentation of emotional memory; and 2) the fantasy proneness hypothesis that claims that because of its overlap with fantasy proneness, dissociation is related to commissions in emotional memory. Undergraduates scoring high (n = 19) or low (n = 19) on the Dissociative Experiences Scale (DES) listened to an aversive story. Next, a free recall task was administered. While high dissociators made more commission errors in their free recall than did low dissociators, fantasy proneness did not account for this difference.