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Biomedical subjects

G J Hitch

Publications and source records attributed to G J Hitch.

9 recordsLinked to original sources
PubMed1992

Manipulation of visual mental images in children and adults.

Recently, there has been a debate on whether visual patterns can be transformed and reinterpreted in mental imagery. In the present study, task demands and age of subjects were manipulated to see whether children and adults were able to discover a novel visual pattern after transforming a mental image. Two tasks, called combination and subtraction, were devised. They consist of either compounding or taking away parts of images to discover a new construal. Results indicate that not only adults, but also children aged 6 and 10, are able to transform a mental image so as to yield another image with a different interpretation. Task demands had a greater effect on children than adults, consistent with the suggestion that the ease of manipulating mental images is a function of the efficiency of control processes.

Adult↗
PubMed1992

Influence of short-term memory codes on visual image processing: evidence from image transformation tasks.

Three experiments showed that phonological recording of visual stimuli in short-term memory (STM) affects coding in long-term memory (LTM) and therefore performance on tasks involving generation and manipulation of visual images of the stimuli. An image transformation task was devised. It consists of mentally subtracting a part of an image to discover in the remainder another object. In Experiment 1, Ss were required to learn a set of easily nameable visual stimuli and then perform the subtraction task on images retrieved from LTM. Performance was significantly better when initial learning was accompanied by articulatory suppression (AS). Experiment 2 confirmed that AS had no effect when the task was performed on an image of a just-presented stimulus. In Experiment 3, the nameability of the stimuli was manipulated. The results replicated the effect of AS for items that were easy to name but showed no effect of AS for stimuli that were difficult to name.

Adult↗
PubMed1992

Verbal recoding of visual stimuli impairs mental image transformations.

Two experiments were carried out to test the hypothesis that verbal recoding of visual stimuli in short-term memory influences long-term memory encoding and impairs subsequent mental image operations. Easy and difficult-to-name stimuli were used. When rotated 90 degrees counterclockwise, each stimulus revealed a new pattern consisting of two capital letters joined together. In both experiments, subjects first learned a short series of stimuli and were then asked to rotate mental images of the stimuli in order to detect the hidden letters. In Experiment 1, articulatory suppression was used to prevent subjects from subvocal rehearsal when learning the stimuli, whereas in Experiment 2, verbal labels were presented with each stimulus during learning to encourage a reliance on the verbal code. As predicted, performance in the imagery task was significantly improved by suppression when the stimuli were easy to name (Experiment 1) but was severely disrupted by labeling when the stimuli were difficult to name (Experiment 2). We concluded that verbal recoding of stimuli in short-term memory during learning disrupts the ability to generate veridical mental images from long-term memory.

Attention↗
PubMed1991

Speech, "inner speech," and the development of short-term memory: effects of picture labeling on recall.

Three experiments explored the effect of overt speech on children's use of "inner speech' in short-term memory (STM). Experiments 1 and 2 compared recall of a series of pictured objects when 5- and 11-year-olds either labeled stimuli at presentation or remained silent. Use of inner speech was assessed by manipulating word length of the picture names (Experiment 1) or phonemic similarity (Experiment 2). Word length and phonemic similarity had greater effects in the older children and when pictures were labeled at presentation. These tendencies were such that 5-year-olds were sensitive to word length and phonemic similarity only with labeling. Experiment 3 compared labeling by the child with labeling by the experimenter in 5-year-olds. There were no significant differences with respect to overall performance or effects of word length and phonemic similarity. It is suggested that speaking or listening to speech activates and internal "articulatory loop,' and that such activation is especially important when the child's ability to use inner speech in STM has not fully developed.

Attention↗
PubMed1989

Visual and phonological components of working memory in children.

Previous studies have shown that young children's immediate memory for a short series of drawings of objects is mediated by a visual component of working memory, whereas older children rely chiefly upon a phonological component. Three experiments investigated the hypothesis that older children rely also, but to a lesser extent, on visual working memory. Experiment 1 confirmed previous evidence that 11-year-olds' memory is disrupted by phonemic similarity of object names, but is unaffected by visual similarity of the objects themselves. However, when articulatory suppression was used to prevent phonological coding, levels of recall were sensitive to visual rather than phonemic similarity. Experiment 2 compared the effects of interpolating an auditory-verbal or a visual postlist task on memory for drawings viewed either with or without suppression. The visual task had a clear disruptive effect only in the suppression condition, where it interfered selectively with recall of the most recent item. Experiment 3 compared the effects of interpolating an auditory-verbal or a mixed-modality (visual-auditory) postlist task when subjects were not required to suppress. There was greater interference from the mixed-modality task, and this effect was confined to the last item presented. These experiments are taken as confirming the presence of a small but reliable contribution from visual memory in 11-year-old children's recall. As in younger children, visual working memory in 11-year-olds is sensitive to visual similarity and is responsible for a final-item visual recency effect. The results also show that older children's use of visual working memory is usually masked by the more pervasive phonological component of recall. Some implications for the structure of working memory and its development are discussed.

Child↗
PubMed1984

Working memory.

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Child↗
PubMed1983

Counting processes in deaf children's arithmetic.

Ten profoundly deaf children and 10 hearing controls matched for arithmetical achievement were given integer additions to classify as right or wrong. Hearing children perform this task by using covert counting strategies which have been assumed to be subvocal. In view of deaf children's poor spoken language abilities it was expected that the deaf group would make little or no use of such covert counting strategies and would rely more on alternative methods such as recalling learned number facts from long-term memory. The results failed to confirm this expectation and showed that classification times for the deaf were generally consistent with the same counting model as for the hearing. There was no difference between the groups in responses to correct sums involving ties or to incorrect sums, potential indicators of the use of associative retrieval. It is suggested that the covert counting processes of both deaf and hearing children in integer addition do not involve subvocalization. Alternative possibilities and general implications of this result for the education of the deaf are discussed.

Child↗