Semantic and surface codes in the memory of deaf children

In three experiments, deaf children in the age range of 6 years, 10 months to 15 years, 5 months were presented with continuous lists of items, and for each item they had to indicate whether it had appeared before on the list. Later items were related to preceding items either in surface form or in meaning or were unrelated. False-recognition errors (i.e., “yes” responses to new items) served as an index of memorial coding. In one experiment, the items presented to the subjects were printed words. The results of this experiment showed a false-recognition effect (i.e., more errors to related words than to unrelated words) for both semantically related words and orthographically similar words. In the other two experiments, the subjects viewed a series of manual signs on videotape. In these experiments, there was a false-recognition effect for signs related semantically and for signs related cherologically (i.e., similar in terms of their manual production). These results establish orthography and cherology as effective memorial codes for deaf children. The finding of a consistently strong semantic effect for young deaf children stands in contrast to findings of weak semantic effects in false-recognition studies with young hearing children. The ascendancy of semantic codes for deaf children was attributed to the absence of competition from the speech code which dominates the linguistic memory of hearing children.     

The form of analog size information in memory

The information used to choose the larger of two objects from memory was investigated in two experiments that compared the effects of a number of variables on the performance of subjects who either were instructed to use imagery in the comparison task or were not so instructed. Subjects instructed to use imagery could perform the task more quickly if they prepared themselves with an image of one of the objects at its normal size, rather than with an image that was abnormally big or small, or no image at all. Such subjects were also subject to substantial selective interference when asked to simultaneously maintain irrelevant images of digits. In contrast, when subjects were not specifically instructed to use imagery to reach their decisions, an initial image at normal size did not produce significantly faster decisions than no image, or a large or small image congruent with the correct decision. The selective interference created by simultaneously imaging digits was reduced for subjects not told to base their size comparisons on imagery. The difficulty of the size discrimination did not interact significantly with any other variable. The results suggest that subjects, unless specifically instructed to use imagery, can compare the size of objects in memory using information more abstract than visual imagery.     

Modeling semantic memory: Effects of presenting semantic information in different modalities

How is semantic information from different modalities integrated and stored? If related ideas are encountered in French and English, or in pictures and sentences, is the result a single representation in memory, or two modality-dependent ones? Subjects were presented with items in different modalities, then were asked whether or not subsequently presented items were identical with the former ones. Subjects frequently accepted translations and items semantically consistent with those presented earlier as identical, although not as often as they accepted items actually seen previously. The same pattern of results was found when the items were French and English sentences, and when they were pictures and sentences. The results can be explained by the hypothesis that subjects integrate information across modalities into a single underlying semantic representation. A computer model, embodying this hypothesis, made predictions in close agreement with the data.