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.     

Perspective ability: The relative difficulty of the other observer's viewpoints

Previous research findings regarding the relative difficulty of the different positions occupied by the other observer in a perspectives task are contradictory; this may be due to a lack of control of the object arrangement and differences in masking from each viewpoint. In the present experiment, an object array was employed in which the views from the experimental positions were objectively of equal difficulty. Children of 6, 8, and 10 years found that representing the 90 and 270° views was equally difficult, but both of these views were easier than the 180° view.     

Child performance on discrimination tasks: Effects of amount of stimulus variation

Two independently conducted studies investigated stimulus variation effects on children's discrimination learning. The stimuli in the first study were generated by a conjunctive rule and were presented in pairs. Mean trials to criterion was significantly lower for the single-feature change treatment (17.4) than for the multiple-feature change treatment (29.9). Single-feature change-treatment transfer scores were significantly higher only for stimuli that differed in terms of one of the features. The second study not only replicated the initial finding concerning the single-feature change treatment but also found that students made more errors in reaching criterion when stimuli were generated by an exclusive disjunctive rule and were presented singly. For all tasks, the single-feature change treatment with stimuli presented in pairs was accompanied by fewer errors to criterion than the other treatments.     

Short-term memory in deaf and hearing children in relation to stimulus characteristics

Experiment 1 examined short-term memory with a serial probe task in 20 younger (mean age: 6 years, 3 months) and 20 older (mean age: 8 years, 8 months) deaf children. Four sets of stimuli were used: familiar animals, unfamiliar nonsense forms, fingerspelled letters, and lower-case print. In contrast to earlier research with hearing children, strong primacy effects were found with all stimuli at both ages, with frequent gestural and/or oral labeling but little cumulative rehearsal evident. To determine whether results were uniquely tied to deafness, identical procedures were used in Experiment 2 with 20 younger (4 years, 9 months) and 20 older (5 years, 10 months) hearing children. Again, overt activity was common, with strong primacy effects on animals and nonsense forms in the older group and on animals in the younger group. Contrasts between present and earlier findings suggest the need to consider the degree to which stimulus labels are overlearned, the role of nonverbal mediators in rehearsal, and the effects of changing educational experiences.     

Conservation training in four-year-old children

In Experiment 1 two training procedures were used to teach four-year-olds to conserve. Verbal rule instruction consisted of providing verbal rules and demonstrations of the operations referred to by the rules. Feedback consisted of providing verbal feedback contingent upon the children's responses. One week after training on conservation of number and length the children were given a posttest which included tests of conservation of number, length, and mass. Children who were given verbal rule instruction conserved significantly more on the number and length posttest problems than children who were not. However, this learning did not transfer to the mass problems, possibly because mass is not naturally acquired until some time after conservation of number and length. The feedback training procedure had no effect on conservation performance. In Experiment 2, the verbal rule instruction procedure was used to train four-year-olds on conservation of length and mass. One week after training the children were tested on both conservation of number, which is typically acquired before length and mass, and conservation of weight, which is typically acquired after length and mass, as well as on conservation of length and mass. Children who were given training conserved more on all four types of problems than children in the control group.     

Behavioral inference in young children

Three experiments are reported on behavioral inference in children of 3 to 5 years of age. In each experiment the children learned two separate sequences of behavior which they were required to put together in the final test stage in order to obtain a reward. In the first experiment moderate levels of behavioral inference were obtained, although a relatively high proportion of children failed to respond in the test phase. In the second experiment different instructions were used in the test phase, the number of nonresponders was greatly reduced and a much higher proportion of children showed behavioral inference. The third experiment obtained similar results under conditions which excluded the possibility of mediation during a memory test, which was included in the previous experiments. It was concluded that behavioral inference is found, under suitable conditions, in children as young as 3-years-old, and that reports by other investigators of failure to find such inference up to the age of about 8 were due to problems with apparatus and instructions.     

Object disappearance and error in Piaget's Stage IV task

Piaget attributes perseverative error in infant manual search to the failure of the infant to conceive of objects as permanent entities which retain their identity when hidden at successive locations A and B. An experiment was performed to test this explanation in which search was compared under three conditions: when the object was hidden at A and B, when the object was covered but visible at A and B, and when the object was visible and uncovered at A and B. Errors occurred under all three conditions taking the form of a conflict in which infants searched persistently either at A or at B. The conflict was at a maximum when the object was hidden, but was evident even when the object was visible but covered. It is suggested that errors may reflect lack of coordination between egocentric and visual frames of reference in relation to which the object is located.     

The effects of attention-directing training on recognition memory task performance of three-year-old children

Thirty-eight 3-year-old children served as subjects in an investigation of recognition memory in which schematic faces differing only in the orientation of the eyes were employed as stimuli. A pretest was administered to all children, after which the two experimental groups received training in either attention to the distinctive feature of the training stimuli (also schematic faces) by means of a matching task, or in labeling the faces according to how they looked (sleepy, happy, sad, mad) and in using the labels to perform a matching task. After the training session all children were given a posttest on recognition memory of the faces. The verbally trained group obtained significantly higher scores on the posttest than either the feature or control groups. These results indicate that although the children were able to discriminate the faces, evidenced in their ease of performance on the training tasks, they were not able to use this knowledge unless given training in attaching labels to the stimuli, which enabled them to store the information for later use. Results are discussed in light of Gibson's (1969) theory of the developmental interrelations of cognitive processes.