Children's selective attention with variation in amount of stimulus exposure

Selective attention in children was measured by means of a central-incidental learning paradigm. Children performed a central task requiring attention to one element in each of several stimuli, after which their incidental learning was assessed by a combination of two tests measuring: (a) recognition of the second, or incidental, element in each stimulus, and (b) association between the incidental and central elements. Principal independent variables were the age of the children (9 vs 12 years) and the amount of exposure time per trial in the central task (6 vs 12 sec). Douling the exposure time increased the incidental as well as the central scores for 9-year-olds, while it increased only the central scores for 12-year-olds. It would appear that younger children maintain a relatively nonselective orientation during an extended exposure period, distributing attention between both relevant and irrelevant stimulus elements, whereas adolescents adopt a more selective approach and concentrate exclusively on task-relevant information. The results are discussed in relation to hypotheses regarding development of selective attention.     

The problem-solving strategies of kindergarten and first-grade children during discrimination learning

Kindergarten and first-grade children (6 and 7 years of age, respectively) were given specially designed discrimination tasks with introtact probes preceding each trial. One group (CON) was given the criterion task without prior training. A second group (LTL) received three pretraining tasks of the same type as the criterion task. A third group (HYP) received the same pretraining tasks, but with explicit instructions designed to teach a simple hypothesis-testing strategy. Several indices, designed to reflect the use of win-stay and lose-shift rules, as well as memory for disconfirmed hypotheses, were computed from the protocols of the criterion task. The indices for Group CON suggested that most of these children were using a guessing strategy that involved quite frequent changes in hypotheses. Moreover, many of these children restricted their hypotheses to the irrelevant cues. The indices for Group LTL revealed a spontaneous use of the hypothesis-testing strategy by nearly half of the children. The results for Group HYP indicated that over four-fifths of these children became highly efficient in the use of the problem-solving strategy.     

Effectiveness of hand overcorrection for topographically similar and dissimilar self-stimulatory behavior

Response contingent hand overcorrection was used to reduce the frequency of self-stimulatory behaviors in four retarded adult males. For two of the subjects, the treated behaviors (hand shaking and nose touching) involved hand movements which were topographically similar to the hand overcorrection procedure. For the other two subjects, behaviors topographically dissimilar to the treatment procedure were treated (inappropriate laughing and head weaving). All four behaviors were decreased in frequency during treatment. However, the hand overcorrection procedure was more effective with the topographically similar behaviors.     

Blocking of a taste aversion by prior pairings of exteroceptive stimuli with illness

Although rats preferentially associate gustatory stimuli with illness, this does not imply that other types of stimuli cannot be associated with illness. In Experiment 1, rats consuming tap water in a distinctive environment prior to illness subsequently suppressed ingestion in that environment, whereas rats poisoned or injected with saline 10 hr later did not. It was also found that rats poisoned after drinking saccharin in the environment paired with illness developed weaker saccharin aversions than identically trained rats which drank saccharin in a different location. In Experiment 2, degrading the correlation between injection-related cues and illness by interpolating saline injections between LiCl preexposures attenuated the decremental effects of illness preexposure. The strength of the exteroceptive cue-illness associations observed in these studies suggests that theories based on evolutionary arguments are not the most appropriate frame of reference for analyzing stimulus selection in poison-induced avoidance.     

Acquired aphasia with convulsive disorders in children: a case study with a seven-year follow-up.

In a 7-year follow-up a case of the “syndrome of acquired aphasia with convulsive disorder” is described. In particular, attention is paid to EEG patterns and linguistic analysis. Although seizures have been controlled medically and EEG abnormalities have tended to improve, no close parallel improvement has been observed in the patient's language disorders.     

The effects of symmetry and contour on recognition memory in children

Children in prekindergarten, kindergarten, and second grade were tested on a delayed match-to-sample task using abstract visual patterns. The patterns varied both in type of visual organization (unstructured, diagonally symmetrical, vertically symmetrical, and horizontally symmetrical) and in amount of contour. Following the initial memory task, we attempted to train half of the children at each grade by directing their attention to axes of symmetry; the other half of the children received a control task. Subsequently, the subjects were given a second delayed match-to-sample test. On both pre- and post-training trials, structure influenced performance, especially in the two younger groups. Vertical and horizontal symmetry generally facilitated performance in the prekindergarteners, while all three types of symmetry facilitated performance in the kindergarteners. In addition, children generally responded more accurately to patterns with lower levels of contour. They also made more like-contour than unlike-contour confusions, indicating that quantitative aspects of patterns were encoded. Group differences suggested that both processing capacity and memory increase during the age range studied. Finally, there was no indication that training improved performance at any age.     

Reaction time for voiced and whispered /a/ in stutterers and nonstutterers

Recent research reviewed in this article suggests that stutterers' inability to initiate phonation promptly could be a significant factor in the occurence of stuttering. Since stuttering is either completely absent or markedly reduced in frequency during whisper, the present study tested the hypothesis that stutterers do not significantly differ from nonstutterers in reaction time (RT) for the initiation of whispered/a/, whereas the two groups differ significantly in RT for the initiation of voiced /a/. Ten adult stutterers and an equal number of comparable nonstutterers produced prolonged versions of the vowel /a/ using voice and whisper in response to tone stimuli. The results showed that stutteres and nonstutterers did not differ in RT for either voiced or whispered /a/. The stutterers, however, exhibited significantly longer RT to produce voiced /a/ than whispered /a/.     

Performance of retarded adolescents and nonretarded children on one- and two-bit logical problems

Groups of adolescents of retarded and borderline intelligence, ranging in IQ from 44 to 80 and in mean MA (mental age) from 8 to 12 yr, and groups of nonretarded children ranging in mean MA from 6 to 12 yr, were given logical problem solving tasks. In the nonretarded groups, on a one-bit problem only the kindergarten children (mean MA = 6 yr) failed to perform above chance, and were not tested further. On a two-bit problem, only the first graders (mean MA = 7 yr) failed to perform above chance.Conversely, in the low IQ groups, only the borderline group (mean MA = 12 yr) performed reliably above chance on the one-bit problem, and none performed above chance on the two-bit problem. There is a profound deficiency in low IQ individuals on certain tasks requiring logic and foresight, and MA markedly over-estimates their performance relative to the performance of nonretarded individuals.