What makes triangles point: Local and global effects in configurations of ambiguous triangles

Perceived pointing of ambiguous triangles was investigated in three experiments. The results show that the probability of seeing an equilateral triangle point in a given direction is strongly influenced by (a) the direction of the ambiguous alternatives, (b) the orientational characteristics of the configuration of elements surrounding the triangle, and (c) the shape of the surrounding elements. These findings are interpreted as supporting the hypothesis that perceived pointing is determined by perceptual reference frames induced at multiple levels of globality: one for the general visual field, one for the entire configuration, and one for the local elements of the configuration.     

Classes and collections: Principles of organization in the learning of hierarchical relations

This study demonstrates that children tend to distort class inclusion relations (e.g., the relation of oaks to trees) into the part-whole structure of collections (e.g., the relations of oaks to a forest). Children aged 6 to 17 were taught novel class inclusion hierarchies, analogous to the relation between oaks, pines, and trees. In one condition, the class inclusion relations were taught by ostensive definition alone, e.g., stating “These are trees” while pointing to trees and, “These are oaks” while pointing to oaks. in the second condition, children were additionally told what would be analogous to “Oaks and pines are two kinds of trees”. With this additional information to constrain their interpretation, even the youngest children correctly interpreted the relation as class inclusion. In contrast, with limited information, children as old as 14 erroneously imposed a collection structure on the inclusion hierarchies. They would deny, for example, that any single tree was a tree (as they should of they thought “tree” meant “forest”), and would pick up several trees despite being asked for a tree. The results indicated that the part-whole structure of collections is simpler to establish and maintain than the structure of inclusion.     

小鼠的记忆与脑内突触结构参数变化的相关性

比较不同月龄小鼠学习记忆力与脑内突触结构参数变化的相关性。选用１月龄和６月龄小鼠,用Ｙ－迷宫检测分辨学习能力,用一次性被动回避反应检测记忆力。然后杀鼠取脑,进行超微结构观察和定量分析测定。结果表明：（１）１月龄小鼠的分辨学习能力优于６月龄小鼠,记忆力也有优于６月龄小鼠的趋势。（２）无论在海马或大脑皮层体区,有两种结构参数有一致性增龄变化,即６月龄小鼠突触界面曲率都比１月龄小鼠显著和极显著增大;而６月龄小鼠上述两脑区的突触后致密物质厚度都极显著地小于１月龄小鼠。实验结果提示,脑内突触界面结构的增龄性变化可能是学习记忆力增龄性变化的结构基础。     

Attention to eye contact opportunity and facial motion by three-month-old infants

Thirty-two 3-month-old infants participated in two experiments showing color videotapes of facial stimuli in a paired comparison format. In Experiment 1, the experimenter, serving as the stimulus, looked either directly at the infant or averted his gaze to the side; the face was presented either still or in motion. Eye contact opportunity had no effect while motion of the head was an effective attractor of visual fixation. In Experiment 2, the amount of available eye contact opportunity was parametrically varied by occluding the eyes with different patterns of blinking, each at the same rate. The no-motion 100% eye contact available condition received less attention than the three blinking stimuli, which were all equally attended to, though they varied with respect to the amount of eye contact opportunity they afforded. The contrast in effect of eye contact availability and rather subtle stimulus motion would imply that 3-month-old infants are comparatively insensitive to being the object of another's visual regard.     

The discourse of thought-disordered schizophrenic children

The conversations of two thought-disordered schizophrenic children and two age- and sex-matched normal children were studied in three different contexts. Cohesive relations and retrieval categories were analyzed. The thought-disordered schizophrenic and normal children demonstrated divergent patterns of discourse. These patterns closely paralleled those previously reported for adults by S. Rochester and J. R. Martin (1979, Crazy talk: A study of the discourse of schizophrenic speakers, New York: Plenum) for schizophrenic and normal adults, although some discrepancies were also observed. Recommendations for future research are offered.     

Identification of language-impaired children on the basis of rapid perception and production skills

Discriminant function analysis was used to determine whether performance on temporal perception and production tasks alone could correctly classify children as language-impaired or normal. The analysis identified six variables, all of which assessed temporal perceptual and production abilities, which taken in combination correctly classified 98% of participating subjects. None of these variables assess the higher-level linguistic abilities (semantic, syntactic, pragmatic) that have classically been considered to be deficient in language-impaired children, or have been used to diagnose them clinically.     

The patterning of agonistic behaviors among friends and acquaintances in programs for emotionally disturbed children

Peer conflicts in two age groups (toddler and preschool) of emotionally disturbed children were examined for developmental trends and for changes over time in an intervention program. Children were observed in their peer groups six times over the course of a year. Prosocial and agonistic social behaviors were coded in a continuous coding observational procedure. Friendship pairs were identified from the observational records and validated by teacher reports. It was hypothesized that agonistic responses to both prosocial and agonistic bids would decrease over time and that friendships would facilitate conflict resolution and conflict avoidance in the emotionally disturbed children. Agonistic responses to agonistic bids decreased over time for all children. Older acquaintances responded to prosocial bids with agonistic responses. Friendship relationships facilitated conflict resolution and avoidance skills in preschool-age but not toddler-age friends. The results are discussed in terms of their implications for intervention.     

Processes of verbal memory failure in Alzheimer-type dementia

Multiple aspects of verbal learning and memory performance in mild as compared to moderate Alzheimer-type dementia (ATD) were studied with the Buschke selective reminding paradigm. Results show that (1) both groups of ATD subjects depend less on long-term memory (LTM) and more on short-term memory (STM) relative to elderly control subjects, (2) mild ATD subjects show less LTM encoding than moderate ATD subjects, (3) moderate ATD subjects retrieve a smaller portion of the items presumed to be encoded into LTM than do mild ATD subjects, and (4) high-imagery words increase LTM encoding and retrieval as compared to low-imagery words for moderate ATD subjects only. These results are explained by the inability of ATD subjects to attend to more than one component of the list-learning task, in conjunction with differences in the deployment of attention between mild and moderate ATD subjects.