The effect of knowledge of reversibility on the reversibility of ambiguous figures

The role of knowledge of the reversibility of reversible figures was tested in four experiments. Two ambiguous figures, the vase-face figure and a depth-reversing pyramid-hallway figure were shown to high school students. In the Uninformed condition, subjects were not told that the figures were reversible. A sampling procedure was used in which subjects reported what they perceived at 5-sec intervals. Viewing durations of up to 3 min were used, and approximately half of all subjects did not reverse at all during the uninformed condition, whereas virtually all subjects reversed quickly and frequently once they knew that the figures were reversible. These results are not consistent with neural fatigue models of perceptual reversal.     

THE EFFECTIVENESS OF REINFORCEMENT,RESPONSE COST,AND MIXED PROGRAMS ON CLASSROOM BEHAVIORS1

Six elementary school children served as subjects in an experiment comparing the relative effectiveness of (1) token reinforcement, in which children received tokens for attending and for correct arithmetic performance; (2) response cost, in which children received “free” tokens at the start of a period but lost them for inattention and for arithmetic performance below a specified level; and (3) a combination of both token reinforcement and response cost. During training, the six subjects received all three procedures in counterbalanced sequence. The effects of the three procedures were assessed by a within-subject comparison divided into three phases: (i) baseline, (ii) training, (iii) withdrawal of tokens. Introduction of the three token procedures markedly increased the two dependent measures. However, there were no differences across the procedures in the amount of change produced in either attending behavior or arithmetic performance. During baseline, the subjects averaged 29% attending behavior and 6.4 correct problems. These levels increased to 85% for attending behavior and 11.4 correct problems for arithmetic performance during training. Removal of all token procedures significantly decreased attending behavior (to an average of 65%), but produced a nonsignificant reduction in arithmetic performance (to an average of 7.6 correct problems). There was evidence that this lack of differential effects of the three token procedures was not due to an inability to discriminate among them. Furthermore, the subjects were evenly divided in their preference for the three procedures.     

Regional cerebral glucose metabolism in aphemia: A case report

Local cerebral metabolism was determined in a patient suffering aphemia following cerebral infarction using the 18FDG-PET technique. The syndrome was characterized by profound ictal nonfluency with sparing of other language functions. Speech subsequently improved so that content and grammar were appropriate but mild dysprosody persisted. Conventional CT showed no lesion of the left hemisphere while PET revealed a discrete focus of hypometabolism on the left which partially resolved on serial studies. The metabolic lesion could be localized to the region of the inferior precentral gyrus and the adjacent subcortical space.     

The toll of ethnic discrimination on sleep architecture and fatigue.

Most work on ethnicity tends to focus on daytime health rather than how aspects of ethnicity affect nighttime functioning. The current study examined how discrimination and ethnic identity relate to sleep architecture and fatigue in 37 African Americans and 56 Caucasian Americans. The authors conducted sleep monitoring with standard polysomnography. African Americans had less slow-wave sleep and reported more physical fatigue than did Caucasian Americans (ps < .05). The authors conducted path analyses to examine relationships between ethnic identity, perceived discrimination, sleep, and fatigue. Perceived discrimination mediated ethnic differences in Stage 4 sleep and physical fatigue. Individuals who reported experiencing more discrimination had less Stage 4 sleep and reported experiencing greater physical fatigue (ps < .05). Although ethnic identity did not mediate ethnic differences in sleep latency, there was a significant relationship between ethnic identity and sleep latency, indicating that individuals who felt more connected to their ethnic group had more difficulty falling asleep while in the hospital (p < .05). These observations suggest that the effects of stress related to one's ethnic group membership carry over into sleep.     

Alternative approaches to equity: Dissonance reduction pro-social motivation and strategic accommodation

Reviews, compares and evaluates a self-justijication and a decision theoretical conceptualization of equity. It is argued that the latter approach reveals an important and often neglected distinction between equity as a goal of social interaction and equity as an interpersonal strategy employed in rhe pursuit of other valued goals. Associated problems of definition and measurement are discussed. After a review of relevant research it is concluded that equity serves predominantly as an accommodative interpersonal strategy, and that future research should focus on analyzing the various functional bases of equity, their relationships, and their eflects on behaviour.     

Dynamic relationships between phonological memory and reading: A five year longitudinal study from age 4 to 9

We reconcile competing theories of the role of phonological memory in reading development, by uncovering their dynamic relationship during the first 5 years of school. Phonological memory, reading and phoneme awareness were assessed in 780 phonics‐educated children at age 4, 5, 6 and 9. Confirmatory factor analyses demonstrated that phonological memory loaded onto two factors: verbal short‐term memory (verbal STM; phonological tasks that loaded primarily on serial order memory) and nonword repetition. Using longitudinal structural equation models, we found that verbal STM directly predicted early word‐level reading from age 4 to 6, reflecting the importance of serial‐order memory for letter‐by‐letter decoding. In contrast, reading had no reciprocal influence on the development of verbal STM. The relationship between nonword repetition and reading was bidirectional across the 5 years of study: nonword repetition and reading predicted each other both directly and indirectly (via phoneme awareness). Indirect effects from nonword repetition (and verbal STM) to reading support the view that phonological memory stimulates phonemically detailed representations through repeated encoding of complex verbal stimuli. Similarly, the indirect influence of reading on nonword repetition suggests that improved reading ability promotes the phoneme‐level specificity of phonological representations. Finally, the direct influence from reading to nonword repetition suggests that better readers use orthographic cues to help them remember and repeat new words accurately. A video abstract of this article can be viewed at https://www.youtube.com/watch?v=70LZfTR0BjE .