Switching pauses in cooperative and competitive conversations

The effects of three variables (conversation type, turn completeness, and sexual composition of the interacting dyad) on switching pause durations was investigated. Conversation type was represented by two categories of conversation: cooperative and competitive. A cooperative conversation is one in which participants cooperate in floor apportionment, while a competitive conversation is one in which the participants compete for the floor. Turn completeness has two levels and refers to the presence or absence of a turn-yielding signal in the utterance immediately preceding a switching pause. Three dyad compositions, male-male, female-female, and male-female were used, with six dyads in each category. The subjects participated in four conversations, two friendly chats and two arguments, on various topics. The switching pauses in competitive conversations were shorter than those in cooperative conversations. Furthermore, conversation type had a significant effect on the switching pause length following imcomplete utterances.     

Tactile spatial ability: Lateralized performance of deaf and hearing age groups

Hearing adults, 8- and 6-year-old children, together with deaf 9-year-old children, were tested on a unimodal haptic matching task. One additional group of adults was tested with a shorter stimulus presentation time. Data indicated that left-hand superiority was most evident in the performances of the older hearing children, and of the adults with the shorter presentation time. Hemispheric specialization was less noticeable for the younger hearing group, but the task may have been too difficult. A slight right-hand superiority was found in the performance of adults with long presentation time. This may reflect the simplicity of the task for these subjects. Deaf children did not show any clear hand differences, but were superior in overall performance to hearing children.     

Hemispheric differences in temporal resolution

A review of the relevant clinical and experimental literature gives the conclusion that the cerebral hemispheres differ in temporal resolution of input, with the language-dominant hemisphere showing finer acuity. This conclusion is supported by evidence from performance of patients with unilateral brain damage on tests of temporal resolution, performance of developmental dyslexics on similar tasks, and left-right sensory field differences in temporal acuity in normal human subjects. While it is unlikely that a hemispheric difference in temporal resolution is sufficient to give a complete account of lateralized functions, such attempts to show more primitive physiological differences between the hemispheres are more likely to be fruitful than attempts which differentiate the hemispheres in terms of higher-order psychological functions.     

Acquired and developmental spelling dyslexia

Two cases of acquired spelling dyslexia and one case of developmental spelling dyslexia are described along with accounts of their performance on various psycholinguistic tasks. It is argued that there is some evidence that spelling dyslexia may exist in developmental form but that parallels are difficult to draw because of the very different histories of child and adult cases. It is also suggested that features of surface dyslexia exist in at least a proportion of spelling dyslexic cases and that this may be influenced by level of premorbid reading skill.     

Change in selectivity of infant social behavior between 15 and 30 weeks

Six infants were filmed at 15 and 30 weeks of age while alone as well as in the presence of an adult (mother or stranger) who interacted with the infant or remained passive. Judges viewing samples of infant behavior tried to identify the social context in which episodes of behavior had occurred. Signal detection analysis of ratings made by the judges showed that infant behavior at both ages varied in accord with whether or not an adult was present. The identity and interactional style of the adult had only limited influence on infant behavior at 15 weeks, but judges could readily establish from the behavior of 30-week infants whether the adult was interactive or passive. Mothers were no more accurate in their ratings of social context than other judges were, even when they were observing the behavior of their own infant. Measurement of specific infant behaviors showed that the presence of the adult at both ages and the interactional style of the adult at 30 weeks exerted selective influence over rates of looking and smiling by infants. Signal detection classification was more sensitive to social context variables than microanalysis, possibly because observers had access to complex behavioral configurations.     

Reinforcement contrast effects on the rewarding and aversive components of intracranial stimulation

Rats performing a free-operant locomotor response in a shuttlebox to initiate and then escape medial diencephalic stimulation were tested daily on a randomized sequence of three stimulation intensities. In spite of a 1-hr interval between stimulation intensity changes, substantial and graded reinforcement contrast effects were obtained. “Elation” effects were obtained both on the rewarding (latency to initiate) and the aversive (latency to escape) components of stimulation whereas “depression” effects were found only on the measure of reward.