Global processing speed as a mediator of developmental changes in children's auditory memory span

This study examined the role of global processing speed in mediating age increases in auditory memory span in 5- to 13-year-olds. Children were tested on measures of memory span, processing speed, single-word speech rate, phonological sensitivity, and vocabulary. Structural equation modeling supported a model in which age-associated increases in processing speed predicted the availability of long-term memory phonological representations for redintegration processes. The availability of long-term phonological representations, in turn, explained variance in memory span. Maximum speech rate did not predict independent variance in memory span.     

Timing variability in circle drawing and tapping: probing the relationship between event and emergent timing

R. Ivry, R. M. Spencer, H. N. Zelaznik, and J. Diedrichsen (2002) have proposed a distinction between timed movements in which a temporal representation is part of the task goal (event timing) and those in which timing properties are emergent. The issue addressed in the present experiment was how timing in conditions conducive to emergent timing becomes established. According to what the authors term the transformation hypothesis, timing initially requires an event-based representation when the temporal goal is defined externally (e.g., by a metronome), but over the first few movement cycles, control processes become established that allow timing to become emergent. Different groups of participants (N = 84) executed either 1 timed interval, 4 timed intervals, or 2 timed intervals separated by a pause. They produced the intervals by either circle drawing, a task associated with emergent timing, or tapping, a task associated with event timing. Analyses of movement variability suggested that similar timing processes were used in the 2 tasks only during the 1st interval. Those results are consistent with the transformation hypothesis and lead to the inference that the transition from event-based control to emergent timing can occur rapidly during continuous movements.     

From egocentric to exocentric spatial orientation: development of posture control in bimanual and trunk inclination tasks

The authors investigated the emergence of independent control of body segments in bimanual tasks involving either voluntary or involuntary trunk motion by tracking the transition from an ego- to an exocentric mode of postural control during childhood (i.e., from body-referenced orientation to externally referenced action). A paradigm combining a seated manual task and various trunk manipulations described the coordination strategies used by 24 children at different ages (2 to 9 years) and by adults. The following questions were asked: (a) When do children begin to dissociate upper limb movements from those of the trunk? (b) What segmental strategies are exhibited by each age group (2-3, 4-6, and 7-9 years, and adults)? Kinematic analyses revealed that younger children (2-6 years) used either the trunk or the support surface as reference to orient the limbs. Older children (7-9 years) began to use a gravitational reference frame similar to that of adults; they uncoupled upper limb motion from the trunk in either voluntary or imposed conditions. Young children patterned the forearm trajectory after the initiating segment (support surface or the trunk), thus reducing the degrees of freedom during the dual task. Echoing previous reports, 7-9 years of age appears to be a critical period in which children master postural control and develop an internal representation of body scheme.     

Role rigidity: a problem of identity misclassification?

When nonstigmatized individuals enact certain role-violating behaviors, they risk becoming "falsely accused deviants" (H. S. Becker, 1963, p. 20). For instance, when heterosexual men perform stereotypically feminine behaviors, they are liable to get misclassified as homosexual. Findings presented here reveal that expectations of identity misclassification fuel nonstigmatized individuals' negative reactions to role violations (Studies 1-2) and that using a disclaimer--that is, informing their audience of their nonstigmatized identity--assuages people's discomfort during a role-violating behavior (Studies 3-4). Moreover, when not concerned about being misclassified, nonstigmatized individuals benefit psychologically from the enactment of a challenging role violation (Study 4). Discussion considers the nature of the threat that misclassified role violators face and compares the plight of the falsely accused deviant to that of the truly stigmatized individual.     

MORPHINE TOLERANCE AS A FUNCTION OF RATIO SCHEDULE: RESPONSE REQUIREMENT OR UNIT PRICE?

Key pecking by 3 pigeons was maintained by a multiple fixed-ratio 10, fixed-ratio 30, fixed-ratio 90 schedule of food presentation. Components differed with respect to amount of reinforcement, such that the unit price was 10 responses per 1-s access to food. Acute administration of morphine, l-methadone, and cocaine dose-dependently decreased overall response rates in each of the components. When a rate decreasing dose of morphine was administered daily, tolerance, as measured by an increase in the dose that reduced response rates to 50% of control (i.e., the ED50 value), developed in each of the components; however, the degree of tolerance was smallest in the fixed-ratio 90 component (i.e., the ED50 value increased the least). When the l-methadone dose-effect curve was redetermined during the chronic morphine phase, the degree of cross-tolerance conferred to l-methadone was similar across components, suggesting that behavioral variables may not influence the degree of cross-tolerance between opioids. During the chronic phase, the cocaine dose-effect curve shifted to the right for 2 pigeons and to the left for 1 pigeon, which is consistent with predictions based on the lack of pharmacological similarity between morphine and cocaine. When the morphine, l-methadone, and cocaine dose-effect curves were redetermined after chronic morphine administration ended, the morphine and l-methadone ED50s replicated those obtained prior to chronic morphine administration. The morphine data suggest that the fixed-ratio value (i.e., the absolute output) determines the degree of tolerance and not the unit price.     

Assessing a microswitch-based stimulation procedure for eye-blinking responses in a young woman with profound multiple disabilities

We applied a new microswitch-based stimulation procedure for eye-blinking responses with a young woman with profound multiple disabilities, and compared effects of this procedure on the eye-blinking responses and smiling with the effects of a caregiver-based stimulation condition. Analysis showed that the microswitch-based stimulation procedure, with stimulation occurring contingent on eye-blinking responses, increased the frequencies of these responses significantly above the levels recorded in baseline and caregiver-based stimulation conditions. No changes in smiling frequencies occurred. Implications of the findings in terms of alertness, learning, and quality of life are discussed.     

Individual characteristics associated with resilience in single-parent families

This study identified individual characteristics as a resource to enhance the resilience of a family dealing with the loss of a parent. 25 white single-parent families who had lost a parent between 1 and 4 yr. previously were identified by four postgraduate students in the Western Cape, South Africa. Each single-parent, 19 women and 6 men (M age=48 yr., SD=7.65), were asked to state the personal qualities which helped the family adapt after the loss, after the Family Attachment and Changeability Index 8 and the Ego-resiliency Scale were completed. The expected positive relationship between personal resilience and family functioning could not be confirmed. However, the qualitative results indicate that optimism, perseverance, faith, expression of emotions, and self-confidence were prominent individual characteristics of resilience viewed as resources in promoting resilience in these single-parent families.     

Personal information in searching for faces

Participants searched for a target on a television monitor either after they viewed pictures and received physical information about the target or received that information augmented by personal information. Based on a levels of processing perspective we predicted that the addition of personal information would stimulate deeper processing and result in better identification performance. Personal information did increase identification accuracy, as anticipated. Personal information also increased the duration of time spent on the search task relative to a distractor task, suggesting that personal information may have done more than deepen the processing at the time of encoding. In the current climate of terrorism, this increase in identification performance via a surveillance camera has clear applied significance.     

Rapid serial naming: relations between different stimuli and neuropsychological factors

We report two studies on rapid serial naming (RSN). Study 1 addressed the relations among RSN tasks comprising different stimuli. Separate components for RSN of alphanumeric and non-alphanumeric stimuli, as well as for tasks in which the stimuli alternated between categories were identified. In Study 2, phonological skills, processing speed, motor dexterity, and verbal fluency were found to explain RSN performance. The studies indicate: (1) that RSN tasks vary in their properties according to the stimuli used and according to the way the tasks are arranged, and (2) that RSN tasks are multi-componented.     

The perception of second language sounds in early bilinguals: new evidence from an implicit measure

Previous studies have suggested that nonnative (L2) linguistic sounds are accommodated to native language (L1) phonemic categories. However, this conclusion may be compromised by the use of explicit discrimination tests. The present study provides an implicit measure of L2 phoneme discrimination in early bilinguals (Catalan and Spanish). Participants classified the 1st syllable of disyllabic stimuli embedded in lists where the 2nd, task-irrelevant, syllable could contain a Catalan contrastive variation (/epsilon/-/e/) or no variation. Catalan dominants responded more slowly in lists where the 2nd syllable could vary from trial to trial, suggesting an indirect effect of the /epsilon/-/e/ discrimination. Spanish dominants did not suffer this interference, performing indistinguishably from Spanish monolinguals. The present findings provide implicit evidence that even proficient bilinguals categorize L2 sounds according to their L1 representations.