Age differences in sensation seeking and impulsivity as indexed by behavior and self-report: Evidence for a dual systems model.

It has been hypothesized that sensation seeking and impulsivity, which are often conflated, in fact develop along different timetables and have different neural underpinnings, and that the difference in their timetables helps account for heightened risk taking during adolescence. In order to test these propositions, the authors examined age differences in sensation seeking and impulsivity in a socioeconomically and ethnically diverse sample of 935 individuals between the ages of 10 and 30, using self-report and behavioral measures of each construct. Consistent with the authors' predictions, age differences in sensation seeking, which are linked to pubertal maturation, follow a curvilinear pattern, with sensation seeking increasing between 10 and 15 and declining or remaining stable thereafter. In contrast, age differences in impulsivity, which are unrelated to puberty, follow a linear pattern, with impulsivity declining steadily from age 10 on. Heightened vulnerability to risk taking in middle adolescence may be due to the combination of relatively higher inclinations to seek excitement and relatively immature capacities for self-control that are typical of this period of development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A low cost,one-piece nitrogen burst processing rack for 3¼× 4 inches and 4×5 inches TEM and SEM negatives

A processing rack designed with a built-in nitrogen burst plenum to accommodate 3¼ × 4 in. and 4 × 5 in. negative can be inexpensively constructed from plexiglass.     

Multidimensionality versus inconclusiveness: The baby and the bathwater.

Replies to comments by A. E. Kazdin (see record 1989-12740-001) and K. B. Schmaling and N. S. Jacobson (see record 1989-12763-001) on the present authors' (see record 1989-12762-001) study on social learning family therapy for aggressive children. It is maintained that analyses of the data yield an inference of powerful behavioral-systemic intervention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Science,technology and China's four modernizations

The crux of the four modernizations is the mastery of modern science and technology. Without them it is impossible to build modern agriculture, modern industry, or national defense.     

Discrimination of temporal relations by pigeons.

In 4 experiments, pigeons were tested on a duration comparison task involving the successive presentation of two visual stimuli that varied in duration from trial to trial. Following presentation of the durations, 2 choice keys were lit, and reinforcement for choices was based on the temporal relation between durations of the pair. In Exp 1, the range of durations was varied over conditions. Responding changed as an orderly function of the ratio of the 2 durations. There was a decrease in discrimination accuracy as average duration increased over conditions. In Exp 2, Ss were transferred from a task involving spatially differentiated choices to one involving hue-differentiated choices. Performance was similar to that of Exp 1. In Exp 3, Ss were exposed to a single duration range that included many durations from the 4 ranges of Exp 1. Discrimination accuracy was comparable on 3 problem duration categories within this range and declined slightly for problems in the 4th and longest category. Manipulation of absolute reinforcement rate in Exp 4 resulted in no change in discrimination accuracy, suggesting that the decline in accuracy over conditions of Exp 1 could not be attributed to decreases in reinforcement rate that accompanied lengthier durations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hydrous oxide formation on gold in base under potential cycling conditions

The formation of hydrous oxide films on gold in base under potential cycling conditions was investigated and found to be less inhibited than the same type of reaction observed when gold is strongly anodized at high potentials under d.c. conditions at high pH. The overall behaviour on cycling is quite similar to that observed with other metals, e.g. platinum. The importance of the lower limit, for instance, again appears to be related to the need under film thickening conditions to significantly reduce the compact oxide layer formed on the metal surface during the anodic sweep. It was noted that the earlier duplex model for this type of system, i.e. an inner compact and an outer dispersed oxide layer, is not always valid. Under certain conditions about six distinct peaks (suggesting six different states of gold oxide hydration, dispersion or polymerization) were observed in cathodic sweeps recorded for the reduction of thick films grown on gold under potential cycling conditions in base.     

The enhancement of memory by hypnosis in the legal investigative situation.

The increasing use of hypnosis on North America to enhance or refresh the memories of victims and witnesses of crime is creating concern, both within the professional hypnosis societies and within the legal profession. The authors review current positions on the issue and survey clinical and experimental data bearing on the efficacy of hypnosis as a means of memory enhancement. The 2 main problems associated with the use of hypnosis in the legal investigative context—confabulation and the creation of pseudo-memories—are discussed, with particular reference to the demand characteristics of the investigative context. Some recent court cases where confabulation was demonstrated unequivocally and several recent American state supreme court rulings are presented. The need for stringent safeguards proposed by M. T. Orne (1978) is discussed, and the relevance of the American experience of the past 15 yrs to the Canadian context is emphasized. (French abstract) (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reflex conditioning in a spinal man.

A 40-yr-old man with a completely transected spinal cord and a spastic neurogenic bladder was conditioned to void upon the presentation of an external stimulus. A classical conditioning paradigm was employed in which strong abdominal shock (UCS) was paired with an initially neutral mild electrical stimulation of the thigh (CS). After the pairing trials, a reliable conditioned response of urination was elicited by the CS alone. The conditioned response did not extinguish over time, and the procedure left the bladder with clinically safe residual amounts of urine. Practical implications of the conditioning technique for the treatment of spastic neurogenic bladder conditions in spinally injured patients are discussed, as is the theoretical significance of conditioning at the reflex level in the absence of cortical involvement. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social learning family therapy with aggressive children: Treatment outcome and maintenance.

Investigated the effectiveness of a time-limited social learning family therapy model in maintaining treatment changes in 43 families of aggressive boys in Grades 2–6. Families were randomly assigned to treatment or a waiting-list control group. Measures to assess the occurrence and maintenance of treatment gains in child behavior, family environment, and family problem solving included the Child Behavior Checklist. There were significant gains in positive child behaviors at home and school, family cohesion, empathy, problem-solving efficiency, and positive family relationships in the treatment group relative to controls. These gains were maintained for 9–12 mo after treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)