Reliability, homogeneity and the construct validity of Cattell's 16PF

This paper reviews criticisms of the psychometric properties of Cattell's Sixteen Personality Factor Questionnaire and examines Cattell's claims that 16PF scale reliabilities and factor validities are seriously underestimated by conventional internal consistency approaches to reliability estimation.On large samples of British adults and undergraduates no evidence was found to support the claim that the 16PF is deliberately heterogeneous in item content. No presence of suppressor effects or balancing of specifics were found in the 16PF scales, most of which were reasonably homogenous by conventional standards. Conventional internal-consistency reliability estimates in fact give very similar results to alternate form reliability coefficients and Cattell's factorial validities. 16PF scales which were particularly poor in terms of scale consistency were L, M and N with C, O and Q4 emerging as measures of essentially the same trait of anxiety.     

Control of CRT intensity via Apple II software

An inexpensive, easy-to-build device for the Apple II microprocessor is described. The modification permits software control of four levels of relative screen intensity (contrast) settings for any video monitor. The relationship of the technology to choice reaction time and perception research is briefly indicated. Principles governing operation of the modification are also discussed. Finally, a set of step-by-step instructions for building the device is provided.     

Apple II/FIRST system control of electrical brain stimulation in the rabbit

An Apple II/FIRST system has been developed to control classical conditioning experiments, collect analog data, and extract dependent variable measures of conditioning from uniphasic (Scandrett & Gormezano, 1980) and multiphasic (Johnson, 1981) response signals. The present paper details the development of an electrical brain stimulation system as a peripheral device to the Apple II/FIRST system. In addition, data are presented that document the capabilities of the EBS system to concurrently stimulate up to eight animals while values along the dimension of each of four stimulation parameters are manipulated by a program written in FIRST. In our judgment, the EBS system has a number of advantages over currently available commercial stimulators, including cost, number of sites that can be independently stimulated, and availability of complete software control.     

Homelessness as psychological trauma. Broadening perspectives.

Most mental health literature on homelessness has focused on characteristics that may be risk factors for homelessness. The authors of this article argue that homelessness itself is a risk factor for emotional disorder and use the construct of psychological trauma--focusing on social disaffiliation and learned helplessness--to understand the potential effects of homelessness. Psychological trauma is likely among homeless individuals and families for three reasons. (a) The sudden or gradual loss of one's home can be a stressor of sufficient severity to produce symptoms of psychological trauma. (b) The conditions of shelter life may produce trauma symptoms. (c) Many homeless people--particularly women--become homeless after experiencing physical and sexual abuse and consequent psychological trauma. Research suggests that negative psychological responses to traumatic events can be prevented or mitigated by a supportive and empowering posttrauma environment. The implications of trauma theory for improving the psychosocial conditions of homeless people are discussed.     

Rater information acquisition processes: Tracing the effects of prior knowledge, performance level, search constraint, and memory demand

Research on performance ratings has tended to neglect factors affecting raters' acquisition of ratee performance information. The present research examined the dynamic effects of this rater information acquisition process. Study 1 examined the effects of prior ratee knowledge (familiarity) and ratee performance level on subsequent acquisition of ratee performance information under varying levels of constraint. After exposure to prior ratee information, raters acquired additional information concerning a set of ratees using a computer controlled information board procedure. The results indicated significant effects on the amount of search for prior knowledge, search constraint, and the interaction between prior knowledge and performance level. Study 2 extended the research by including a memory component (time delay) between the exposure to prior information and subsequent search. Results were congruent with Study 1. They indicated significant main effects on the amount of search for prior knowledge, ratee performance level, search constraint, and on the interaction between prior knowledge and performance level. In addition, the results indicated a significant interaction between memory demand and prior knowledge. Implications of these results, limitations, and extensions of this research approach are discussed.     

Microsecond resolution timing with Sun workstations

A high-resolution clock is often indispensable for the accurate measurement of millisecond or microsecond resolution intervals, and it is impossible to measure the probability distribution of short intervals without one. This paper describes a microsecond clock for Sun 3 and 4 workstations that we designed, built, and have made publicly available. It also explains how to measure intervals shorter than a computer’s clock resolution, and derives confidence intervals for such measurements.     

Real-time clocks for microcomputers in behavioral research

Real-time clock strategies are described for microcomputers in behavioral research. Software-oriented and hardware-oriented counters are described in both free-running and strobed modes. An example of a clock using the Intel 8253 is given, along with driving software in 8080 assembly code and hardware for the S-100 bus.     

Parental Visitation of the Institutionalized Retarded

An inverse relationship was found between the number of parental visits an institutionalized retarded child received and the distance of the parental home from the institution. When the natural parents were living together, the retarded child was shown to receive more visits than when the child's parents were separated or one parent was deceased. Single mothers were found to be living significantly closer to the facility than single fathers. Single fathers appeared to put more effort into visiting, since they visited just as often as the mothers, but had to travel further distances than the mothers to do so. Visitation frequency followed a curvilinear pattern, decreasing uniformly from 20–60 miles (from 0–20 miles visitation frequency is uniform), and then leveling off.