Commitment to “Safer” Sex as a Predictor of Condom Use Among 16-20-Year-Olds1

The AIDS risk reduction model (ARRM) is explored in the context of a prospective study of adolescent condom use. This three-stage model characterizes the social and psychological facilitation of change in attitudes and sexual behaviors related to HIV transmission. The social and behavioral consequences of AIDS for 63 adolescents (aged 16-20 years), from an urban part of North West London, were mapped over a one-year period. Indices were created according to the proposed model which reflect (a) labelling of a high risk behavior as problematic (e.g., unprotected sexual intercourse) (b) commitment to change (e.g., desiring and valuing “safe” sex), and (c) seeking and enacting appropriate solutions (e.g., use of condoms). Nested regression analysis enabled the inter-relationship between significant social and psychological predictors (Time 1) and behavior (Time 2) to be traced. Overall the model accounted for 30% of the variance in condom use. Contemporaneous behavior was also modeled to identify baseline social and psychological predictors. Twenty-seven percent of the variance in condom use is explained. The social and psychological patterning of the indices is compared with that evidenced for prospective behavior. It appears that social representations which embody normative and value considerations underlie commitment to safer sex (at a general level) and override intentions (at a specific level) in the explanation of prospective behavior. The methodological and theoretical implications of this are identified and discussed.     

Matrix analysis of identifiability of some finite markov models

Methods developed by Bernbach [1966] and Millward [1969] permit increased generality in analyses of identifiability. Matrix equations are presented that solve part of the identifiability problem for a class of Markov models. Results of several earlier analyses are shown to involve special cases of the equations developed here. And it is shown that a general four-state chain has the same parameter space as an all-or-none model if and only if its representation with an observable absorbing state is lumpable into a Markov chain with three states.This research was supported by the U.S. Public Health Service under Grant MH-12717 to Indiana University and Grant GM-1231 to the University of Michigan.Now at the University of Texas, Austin.     

Teaching a computer to teach

The long-range goal of computer-assisted instruction (CAI) should be to construct computer programs that interact with a student as a human tutor does. In order to make computers act as intelligent tutors, we must consider three aspects of teaching; (1) A tutor makes use of many different knowledge sources. (2) A tutorial session is a kind of problem-solving situation in which the tutor is trying to solve the problem of imparting understanding to the student. (3) There is an analogy between the process of communication and those of teaching in that both require the participants to make a number of inferences about each other’s states and responses. A tutor designs an “instructional act,” anticipating how the student will interpret and learn from it, and the student interprets and learns from the instruction in a manner that depends on his hypotheses about the intent of the tutor. The paper reviews the relevant literature and discusses how we will incorporate such ideas into CAI systems.     

An analysis of generative representation systems

Three ideas are basic to generative theory: (a) Subjects are assumed to attend to the relations among stimuli, extracting the transformations relating pairs of stimuli; (b) the set of abstracted transformations is decomposed or reduced to an elementary set of generators; (c) subjects use the elementary generators as the basis for judging similarity. The purpose of this paper is to illustrate these ideas with an experiment in which subjects were asked to rate the similarity between stimulus pairs. The stimulus materials consisted of the permutations of a 4-item pattern with the properties of a dihedral group which insured the existence of sets of elementary transformations. Three analytic techniques were used to determine the generator set of transformations abstracted by subjects. The first analysis consisted of a monotonic regression between dissimilarity ratings and the number of elementary generators of a given permutation. The residual variance of this monotone regression, suitably normalized, was used as a quantitative goodness-of-fit measure. For the stochastic analysis, cumulative distributions of dissimilarity ratings were obtained for permutations requiring one, two, or three generators. The idea was that permutations requiring fewer generators should be associated with distributions of lower dissimilarity values (higher similarity scores) as compared to permutations predicted to be transformationally more complex. The final analysis, a multidimensional scaling of dissimilarity ratings, converted subjects' ratings into spatial structures to determine whether individual subjects' ratings exhibited the predicted spatial arrangement. The monotone regression and stochastic analyses abstracted similar generator sets for individual subjects, some of which provided perfect fits to the data. Although the scaling analysis yielded similar estimates of generators, for some subjects, transformations with the same number of generators yielded unequal “cognitive” distances resulting in some-what deformed spatial structures for these subjects. It was concluded that the results generally supported a generative model as an approximation to subjects' representations of interstimulus relationships.     

Psychological Contracts, Organizational and Job Commitment

Increased use of time-limited contracts as the mainstay of employer-employee relations has implications for the psychological character of the exchange relationship. To investigate this, the current study is framed by Rousseau's (1995) psychological contract model (PCM). The psychological contract pertains to beliefs held by individuals about their contractual terms and conditions. The findings yield evidence for Rousseau's distinction between two types of contractual belief (relational and transactional), as well as the explanatory potential of the PCM over and above the concept of organizational commitment. As predicted. temporary workers were more transactional than relational in their contractual orientation. The findings are discussed with reference to a need to develop a theoretical basis for research on organizational involvement.     

The direct measurement of hypothesis-sampling strategies

The concept-identification (CI) literature supports a hypothesis-sampling theory. Hypotheses based on attributes, sample sizes greater than one, and nonreplacement of eliminated hypotheses all occur. An experimental procedure was developed to measure hypothesis-sampling directly where the subject is allowed to select attributes that he wishes to see, then randomly selected values on the selected attributes are presented.Generally, the average sample size before the trial of the last error (TLE) does not change but does change after TLE. The probabilities of eliminating inconsistent hypotheses and keeping consistent hypotheses increase over problems. The proportion of eliminated attributes which are resampled decreases over problems. Individual subjects are extremely varied in sample size, efficiency measures, and resampling tendencies. The rate of solution, TLE, is related to the efficiency and resampling measures but not to the sample size.