Tower of Hanoi performance of retarded young adults and nonretarded children as a function of solution length and goal state

Three experiments were conducted with the Tower of Hanoi task to assess problem solving ability in 6-, 7-, 8-, and 10-year-old nonretarded children and mentally retarded young adults of varying maturational ages. In Experiment 1 we gradually reduced the number of moves required for solution until subjects could solve the 3-disk tower-ending problem. Although all groups experienced difficulty with the standard 7-move problem, all but the trainable retarded group readily solved the 6-move problem. The trainable group did not reach a comparable level of success until the 4-move problem. On the 7-move problem the retarded groups performed at the level of nonretarded groups that were maturationally $\text{1}\text{1}\text{2}$ to 3 years younger. An analysis of first moves indicated that subject groups differed in the strategies they used to solve the problems. In Experiment 2, practice effects were ruled out as a source of the superior performance on the 6- than on the 7-move problem. In Experiment 3, 7- and 10-year-old nonretarded children and mentally retarded young adults did not differ on 5-move problems in which configuration of the goal states was varied. A comparison of all 5-move problems judged to have the same depth of search requirements indicated that the tower-ending problems were significantly easier to solve than the partial-tower-ending problems, which in turn were easier than the flat-ending problems. A limited depth of search capacity sets boundaries on the use of sophisticated strategies and, to a large extent, accounts for the retarded groups' maturational lag.     

Maximum likelihood estimation for Luce's choice model

A terminology for general choice models based on the choice axiom is given. It applies to all kinds of choice experiments, such as confusion choice experiments, paired comparisons, triadic comparisons, directional rankings, scores on binary test items, and others. Maximum likelihood estimation for such general choice models is considered. Conditions for the uniqueness of maximum likelihood estimates are given, and it is shown that the estimates can be derived by iterative proportional fitting. This offers the opportunity of a general test of the choice axiom for all kinds of choice experiments using the likelihood ratio. The estimation and testing procedure is applied to data from a form recognition experiment, reported by W. A. Wagenaar (Nederlands Tijdschrift voor de Psychologie, 1968, 23, 96–108).     

The salience of the self in responses to inequity

Previous research has shown that people strive to conform with the standards of significant others in distributive justice. The present research was concerned with the role of attention to the self in the same paradigm. If people are motivated to personally evaluate their own behavior as fair, then self-focus should result in heightened attempts to redress an overpayment inequity. After the subject's criterion of a fair wage was assessed, they were paid either that amount or double it. Orthogonal to this manipulation, subjects were either made objectively self-aware (OSA) or not, by the presence or absence of a mirror. Consistent with the hypothesis, overpaid OSA subjects did more work, but of a poorer quality, than overpaid not-OSA subjects. This was taken as evidence of more zealous attempts to restore a sense of equity, implicating a greater personal need to eliminate the injustice when the discrepancy between pay level and a personal standard of fairness was made more prominent to the self.     

Counting eliminates the repetition effect in judgments of temporal duration.

College student subjects estimated the duration of time intervals (8–54 sec) by counting or not (N=35 per group). Counting eliminated the repetition effect (a decline in the magnitude of estimations across trials), and resulted in a truncation of the psychophysical function. The former result was interpreted as contrary to Treisman's (1963) model. The latter result was attributed to the effortfulness of counting, which was established in a subsequent experiment.     

Vocational maturity in adulthood: Toward turning a model into a measure

It is postulated that adult vocational maturity needs to be assessed because of the changing developmental tasks encountered during the course of a career. Vocational maturity having been found to be multidimensional, existing undimensional inventories of adult vocational maturity are considered of limited although demonstrated validity. Relevant theories of adult vocational development and adjustment are reviewed. Super's proposed adult vocational maturity model is examined for the promise that it offers and for the problems that arise in developing a multidimensional measure of vocational maturity. A way of surmounting these problems is proposed as a basis for work now being undertaken.     

Habit reversal treatment: Learning an incompatible response or increasing the subject's awareness?

The elements of the Habit Reversal Treatment Package developed by Azrin and Nunn (1973) to counteract nervous habits were systematically analysed. Fifty nail biters (92% reported biting their nails for more than 5 yr) were randomly assigned to one of the following treatments: Habit Reversal, Habit Reversal and Self-Monitoring, Self-Monitoring, Self-Monitoring and Daily Graph Plotting, Waiting List control, Pictures of both hands were taken prior to the commencement of treatment and at 6 and 12 weeks after treatment termination. The results showed that the four treatment groups improved equally compared with the control subjects. Such data cast doubt on the importance of learning an incompatible response in Habit Reversal Treatment. An alternative explanation based on increasing the subject's awareness is put forward.     

Obsessional slowness: a meticulous replication.

The treatment of an apparently authentic case of obsessional slowness is described. The relationship between behaviour change and emotional events is discussed. The findings replicate those of Rachman (1974).