A comparison of five methods of illusion measurement

The relative efficiency of five techniques of illusion measurement were tested on parametric variations of the Mueller-Lyer and Ebbinghaus figures. The methods of average error, reproduction, and selection from a graded series all showed significant effects of configurational variations. The subjective scaling techniques each failed to measure adequately changes in illusion magnitude for one illusion configuration. The suitability of the tested measures for group administration is also discussed.     

Polydipsia induced in the rat by a second-order schedule

Drinking was studied in rats pressing a bar on a second-order schedule in which every third completion of a 1-min fixed interval was followed by food presentation. A brief flash of light signaled the completion of each fixed-interval component. The rats drank not only after the food presentations but also after presentations of the light flash alone. A high rate of steady drinking followed intervals terminated by a food presentation. Drinking that followed intervals terminated by a light flash alone was of comparable rate, but characteristically interrupted by bar pressing. When 250-mg food pellets were used instead of 45-mg pellets, both drinking and bar-pressing rates increased substantially.     

The effect of two schedules of primary and conditioned reinforcement

Of 23 pigeons, 11 received continuous reinforcement for key pecking, and 12 received an FR 10 schedule of reinforcement. The birds were then tested without food, but with potential conditioned reinforcers presented either on the same schedule as in training, on the other schedule, or not at all. Each bird in the subgroup trained on CRF and tested with S^r's at FR 10 not only gave more responses in testing than did each bird in both subgroups receiving no S^r's, but also gave more responses than did each bird in the S^r subgroup receiving CRF training and S^r's at CRF. Cumulative records are presented to show the effects of different schedules of conditioned reinforcers.     

Kinaesthetic judgements of the direction of line by young children

The ability of young children to make kinaesthetic judgements of direction of line has been studied under recognition and detection conditions. Some children were not more accurate than chance when they were required to indicate the same one of a pair of mirror image obliques lines over a series of trials; these children could, however, detect whether two obliques were oriented in the same direction or in different directions. These latter data suggest that the poor recognition of mirror image obliques arises from deficiencies in spatial categorizing and not in input coding. This conclusion is supported by the finding that children who performed poorly on the kinaesthetic recognition of obliques performed poorly on the visual recognition of these figures.     

Escape behavior under continuous reinforcement as a function of aversive light intensity

In 11 male albino rats, lever-pressing responses, maintained under a CRF escape schedule with light as the aversive stimulus, were examined at each of five intensities, viz., 2.5, 18, 105, 190, and 386 ft-C. The function relating reciprocal of latency of the escape response to aversive light intensity passed through a maximum.     

Book reviews

The Word Speaks to the Faustian Man. Som Raj Gupta. Delhi, Motilal Banarsidass. 455+xvi pp., Rs. 500

A History of Indian Buddhism, From Sākyamuni to Early Mahāyāna. Hirakawa Akira, translated and edited by Paul Groner, 1990. Asian Studies at Hawaii, No. 36. Honolulu, HI, University of Hawaii Press. xix +402, £33.25

The Doctrine of the Upanisads and the Early Buddhism. Hermann Oldenberg, translated by Shridhar B. Shrotri, 1991. Delhi, Motilal Banarsidass. Rs. 225

Evil and the Mystics’ God: Towards a Mystical Theodicy. Michael Stoeber. London, Macmillan. x+225 pp., £40     

Experimental Construct Validity of the Outcomes of Study Skills Training and Career Counseling as Treatments for the Retention of At-Risk Students

The authors evaluated the separate and combined effects of study skills training and career counseling on student retention. Participants who were at high risk for dropping out of college were randomly assigned to one of four treatment or control conditions. The study-skills-alone treatment had a significant impact on retention; all of these participants continued their enrollment in the following two semesters. Career-counseling-alone and a combined (study skills plus career counseling) treatment did not register significant effects. Participants who received the study-skills-alone treatment also achieved significantly greater academic success; 88% had grade point averages (GPAs) equal to or greater than 2.0, whereas most other treatment and control participants had GPAs lower than 2.0 and were placed on academic probation. Issues relevant to the construct validity of these changes are discussed.