SKED-controlled experimentation in an undergraduate instructional laboratory

A SKED-based facility for undergraduate instructional research has been operating for over a year. The two-computer approach, with one machine for programming and the other for running experiments, is used. Criteria for computerized undergraduate research laboratories, benefits of SKED, and the two-computer approach are discussed.     

A low-cost interactive coordinate plotter

An inexpensive system for on-line coordinate plotting is described. Users with access to a computer running ALGOL or FORTRAN, and equipped with analog-to-digital converters, can build the system for less than $50. The program is readily modified for the individual user’s requirements, and interactive features allow data correction and analysis to be carried out during coordinate plotting, with operators warned of plotting errors as they occur.     

An economical dispenser to improve control of food reinforcement in the rat

A hopper dispenser designed for the study of food reinforcement in rats is described. By using ordinary rat chow, it significantly reduces the cost of reinforcing rats with food. By preventing stockpiling, it also guarantees control of the accessibility, as well as the presentation of food.     

The effect of aversive consequences upon persistent behavior

It was hypothesized that if a behavior is freely engaged in with the expectancy that an aversive consequence will follow, the intrinsic motivation to perform that behavior will increase when the aversive consequence is no longer present. Subjects either worked on a list of anagrams while receiving electric shock on a VR schedule, while being threatened by electric shock, or in the absence of shock. The experimenter then left the subject alone for 10 minutes with a new list of anagrams. Subjects in the shock condition solved more anagrams on the posttest than subjects in the threat-of-shock and noshock conditions. Subjects in both the shock condition and the threat-of-shock condition reported that they spent more of their free time on the anagrams than subjects in the no-shock condition.     

Vowel recognition: Inferences from studies of forward and backward masking

The recognition of brief vowels was studied in forward and backward masking tasks. In a series of experiments in which both target and mask parameters were systematically varied, two populations of subjects were identified. The majority (Nonmaskers) evidenced little masking at any interstimulus interval, while relatively fewer subjects (Maskers) evidenced backward masking (but not forward masking) over a 100-200 ms interval. Increasing target set size systematically increased masking for the Maskers but not for the Nonmaskers. Adding white noise to the targets increased the extent of masking for both groups. These results suggest (1) that masking does not impose a substantive constraint on vowel perception in running speech, and (2) that multiple strategies may exist for vowel recognition.     

Response coding in recall of colours by monkeys

Two monkeys learned a recall task with colours as the samples and spatial discriminanda at the retention test. The relationship between the sample colours and the retention test discriminanda was such that it was possible to distinguish between errors that were related to the visual similarity of the sample colours and those that were related to the similarity of the recall responses. When errors were induced by lengthening the delay between sample and retention test, they were related to the similarity of the recall responses. But in a comparable recognition memory task with colours, performance was related to the visual similarity of the colours. These results imply that the monkeys recognised the colours directly from a visual trace but recalled them indirectly from a response-coded trace.     

Grade Expectations as a Function of Sex, Academic Discipline, and Sex of Instructor

Twelve hundred and fifty college students starting introductory courses in thirteen academic disciplines were asked to predict their grade in the course. Results showed that overall, males predicted higher grades for themselves than did females (p <.001). This held true for entering freshmen as well as for those with previous college experience. The phenomena was noted in 26 of 37 classes tested, including 7 of 9 in the natural sciences, 11 of 13 in the social sciences, but only 8 of 15 in the humanities. Sex of the instructor was irrelevant, raising the question of whether female instructors as role models have the positive effect upon women students that has been claimed. The differences found were slight, but persistent. Both sexes predicted very high grades. The data suggest that sex differences in prediction were not based on a female sense of incompetence, but upon a greater willingness among males to make highly positive predictions.     

The effect of alcoholic intoxication upon calorically induced oculogyral illusion

Ten male and 10 female subjects, half of whom were classified as “heavy” and half as “light” drinkers, ingested a 4-1 combination of tonic water and 80-proof vodka in an amount calculated to produce a state of moderate intoxication (average estimated peak blood alcohol level=.075). This resulted in an increased sensitivity (latency, magnitude, and duration) to the calorically induced “oculogyral illusion” (OGI) relative to a placebo (tonic water) condition. “Heavy” and “light” drinkers did not differ significantly on any of the measures. It was speculated that the alcoholic enhancement of the OGI was due either to a decreased ability to suppress vestibular nystagmus when attempting to fixate a visual stimulus or to the expenditure of extra-normal effort in order to maintain fixation.