Concurrent validity of the Wheeler signs of homosexuality in the Rorschach: P (Ci/Rj).

The Rorschach protocols of 43 males consecutively admitted to a university outpatient clinic were scored for frequency of the 20 Wheeler signs of homosexuality. Based on case history data, patients were assigned to homosexual, sex-role disturbed, or normal-control groups. In addition to the traditional group comparison the results were analyzed to yield P (Ci/Rj); that is, the probability of criterion group membership given test indicator. Both the homosexual and sex-role disturbed group displayed significantly more Wheeler signs than normals. Furthermore, given a Wheeler sign score of 15%, .75 of the predicted-homosexual group would be correctly classified compared to a .21 baserate prediction. It was suggested that expressing results as P (Ci/Rj) provides information more relevant to the clinician than is provided by the traditional practice of reporting significant differences between groups.     

Responding under discrete-trial fixed-interval schedules of reinforcement

A fixed-interval schedule of reinforcement was modified by dividing each interval into 4-sec trial periods. No more than one response could occur during each trial because the operandum was inactivated for the remainder of any trial in which a response occurred. For example, under a 28-sec schedule, no more than seven responses could be emitted between reinforcements. Probabilities of responding by pigeons under six values of this discrete-trial fixed-interval schedule were best described by a two-state model: responding was either absent or infrequent immediately after reinforcement; then, at some variable time after reinforcement, there was an abrupt transition to a high and constant probability of responding on each trial. Performances under the discrete-trial procedure were less affected by uncontrolled sources of variance than performances under equivalent free-operant fixed-interval schedules.     

Sex differences in investigatory and grooming behaviors of laboratory rats (Rattus norvegicus) following exposure to novelty

Prior research suggested that during exposure to novel stimuli, rodent investigation and self-grooming behaviors may be sexually dimorphic and interact with ambient illumination. To test this notion we compared the behavior of adult male and female groups of Long-Evans hooded rats in normal room lighting (860 lx) and in very dim, red light (0.2 lx) following exposure to a novel juvenile conspecific. Illuminance level had little or no effect, but investigatory and subsequent self-grooming behaviors of males were substantially greater than those of females, and females engaged in greater ambulatory activity than did males. In a second experiment adult males and females were exposed to a novel inanimate object. No reliable sex differences were observed. We conclude that social novelty, as provided by exposure to a juvenile conspecific, stimulates greater investigation and postinvestigatory self-grooming than exposure to a novel inanimate object and that exposure to novel conspecifics presents a useful method for the investigation of sex differences, gonadal hormone effects, and interactions of hormones with neurotransmitter systems governing motor control systems.     

Micro Experimental Laboratory: An integrated system for IBM PC compatibles

Micro Experimental Laboratory (MEL) is a third-generation integrated software system for experimental research. The researcher fills in forms, and MEL writes the experimental program, runs the experiments, and analyzes the data. MEL includes a form-based user interface, automatic programming, computer tutorials, a compiler, a real-time data acquisition system, database management, statistical analysis, and subject scheduling. It can perform most reaction time, questionnaire, and text comprehension experiments with little or no programming. It includes a Pascal-like programming language and can call routines written in standard languages. MEL operates on IBM PC compatible computers and supports most display controllers. MEL maintains millisecond timing with high-speed text and graphics presentation. MEL provides a systematic approach to dealing with nine concerns in running an experimental laboratory.     

RWMODEL: A program in Turbo Pascal for simulating predictions based on the Rescorla-Wagner model of classical conditioning

A Turbo Pascal computer program is described that simulates the Rescorla-Wagner model of classical conditioning. The menu-driven program makes it possible to compute associative strengths for differential conditioning, conditioned inhibition, compound and contextual conditionings, trans-switching, and other designs.     

The masking of octave-band noise by broad-spectrum noise: A comparison of infant and adult thresholds

Localization responses to a 4,000-Hz octave-band noise in a background of broad-spectrum noise were obtained from infants, 6, 12, 18, and 24 months of age, and adults. A two-alternative, forced-choice procedure was used to determine thresholds at each of two levels of masking noise, 42 and 60 dBC. Adults were also tested for their localization of pure tones in noise and their detection of octave-band noises with the more traditional two-interval, forced-choice task. Increasing the masking noise from 42 to 60 dBC resulted in comparable threshold shifts for all age groups. However, infant thresholds were 16–25 dB higher than those obtained for adults. The theoretical implications of these findings are discussed.     

Low-cost microcomputer networking: How to get high throughput on a low budget

A very low-cost, high-throughput laboratory data acquisition and experiment control system may be configured by using a star network architecture with a low-cost microcomputer as network controller and one or more microprocessor-based single-board controllers as satellites. A network of this type, using Apple II microcomputer ($1,500 with 48K RAM and one minidiskette drive) as main node and up to seven KIM-1 microcontrollers ($159 each) as satellites is described, and its development is discussed in detail.