Temporal manipulation of stimulus patterns using the Apple II: Tachistoscopic and part presentation

A technique is described in which line-drawn pictures can be rapidly interlaced, allowing for sequential part presentation or tachistoscopic presentation on the Apple II. This is accomplished using a two-stage process in which the pictorial stimuli are converted into machine code data files and then used to create a rapidly changing display consisting of two or more line drawings. The latter stage could be accomplished in less than 2 msec but is limited by the frame time of the monitor (17–20 msec).     

A microcomputer-dependent statistics and design course

A one-semester course in statistics and research design is described. All computations are carried out by a Macintosh computer. No hand calculation is expected of the students, and little class time is spent on computational procedure. The course covers much more statistical content than is the norm for a one-semester course, and student understanding of the logic of the material and its application is enhanced.     

Variables which differentiate placement of adolescents into juvenile justice or mental health systems

Studies of the variables that determine whether an adolescent is placed in the mental health or juvenile justice system for treatment have led to conflicting conclusions based on impressionistic data. The primary hypothesis of this study--that demographic variables would and personality/psychopathology variables would not differentiate into which system a youth will be placed--was supported. Adolescents were studied at intake into both the juvenile justice system and the mental health system. Data were collected on demographics (structured interviews), personality/psychopathology (MMPI), social adjustment (CAAP), and academic achievement (PIAT). A discriminant function analysis identified eight statistically significant variables which differentiated the two groups. In order of decreasing importance they are: ethnicity, gender, MMPI-depression, previous mental health history, CAAP-productivity, drug use, parental marital history, and parental religious preference.     

Autism and Accuracy in Adolescent Perceptions of Friends' Sexual Attitudes and Behavior

This study uses data from adolescents matched with data from their friends to examine whether reference group effects on adolescent sexuality should be thought of as operating through the sharing of norms or the modeling of behavior. We observe that perception of attitudes has such a trivial reality component and such a strong autistic component that it cannot serve as a mechanism of peer influence. Perception of sexual behavior has a reality component which is as large as its autistic component, and large enough to serve as a route of influence. We reach two conclusions: (1) Reference group effects on adolescent sexual behavior probably work through behavior modeling rather than through normative influence. (2) Studies which infer peer influence on sexual behavior using only perception of peers will arrive at erroneous conclusions.     

Superimposition of response-independent reinforcement

Studies that have superimposed response-independent reinforcement (or reinforcers scheduled by contingencies placed on the absence of responding) upon conventional response-dependent schedules are reviewed. In general, providing alternative sources of reinforcement reduced response rates below the levels observed when alternative reinforcement was absent. However, response-rate elevation was sometimes found, particularly when rates of superimposed response-independent reinforcement were low. Superimposition of schedules providing reinforcers contingent on the absence of responding usually produced more severe response-rate decrements than superimposition of response-independent reinforcement. A variant of Herrnstein's equation, which assumes that some of the alternative reinforcers function as if they were delivered by baseline response-dependent source of reinforcement, is in qualitative agreement with the overall body of results obtained, and can predict both increases and decreases in response rate as resulting from superimposed reinforcers.     

Relationship between specific disfluency variables and dichotic listening in stutterers

86 stutterers' disfluency patterns were examined in relation to their laterality preferences. Results suggest that young stutterers are a heterogeneous group and that specific disfluency variables were not related to ear preferences on a dichotic consonant-vowel listening task.