Violent behavior in adolescents and young adults: A person and environment model

We explore a model that examines how personal and environmental variables explain violent behavior by adolescents. Repeated interviews with youths from 1984–1992 from 10 cities across the United States provided the data. These interviews first occurred with 2,787 youths when they were adolescents (1984–85 and 1986–87) and the interviews were repeated on a subsample of 602 youths when they were young adults (1989–90 and 1991–92). Longitudinal multivariate analyses showed that almost a third of the variance in adolescent violent behaviors was predicted by a combination of personal variables (gender, substance misuse) and environmental variables (history of child abuse, stressful events, traumatic events, and city rates of unemployment). Further, almost a third of the variance in change in violent behaviors from year to year was predicted by prior violent behavior and a combination of personal variables (gender, suicidality, and substance misuse) and environmental variables (stressful events).     

On optimal smoothing and derivative estimation from noisy displacement data in biomechanics

Estimating derivatives from noisy displacement data is a notoriously ill-posed problem in signal processing and biomechanics. Following the work of Wood and Jennings (1978) and Hatze (1979, 1981), the present paper describes the use of optimally regularized, natural quintic splines for estimating smoothed positions, velocities, and accelerations from equidistantly sampled, noisy position measurements. It appears that the nature of the boundary conditions of the data is of some importance, since various algorithms used hitherto result in artefacts throughout the data if the true derivatives at the record ends differ significantly from zero. Natural quintic splines do not suffer from this disadvantage below the third derivative.The ill-posed character of movement analysis has some interesting implications for movement synthesis and optimization, similar to the indeterminacy of muscular co-contraction from merely external, biomechanical measurements.     

Beyond the relational principle of reinforcement

Behavior under baseline conditions in which the contingency is absent can shed some light on the individual's performance under a schedule, but is insufficient as a basis for prediction of performance. This insufficiency of the baseline data runs counter to a recent formalization of the relational principle of reinforcement (Donahoe, 1977). A more satisfactory predictive model must incorporate not only the baseline level of the instrumental response and that of the contingent response, but also the schedule requirements, the character of each response in relation to the other, and the behavior required in simply switching from each to the other.     

Parameters for vowel substitutions in Broca''s aphasia

Most phonological investigations of aphasic speech have focused on consonants. In this study, the vowel substitutions of five English-speaking Broca's aphasics were investigated with respect to several major explanatory hypotheses. An important possible motivating factor for aphasic substitutions, phonological environment, is an unlikely origin for these errors, since most substitutions occur along the paradigmatic axis. Another prominent hypothesis, markedness, also has no predictive power for the data of this sample. However, an analysis of the five Chomsky and Halle (1968, (The Sound Pattern of English), New York: Harper and Row) vowel features indicates that the two features for vowel height are selectively impaired: There is a strong tendency for lower vowels to replace higher targets. Moreover, the substitution sounds tend to be close to their target sounds along the height axis. Four possible hypotheses are advanced to account for this consistent lowering tendency.     

The use of a self-control package to enhance temporal generality of a parent training program

The purpose of the present study was to examine the effectiveness of a self-control package in enhancing temporal generality of a parent training program. Sixteen mothers and their clinic-referred noncompliant children were assigned to either a parent training alone group, or a parent training plus self-control group. All mother-child dyads were treated individually by teaching the mother to reward compliance and other prosocial behavior, and to use time-out for noncompliance. In addition, mothers who also received self-control training learned to self-monitor their use of their new parenting skills and to reinforce themselves for use of the skill during a 2 month follow-up period. Assessment consisted of four home observations by independent observers prior to treatment, after treatment, and at a 2 month follow-up. The data indicated that the children in the parent training plus self-control group were significantly more compliant and less deviant at the 2 month follow-up than the children in the parent training alone group. Parental behavior did not differ between the two groups at the follow-up.     

Development of comprehension of sentences with “because” or “if”

The comprehension of sentences with “because” or “if” was investigated in children aged 2;9–11;11. Imitation, comprehension (choosing one of two picture sequences to go with a sentence), recognition (judging sentences with connective or structure differences as heard before or not), and synonymy (judging equivalence of meaning in sentences with different connectives or structures) tasks were administered, along with logical ordering, reversibility, and classification tasks. Above-chance responding in the comprehension task occurred by age 8, and in recognition and synonymy by age 10. Cognitive performance predicted 28.4% of the variance in the linguistic scores and cognitive success was concurrent with or preceded linguistic success. Comprehension of “because” and “if” appears to develop gradually, and is related to the development of certain operative rules.     

Studies in social influence: V. Minority influence and conversion behavior in a perceptual task

The effects of influence attempts by a majority and by a minority were examined on both a manifest response level and a latent perceptual level. Female subjects were exposed to a series of blue slides that were consistently labeled as green by a female confederate. The confederate was presented as a member of either a majority or a minority. On each trial, subjects were required to indicate the color of the slide presented and the color of the afterimage perceived on a white screen following removal of the slide. It was predicted that (a) the subject's judgment of the chromatic afterimage would be modified when the influence agent represented a minority, and (b) this modification will be more pronounced when the source of influence is absent than when it is present. The results supported the prediction in both the main study and its replication.     

Visual processing of multielement arrays and selective backward masking

In the first of two selective masking experiments, 7-letter rows were followed at several ISIs by a mask or no-mask and a bar-marker partial report cue. The results suggest that the arrays were processed ends-first and then, in general, from both ends towards the middle. In the second experiment, bar-marker partial report cues were presented at the onset or offset of 6-letter/1-digit or 7-letter rows. The subjects could not anticipate the category of the to-be-reported item with the alphanumeric displays. With a delayed cue, selective masking was obtained with both mixed category and pure letter arrays, but with simultaneous cuing, masking was always distributed across all serial positions. The results suggest that the subjects: (a) abstracted some information about category from the mixed arrays during an initial parallel stage of processing, (b) selectively attended to mainly the cued item with simultaneous probes with homeogeneous and mixed category displays, and (c) employed an ends-first processing strategy with both types of arrays when the bar-marker partial report cue was delayed.     

Relationship between response to graded exposure and marital satisfaction in agoraphobics

Agoraphobics who were satisfied in their marriage responded well to graded exposure and maintained their improvement to 3-months follow-up. Satisfaction with self and partner remained unchanged in patient and spouse. Agoraphobics who were dissatisfied with their marriage improved initially with graded exposure but later lost most of their gains and reported no change in general neurotic symptoms. Marital dissatisfaction also remained unchanged. Patients' dissatisfaction with their spouses, measured before therapy, predicted outcome in the sample as a whole.