Noncontingent reinforcement, alternative reinforcement, and the matching law: a laboratory demonstration

Basic researchers, but not most applied researchers, have assumed that the behavior-decelerating effects of noncontingent reinforcement result at least partly from adventitious reinforcement of competing behaviors. The literature contains only sketchy evidence of these effects because few noncontingent reinforcement studies measure alternative behaviors. A laboratory model is presented in which concurrent schedules of contingent reinforcement were used to establish a "target" and an "alternative" behavior. Imposing noncontingent reinforcement decreased target behavior rates and increased alternative behavior rates, outcomes that were well described by the standard quantitative account of alternative reinforcement, the generalized matching law. These results suggest that adventitious reinforcement of alternative behaviors can occur during noncontingent reinforcement interventions, although the range of conditions under which this occurs remains to be determined in future studies. As an adjunct to applied studies, laboratory models permit easy measurement of alternative behaviors and parametric manipulations needed to answer many research questions.     

Immediate spatial distortions of pointing movements induced by visual landmarks

We tested the influence of two horizontally aligned visual landmarks on pointing movements to memorized targets, to investigate whether the visuomotor system can make use of an egocentric representation unaffected by visual context. The endpoints of pointing movements were systematically distorted toward the nearest visual landmark, indicating that spatial representations included both target and nontarget information. These distortions were not due to the presence of the landmarks during the movement but, rather, to their presence in the encoding phase. Qualitatively similar distortions were present even with the shortest possible retention phase, when the target was extinguished at movement onset. Finally, we found the same pattern of distortion when participants were forced to remember the target within an allocentric frame of reference. We argue that even early memory representations for pointing movements are influenced by visual information in the surrounding visual field.     

Negative and positive congruence effects in letters and shapes

In six experiments in which a binary classification task was used, letter and nonletter (geometrical shapes, pseudoletters, or rotated letters) targets were presented either in isolation or surrounded by a geometrical shape. The surrounding shape could be congruent or incongruent with the target. When the classification required a distinction between letters and nonletters, either explicitly (Experiments 1-3) or implicitly (Experiment 4), a negative congruence effect was obtained for letters, contrasting with a regular, positive congruence effect for nonletters. When no distinction was to be made, letters and nonletters invariably showed a positive congruence effect (Experiments 5 and 6). In particular, between Experiments 1-4 and Experiments 5 and 6, the occurrence of negative or positive congruence effects for the same stimuli depended on the task. Feature interaction, target selection, and response competition explanations were tested against a feature integration approach. The results are explained in terms of different feature integration strategies for letters and nonletters.     

Reading units that include interword spaces: Filling spaces around a letter can facilitate letter detection

College students searched for the letter "a" in prose passages typed normally, with an asterisk (Experiments 1 and 2) or the letter "x" (Experiment 3) replacing every interword space, or with asterisks replacing only some of the interword spaces (Experiment 2). Contrary to predictions based on masking through lateral interference but consistent with predictions based on studies of eye movement monitoring and unitization, asterisks or instances of the letter "x" surrounding the word "a" actually made the letter "a" easier to detect in that word, but generally not in other words in the text. It is concluded that for very common words, reading units may extend beyond the word boundary to include the surrounding interword spaces.     

A comparative analysis of North American adolescent and adult mass murderers

Thirty adult mass murderers and 34 adolescent mass murderers in North America are compared on both offender and offense variables to delineate similarities and differences. Findings indicate a plethora of psychiatric disturbances and odd/reclusive and acting-out personality traits. Predisposing factors include a fascination with weapons and war among many of the adolescents and the development of a "warrior mentality" in most of the adults. Precipitating factors indicate a major rejection or loss in the hours or days preceding the mass murder. Results are interpreted through the lens of threat assessment for targeted violence (Borum, Fein, Vossekuil, & Bergland 1999), recognizing that a fact-based, dynamic behavioral approach is most useful for mitigating risk of such an extremely low-base-rate violent crime.     

The formation of the therapeutic alliance in couple therapy

This study examines the predictive validity of several clinical variables--including marital distress, individual symptomatology, and family-of-origin experiences--on the formation of the alliance in couple therapy. Eighty people who were treated with a naturalistic course of integrative conjoint psychotherapy at a large midwestern outpatient clinic were assessed on the clinical variables before session 1. They also completed ratings of the therapeutic alliance after sessions 1 and 8. Individual symptomatology did not predict alliance formation at either treatment stage. Higher levels of marital distress predicted poorer alliances to treatment between partners at session 1. Marital distress also predicted therapeutic alliance quality for men and women at session 8. Family-of-origin distress predicted alliance quality for men at session 1, and for women at session 8. Family-of-origin distress for men and women predicted split alliances early in treatment, and marital distress predicted split alliances for women at session 8. Clinical implications for the assessment and treatment of couples are discussed.     

Are there biological programming effects for psychological development? Findings from a study of Romanian adoptees

Associations between experiences and outcomes could be due to (a) continuation of adversity or (b) organismic changes, including experience-expectant and experience-adaptive developmental programming. The adoption into British families of children who had been reared in profoundly depriving institutions in Romania presented an opportunity to test mechanisms. Romanian children reared from infancy in very depriving institutions for periods up to 42 months were compared with 52 nondeprived UK-born children placed into adoptive families before the age of 6 months. The results at 6 years of age showed substantial normal cognitive and social functioning after the provision of family rearing but also major persistent deficits in a substantial minority. The pattern of findings suggests some form of early biological programming or neural damage stemming from institutional deprivation, but the heterogeneity in outcome indicates that the effects are not deterministic.     

Identifying shared environmental contributions to early substance use: the respective roles of peers and parents

Although behavior genetic studies have suggested that early substance use is primarily environmentally mediated, no study has sought to identify the specific sources of environmental variance. Using data obtained from multiple informants, this study assessed the contributions of peer deviance and parent-child relationship problems to substance use in 14-year-old male and female twins (N = 1,403) drawn from the Minnesota Twin Family Study (MTFS). All three phenotypes were influenced primarily by shared environmental variance (average c(2) =.51), as was the overlap among them. Moreover, peer deviance and parent-child relationship problems accounted for approximately 77% of the variance in early substance use. Findings also indicated that peer deviance, but not parent-child relationship problems, accounted uniquely for variance in early substance use.