Relative allocation on concurrent schedules can depend on schedule parameters when behavioral parameters are constant

We develop a simple model of switching between the initial links of a concurrent-chain procedure. Behavior is determined by four parameters μ₁, μ₂, q₁, and q₂. The first two are the basic rates of switching from Schedule 1 and Schedule 2, respectively. The second two are the probabilities of leaving Schedule 1 and Schedule 2 after the corresponding terminal link has been completed. We show that for fixed values of these four parameters, the relative allocation on the initial links may change as a result of changes in initial-link schedules. The effect can be quite large if the switching rates are low. An implication is that relative allocation is not necessarily a good measure of behavior.     

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).     

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.     

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.     

Adjustment to rape

This questionnaire study of rape victims' reactions, causal attributions for the rape, coping behaviors after the rape, and psychological adjustment to the rape were examined. As in previous research, high levels of behavioral and characterological self-blame for rape were found. Contrary to prior hypotheses, behavioral self-blame was not associated with good adjustment. Rather, both behavioral and characterological self-blame were associated with poor adjustment. Societal blame was the only causal attribution for rape that was unassociated with adjustment. Remaining at home and withdrawing from others were both associated with poor adjustment, and the use of stress reduction techniques was associated with good adjustment. The implications of the results for theories of victimization and for clinical interventions with rape victims are discussed.     

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.     

Real and virtual features in texture perception

The texton theory of preattentive texture perception was recently adopted over a prior model based on the global computation of dipole statistics. It is shown here that the dipole model remains a necessary adjunct unless the texton theory is modified to distinguish real from virtual features of texture perception.