Single-subject statistical analysis of computer-assisted biofeedback

Single-subject statistics were used to analyze physiological data [electromyographic (EMG) temperature] recorded from two patients receiving computer-assisted biofeedback treatment in a clinic. When the data were analyzed by an ANOVA method or a regression technique, the results demonstrated that both patients learned to significantly reduce EMG levels. The rationale of using single-subject statistics is discussed, and the applicability of the statistical technique to the clinic population is illustrated.     

Determination of a behavioral transfer function: White-noise analysis of session-to-session response-ratio dynamics on concurrent VI VI schedules

Six pigeons were exposed to concurrent variable-interval schedules in which the programmed reinforcer ratios changed from session to session according to a pseudorandom binary sequence. This procedure corresponded to the stochastic identification paradigm (“white-noise experiment”) of systems theory and enabled the relation between log response ratios in the current session and log reinforcer ratios in all previous sessions to be determined. Such dynamic relations are called linear transfer functions. Both nonparametric and parametric representations of these, in the form of “impulse-response functions,” were determined for each bird. The session-to-session response ratios resulting from the session-to-session pseudorandom binary variations in reinforcer ratios were well predicted by the impulse-response functions identified for each pigeon. The impulse-response functions were well fitted by a second-order dynamic model involving only two parameters: a time constant and a gain. The mean time constant was 0.67 sessions, implying that the effects of abrupt changes in log reinforcer ratios should be 96% complete within about five sessions. The mean gain was 0.53, which was surprisingly low inasmuch as it should equal the sensitivity to reinforcement ratio observed under steady-state conditions. The same six pigeons were subjected to a similar experiment 10 months following the first. Despite individual differences in impulse-response functions between birds within each experiment, the impulse-response functions determined from the two experiments were essentially the same.     

Aggression in toddlers: Responses to the assertive acts of boys and girls

Sex Roles - Forty-eight toddler boys and girls, 18 to 36 months of age, were observed in play groups. The assertive acts of each child and the responses of peers and teachers were recorded. The...     

Appetitive differential conditioning of the rabbit’s jaw movement response

Two experiments examined appetitive differential conditioning of the rabbit’s jaw movement response (JMR) in a two-phase procedure. The first phase entailed reinforced training with one conditioned stimulus (CS+), and the second phase involved intermixed presentations of CS+ and an unreinforced stimulus (CS?). In Experiment 1, CS+ was a 600-Hz tone, and CS-was either a 660-,1,000-, or 2,100-Hz tone. In Experiment 2, the magnitude of the water unconditioned stimulus (US) paired with CS+ was either 1, 3, or 9 ml. The experiments revealed that 1) the level of responding to CS-rose for several days and then declined over the remainder of training; 2) the physical similarity between CS+ and CS?directly affected the level of responding to CS?but had no discernable effect on the level of responding to CS+ ; and 3) US magnitude positively affected the level of responding to CS + and, to a lesser extent, CS?. The results are discussed in terms of their implications for Spence’s gradient interaction theory and Pavlov’s external inhibition hypothesis.     

Accommodation to increased accuracy demands by the right and left hands

This study was designed to identify the phase of rapid aimed movements responsible for hand differences in motor skill, and to evaluate potential differences between the hands in accommodating to greater accuracy demands. In both experiments, an accelerometer mounted on a stylus allowed key changes in acceleration to be used to partition the movement into phases. In Experiment 1, slower left hand movement times were attributable primarily to a terminal homing-in phase, especially as target size decreased. Since error rates varied as a function of hand and target size, speed-accuracy trade-offs may have occurred. Experiment 2 rigidly controlled error rate and confirmed the major hand difference to occur in the latter phase of the movement where error correction is presumed. Although less pronounced, adjustments were made in the earlier movement phases as well. Accommodation to greater accuracy demands involved moving the stylus closer to the target before decelerating to engage in error correction. This adjustment to gain enhanced precision was more pronounced in the left hand.     

Perception of social distributions

Accurate representation of the distribution of social attitudes and behaviors can guide effective social behavior and is often essential for correct inferences. We examined the accuracy of people's beliefs about the distributions of a large number of attitudinal and behavioral dimensions. In two studies we measured actual attitudes and behaviors in a student population, and we assessed beliefs by asking subjects to estimate the distribution of 100 students on these dimensions. We examined the accuracy of subjects' perceptions of the means, standard deviations, and distribution shapes. Subjects showed a number of systematic biases, including overestimation of dispersion and overestimation of the means of behavioral distributions and a false consensus bias, but their overall accuracy was impressive.