The effects of temporal-precision and time-minimization constraints on the spatial and temporal accuracy of aimed hand movements

Discrete aimed hand movements, made by subjects given temporal-accuracy and time-minimization task instructions, were compared. Movements in the temporal-accuracy task were made to a point target with a goal movement time of 400 ms. A circular target then was manufactured that incorporated the measured spatial errors from the temporal-accuracy task, and subjects attempted to contact the target with a minimum movement time and without missing the circular target (time-minimization task instructions). This procedure resulted in equal movement amplitude and approximately equal spatial accuracy for the two task instructions. Movements under the time-minimization instructions were completed rapidly (M = 307 ms) without target misses, and tended to be made up of two submovements. In contrast, movements under temporal-accuracy instructions were made more slowly (M = 397 ms), matching the goal movement time, and were typically characterized by a single submovement. These data support the hypothesis that movement times, at a fixed movement amplitude versus target width ratio, decrease as the number of submovements increases, and that movements produced under temporal-accuracy and time-minimization have different control characteristics. These control differences are related to the linear and logarithmic speed-accuracy relations observed for temporal-accuracy and time-minimization tasks, respectively.     

Sensorimotor synchronization: Motor responses to pseudoregular auditory patterns

Musically trained and untrained subjects (N=30) were asked to synchronize their finger tapping with stimuli in auditory patterns. Each pattern comprised six successive tonal stimuli of the same duration, the first of which was accented by a different frequency. The duration of interstimulus onset intervals (ISIs) gradually increased or decreased in constant steps toward the end of the patterns. Four values of such steps were used in different trials: 20, 30, 45, and 60 msec. Various time-control mechanisms are hypothesized as being simultaneously responsible for subjects’ incorrect reproduction of the internal temporal ratios of the stimulus patterns. The mechanism of assimilation (of a central tendency) led subjects to enforce a regular (isochronous) structure on the patterns. The influence of other time-control mechanisms (distinction, subjective expression of an accent, sequential transfer) was expressed mainly in differences between intertap onset intervals (ITIs) and the corresponding ISIs at the beginning of the patterns. The duration of the first two ITIs was in the majority of the trials in an inverse ratio to the ratio of the respective ISIs. The distortions resulting from the timing mechanisms concerned were more pronounced in the performance of nonmusicians than in that of musicians.     

Retention characteristics of movement rate information

The retention characteristics of fast and slow movements were investigated in two experiments. Experiment 1 examined the reproduction of either fast or slow preselected movement rates after 0-sec rest, 15-sec rest or a 15-sec filled delay. Both fast and slow movement rates were rehearsable. Experiment 2 examined reproduction accuracy after subjects were required to perform a competing secondary task during the production of fast and slow movements. Although the secondary task degraded the reproduction of slow movements, it had no apparent effect upon the reproduction of fast movements. These results were interpreted as indicating partial support for Jones' (1974) notion of central monitoring of efference, and suggested that the contribution of proprioceptive feedback to movement control varies as a function of movement rate.     

Validity of teacher nominations of child behavior problems

The purpose of this study was to examine the validity of teachers' identification of problem children. Ninety-five third-grade children served as subjects. Teachers nominated children as a conduct problem, withdrawal problem, or normal, resulting in 16, 14, and 65 children being assigned to the three groups. Behavioral observations, peer sociometric ratings, and academic achievement scores were collected. The results indicated that conduct problem children differed from normal children on behavioral, sociometric, and academic measures, whereas withdrawn children differed from normals on the latter two measures. Conduct problem and withdrawal problem children did not differ on any of the dependent measures. The results suggest that teachers can identify children who are having difficulties in class but may be less accurate in differentiating between different types of problem children.This research was supported in part by NIMH grant MH-28859-01. Data reported in this article are part of a larger project assessing the social skills of children.     

A process analysis of group development

A process analysis of group development forms the basis of a methodology for identifying group phase boundaries and describing moment-to-moment process in psychotherapy groups. This paper presents the general rationale for identifying variables, the statistical technique for producing graphs and the first of three variables used in the process analysis. The focus is on phases two and three as defined by Beck's theory of group development. The first variable tracks the members' responses toward the Scapegoat Leader in terms of supportiveness, criticism or hostility. Results on two groups show a clear shift in responses from negative to supportive as the group moves from phase two to phase three.     

The effects of attentional focus and partner arousal on sexual responding in functional and dysfunctional men

The effects of attentional-focus instructions (self vs partner focus) and level of partner arousal (high, low and ambiguous) on sexual responding, both objectively and subjectively measured, were examined with sexually-functional (N = 8) and sexually-dysfunctional (N = 8) men. These instructional sets were delivered just before the subjects viewed an erotic film depicting a heterosexual couple in which they identified with the male. When both groups were focusing on themselves rather than their partner, higher tumescence was observed when their partner was displaying low arousal. When the partner's level of arousal was ambiguous, highest tumescence was achieved during partner attentional focus. When the partner was displaying high sexual arousal, functional subjects reached highest levels of tumescence during partner focus, while dysfunctional subjects reached highest levels of tumescence during self focus. In fact, high partner arousal seemed to inhibit dysfunctional subjects' tumescence under partner focus. Examination of self-report of arousal data as measured by a subjective lever revealed interesting group differences. Results are discussed in light of possible maintaining factors in sexual dysfunction and their treatment implications.     

Cognitive therapy. A 30-year retrospective

Several lines of investigation have evolved from the initial cognitive model of depression and other disorders. A large number of studies have tested the cognitive model using both clinical and laboratory-based strategies. In general, studies that most closely approximate the clinical conditions from which the theory was derived are supportive of the cognitive model of depression. Studies of anxiety and panic, although fewer, generally support the cognitive model of anxiety and panic. The application to the treatment of clinical problems has been promising and supports the concept of cognitive specificity. The cognitive therapy of depression has led to the utilization of specific cognitive strategies based on the specific conceptualizations of a given disorder to a wide variety of disorders. Study of abnormal reactions has also provided clues to the cognitive structure of normal reactions.