An impulse-timing theory for reciprocal control of muscular activity in rapid, discrete movements

Much remains to be learned about how agonist and antagonist muscles are controlled during the production of rapid, voluntary movements. In an effort to summarize a wide body of existing knowledge and stimulate future research on this subject, an impulse-timing theory is presented which attempts to predict the activity of reciprocal muscles based on certain characteristics of a movement. The basic tenet of the theory is that variables of movement time, movement distance and inertial load have fairly predictable effects on the underlying muscular activity of the agonist and antagonist muscles during the production of rapid and discrete, voluntary movements. The theory is derived from the kinematic work of Schmidt, Zelaznik, Hawkins, Frank and Quinn (1979) and supporting evidence from studies which have used electromyographic (EMG) recordings of agonist and antagonist muscles during rapid movements. Issues related to synergistic muscle control, central and peripheral control of reciprocal muscle activity, muscle control, and neurological disorder and the relationship between impulse-timing and mass-spring control are discussed in the final section.     

Faith for atheists and agnostics

Conclusion In this paper I challenge both the contemporary secular view that religious faith is not a virtue, and also the contemporary theistic view that religious faith is a virtue that is unavailable to nonbelievers. Although these views appear reasonable from the respective sides when faith is interpreted as belief, if faith is understood to be the entrusting of one’s ultimate concerns to whatever powers are in control (as I suggest), then such faith, with its accompanying ‘freedom from bondage’ (Spinoza), not only appears to be a virtue in itself, but it also appears to be one that can be achieved by nonbelievers as well as by theists. This is not to claim, however, that theists should hold the nonbeliever’s faith to be as viable as their own (or vice versa); rather, it is to claim that there is no more reason for theists to hold that nonbelievers must be without faith than there is for them to hold that nonbelievers must be without hope or love. Still, of course, it may be that God does exist and that the belief that he exists is part of the formula for the realization of some ultimate religious concern, such as eternal life. (For example, it could have been that there was a person conducting a rescue mission for the mountain climbers, but who refused to bring those who did not believe so to final safety, even though they has boarded the platform.) So, if God does exist and if the formula for eternal life, for example, does include the requirement that creatures believe that he exists, then atheists and agnostics will certainly have erred by not embracing theism. But their error then (assuming their doubts not to be the products of such vices as pride or dishonesty) will have been an error in calculative judgment, rather than a failure in virtue: they will have erred by not having engaged a hypnotist—at least in last resort— to equip them with a precautionary theism.     

The influence on recognition of spoken words that are misperceived

Two experiments were performed that involved an initial word-identification task in which the acoustic signal was degraded by either 50% or 60% compression of the recorded words. A control group was tested at the original recording rate (0% compression). The compression manipulation was successful in increasing the number of identification errors. During the second stage of the experiments, words were read at a normal rate. In Experiment 1, the subjects indicated whether each word had appeared on the prior list, and in Experiment 2, the subjects estimated the number of times each word had been read on the prior list. The false-negative rate decreased and frequency ratings increased as a function of the number of prior presentations (one, two, or three) of the target words. The most interesting result was that the effect of repetitions was present even for words that had been misperceived.     

Effects of background anger,provocation, and methylphenidate on emotional arousal and aggressive responding in attention-deficit hyperactivity disordered boys with and without concurrent aggressiveness

We investigated the effects of background anger, provocation, and methylphenidate on emotional, physiological, and behavioral responding in children with attentiondeficit hyperactivity disorder (ADHD) with and without concurrent aggression. Our study revealed that ADHD boys showed more emotional and physiological distress when exposed to an interaction in which an administrator chastised each boy's favorite counselor, compared to a friendly interaction between the two adults. The background anger manipulation did not affect the aggressive behavior of the boys against an opponent in an aggressive game. High-aggressive (HA) ADHD boys were more likely to respond to provocation with aggression than low-aggressive (LA) ADHD boys, but only LA boys showed increased physiological reactivity with increasing provocation. Methylphenidate resulted in increased heart rates under all conditions and did not interact with any of the other findings.This project was conducted while the first author had the support of National Institute of Alcohol Abuse and Alcoholism grant AA 06267.The authors wish to thank the staff members of the 1987 Summer Day Treatment Program who assisted in conducting this project. The authors also express their appreciation to Karen Guthrie for coordinating the medication assessment and to Hart Blanton for computer programming.     

Quality of mental health services and method of payment: an empirical study

Data from a sample of clinicians are examined to study the relationship of the lower socio-economic client and therapist. Therapist practice variables are regressed on variables measuring client income and contrasting client's use of Medicaid with the use of private insurance or out-of-pocket funds. It is found that therapist practice variables can predict a significant proportion of the variance of these criterion variables. These relationships and their implications for the therapeutic needs of indigent clients with less severely impaired conditions are discussed.     

An analysis of motor coordination components for various localization tasks

Localization abilities of subjects in three perceptual-motor tasks were considered before and after an exposure to a visual distortion. During this distortion the subject observed his hand ballistically point to an invisible but audible target while either receiving or not receiving knowledge of results (KR) concerning pointing accuracy. Also, subjects either received a 1- or a 4-sec rest period between each of 30 exposure ballistic pointing actions. The pre- and postexposure tasks involved the ability of a subject to accurately point to an occluded and stationary auditory target, to point to the straight-ahead position in space, and to indicate when a moving, auditory target was perceived as being in the straight-ahead position. For these tasks, the pre- vs. postexposure localization difference scores are referred to as the negative aftereffect, the proprioceptive shift, and the auditory shift, respectively. Wilkinson's (1971) two-component additive model (negative aftereffect = proprioceptive shift plus auditory shift) held when KR was given regardless of amount of rest between exposure pointing responses. With a 4-sec rest and no KR, the relationship between coordination components was nonadditive (negative aftereffect greater than proprioceptive shift plus auditory shift).     

Avoidance extinction in goldfish

Independent groups of goldfish trained to avoid shock in a shuttlebox situation were presented with several extinction procedures in which the relationships between the conditioned stimulus and shock were altered and/or response contingencies removed. Random shock presentations, equivalent to the number of shocks received during avoidance acquisition, resulted in response decrements similar to those obtained when the conditioned stimulus was presented alone. Pairing the conditioned stimulus with shock on every trial, however, served to maintain response levels. When response-contingent punishment was superimposed upon these Pavlovian pairings, performance was facilitated slightly although punishment alone resulted in somewhat faster response reduction than that produced by exposure only to the conditioned stimulus. Extinction of avoidance responding produced by exposure to the conditioned stimulus alone was dependent on the total duration of exposure and independent of both number of stimulus onsets and response prevention. These experiments demonstrated that, in general, the procedures used to reduce avoidance responding in rats were equally effective for goldfish, with one exception: the introduction of a Pavlovian contingency following avoidance acquisition, making the previously avoidable shock unavoidable, maintained response probabilities near previously established levels.     

Risk–need–responsivity and its application in behavioral health settings: A feasibility study of a treatment planning support tool

The risk–need–responsivity (RNR) model suggests several key practices for justice‐involved populations under correctional supervision. Behavioral health treatment planning aligned with RNR principles for offender populations with co‐occurring mental health and substance use disorders (CODs) could be one method for integrating RNR into clinical care. To explore a unique approach to working with behavioral health and RNR principles, the authors implemented a mixed‐methods feasibility study of the acceptability, usability, and utility of a newly developed RNR treatment planning support tool (RNR TST). The tool was implemented in a re‐entry program serving adults with co‐occurring mental health and opioid use disorders. Chart reviews of RNR TSTs (N = 55) and a focus group (N = 14 re‐entry clinical staff) were conducted. Ninety‐six percent of the RNR TSTs incorporated the use of a validated risk–need assessment and 70% of the RNR TSTs were semi‐complete to complete. Focus group interviews highlighted behavioral health staff perspectives on the acceptability, usability, and utility of the RNR TST. This novel RNR TST has the potential to assist behavioral health providers in integrating RNR principles into treatment planning. Further development and testing are needed to determine its impact on client care and outcomes.