Investigating speech motor practice and learning in people who stutter

In this exploratory study, we investigated whether or not people who stutter (PWS) show motor practice and learning changes similar to those of people who do not stutter (PNS). To this end, five PWS and five PNS repeated a set of non-words at two different rates (normal and fast) across three test sessions (T1, T2 on the same day and T3 on a separate day, at least 1 week apart). The results indicated that PWS and PNS may resemble each other on a number of performance variables (such as movement amplitude and duration), but they differ in terms of practice and learning on variables that relate to movement stability and strength of coordination patterns. These findings are interpreted in support of recent claims about speech motor skill limitations in PWS.

Educational objectives: The reader will be able to: (1) define oral articulatory changes associated with motor practice and learning and their measurement; (2) summarize findings from previous studies examining motor practice and learning in PWS; and (3) discuss hypotheses that could account for the present findings that suggest PWS and PNS differ in their speech motor learning abilities.     

Female degus (Octodon degus) monitor their environment while foraging socially

Vigilance or scanning involves interruptions in foraging behavior when individuals lift their heads and conduct visual monitoring of the environment. Theoretical considerations assume that foraging with the "head down", and scanning ("head up") are mutually exclusive activities, such that foraging precludes vigilance. We tested this generalization in a socially foraging, small mammal model, the diurnal Chilean degu (Octodon degus). We studied spontaneous bouts of scanning of captive degus when foraging in pairs of female sibs and non-sibs. We examined the extent to which foraging (head down postures) and scanning (head up postures) were mutually exclusive in subjects exposed to none, partial, and complete lateral visual obstruction of their partners. In addition, we monitored the orientation of their bodies to examine the target of attention while foraging and scanning. Lastly, we examined the temporal occurrence of scanning events to assess the extent of scanning coordination, and whether this coordination is kin-biased. Visual obstruction had a significant influence on degu vigilance. Focal degus increased their quadrupedal and semi-erect scanning when foraging under a partially obstructed view of their partners. Degus oriented their bodies toward partners when foraging and scanning. Despite this, degus did not coordinate scanning bouts; instead, they scanned independently from one another. Relatedness among cage mates did not influence any aspect of degu behavior. Contrary to theoretical expectations, these results indicate that foraging and vigilance are not mutually exclusive, and that kinship per se does not influence scanning behavior and coordination.     

Effects of differing response-force requirements on food-maintained responding in CD-1 mice

The effect of force requirements on response effort was examined using outbred (CD-1) mice trained to press a disk with their snout. Lateral peak forces greater than 2 g were defined as threshold responses (i.e., all measured responses). Different force requirements were used to define criterion responses (a subclass of threshold responses) that exceeded the requirement. The reinforcer was sweetened, condensed milk, and it was delivered upon response termination. All mice were exposed to two ascending series of criterion force requirements (2, 4, 8, 16, and 32 g). Increasing the force requirement decreased criterion response rates, but increased threshold response rates. The time-integral of force (area under the force-time curve for individual responses, which is proportional to energy expenditure for each response) increased with the increase in the force requirement. These results conflict with the hypothesis that higher force requirements have aversive qualities and suggest that increased force requirements are more analogous to intermittent schedules of reinforcement. These data suggest that estimations of effort or energy expenditure should be measured independently of the force requirement. Individual differences in responding were found for the CD-1 outbred stock.     

Inhibitory response capacities of bilateral lower and upper extremities in children with developmental coordination disorder in endogenous and exogenous orienting modes

This study was designed to investigate separately the inhibitory response capacity and the lateralization effect in children with developmental coordination disorder (DCD) in the endogenous and exogenous modes of orienting attention. Children with DCD on the lower extremities (DCD-LEs), along with age-matched controls, completed four tasks that involved various applications of asynchronous stimuli to the feet or hands at various intervals. The results demonstrated that children with DCD-LEs had a significantly longer reaction time than the controls for all tasks, and were not alert to the appearance of the target. However, they displayed a deficit in volitional shifts of attention (endogenous mode), but not in automatic dislocation of attention (exogenous mode), whenever they performed the tasks with either their lower or their upper-limbs-even 6 months after the initial study. These findings confirm the deficit in the inhibitory response capacity in terms of volitional movement of attention by children with DCD. Additionally, the negative effect of lateralization on the bilateral extremities was not present in children with DCD-LEs. Significantly differences in response ability were detected only between the dominant and non-dominant sides of upper-limbs, but not between the lower-limbs, suggesting a future avenue for further experimentation on bilateral extremities.     

Mechanisms of deficit of visuospatial attention shift in children with developmental coordination disorder: A neurophysiological measure of the endogenous Posner paradigm

The purpose of this study was to investigate and compare the mechanisms of brain activity, as revealed by a combination of the visuospatial attention shifting paradigm and event-related potentials (ERP) in children with developmental coordination disorder (DCD) and typically developing children. Twenty-eight DCD children and 26 typically developing children were recorded with regard to their behavioral performance and ERP measures during a variant of the endogenous Posner paradigm, in which they should react to visual targets preceded by spatial cues or presented uncued. Children with DCD showed longer reaction time and a deficit in inhibitory response capacity when compared to typically developing children. The electrophysiological characteristics also showed distinct modulatory effects upon attentional orienting, anticipatory mechanisms, and cognitive-to-motor transfer in children with DCD: longer cue-P3 and target-N1 latency, smaller target-P3 amplitude, an elongated interval between N2 and the motor response (N2-RT), and small areas on contingent negative variation (CNV). The combined analysis of behavioral performance and ERP data suggested that children with DCD had deficits of slower target identification (N1), less ability in interhemispheric (P3) and cognitive-to-motor transfer speed (N2-RT), as well as a less mature anticipatory and executive process (CNV).     

Manual dexterity in the gorilla: bimanual and digit role differentiation in a natural task

The manipulative actions of mountain gorillas Gorilla g. beringei were examined in the context of foraging on hard-to-process plant foods in the field, in particular those used in tackling thistle Carduus nyassanus. A repertoire of 72 functionally distinct manipulative actions was recorded. Many of these actions were used in several variants of grip, finger(s) and movement path, both by different individuals and by the same individual at different times. The repertoire appears somewhat greater than that observed in comparable studies of monkeys, but a far more striking difference is found in the use of differentiated actions in concert. Mountain gorillas routinely and frequently deal with problems that involve: (1) bimanual role differentiation, with the two hands taking different roles but synchronized in time and space, and (2) digit role differentiation, with independent control of parts of the same hand used for separate purposes at the same time. The independent control that allows these abilities, so crucial to human manual constructional ability, is apparently general in African great apes. Role differentiation, between and within the hand, is evidently a primitive characteristic in the human arsenal of skills. Accepted after revision: 6 April 2001 Electronic Publication     

God as Spirit—and Natural Science

The biblical sentence "God is Spirit" (John 4:24) occasioned the development of the Christian doctrine about God as Spirit. But since patristic times "spirit" was interpreted in the sense of Nus, which rather means "intellect." The biblical concept of spirit (pneuma), however, has its root meaning in referring to "air in movement," as in breath or storm. The similar concept of pneuma in Stoic philosophy has become the "immediate precursor" (Max Jammer) of the field concept in modern physics, so that the conclusion is suggested that God is spirit as something like a field of force rather than as intellect. This essay argues for such a conception by relating the divine eternity and immensity to the concepts of space and time, the basic requirements of any physical field. God's eternity and immensity are interpreted in terms of undivided infinite space (and time) which is presupposed in all concepts of parts of space or time (or space-time), therefore in all mathematical and physical measurement.     

Making life easier with effort: Basic findings and applied research on response effort

Early basic research showed that increases in required response effort (or force) produced effects that resembled those produced by punishment. A recent study by Alling and Poling determined some subtle differences between the two behavior-change strategies, but also confirmed that increasing required effort is an effective response-reduction procedure with enduring effects. In this paper we summarize basic research on response effort and explore the role of effort in diverse applied areas including deceleration of aberrant behavior, attention deficit hyperactivity disorder, oral habits, health care appointment keeping, littering, indexes of functional disability, and problem solving. We conclude that renewed interest in response effort as an independent variable is justified because of its potent effects and because the political constraints imposed on punishment- and reinforcement-based procedures have yet to be imposed on procedures that entail manipulations of response effort.     

Jeopardy Not Bonus Status for African American Women in the Work Force: Why Does the Myth of Advantage Persist?

African American women in the United States have a long history of employment outside of their homes. Their experiences are unique from other groups of majority and minority men and women due to the interaction of race, gender, and class. Despite long-standing and continuing struggles against discrimination, harassment, low pay, tokenism, and stereotypes, a myth that African American women enjoy a bonus or advantaged status in the work force has developed and persisted. In this article, Black women's work force experiences are examined from a social constructionist framework, misperceptions of Black women are critiqued, explanations are developed that explain the unique status of African American women and recommendations are proposed to eradicate the discrimination and marginal status that Black women have endured in the work force.     

May the force be with you

This paper is a critical assessment of argumentum ad baculum, or appeal to force. Its principal contention is that, contrary to common opinion, there is no general fallacy of ad baculum. Most real-life ad baculums are, in fact, fairly strong. A basic logical form for reconstructed ad baculums is proposed, and a number of heterodoxical conclusions are also advanced and argued for. They include that ad baculum is not necessarily a prudential argument, that ad baculum need not involve force, violence, or threats, and that one can argue ad baculum to oneself. The starting point of the paper, however, is a critical evaluation of three ad baculums from the exercise sets of Irving Copi's well-known Introduction to Logic.