Evaluation of arm dominance by using the mechanomyographic signal

The authors collected and compared mechanomyo-graphic (MMG) signal behavior from the biceps brachii of left and right arms of right-handed men (n = 19) and women (n = 20) who performed isometric contractions at 5 contraction levels. Mean frequency (MF) and RMS values were calculated from the MMG signals that arose from lateral oscillations of muscle fibers. Across genders and arms, RMS values increased with contraction level and MF values decreased with increase in muscle contraction. The authors found no significant difference in those parameters between dominant and nondominant arms. Therefore, summation of muscle twitches obtained from the MMG signal collected in biceps brachii muscle does not reveal any difference between dominant and nondominant arms.     

Willingness to use microbicides varies by race/ethnicity, experience with prevention products, and partner type.

OBJECTIVE: To investigate women's willingness to use vaginal microbicides to reduce/prevent HIV infection, using measures grounded in the individual, behavioral, and social contexts of sex. DESIGN: A cross-sectional study that enrolled a sample (N = 531) of 18-55 year old Latina, African-American, and White women in the U.S. between October, 2004, and July, 2005. MAIN OUTCOME MEASURES: Willingness to use microbicides and individual- and context-related variables (e.g., demographics, relationship status). RESULTS: Exploratory and confirmatory factor analyses supported a one-dimensional, 8-item scale, with high internal consistency (alpha = .91). Subgroup analyses within the Latina (n = 166), African- American (n = 193), and White sub-samples (n = 172) also supported a unidimensional scale with strong internal validity and high reliability. Race/ethnicity as a contextual factor, a woman's history of using prevention products, and the nature of the sexual partnership were predictive of willingness to use microbicides (R = .41). That is, women with greater frequencies of condom use, a history of spermicide use, and non-main sexual partners had higher predicted Willingness to Use Microbicides scale scores, while White women had lower predicted scores. CONCLUSION: The Willingness to Use Microbicides scale serves as the first psychometrically validated measure of factors related to microbicide acceptability. Developing and implementing psychometrically validated and contextualized microbicide acceptability measures, in an effort to understand microbicide users and circumstances of use, is crucial to both clinical trials and future intervention studies.     

Lexical selection is not by competition: a reinterpretation of semantic interference and facilitation effects in the picture-word interference paradigm

The dominant view in the field of lexical access in speech production maintains that selection of a word becomes more difficult as the levels of activation of nontarget words increase--selection by competition. The authors tested this prediction in two sets of experiments. First, the authors show that participants are faster to name pictures of objects (e.g., "bed") in the context of semantically related verb distractors (e.g., sleep) compared with unrelated verb distractors (e.g., shoot). In the second set of experiments, the authors show that target naming latencies (e.g., "horse") are, if anything, faster for within--category semantically close distractor words (e.g., zebra) than for within--category semantically far distractor words (e.g., whale). In the context of previous research, these data ground a new empirical generalization: As distractor words become semantically closer to the target concepts--all else being equal--target naming is facilitated. This fact means that lexical selection does not involve competition, and consequently, that the semantic interference effect does not reflect a lexical level process. This conclusion has important implications for models of lexical access and interpretations of Stroop-like interference effects.     

The ‘Conditional Position Problem’ for epistemic externalism

Synthese - In this paper, I develop a problem I call the “Conditional Position Problem” that arises for Ernest Sosa’s externalist epistemology. The problem is that, due to a...     

Teachers and students: Reflections on social control and future performance

To instruct consists of arranging controls between teacher, student, and subject matter. Initial controls must emanate from the teacher since those of the subject matter are minimal, crude, or missing. Teachers mand students to behave in certain ways with respect to a given subject matter. Eventually, however, the teacher must transfer the teacher mediated and managed control of the student to natural controls functioning directly through student interaction with the subject matter. Difficulty in doing this occurs due to the reinforcers for both student and teacher derived from social contact. Nevertheless, the student eventually must be taught to interact with the subject matter independent of teacher involvement if the student is to maintain effective contact with the subject matter beyond the period of formal instruction.     

Programmed instruction: What it is and how to do it

Five behaviorological features of programmed instruction are outlined: behavioral objectives, reinforcement, activity rate: high and relevant, successive approximation, and mastery progression. Each of these topics is explained, and examples are given to illustrate the differences between programmed instruction and the more common transmission model of teaching. A final section provides suggestions on specific techniques of successive approximation.