The alteration of behavior in a special classroom situation.

Unproductive classroom behavior was eliminated in two emotionally disturbed boys by removing social consequences of the behavior. Behavior which was more adequate and efficient with respect to social and scholastic adjustment was shaped and maintained with social reinforcers.     

Chained VI performance of pigeons maintained with an added stimulus

Pecks at a first (left) key were reinforced by a partial movement (advance) of the voltmeter behind the key toward the maximum position. When the meter reached maximum deflection, pecks at a second key were continuously reinforced with food. The schedule of reinforcement by which pecking the first key produced a deflection, as well as the size of the deflection, were varied in a series of experiments. The rate of responding on the first key was more affected by changes in the number of steps required to move the meter to the maximum position (the size of the deflection) than by the value of the variable-interval schedule by which pecking produced a meter deflection. The rate at which the bird pecked was low when the meter was near the null position, and high as the meter approached the maximum deflection.     

Fixed-interval performances with added stimuli in monkeys

The performance of two monkeys, on fixed-interval schedules, was examined with a visual, an auditory and a combined auditory-visual clock. The clock, a voltmeter and/or a variable frequency tone, produced performances different in many aspects from those recorded earlier with pigeons. Instead of the sustained high rates of responding at the optimal settings of the clock, the monkey's rates of responding were often extremely low even though a limited-hold contingency was utilized.     

A revised orthogonal rotational solution for Thurstone's original primary mental abilities test battery

By extension of the rotational process, meaningful orthogonally related positions were found for all of the thirteen centroid factors which Thurstone extracted from his original PMA intercorrelations. Most of the original primary ability factors were more sharply delineated and corresponded more closely to the Army Air Force factors that bear similar names (demonstrating greater invariance from analysis to analysis). While such different results obtained by two investigators applying the same methods on the same data may initiate some concern, the results strengthen rather than weaken the idea that more psychological meaningfulness and greater invariance will result if centroid axes are rotated, using the concepts of a simple structure and positive manifold.Thurstone considered loadings between ±.20 as negligible and considered only loadings of at least .40 in naming factors.     

Measuring lexical diversity in children who stutter: application of vocd

There is growing but equivocal evidence that the language abilities of young children who stutter (CWS) may be depressed when compared to those of their fluent peers. In particular, the lexical skills of CWS have variously been reported to be weaker or stronger than comparison children in a number of recent studies. One source for such disagreement may be the measures used to compute lexical characteristics of these children’s spoken conversations. In this study, we examined the concurrent validity of two measures of lexical diversity in spontaneous language samples, Type-Token Ratio (TTR) and the newly developed utility vocd (Malvern & Richards, 1997), using a standard test of expressive vocabulary as the comparison measure. Findings indicated that vocd values (“D”) correlated well with standardized measures of expressive vocabulary, while TTR values did not. In addition, both the standardized measure and vocd revealed significantly poorer expressive lexical skills of CWS, whereas TTR analyses did not evidence this difference. Results are discussed in relation to the relative strength of vocd over TTR as a method for describing lexical characteristics of the spontaneous language samples of this population.

Educational objectives: The reader will learn about and be able to (1) identify several common measures of conversational vocabulary and the strengths and weaknesses of each, and (2) compare the performance of the young CWS in this study to their normally fluent peers in terms of vocabulary performance on both formal and conversational measures of vocabulary.     

Demonstrating “Reasonable Fear” at Trial: Is it Science or Junk Science?

This paper explores how scientific knowledge is used in a criminal case. I examine materials from an admissibility hearing in a murder trial and discuss the dynamics of contesting expert scientific opinion and evidence. The research finds that a purported form of “science” in the relevant scientific community is filtered through, tested by, and subjected to legal standards, conceptions, and procedures for determining admissibility. The paper details how the opposing lawyers, the expert witness, and the judge vie to contingently work out what will count in court as appropriate scientific authority, methods and evidence, and as a scientifically valid and legally admissible account of “reasonable fear.” When science becomes enmeshed in legal controversies, science does not trump law. Rather, it is the court’s canons of proper procedure and measures of substantive adequacy that take precedence.

A lateralization of function approach to sex differences in spatial ability: a reexamination

The current study assessed the lateralization of function hypothesis (Rilea, S. L., Roskos-Ewoldsen, B., & Boles, D. (2004). Sex differences in spatial ability: A lateralization of function approach. Brain and Cognition, 56, 332–343) which suggested that it was the interaction of brain organization and the type of spatial task that led to sex differences in spatial ability. A second purpose was to evaluate explanations for their unexpected findings on the mental rotation task. In Experiment 1, participants completed the Water Level, Paper Folding, and mental rotation tasks (using an object-based or self-based perspective), presented bilaterally. Sex differences were only observed on the Water Level Task; a right hemisphere advantage was observed on Water Level and mental rotation tasks. In Experiment 2, a human stick figure or a polygon was mentally rotated. Men outperformed women when rotating polygons, but not when rotating stick figures. Men demonstrated a right hemisphere advantage when rotating polygons; women showed no hemisphere differences for either stimulus. Thus, hemisphere processing, task complexity, and stimulus type may influence performance for men and women across different spatial measures.     

Highlighting human form and motion information enhances the conspicuity of pedestrians at night

Exploring how biological motion can make pedestrians more conspicuous to drivers at night, one-hundred-and-twenty participants were driven along an open-road route at night and pressed a button whenever they recognized that a pedestrian was present. A test pedestrian wearing black clothing alone or with 302 cm2 of retroreflective markings in one of four configurations either stood still or walked in place on an unilluminated sidewalk. Participants' response distances were maximal for the full biological-motion configuration and remained surprisingly long when convenient subsets of reflective markers were positioned on the pedestrian's ankles and wrists. When the pedestrian wore a reflective vest, the responses were no better than when he wore no reflective markings. The biological-motion advantage actually results from interacting form-perception and motion-perception mechanisms. These results confirm that basic perceptual phenomena-observers' sensitivity to human form and motion can be harnessed to reduce an important problem of traffic safety.     

Working memory capacity moderates the predictive effects of drug-related associations on substance use

Some theories suggest that spontaneously activated, drug-related associations in memory may have a "freer reign" in predicting drug use among individuals with lower working memory capacity. This study evaluated this hypothesis among 145 at-risk youth attending continuation high schools (CHS). This is the 1st study to evaluate this type of dual-process interaction in the prediction of drug use among a sample of at-risk adolescents. The CHS students completed assessments of drug-related memory associations, working memory capacity, and drug use. Control variables included age, gender, ethnicity, and acculturation. Robust multiple regression using least trimmed squares estimation indicated that there was a significant linear by linear interaction between working memory capacity (assessed with the self-ordered pointing task) and drug-related associations (assessed with verb generation and cue-behavior association tasks) in the prediction of alcohol and cigarette use. Consistent with dual-process cognitive theories, drug-related associations in memory predicted drug use more strongly in students with lower levels of working memory capacity. These findings add to the literature implicating the influence of dual cognitive processes in adolescent risk behaviors.