Ronald D. Zellner

Attentional deficit in learning-disabled children: Evidence from visual half-field asymmetries

The structural theory of cerebral lateralization has been typically used to explain hemispheric asymmetries. However, the attentional model of brain functioning may help resolve some of the inconsistent findings with groups of learning-disabled children. To test this hypothesis, a visual half-field paradigm for word recognition was employed in a group of 26 learning-disabled and 26 normal children matched for sex, chronological age, and handedness. Three experimental conditions (unilateral, cued unilateral, and bilateral) and two word error types (visually and acoustically confusable words) were analyzed. The results indicated that normals produced the expected RVHF superiority under all experimental conditions, but the learning-disabled produced the expected RVHF superiority only under the cued unilateral condition. Learning-disabled children also made significantly more visually and acoustically confusable errors than normals and unlike normal children increased the number of acoustic errors in the RVF under bilateral stimulation. These results provide evidence that learning-disabled children may process information inefficiently and have brain activation patterns that are more susceptible to attentional effects.

The Use and Efficacy of Handheld Computers for School-Based Data Collection: A Literature Review

Given the increasing influence of technology and the explosion in data collection demands, the acceptance and assimilation of new paradigms and technologies require todays educators, researchers, and evaluators to consider alternative tools, and apply them effectively. One of these alternatives, handheld computers, also known as personal digital assistants (PDAs), makes the benefits of computerized data collection more accessible to field-based researchers. An evaluation of handheld computers as data collection tools in research settings requires an understanding of their use from different perspectives in existing research. This review examines the willingness of teachers to adopt handheld data collection systems by focusing on 5 main features: (a) ease of use, (b) usefulness, (c) subjective norms, (d) intention to use, and (e) dependability.

Determining legibility distance for highway signs: is the within subject variability being overlooked?

Laboratory studies of warning symbol signs have been shown to underestimate legibility distances by up to a factor of two when compared with field studies. However, this research suggests it is more than simply experimental setting contributing to disparity in research findings. Using a group of old and young drivers, six symbol signs were investigated in both settings. With six trials per sign, legibility distances, defined as the distance at which the sign is correctly identified from a menu, were collected. Large within subject variability was discovered in both age groups. This variability led to alternative ways of defining the dependent variable equivalent to designs of past studies examining legibility distances of the same signs. Different results arose out of the subsets created. The consideration is not just should a field-based versus laboratory-based methodology be used. An argument is posed that recommended distances at which signs are placed must be determined from a “worst-case” scenario. This premise requires a reexamination of our research methodologies for determining placement of highway signs.

Children's Preference for Response Cost or Positive Reinforcement as Working Conditions.

Summary In a four-way lever-pulling task, 80 boys and girls at two grade levels (first and third) and two percentage of win conditions were exposed to response cost or positive reinforcement to determine their effects upon response time and task preference. Pennies were either withdrawn or withheld from children in a game where the outcomes were contrived. Significant results favored positive reinforcement and high win ratio in producing shorter average times to complete a response. Ss exhibited a preference to continue the task under the positive reinforcement condition. No significant interactions occurred, so that results were constant across grade level and sex.