Seeing textons in context

Texton theory holds that visual texture segregation occurs through the preattentive detection of local differences in primitive visual units called “textons.” Three textons have been proposed for shape: lines, line terminators, and line intersections. The experiments reported here show that line closure also behaves like a texton under some conditions. In addition, the experiments show that texture segregation is not determined by texton differences per se, but by the extent to which the unique textons in a region are salient in the context of the textons common to regions. This suggests that preattentive vision is not as simple minded as texton theory claims it to be.     

The electronic chalkboard

The present paper describes “the electronic chalkboard” (TEC), a teaching innovation made possible by the recent development, under a FIPSE grant to CONDUIT, of specialized instructional software. The instructional power of TEC casts the computer in the role of catalyst in the student-teacher dyad and leads to the emergence of the more powerful student-computer-teacher triad. Relevant educational principles and CAI techniques that should ensure the intelligent use of TEC are discussed.     

An evaluation of the yellow brick road test through a full prediction-performance comparison matrix

The purpose of the present study was to evaluate the predictive validity of the Yellow Brick Road Test (YBRT) relative to performance in reading as measured by the Metropolitan Achievement Test (MAT). A full prediction-performance comparison matrix was employed to compare three different cutoff scores for the YBRT for the identification of “at-risk” children. Four hundred and fourteen kindergarten-aged children were administered the YBRT, 214 of whom were followed to the end of second grade. It was concluded that the YBRT is a moderately valid instrument for predicting the level of reading achievement in a population with a different average performance level from the normative sample. However, the results of this study failed to support the utility of the test author's suggested use of a score of 120 as the cutoff score. Finally, it is recommended that a prediction-performance comparison study be considered standard methodology for the evaluation of the validity and efficiency of screening instruments.     

Factors influencing readability of rapidly presented text segments

Experiment 1 compared paragraph comprehension for texts shown either as normal pages on a computer terminal screen or as rapid serial visual presentations (RSVPs) of small text segments to a common location. Over several days of practice, reading comprehension was equivalent in the normal presentation mode and the RSVP format. When successive RSVP segments contained some information in common, to mimic the experience of successive parafoveal and foveal views of words in normal reading, comprehension was somewhat worse than when successive segments contained no overlapping information. Experiment 2 used a variety of segment size and segment duration combinations to investigate the optimal means of presenting text in the RSVP format. Across a variety of presentation rates and text difficulties, comprehension was maximal for segments averaging about 12 character spaces in length. In Experiment 3, texts were divided into short idea units or into random segments of equal average length. Comprehension was shown to be greater in the structured condition than in the random condition. An optimal means of presenting text in the RSVP format could be superior to normal presentation methods for reading and other text-processing tasks.     

A word’s meaning affects the decision in lexical decision

The influence of an isolated word’s meaning on lexical decision reaction time (RT) was demonstrated through four experiments. Subjects in two experiments made lexical decision judgments, those in a third experiment pronounced the words used in the lexical decision task, and those in a fourth experiment quickly pronounced their first associative response to the words. Differences in lexical access time for the words were measured with the pronunciation task, and differences in meaning were assessed with the association task. Multiple regression analyses of lexical decision RT were conducted using associative RT, pronunciation RT, and other target word properties (printed frequency, length, instance dominance, and number of dictionary meanings) as predictor variables. These analyses revealed a relationship between lexical decision RT and associative RT after the effects of other variables had been partialed out. In addition, word frequency continued to have a significant relationship to lexical decision RT beyond that shared with pronunciation RT and the other variables. The results of these experiments indicate that at least some of the effect of word meaning and word frequency in lexical decision is attributable to a decision stage following lexical access.     

The hierarchy of consistency: A review and model of longitudinal findings on adult individual differences in intelligence,personality and self-opinion

When viewed in the aggregate, studies of the longitudinal consistency of intelligence, personality traits and self-opinion (self-esteem, life satisfaction etc.) show a hierarchy of consistency. Uncorrected retest coefficients over periods of 6 months to 50 yr are analyzed as the product of period-free reliability (R) and the true stability of the construct (sⁿ, where s is the coefficient of annual stability and n the number of years of the retest interval). The annual stabilities of intelligence, personality traits and self-opinions are estimated as 0.99, 0.98 and 0.94, respectively. While intelligence and personality may be regarded as relatively stable characteristics over the length of the adult lifespan, self-opinion has little stability over periods of more than 10 yr. The hierarchy of consistency should be taken into account in causal models of human development. Although self-opinion is not a longitudinally-stable characteristics, it may still be predicted over long periods of time by higher-order constructs such as personality traits and intelligence.     

Cognitive dysfunction in compulsive checkers: Further explorations

Recent evidence suggests a relationship between certain memory deficits and compulsive-checking behavior. The present study explores this relationship in the context of several additional memory capacities not yet investigated. Using the Maudsley Obsessional-Compulsive Inventory and the Everyday Checking Behavior Scale four groups of Ss were identified: (1) frequent checkers, (2) occasional checkers, (3) infrequent checkers and (4) noncheckers. Consistent with previous research, a memory-for-actions task indicated a deficit among compulsive checkers. Furthermore, checking status was found to be negatively related to memory functioning as measured by the Wechsler Memory Scale (WMS) and the Cognitive Failures Questionnaire (CFQ). This memory deficit was most pronounced on the Logical Memory subtest of the WMS. Checkers appear to have difficulty recalling details of meaningfully linked sequences, either presented in narrative form or engaged in personally. Although the reasons for these checking-related deficits are not clear, a complete understanding of checking phenomena will involve an appreciation of the role played by memory deficits.     

Physiological and psychological effects of acute intentional hyperventilation

Research is reviewed which suggests that hyperventilation syndrome is an underdiagnosed disorder for the presentation of many patients experiencing apparent anxiety states. In a test of this hypothesis, 21 normal individuals (9 female) underwent a 2 min period of intentional hyperventilation following a 10 min baseline phase. Hyperventilation was accompanied by increased subjective anxiety and tachycardia, and indications of peripheral vasoconstriction. Following hyperventilation, Ss experienced increased levels of state anxiety and perceived autonomic arousal, as indexed by self-report instruments. These results support the hypothesis that undiagnosed hyperventilatory phenomena may be etiologically implicated in states of pathologic anxiety.     

THE IMPACT OF PSYCHOLOGICAL TESTING ON EDUCATIONAL AND PERSONNEL SELECTION IN AFRICA

Psychological testing for Education and Personnel selection is of great importance in the efforts by many African countries to ensure that suitable candidates are selected for education beyond the primary school level and for training for different employment. Major investigations directed to this need have been in the area of adapting tests already available in Western countries and determining the reliability and predictive validity of battery of tests so adapted and their tryout in African schools to determine their efficiency as tools for selection.