Use of derivational morphology during reading

This study examines contrasting predictions made by models of the lexicon in which stem morphemes play a central accessing role versus models in which stem morphemes play no particular role. Models which assign an independent role to morphemes predict that derivationally suffixed words have both inhibitive and facilitative effects on the reading process. A reading comprehension task was administered to good and poor high-school-age readers to assess their use of both the lexical-semantic and syntactic information provided by morphemes in derivationally suffixed target words. The subjects appeared to use the stem morpheme of a derivationally suffixed word to establish overall sentence meaning but often did not use the syntactic information contained in the derivational suffix. The failure to use syntactic information in the suffix was significantly greater for lower-ability readers than for those reading at or above grade level. The results offer support for morphologically organized models of the lexicon.     

Progamming time in serial tapping responses as a function of pathway constraint

Summary This study varied the accuracy demand within a linear series of targets to investigate the effect of movement-pathway constraints on response-programming time. Sidaway, Christina, and Shea (1988) have suggested that constraints placed upon movement initiation by the demand for response precision may play an important role in determining the length of the programming process. By varying the subtended angles of a series of three targets, this experiment tested the specific prediction of Sidaway et al. that programming time may be a function of the target, within a line of targets, that subtends the smallest angle at the start position. It is this target that demands the greatest precision in the movement pathway. Subjects participated in a series of conditions in which the size and placement of the target that imposed the maximal constraint was varied. In each condition the subjects were required to strike a series of three targets with a stylus in a simple reaction-time paradigm. Analysis of the reaction-time results revealed a significant effect of size of constraint, but no effect of position of constraint. Analysis of the movementtime data dispelled movement-duration and movement-velocity interpretations of the results and intimated a possible online trajectory-correction process.Portions of these data were first presented at the Annual Meeting of the Psychonomic Society in Atlanta, Georgia, November 1989.     

Explicit syllable and phoneme segmentation in the young child

To write a language, one must first abstract the unit to be used from the acoustic stream of speech. Writing systems based on the meaningless units, syllables and phonemes, were late developments in the history of written language. The alphabetic system, which requires abstraction of the phonemic unit of speech, was the last to appear, evolved from a syllabary and, unlike the other systems, was apparently invented only once. It might therefore be supposed that phoneme segmentation is particularly difficult and more difficult, indeed, than syllable segmentation. Speech research suggests reasons why this may be so. The present study provides direct evidence of a similar developmental ordering of syllable and phoneme segmentation abilities in the young child. By means of a task which required preschool, kindergarten, and first-grade children to tap out the number of segments in spoken utterances, it was found that, though ability in both syllable and phoneme segmentation increased with grade level, analysis into phonemes was significantly harder and perfected later than analysis into syllables. The relative difficulties of the different units of segmentation are discussed in relation to reading acquisition.     

Overall nutrient intake of preschool hyperactive and normal boys

Studies examining the relationship between sugar intake of hyperactive children and behavior problems have reported inconsistent results. We hypothesized that if the problem behaviors of attention deficit-disordered children with hyperactivity (ADDH) are exacerbated by food, then this might be due to differences in their background nutrition relative to non-ADDH children. Parents and day care workers of 24 ADDH and 27 non-ADDH preschoolaged boys were trained to keep food diaries for 21 days. Analysis of the last 14 days for each child revealed no differences in overall nutrient intake between the two groups. On the other hand, for 5 ADDH and 3 non-ADDH children the within-subject correlations between daily behavior and sugar intake were significant. We concluded that nutrition-behavior interactions are more likely a function of idiosyncratic sensitivities, rather than a general tendency for ADDH children to eat differently from non-ADDH children.This research was funded by the Alberta Mental Health Research Advisory Council, and by the National Health Research and Development Program of Health and Welfare Canada. We think Jeannine Fraser for help with data analyses.     

NONVOCAL LANGUAGE ACQUISITION IN ADOLESCENTS WITH SEVERE PHYSICAL DISABILITIES: BLISSYMBOL VERSUS ICONIC STIMULUS FORMATS

This study compared training in two language systems for three severely handicapped, nonvocal adolescents: the Bliss symbol system and an iconic picture system. Following baseline, training and review trials were implemented using an alternating treatments design. Daily probes were conducted to assess maintenance, stimulus generalization, and response generalization, and data were collected on spontaneous usage of either language system throughout the school day. Results showed that students required approximately four times as many trials to acquire Bliss symbols as iconic pictures, and that students maintained a higher percentage of iconic pictures. Stimulus generalization occurred in both language systems, while the number of correct responses during responses generalization probes was much greater for the iconic system. Finally, students almost always showed more iconic responses than Bliss responses in daily spontaneous usage. These results suggest that an iconic system might be more readily acquired, maintained, and generalized to daily situations. Implications of these findings for the newly verbal person were discussed.     

A programmable circuit for varying light intensity

An inexpensive circuit is described for the control of light intensity. The control is obtained by a method that produces no color changes and may be programmed by any system that can express itself in four-digit binary numbers.