Bilateral writing ability, cerebral organization, and hand posture

Among a group of 12 persons selected for the ability to write with ease with either hand, none were found to write using a hooked hand posture with either the right or left hand. Tests of verbal and manipulospatial ability indicated a normal balance of these two types of abilities, usually associated with the left and right hemispheres. Findings are discussed in terms of implications for cerebral organization and hand position in writing.     

Axiomatic and numerical conjoint measurement: An evaluation of diagnostic efficacy

Synthetic data are used to examine how well axiomatic and numerical conjoint measurement methods, individually and comparatively, recover simple polynomial generators in three dimensions. The study illustrates extensions of numerical conjoint measurement (NCM) to identify and model distributive and dual-distributive, in addition to the usual additive, data structures. It was found that while minimum STRESS was the criterion of fit, another statistic, predictive capability, provided a better diagnosis of the known generating model. That NCM methods were able to better identify generating models conflicts with Krantz and Tversky's assertion that, in general, the direct axiom tests provide a more powerful diagnostic test between alternative composition rules than does evaluation of numerical correspondence. For all methods, dual-distributive models are most difficult to recover, while consistent with past studies, the additive model is the most robust of the fitted models.Douglas Emery is now at the Krannert Graduate School of Management, Purdue University, West Lafayette, IN, on leave from the University of Calgary.     

Models for within-proposition representation tested by cued recall

A model is presented to account for the data from incremental cuing experiments that have been carried out to identify the representation of propositions in memory. In such experiments subjects first learn a list of sentences and are afterward cued for recall with words from the learned sentences. The model proposed distinguishes between a memory structure and stimulus and response processes. The all-or-none tendency in the data is captured by a Gestalt-like memory code. The model is compared with the stochastic theory of Anderson and Bower and the fragmentation hypothesis of Jones.     

Auditory processing and anxiety in stutterers

This study utilized the Synthetic Sentence Identification/Ipsilateral and Contralateral Competing Message subtests and the State-Trait Anxiety Inventory to examine auditory processing deficits, anxiety levels, and the interaction of these two components in 15 adult stutterers and 15 nonstutterers. Results support brainstem auditory processing deficits in stutterers and equalization of cortical functioning between groups. Group differences were not found in anxiety levels. Nonsignificant correlations between anxiety levels and auditory processing were revealed.     

Reinforcement as positive or negative meaning-extension: An empirical demonstration

According to logical learning theory, a reinforcement involves the extension of meanings predicated by subjects who are asked to perform in a learning task. Based on this theoretical position, it is predicted that subjects who are administered a reinforcement following their successful anticipation of the second member of a paired-associates unit will acquire their liked trigrams more readily than their disliked trigrams (mixed lists). Conversely, it is predicted that subjects who are reinforced following their incorrect anticipations of the second paired-associates member will acquire their disliked trigrams more readily than their liked. College students (divided equally by sex) were exposed to one of three reinforcement conditions: positive reinforcement, negative reinforcement, and no reinforcement (control). Trigrams reliably rated for likability by each subject were used as learnable materials. Although the control condition did not perform as expected, the remaining experimental conditions support the hypotheses.     

Influence of six types of visual structure on complexity judgments in children and adults

Individuals at five grade levels (kindergarten, Grade 2, Grade 4, Grade 6, and college) made pair-comparison judgments of visual complexity. The influence of the presence or absence of six types of visual structure (double symmetry, vertical symmetry, horizontal symmetry, diagonal symmetry, checkerboard organization, and rotational organization) and of amount of contour were examined. Two general developmental trends were revealed: First, the age at which visual structure initially affected complexity judgments varied with the type of structure, independent of amount of contour, within the range of contour values used. Second, there was a uniform increase in the effect of structure on complexity judgments between the fourth and sixth grades. These results are discussed in relation to possible mechanisms of visual pattern encoding and complexity judgment.     

Effect of posttrial episodes on conditioning in compound conditioned stimuli

The effect of signaled and nonsignaled posttrial episodes (PTEs) on conditioning to the target CS of a preceding compound CS-US trial was examined in two conditioned emotional response (CER) experiments with rats. Experiment 1 revealed that a nonsignaled PTE, a second shock US, interfered with conditioning to the preceding target CS and that the interference effect of the PTE was greater when it occurred 5 sec as opposed to 1,800 sec after the preceding compound CS-US trial. Experiment 2 revealed that if the shock PTE was signaled by a CS, its ability to interfere with conditioning was reduced. This second study also revealed that omission of an "expected" US interfered with conditioning to the target CS. The implications of these data for information processing models of Pavlovian conditioning are discussed.