Visual Elaboration Scale as a measure of imagery

We studied the correlation of one measure of imagery ability, the Visual Elaboration Scale, with two others, absorption of image and effort required to form a mental image. Significant correlations were obtained between the Visual Elaboration Scale and the other scales, with the exception of Absorption for women.     

Hemispheric dominance inferred from Your Style of Learning and Thinking on reports of Necker cube reversals and maze learning

30 subjects volunteered from three sources: community adults (M age = 32.8, SD = 13.4), college adults (M age = 23.8, SD = 8.3), and children (M age = 9.5, SD = 1.7) and were categorized as 'left-' and 'right-dominant' by scores on Your Style of Thinking and Learning. They reported the number of Necker cube reversals perceived in 90 sec., attempted to locate four embedded figures, and blindly traversed a 16-choice point finger maze in that order. 'Right-dominant' subjects located more embedded figures and made fewer errors on the finger maze than did 'left-dominant' subjects. College adults reported more Necker cube reversals than did community adults and children, and community adults reported more reversals than did children. Confounds of performance measures with fatigue and/or practice require further research.     

Effect of reaction time condition on EMG activities of the biceps brachii muscle in elbow flexion and forearm supination

Under simple- and choice-RT conditions, the biceps brachii muscle was examined in 8 healthy male subjects to determine how the temporal and spatial characteristics of elbow flexion and forearm supination differed at the initial phase of EMG activity and whether preparation or the presence of response uncertainty influenced the EMG outputs of the two movements. In the simple-RT condition, RT of supination was significantly faster than that of flexion but EMG activity of supination was less than that of flexion. In contrast, in the choice-RT condition, RT of flexion was significantly faster than that of supination but EMG activity of flexion was significantly reduced compared to supination. These findings indicate that advanced preparation or motor set facilitates the differentiation of RTs and EMG activities of the response movements and that response uncertainty causes a significant change in the temporal and spatial specificity of both elbow flexion and forearm supination.     

Sample size determinations for the two rater kappa statistic

This paper gives a method for determining a sample size that will achieve a prespecified bound on confidence interval width for the interrater agreement measure,. The same results can be used when a prespecified power is desired for testing hypotheses about the value of kappa. An example from the literature is used to illustrate the methods proposed here.     

Stress in time

The goals of this research were to determine whether speakers adjust the stress patterns of words within sentences to create an alternation between strong and weak beats and to explore whether this rhythmic alternation contributes to the characteristics stress differences between two major lexical categories of English. Two experiments suggested that speakers do alter lexical stress in accordance with rhythmic biases. When speakers produced disyllabic pseudowords in sentence contexts, they were more likely to place stress on the first syllable when the pseudoword was preceded by a weak stress and followed by a strong one than when the strong stress preceded and the weak followed. This occurred both when the pseudowords served as nouns and when they served as verbs. Text analyses further revealed that weakly stressed elements precede nouns more often than verbs, whereas such elements follow verbs more often than nouns. Thus, disyllabic nouns are more likely than disyllabic verbs to occupy contexts biased toward trochaic rhythm, a finding consistent with leftward dominant stress in disyllabic English nouns. The history of stress changes in English nouns and verbs also conforms with the view that rhythmic context may have contributed to the evolution of stress differences. Together, the findings suggest that the citation stress patterns of words may to some degree reflect adaptations of lexical knowledge to conditions of language performance.     

Multiunit changes in hippocampus and medial geniculate body in free-behaving rats during acquisition and retention of a conditioned response to a tone

Multiunit activity (MUA) was recorded chronically in the hippocampus (CA3) and the medial geniculate body (mMG) during habituation to a tone followed by conditioning (tone paired with footshock) or pseudoconditioning (tone/footshock unpaired) in rats previously trained in a lever-pressing for food task (VI 60). In the conditioned group pairing tones with footshocks rapidly induced an increase in the initial CS-evoked response in the mMG, followed by the emergence of a hippocampal response and a marked conditioned suppression of lever-pressing to the tone. In contrast, in the pseudoconditioned group, the stimulus induced only transient cellular changes in the hippocampus and in the mMG, while no behavioral suppression to the tone could be seen. Moreover, presentations of the CS 45 days later induced multiunit and behavioral responses in both structures, only in the conditioned group. These results are used for discussion of the role of learning-induced changes in the sensory structure (mMG) as compared with changes in an associative structure (hippocampus), during acquisition and retention of a conditioned response.     

Psychoneurogenic stress influences upon retention of an inhibitory avoidance response in the rat

Hormones and peptides involved in the response of an organism to stress play a modulating role in learning and memory processes. We studied whether psychoneurogenic stressors such as sound stimulation or novelty influence retention of an inhibitory avoidance response. An impairing effect on retention was observed when these stressors were applied shortly after the acquisition trial, but not after a 3-h delay. However, sound stimulation and novelty applied shortly before the retention test may facilitate retention behavior. It is suggested that the effect of psychoneurogenic stressors on retention behavior may be linked to influences on consolidation and retrieval processes mediated through the neurohumoral response of the organism to stress.