Performance of dyslexic children on speech perception tests

Several researchers who have compared the performance of dyslexic and normal-reading children on a variety of different tasks have suggested that dyslexic children may have subtle deficits in the phonemic analysis of spoken as well as written language. Thus it is of interest to know how children who have extraordinary difficulty learning to read can perform explicity auditory-phonetic tasks. Seventeen dyslexic children (10 years of age) and a group of 17 controls were administered tests of identification and discrimination of synthesized voiced stop consonants differing in place of articulation. These were tests of the type used to study categorical perception in adults, adapted for use with young children. Significant differences between dyslexics and controls were found in both kinds of tasks; the pattern of identification and discrimination differences suggests an inconsistency in the dyslexics' phonetic classification of auditory cues. A significant relationship was found between reading level and speech discrimination.     

The effect of modification of expressive displays on vicarious emotional arousal

Several recent experiments have demonstrated that modulation of the facial expressive response is accompanied by changes in autonomic arousal and subjective response to painful stimuli. The present study asked whether facial self-regulation may also bring about changes in covert vicarious emotional experience. Three groups of subjects were exposed to a videotaped model displaying intermittent pain to shock in a differential vicarious autonomic conditioning paradigm. Subjects in the inhibit and amplify groups were asked, respectively, (a) to inhibit their facial muscles or (b) to pose a facial response of pain when the model was shocked. It was predicted that the inhibit group would show less autonomic arousal to the model's expressive display (empathy) and less conditioning (as measured by skin conductance and heart rate change), and the amplify group more empathy and conditioning, than a third group who was given no facial instruction. In fact, the amplify group showed more skin conductance arousal, heart rate acceleration, and activity in response to the model's expressive display of pain than did the other two groups (which were not different from each other), but no more autonomic or facial conditioning. The overall pattern of physiological data is interpreted as generally supportive of a facial feedback theory of emotion: where significant between-groups' differences were obtained in facial activity, as in vicarious instigation, autonomic arousal differences also emerged; where no expressive differences were obtained, as in vicarious conditioning, no differences in autonomic arousal were found.     

On the form and location of the Psychometric Bisection Function for time

The Psychometric Bisection Function for time relates the discriminability of intermediate duration stimuli to a short and long training duration. Bisection Functions for animals (R. M. Church & M. Z. Deluty, Journal of Experimental Psychology: Animal Behavior Processes, 1977, 3, 216–228) confirm Weber's Law and also show indifference between short and long reports at the geometric mean of the training durations. Two discrimination processes are studied which, in combination with different constructions of the subjective time scale, result in Bisection Functions which differ in form and location. The two discrimination processes use a likelihood ratio rule or a similarity rule to compare intermediate durations to the training durations. These rules in combination with two different constructions of the subjective time scale result in four models which conform to Weber's Law. For one of the scales subjective time is a power function of real time with the scalar property on variance (Scalar Timing). For the other, subjective time is a logarithmic function of real time with constant variance (Log Timing). Both Log and Scalar Timing assume normality on the subjective scale. Only three of these models also entail the geometric mean at the indifference point. The exception is Scalar Timing with the likelihood ratio discrimination rule. This model entails indifference at approximately the harmonic mean of the training stimuli. Variants of the remaining three models differ theoretically but alternatives are difficult to discriminate empirically. A contrast is provided by a Poisson Timing subjective scale in which variance increases directly with the mean. This scale results in indifference at the geometric mean for both discrimination rules but violates Weber's Law in both cases.     

Stuttering and fluency: Exclusive events or points on a continuum?

In recent years, several studies have been conducted in which the fluency of stutterers was compared with that of normal speakers. These investigations have been of two basic types, some involving objective measures of physiologic, aerodynamic, or acoustic features of the subjects' fluent speech signal, and others involving experiments performed in which listeners attempted to distinguish the fluency produced by stutterers from that generated by normal speakers. The body of literature pertaining to each of these two types of investigations is reviewed and interpreted. The interpretations offered are then developed in an effort to shed further light on both fluency and stuttering. Implications for further research, as well as for the evaluation, treatment, and post-therapy assessment of stutterers are drawn.     

Discrete dynamic choice: An extension of the choice models of thurstone and luce

The present paper deals with the extension of two well-known static discrete choice theories to the dynamic situation in which individuals make choices at several points in (continuous) time. A dynamic version of Luce's Axiom, “independence from irrelevant alternatives”, is proposed and some of its implications are derived. In the static case Yellott (J. Math. Psych. 1977, 15, 109–146) and others have demonstrated that an independent random utility model generated from the extreme value distribution exp(?e^?ax?b) becomes equivalent to Luce's Axiom. Yellott also introduced an axiom called “invariance under uniform expansions of the choice set”, and he proved that within the class of random utility models with independent identically distributed utilities (apart from a location shift) this axiom is equivalent to Luce's Axiom. These results are extended to the dynamic situation and it is shown that if the utility processes are expressed by so-called extremal processes the corresponding choice model is Markovian. A nonstationary generalization is proposed which is a substantial interest in applications where the parameters of the choice process are influenced by previous choice experience or by time-varying exogenous variables. In particular, it is demonstrated that the nonstationary model is Markovian if and only if the joint choice probabilities at two points in time have a particular form. Thus, the paper provides a rationale for applying a specific class of Markov models as the point of departure when modelling mobility processes that involve individual discrete decisions over time.     

An axiomatization of the ratio/difference representation

If ≥_r and ≥_d are two quaternary relations on an arbitrary set A, a ratio/difference representation for ≥_r and ≥_d is defined to be a function f that represents ≥_r as an ordering of numerical ratios and ≥_d as an ordering of numerical differences. Krantz, Luce, Suppes and Tversky (1971, Foundations of Measurement. New York, Academic Press) proposed an axiomatization of the ratio/difference representation, but their axiomatization contains an error. After describing a counterexample to their axiomatization, Theorem 1 of the present article shows that it actually implies a weaker result: if ≥_r and ≥_d are two quaternary retations satisfying the axiomatization proposed by Krantz et al. (1971), and if ≥_r′ and ≥_d′ are the relations that are inverse to ≥_r and ≥_d, respectively, then either there exists a ratio/difference representation for ≥_r and ≥_d, or there exists a ratio/difference representation for ≥_r′ and ≥_d′, but not both. Theorem 2 identifies a new condition which, when added to the axioms of Krantz et al. (1971), yields the existence of a ratio/difference representation for relations ≥_r and ≥_d.     

The effects of control on perceived fairness of procedures and outcomes

On the basis of Thibaut and Walker's theory of procedural justice, it was predicted that subjects who experienced control through choosing a trial decision rule would be more satisfied with the outcome of a dispute and the conflict resolution procedure than would yoked subjects who were not given control. Two additional conditions were added to the design in order to investigate the extent to which control had an influence on trial evaluations independent of being allowed to discuss the rules and obtaining a preferred rule in the absence of actual choice. Regardless of role in the dispute (accuser, accused, or no knowledge) and the nature of the rule adopted, those subjects who exercised control through rule choice evaluated all aspects of the trial experience more positively than subjects who did not exercise control through rule choice. The results also revealed that discussion of the rules and obtaining the preferred rule without choice contributed positively to evaluations of the trial procedure and verdict.     

Neuropsychological assessment of learning disabilities: a discriminant analysis

The neuropsychological test scores of 23 learning disabled children were compared with those of a matched population of normal children in the 9-1 to 13-1 age range. All children were administered the Wechsler Intelligence Scale for Children-Revised (WISC-R), a dichotic listening task involving both free and directed recall conditions, a handedness inventory, the Tactile Performance Test and the Category Test from the Halstead-Reitan Neuropsychological Test Battery. A multivariate analysis of variance resulted in a significant separation between groups (p less than .001) using these procedures. A stepwise discriminant function analysis revealed that both of the directed dichotic tasks contributed the most of all 13 measures to the significant group separation. In addition, other cognitive tasks found to discriminate normal from learning disabled children include general verbal processes, concept formation, and tactile memory. These findings suggest that the directed dichotic listening procedure and the WISC-R Verbal IQ measure are reasonably valuable clinical tools in the classification of learning disabilities.     

Fluid and crystallized intelligence and primacy/recency components of short-term memory

Primacy and recency recall measures, obtained from both free and probed-recall tasks, were included in a battery of tests which also contained markers for fluid intelligence, crystallized intelligence, and cognitive speed factors. Our results confirmed previous findings that for subjects within the normal range of abilities, recency recall from probed-recall tasks is more closely linked to intelligence than is primacy recall. A new finding was also obtained: that primacy recall is correlated more with measures of cognitive speed than is recency recall. These results are discussed in terms of the concept of working memory and its relation to intelligence.