Self-monitoring of stuttering: Reactivity and accuracy

The effects of self-monitoring were examined among 33 adult and adolescent stutterers who were divided into three equal-sized groups representing three levels of self-report accuracy. The overall results were in general agreement with the numerous previous reports of the ameliorative effects of self-observation. However, when the data were examined in relation to level of self-report accuracy, the self-monitoring procedure was found to be reliably reactive only for the least accurate group. This unexpected result may have been due to the influence of differences in the severity of disfluencies between subjects. Moreover, present findings suggest that the discrepant conclusions of previous research on the self-monitoring of stuttering may have been the result of a failure to investigate sufficiently large and representative numbers of subjects.     

The accuracy of four approximations to noncentralF

The accuracy of the two-moment, three-moment, square root, and cube root approximations to the noncentralF distribution was assessed using 7,920 entries from Tiku’s (1967) power tables. Tiku’s tables list exact values of β for α= .005?.05, ν₁ = 1?12, ν₂ = 2?120, and ?= 0.5?3.0. Analysis of the errors showed generally satisfactory performance for all four approximations. The three-moment approximation was most accurate, registering a maximum error of only .009. The other three approximations had maximum errors of ±.02, except for the square root approximation at ν₂ = 2, where maximum errors of .05 occur. Approximation error increased with decreases in ν₁ and, less consistently, with increases in ν2. Error was nonmonotonically related to ?. A second investigation explored the accuracy of the approximations at values of αranging from .10 to .90. All four approximations degraded substantially in this situation, with maximum errors ranging from ?.09 to .05. If the analysis is restricted to cases where ν₁ τ; 1 and ν₂ τ; 2, maximum errors drop to roughly ±.03. We conclude that the approximations perform reasonably well for small αand moderately well for larger values, if certain restrictions are imposed. From a computational standpoint, however, there is little advantage to using approximate as opposed to exact methods unless exact values ofF _α are known in advance.     

The predictive accuracy of intertemporal‐choice models

How do people choose between a smaller reward available sooner and a larger reward available later? Past research has evaluated models of intertemporal choice by measuring goodness of fit or identifying which decision‐making anomalies they can accommodate. An alternative criterion for model quality, which is partly antithetical to these standard criteria, is predictive accuracy. We used cross‐validation to examine how well 10 models of intertemporal choice could predict behaviour in a 100‐trial binary‐decision task. Many models achieved the apparent ceiling of 85% accuracy, even with smaller training sets. When noise was added to the training set, however, a simple logistic‐regression model we call the difference model performed particularly well. In many situations, between‐model differences in predictive accuracy may be small, contrary to long‐standing controversy over the modelling question in research on intertemporal choice, but the simplicity and robustness of the difference model recommend it to future use.     

Cognitive models of risky choice: parameter stability and predictive accuracy of prospect theory

In the behavioral sciences, a popular approach to describe and predict behavior is cognitive modeling with adjustable parameters (i.e., which can be fitted to data). Modeling with adjustable parameters allows, among other things, measuring differences between people. At the same time, parameter estimation also bears the risk of overfitting. Are individual differences as measured by model parameters stable enough to improve the ability to predict behavior as compared to modeling without adjustable parameters? We examined this issue in cumulative prospect theory (CPT), arguably the most widely used framework to model decisions under risk. Specifically, we examined (a) the temporal stability of CPT’s parameters; and (b) how well different implementations of CPT, varying in the number of adjustable parameters, predict individual choice relative to models with no adjustable parameters (such as CPT with fixed parameters, expected value theory, and various heuristics). We presented participants with risky choice problems and fitted CPT to each individual’s choices in two separate sessions (which were 1 week apart). All parameters were correlated across time, in particular when using a simple implementation of CPT. CPT allowing for individual variability in parameter values predicted individual choice better than CPT with fixed parameters, expected value theory, and the heuristics. CPT’s parameters thus seem to pick up stable individual differences that need to be considered when predicting risky choice.     

Evidence-based treatment of stuttering: II. Clinical significance of behavioral stuttering treatments

An evidence-based framework can be described as an empirically-driven, measurement-based, client-sensitive approach for selecting treatments. It is believed that using such a framework is more likely to result in a clinically significant outcome. For this paper, a clinically significant outcome was defined as a meaningful treatment change. It was suggested that there are at least three groups for whom a treatment's outcome is meaningful. These groups include clinicians/clinical researchers, the clients, and relevant others who have some interest in the outcome (e.g., parents of a child who stutters). The meaning and measurement of clinical significance was discussed for each of these three groups, based on research from the behavioral stuttering treatment literature. EDUCATIONAL OBJECTIVES: The reader will learn about and be able to (1) broadly define a clinically significant outcome and identify some of the groups who are interested in such an outcome and (2) describe how clinical significance has been evaluated in stuttering treatment within an evidence-based framework.     

An other perspective on personality: meta-analytic integration of observers' accuracy and predictive validity

The bulk of personality research has been built from self-report measures of personality. However, collecting personality ratings from other-raters, such as family, friends, and even strangers, is a dramatically underutilized method that allows better explanation and prediction of personality's role in many domains of psychology. Drawing hypotheses from D. C. Funder's (1995) realistic accuracy model about trait and information moderators of accuracy, we offer 3 meta-analyses to help researchers and applied psychologists understand and interpret both consistencies and unique insights afforded by other-ratings of personality. These meta-analyses integrate findings based on 44,178 target individuals rated across 263 independent samples. Each meta-analysis assessed the accuracy of observer ratings, as indexed by interrater consensus/reliability (Study 1), self-other correlations (Study 2), and predictions of behavior (Study 3). The results show that although increased frequency of interacting with targets does improve accuracy in rating personality, informants' interpersonal intimacy with the target is necessary for substantial increases in other-rating accuracy. Interpersonal intimacy improved accuracy especially for traits low in visibility (e.g., Emotional Stability) but only minimally for traits high in evaluativeness (e.g., Agreeableness). In addition, observer ratings were strong predictors of behaviors. When the criterion was academic achievement or job performance, other-ratings yielded predictive validities substantially greater than and incremental to self-ratings. These findings indicate that extraordinary value can gained by using other-reports to measure personality, and these findings provide guidelines toward enriching personality theory. Various subfields of psychology in which personality variables are systematically assessed and utilized in research and practice can benefit tremendously from use of others' ratings to measure personality variables.     

Listener perceptions of stuttering and stuttering modification techniques

PurposeThe purpose of this study was to analyse naïve listener perceptions of speech containing unmodified stuttering, use of the pull-out technique, and use of preparatory-sets.MethodParticipants (N = 62) were randomly assigned to listen to one audio sample (unmodified stuttered speech, speech with pull-outs, or speech with preparatory-sets) and completed a survey assessing perceptions of the speaker’s speech and personality and the listener’s comfort level and willingness to social interact with the speaker.ResultsSurvey results revealed low perceptual ratings in all experimental conditions. Unmodified stuttered speech received significantly more positive ratings than the stuttering modification conditions in all measurements except for speech naturalness. Listeners reported being less willing to socially interact with those who use preparatory-sets than unmodified stuttered speech.ConclusionThe use of stuttering modification techniques did not improve listeners’ perceptions or willingness to interact with persons who stutter. Clinicians and those who stutter should be aware that the use of speech techniques will not decrease negative social interactions or stereotypes.     

Voluntary stuttering suppresses true stuttering: a window on the speech perception-production link

In accord with a proposed innate link between speech perception and production (e.g., motor theory), this study provides compelling evidence for the inhibition of stuttering events in people who stutter prior to the initiation of the intended speech act, via both the perception and the production of speech gestures. Stuttering frequency during reading was reduced in 10 adults who stutter by approximately 40% in three of four experimental conditions: (1) following passive audiovisual presentation (i.e., viewing and hearing) of another person producing pseudostuttering (stutter-like syllabic repetitions) and following active shadowing of both (2) pseudostuttered and (3) fluent speech. Stuttering was not inhibited during reading following passive audiovisual presentation of fluent speech. Syllabic repetitions can inhibit stuttering both when produced and when perceived, and we suggest that these elementary stuttering forms may serve as compensatory speech gestures for releasing involuntary stuttering blocks by engaging mirror neuronal systems that are predisposed for fluent gestural imitation.     

Subtyping stuttering I: a review

A reliable and practical subtype system of stuttering should enhance all related scientific work concerned with this disorder. Although a fair number of classification systems have been offered, to date, none has received wide recognition or has been routinely applied in research or clinical spheres. Whereas progress has been made in understanding and treating the disorder, for the most part stuttering continues to be viewed and addressed as a unitary problem. The objectives of the current article are to (a) highlight the motivation for identifying sub-types of stuttering, (b) outline the issues involved in researching subtypes, and (c) address the question of whether or not subtyping is plausible for this disorder. Toward these ends, a broad-based review of past concepts regarding subtypes of stuttering and stutterers is presented according to seven categories that reflect the various authors' conceptual or experimental approaches. Selected studies for each category are also presented to illustrate the research problems and challenges. It is concluded that islands of progress can be identified in subtype research, particularly in studies of children. It is recommended that future studies include multiple factors or domains in the data collection process, especially with young children during the formative years of the disorder, when substantial overlap in the development of several speech/language domains occurs. EDUCATIONAL OBJECTIVES: (a) Readers will be able to describe the theory and research concerning the numerous attempts to subtype stuttering, particularly during the past 50 years; (b) Readers will be able to explain the general issues that need to be resolved in order to identify subtypes as well as current and future research strategies aimed at achieving these goals.     

"Roadblocks" revisited: neural change, stuttering treatment, and recovery from stuttering

In light of emerging findings concerning untreated recovery and neural plasticity, this paper re-examines the viability of an NIH conference recommendation [Cooper, J. A. (1990). Research directions in stuttering: Consensus and conflict. In Cooper, J. A. (Ed.), Research needs in stuttering: Roadblocks and future directions (pp. 98-100). Rockville, MD: American Speech-Language-Hearing Association.] that adults who have recovered from stuttering might inform our understanding of the nature and treatment of persistent stuttering. It is suggested that those who have recovered could constitute a behavioral, cognitive, and neurophysiologic benchmark for evaluating stuttering treatment for adolescents and adults, while helping to identify the limits of recovery from a persistent disorder. This possibility seems especially promising because of findings from recent studies investigating untreated recovery during childhood and adulthood, the emerging evidence concerning neural plasticity and reorganization, and reports of neural system changes during stuttering treatment. Potential obstacles to applying findings from unassisted recovery to treatment do exist, but the benefits of attempts to fully understand stuttering certainly outweigh the difficulties. EDUCATIONAL OBJECTIVES: After completing this activity, the learner will be able to: (1) describe two complexities involved in determining whether recovery from stuttering was assisted or unassisted; (2) discuss the implications for stuttering research of two neural plasticity research findings from areas other than stuttering; and (3) evaluate the possible implications for stuttering treatment of a coordinated research program that addresses behavioral, cognitive, and neurological characteristics of assisted and unassisted recovery from stuttering.     

Violence risk assessment and women: predictive accuracy of the HCR-20 in a civil psychiatric sample

Research to date has not adequately demonstrated whether the HCR-20 Violence Risk Assessment Scheme (HCR-20; Webster, Douglas, Eaves, & Hart, 1997), a structured violence risk assessment measure with a robust literature supporting its validity in male samples, is a valid indicator of violence risk in women. This study utilized data from the MacArthur Study of Mental Disorder and Violence to retrospectively score an abbreviated version of HCR-20 in 827 civil psychiatric patients. HCR-20 scores and predictive accuracy of community violence were compared for men and women. Results suggested that the HCR-20 is slightly, but not significantly, better for evaluating future risk for violence in men than in women, although the magnitude of the gender differences was small and was largely limited to historical factors. The results do not indicate that the HCR-20 needs to be tailored for use in women or that it should not be used in women, but they do highlight that the HCR-20 should be used cautiously and with full awareness of its potential limitations in women.     

fMRI of developmental stuttering: a pilot study

The purpose of this investigation was to explore the feasibility of fMRI in the study of developmental stuttering. Speech contrasts (loud versus silent reading) and language contrasts (reading of semantically meaningful text versus nonsense words) of six developmental stutterers and six nonstutterers were compared using a commercial 1 Tesla MR-Scanner (Siemens Expert). Results indicate that mapping cortical function in persons who stutter is indeed feasible, even with a 1TMR-system. Compared to normals the stutterers seemed to employ different and particularly less differentiated auditory and motor feedback strategies in speech. They apparently rely on auditory processing and on cerebellar contribution as much during silent reading as during reading aloud. Moreover, they showed a greater involvement of the right hemisphere in language processing, activating not only the typical language areas on the left but also and with equal magnitude the right side homologues of these areas. In spite of the promising results, at present several practical problems such as possible movement artifacts and possible masking through scanner noise still hamper a more straightforward use of fMRI in the study of developmental stuttering.     

Forensic verification of stuttering

Although distinguishing between actual and pseudostuttering is usually straightforward, there are occasions, such as the case described, when the distinction is problematic. The subject of this report is a 33-year-old man who was accused of child molestation, and whose speech was a decisive issue in an earlier trial. The results of a speech assessment indicated that the subject was probably a stutterer, although there was no feasible means to determine his actual severity. It is suggested that, for several reasons, he probably could have been fluent during the criminal circumstances described. The author's conclusions, and recommendations to speech pathologists facing similar cases, are presented.     

Voice onset and articulatory constriction requirements in a speech segment and their relation to the amount of stuttering adaptation

This study evaluated the hypothesis that the amount of stuttering adaptation increases as the number of requirements for the prompt onset of phonation and complete articulatory constriction across passages decreases. To test this prediction, three special reading passages were constructed. The number of requirements for the quick initiation of phonation and complete articulatory constriction decreased from passages I to II to III. Eleven stutterers read each passage five times. Of these individuals, seven exhibited the well-known adaptation effect on all three selections. However, adaptation increased significantly from passage I to II to III. Among the remaining four subjects, three failed to adapt on passage I which contained the greatest number of requirements for the prompt onset of phonation and complete articulatory constrictions. These results were interpreted as supporting the hypothesis under test.