The perceived strength of illusory contours

Illusory contours are not well understood, partially because a lack of physical substance complicates their specification via physical standards. One solution is to gauge illusory contours with respect to luminance-defined contours, which are easily quantified physically. Accordingly, we chose a metric (perceived contrast) that expresses illusory contour strength in terms of the physical contrast of luminance-defined contours. Using this metric, adult observers adjusted the contrast of a luminance-defined contour until it matched the perceived contrast of an illusory contour. Illusory contour length, inducer size, and inducer contrast all influenced illusory contour strength.. The results are adequately explained via low-level visual processes. It appears that matching paradigms can be beneficial in quantitative studies of illusory contours.     

REDUCTION OF SELF-INJURIOUS HAND MOUTHING USING RESPONSE BLOCKING

We evaluated a response-blocking procedure for reducing the self-injurious hand mouthing of 2 adults with profound disabilities. The procedure reduced mouthing in both cases. The results suggest research is warranted to delineate the behavioral process responsible for the effect of response blocking and to determine the procedure's long-term utility.     

Brief report: Psychometric properties of the adaptive behavior scale with psychiatric inpatients

This study investigated the psychometric properties of the Adaptive Behavior Scale (ABS) with a sample of chronic psychiatric inpatients. Patients (N = 117) on extended care wards of a state hospital were assessed with the ABS. An orthogonal principal-components analysis revealed three underlying factors (independent functioning, general maladaptation, and inappropriate social behavior). Evidence for construct validity was demonstrated by analyses demonstrating that the ABS could discriminate among patients according to age, diagnosis, and length of hospitalization. The results are consistent with previous data which suggest that the ABS can be appropriately used with psychiatric patients. Implications of the results for suggestions regarding possible revision of the ABS are discussed.     

Naming cAsE aLtErNaTeD words

A dual-route approach was used as an initial framework to examine the relation between presentation format and lexical processing in a naming task. In Experiments 1 and 3, words were presented in lowercase versus case-alternated format. Presentation format interacted with word frequency and regularity: For irregular words (e.g., pint), case alternation was additive with frequency, whereas for regular words (e.g., mint), case alternation and frequency interacted. Experiment 2 dissociated the locus of case-alternation effects from those of stimulus intensity. Stimulus intensity was additive with frequency and regularity, suggesting that whereas stimulus intensity affects encoding, case alternation affects lexical processing at a postencoding stage in the word recognition system. It was concluded that a dual-route approach provides a suggestive but incomplete account of how case alternation influences lexical processing. As an alternative to a dual-route approach, we show that the present results can be addressed and successfully simulated using an implemented version of Norris's (1994) multilevel model.     

Development of Adolescent Problem Behavior

The developmental model of adolescent antisocial behavior advanced by Patterson and colleagues (e.g., Patterson, Reid, & Dishion, 1992) appears to generalize the development of a diverse set of problem behaviors. Structural equation modeling methods were applied to 18-month longitudinal data from 523 adolescents. The problem behavior construct included substance use, antisocial behavior, academic failure, and risky sexual behavior. Families with high levels of conflict were less likely to have high levels of parent–child involvement. Such family conditions resulted in less adequate parental monitoring of adolescent behavior, making associations with deviant peers more likely. Poor parental monitoring and associations with deviant peers were strong predictors of engagement in problem behavior. These constructs accounted for 46% of the variance in problem behavior. Although association with deviant peers was the most proximal social influence on problem behavior, parental monitoring and family factors (conflict and involvement) were key parenting practices that influenced this developmental process.     

Trends in community mental health programming

One hundred-seventy-three mental health centers responded to a survey inquiring about allocation of staff time for mental health services and about the availability of an array of services at present, 3 years previous, and 3 years hence. The data reflect an emphasis upon reactive services as opposed to those considered proactive, and on services directed to individuals as opposed to other groups. However, this emphasis seems to be changing. Future projections call for a de-emphasis on individual reactive programs and increased emphasis on programs directed toward families and small groups, and toward proactive programs directed to the communities-at-large. Data about specific programs and services further suggest de-emphasis of services that involve the mental health professional and the client in direct interaction, and continued growth in services that can be delivered by less formally trained mental health workers or volunteers.     

A naturalistic study of the word frequency effect in episodic recognition

In order to separate the effects of experience from other characteristics of word frequency (e.g., orthographic distinctiveness), computer science and psychology students rated their experience with computer science technical items and nontechnical items from a wide range of word frequencies prior to being tested for recognition memory of the rated items. For nontechnical items, there was a curvilinear relationship between recognition accuracy and word frequency for both groups of students. The usual superiority of low-frequency words was demonstrated and high-frequency words were recognized least well. For technical items, a similar curvilinear relationship was evident for the psychology students, but for the computer science students, recognition accuracy was inversely related to word frequency. The ratings data showed that subjective experience rather than background word frequency was the better predictor of recognition accuracy.     

Optimal sequences of trials for balancing practice and repetition effects

This paper describes procedures for generating trial sequences to balance out practice effects and intertrial repetition effects in experiments consisting of repeated trials. In the sequences presented, each stimulus appears an equal number of times, is preceded equally often by itself and by each other stimulus, and is distributed in a “balanced” manner throughout the block of trials. Two criteria for balance are employed. One criterion aims to equalize the average position of each stimulus in the sequence. The second criterion maintains, as much as possible, a uniform interval between appearances of each stimulus in the sequence. For each criterion, optimal or near-optimal sequences are presented for experiments involving from three to nine different stimulus conditions. Suggestions are included for extending (e.g., doubling or tripling) the length of the sequences.     

The Possible-Word Constraint in the Segmentation of Continuous Speech

We propose that word recognition in continuous speech is subject to constraints on what may constitute a viable word of the language. This Possible-Word Constraint (PWC) reduces activation of candidate words if their recognition would imply word status for adjacent input which could not be a word - for instance, a single consonant. In two word-spotting experiments, listeners found it much harder to detectapple,for example, infapple(where [f] alone would be an impossible word), than invuffapple(wherevuffcould be a word of English). We demonstrate that the PWC can readily be implemented in a competition-based model of continuous speech recognition, as a constraint on the process of competition between candidate words; where a stretch of speech between a candidate word and a (known or likely) word boundary is not a possible word, activation of the candidate word is reduced. This implementation accurately simulates both the present results and data from a range of earlier studies of speech segmentation.