Bisecting RT with lateralized readiness potentials: Precue effects after LRP onset

Recent work has sought to use the time at which the Lateralized Readiness Potential (LRP) first develops (LRP onset) as a temporal landmark to bisect experimental effects on reaction time (RT). Many studies have found experimental effects on the time between the signal and LRP onset, but few have found effects on the time between LRP onset and RT (LRP-RT interval). The primary goal of this study was to produce an effect on the LRP-RT interval. We employed precuing, a manipulation likely to influence motor-programming processes at the end of the RT interval. Subjects performed a 4-alternative choice-RT task in which a signal prompted a button-press with the index or middle finger on the left or right hand. Precues preceded the signals and were either informative, reducing the set of response alternatives from four to two, or uninformative. Besides RT and LRP, we also measured electromyographic (EMG) activity and the P300 ERP component. RT, P300 latency, and the interval between the signal and LRP onset were all shorter with informative than uninformative precues, but the timing of EMG activity relative to RT remained the same. Most importantly, precuing affected the LRP-RT interval. Implications for bisecting RT with LRPs and the identity of processes affected by precuing are discussed.     

Gender and computer-mediated communication

A case study analyzed employees' attitudes toward, and experiences with, an intraorganizational electronic mail system. Results revealed that females perceived e-mail to be easier to use, more efficient, and more effective than males. They also gave higher ratings of appropriateness for using e-mail to transmit certain types of messages. Females (particularly managers) were more likely than their male counterparts to rely on co-workers to learn how to use e-mail. More females used the computer system for word processing, while more males and whites (who comprised 82.2% of the sample) had off-site connections to the computer system. No other distinctions were found regarding race—ethnicity. Implications for future research are discussed.The author is grateful to Karen Tracy, Robert Craig, and anonymous reviewers for their insights and suggestions.     

Social integration and social support in a life crisis: Effects of macrosocial change in east Germany

This process evaluation study examined what variables moderate and mediate treatment effects on days in stable housing and client satisfaction for homeless mentally ill clients. In general, demographic characteristics did not moderate either outcome variable. Housing contacts, entitlement contacts, mental health contacts, and supportive services were significant mediators of the treatment effect on days in stable housing. Program contacts, mental health contacts, and supportive services were significant mediators of client satisfaction. The authors thank the National Institute of Mental Health for their financial support (MH43248, MH42357) for this project, Dorothy Gano for word processing and editorial assistance, and Gitry Heydebrand, Melissa Dannelet, Betty Tempelhoff, Ruth Smith, and Laeeq Ahmad for assisting in the interviews of clients. We are also appreciative of the cooperation given to us by the staffs of Malcolm Bliss Mental Health Center, St. Patrick's Center, the Community Advocacy and Support Alliance Program, and the St. Louisemergency shelters. Finally, we thank all of the participants in this study; we hope that their homelessness has now ended. (The conclusions presented in this paper are the sole responsibility of the authors and do not necessarily reflect official National Institute for Mental Health policy.)     

Monitoring running-wheel movement using a serial mouse and an IBM-compatible system

A running-wheel-movement-detection system is described for use with an IBM-compatible system and a serial mouse. It is an adaptation of a system developed for use on a Commodore 64. The IBM-compatible system provides obvious advantages in speed, memory, data storage, and programming ease over the earlier Commodore 64 system.     

Parental Smoking and the “Epidemic” Spread of Cigarette Smoking1

“Epidemic” models of transitions between stages of cigarette smoking describe the spread of smoking behavior through face-to-face encounters. An epidemic model was successfully fitted that allowed epidemic parameters to be conditioned on the smoking status of adolescents' parents. Model comparisons supported the conclusion that the transition from nonsmoker to trier involved social contacts, whereas the transition from trier to regular smoker was best modeled as a constant rate (i.e., did not depend on the population prevalence of smokers). The transition rate from nonsmoker to trier was more rapid in children of smoking parents than in children of nonsmoking parents. Adolescents with and without smoking parents did not differ in the rate of transition from trier to regular smoking.     

Nasality and precision of articulation

Two reading passages, one with nasal consonants and one without, were tape-recorded for 72 subjects: 34 selected as having precise articulation and 38 selected as having imprecise articulation. These speech samples were evaluated for degree of precision and also for degree of nasality by the psychological scaling method of equal-appearing intervals employing a 7-point scale. Analysis indicated a relationship between degree of precision and degree of unpleasant nasality, that is, a tendency for decreases in precision to be accompanied by increased nasality and a tendency for males to be more imprecise in articulation and more nasal than females.     

Reinforcing effects of prerecorded words and delayed speech feedback on the verbal behavior of a neologistic schizophrenic

The possibility of using prerecorded words and 2-sec. delayed speech feedback as reinforcement in the reconditioning of intelligible verbal responses in a chronic, neologistic schizophrenic patient was investigated. A test situation was devised which involved daily presentation of 100 stimulus word-picture cards to elicit verbal responses. The results indicated that both singly presented prerecorded words and delayed speech feedback apparently strengthened correct and intelligible verbal responding.     

A method for simulating non-normal distributions

A method of introducing a controlled degree of skew and kurtosis for Monte Carlo studies was derived. The form of such a transformation on normal deviates [X N(0, 1)] isY =a +bX +cX ² +dX ³. Analytic and empirical validation of the method is demonstrated.This work was done while the author was at the University of Illinois at Champaign-Urbana.