Methods for improving the signal-to-noise ratio of endogenous-evoked potentials

A stimulus leads to a cortical response (i.e., evoked potential [EP]) which may be recorded from electrodes attached to the scalp. However, background cortical activity, considered as noise (n), is typically of equal or greater magnitude than the response, which is considered as signal (s). This situation leads to the masking of the presence of the electrocortical signal. Two methods are described which enable the enhancement of the signal with respect to the noise. The first method outlined is time-domain averaging. Its relation to Fourier averaging is also presented. Time averaging can lead to an enhancement of the signal with respect to the noise, known as the signal-to-noise ratio (SNR), by a factor of root N; N being the number of trials recorded. However, latency variability (i.e., jitter) present in the signal leads to a decrement in this maximal potential enhancement. The second technique is an adaptive filter method of averaged cross-correlations, developed by Woody (1967), which deals with the variable latency problem. The development of a latency corrected average developed by McGillem and Aunon (1977) is also presented. The final section describes methods for data handling once the electrocortical signal has been enhanced. It is then necessary to describe the EP quantitatively. Principal Components Analysis (PCA) allows for the quantitative compact representation of the evoked potential waveform. The method also allows for the testing of the effects of explanatory variables on the EP.     

Development of perceived adolescent relationship scale

The purpose of the present study was to develop an easily administered scale to assess adolescents' perceptions of both their own social competence and social participation in relationships. Six items were used to generate two factors that accounted for about 68% of the variance.     

Common problems and coping strategies II: Findings with adolescent suicide attempters

This study investigated the most common precipitants of adolescent suicide attempts and the strategies used to cope with such problems. Adolescent suicide attempters were compared with both distressed and nondistressed nonsuicidal adolescents on problems reported and coping strategies utilized. All three groups reported four problems as occurring most frequently: school, parents, friends, or boyfriend/girlfriend. The suicide attempters and distressed controls reported problems with parents more frequently than did nondistressed controls, while this latter group reported problems at school more frequently than did suicide attempters or distressed controls. Suicide attempters used social withdrawal, problem solving, and emotional regulation more than did nondistressed controls, but not more frequently than distressed controls. Distressed controls used wishful thinking and resignation more than did suicide atempters. Results are discussed in terms of the similarities between suicide attempters and nonsuicidal distressed adolescents and the need to more closely investigate specific subgroups of suicide attempters.     

Common problems and coping strategies I: Findings with normal adolescents

This study investigated problems commonly experienced by adolescents and the strategies they use to cope with these events. Coping strategies were examined across the subjects' omotional state and their evaluation of the problem. In general, adolescents reported four common Stressors that were similar across age groups and gender. However, males differed from females in the frequency of these problems. Further, while the Stressors were similar, the frequency with which the coping strategies were employed and the efficacy ascribed to them differed across sex and across problem type. These findings are discussed in terms of the stress and coping literature with adults and the implications for clinical assessment and treatment of adolescents.     

Lesbians' and gay men's experiences of discrimination and harassment in a university community

A survey of 125 lesbians and gay men in a university community was conducted to determine the incidence of discrimination, harassment, and violence. Nearly three fourths had experienced verbal abuse; 26% were threatened with violence; and 17% had personal property damaged. Students and roommates were most often those responsible. Most incidents were not reported to authorities, and many made changes in their daily routines to avoid harm. Over half of the sample feared for their personal safety; their fear was related to the amount of harassment and previous property damage. Men were more often victimized than women.     

Teaching self-treatment of cold symptoms to an anoxic brain injured adult

Traumatic brain injury can result in behavioral and physical deficits that require intensive post-acute residential rehabilitation. Behaviors targeted by such programs include basic self-care and living skills. We examined the efficacy of a behavioral training strategy to teach appropriate medical treatment of four different groups of simulated cold symptoms to an anoxic brain injured adult. The strategy included instructor prompting and feedback in the use of written task analyses and picture cues as self-administered prompts. Subsequent to baseline, the participant used written generic task analyses combined with picture cues and then, if necessary, written specific task analyses combined with picture cues to prompt appropriate self-treatment of the four types of colds. Written individualized task analyses, tailored to participant errors, were used to fade specific task analysis prompts and transfer stimulus control to the discriminative stimuli present in the picture cues. A multiple baseline design across responses showed that skill acquisition did not occur after generic task analysis training, but did so after specific task analysis training. The participant responded to all four types of colds for three consecutive trials at 100% correct under baseline conditions. Follow-up results indicated that transfer of stimulus control to the cold symptoms simulated by the picture cues alone did not maintain over time. Correct responding was retrained using generic and, if necessary, individualized task analysis training conditions.     

Teaching dancercise to persons who are mentally handicapped: Programming transfer of stimulus control to a community setting

This study demonstrated procedures to promote the acquisition and transfer of stimulus control of an age-appropriate exercise skill. Three young adults diagnosed as mentally handicapped in a residential setting were taught a commercial dancercise routine during individual training sessions using a package of instructional procedures. A combination of a multiple baseline across subjects and a multiple baseline across response groups design showed that skill acquisition occurred only after each subject received training, and that performance did not generalize across exercise response groups. Training progressively incorporated more participants, new teachers, and new settings. Ultimately, subjects performed in a community dancercise class attended by 100 nonhandicapped persons.     

Ask and You Shall be Given: Request Size and Donations to a Good Cause1

In an attempt to replicate the findings reported in this Journal by Weyant and Smith (1987), members or recent donors to a Canadian civil liberties organization were asked to donate money under one of three conditions: (a) In the control condition, they were simply asked for a donation; (b) in the “smaller request” condition, they were asked to make a donation, but amounts of Canadian $30 to $100 were suggested; and (c) in the “larger request” condition, amounts of $50 to $250 were suggested. Unlike the Weyant and Smith studies, we found no difference in the proportion of respondents making a donation, but significant differences in the size of the donations made by those making donations. In our study, the most effective way of getting large donations was to ask for a large amount. It was suggested that the most likely explanations for the differences in the results of the two studies were the following: First, our target population were previous donors to the organization, whereas those in the Weyant and Smith studies were not likely to have been. Previous research suggests that those who had been donors previously are influenced, positively, by requests for a specific large donation, whereas those not previously approached are, if anything, negatively influenced. Second, our “larger request” appears to be within a plausible range for donations, whereas the larger request in the Weyant and Smith study may have been seen as being outside of the plausible range. In any case, however, we would recommend caution in drawing a conclusion about the most effective request size to encourage people to donate money to charity.     

Energy and psychical pain

Several relationships between energy and psychical pain are developed in this paper. These concepts are a-structural and existential in spirit, although developed in the framework of some analytic formulations on personality. A key concept developed is that the nature of psychical pain is determined, in part, by the manner in which the state of psychical energy associated with the pain departs from a given healthy ideal.