The diagnostic meaning of "nervous breakdown" among lay populations.

Two studies investigated the nature of nervous breakdown (NB): a mental illness commonly referred to by individuals not professionally related to the field of mental health. The clinical profile of NB was first surveyed among 121 undergraduates using a symptom checklist. Descriptive statistics and analysis of variance indicated NB is a time-limited condition that presents with primarily anxious and depressed features, associated with a series of external precipitating stressors (e.g., interpersonal, employment, and financial losses). Dimensions significantly uncharacteristic of NB included psychoticism, somatization, phobic anxiety, and mania. These results were replicated in a community sample of 189 adults from urban and suburban areas of a large metropolitan city. Respondents held a relatively unitary view of NB: Combined-sample cluster analysis (N = 310) revealed 2 groups with similar symptom profiles that differed primarily with regard to level of distress associated with disorder. Thus, among this population, NB is not an amorphous term for generalized psychiatric disturbance.

A note on state individual differences in accuracy of response imagery: aftereffects and reminiscence.

In two sessions, separated by 7 days, subjects imagined themselves performing a tracking task under a massed practice schedule. After conditions of interpolated rest and no-rest, which were counterbalanced across sessions, subjects actually performed the tracking task. During imagery practice, subjects verbally reported the temporal component of the task. The temporal accuracy of verbal reports varied widely across subjects, but not within subjects. Furthermore, a performance gain was demonstrated as a function of interpolated rest versus no-rest (reminiscence effect). Finally, the accuracy of verbal reports predicted imagery aftereffects, but not reminiscence effects.

Response imagery: aftereffects and reminiscence.

In two experiments, subjects imagined themselves performing a tracking task under a massed practice schedule. After interpolated rest or no rest, subjects actually performed the criterion task. Some subjects' imagery was augmented with sounds that matched the temporal characteristics of the criterion task. These subjects produced greater aftereffects than subjects who imaged without augmentation or subjects provided with imagery augmentation matching a variation of the criterion. Reminiscence (performance gain attributed to interpolated rest) was demonstrated with imagery, except when the accompanying augmentation was faster than the criterion.

Environmental and personal determinants of support perceptions: three generalizability studies.

The extent to which perceived social support reflects characteristics of the environment, the personality of the perceiver, and their interaction is unknown. This article shows how the methods of generalizability theory can be used to address these questions. When participants rate the same targets on the targets' supportiveness, generalizability theory provides methods for determining the extent to which support judgments are determined by effects due to targets (supporters), perceivers, and their interaction. In 3 studies, each source of variance made significant contributions to support judgments, with the Perceivers x Supporters interaction, characteristics of supporters, and biases of perceivers making the largest contributions, respectively. The implications for theoretical models of perceived support are discussed.

Imaging goal-directed movement.

The main purpose of the present investigation was to determine how Shepard's (1968) second-order isomorphic principle relates to imaging goal-directed movement. Reports of movement times for actual and imaged movements were obtained using Fitts-type tapping tasks. Displays consisted of two different (referential) or two identical (nonreferential) stimulus pairs. In Experiments 1a and 1b, target width and amplitude were manipulated to produce two indexes of difficulty. In Experiments 2a and 2b, the index of difficulty was constant, and biases were created by indicating that movement time increased with decreases in target width or increases in amplitude. In all four experiments, reported movement time reflected Fitts' (1954) law for actual tapping and during early trials for referential imagery. In Experiments 1a and 1b, reported movement times for the two indexes of difficulty were similar for nonreferential imagery and at later trials for referential imagery. In Experiments 2a and 2b, reported movement times reflected the biases for nonreferential imagery and at later trials for referential imagery. The results suggest that propositional knowledge and information processing interact to control movement imagery.

Motor response variations: peripheral and central sources of error.

The purpose of this research was to test the hypothesis that the relative involvement of peripheral versus central nervous system activity during response variations determines the locus of error production in a subsequent criterion response. The hypothesis was tested by comparing ipsilateral and contralateral transfer of a criterion response following response variations that emphasized proportionately different involvement of the peripheral and central systems. When subjects were provided with knowledge of results (KR) to maintain a 30% maximum voluntary contraction (MVC), ipsilateral but not contralateral bias errors occurred on a subsequent dynamic response. When subjects maintained a 30% MVC without KR, however, subsequent ipsilateral bias errors were greater than contralateral bias errors. Finally,when subjects imaged a 30% MVC, subsequent bias errors were equivalent across limbs. These results are interpreted as support for the hypothesis.

Time, capacity, and selection between perceptual attributes.

Three experiments were run to determine whether time and central-processing capacity are requried to select between perceptual attributes. A same-different matching task was employed for all experiments. In Experiments 1 and 2, three sets of stimulus pairs were used, each of which varied along only one relevant perceptual dimension (color, size, or form). In Experiment 1, reaction time on the matching task was shown to be faster when the stimuli were presented in blocks in which all stimulus pairs came from the same set (blocked presentation) than when stimulus pairs from each of the three sets were randomly intermixed (random presentation). In Experiment 2, reaction time on a secondary probe task was faster during the encoding stage of a sequential mathcing task with blocked presentation than with random presentation. Experiment 3 indicated that this outcome could not be attributed to a difference in the number of possible stimulus alternatives. Thus, the results support the hypothesis that time and central-processing capacity are required to select between perceptual attributes.

Temporal characteristics of primary-secondary message interference in a dichotic listening task.

Previous experiments have shown that during performance of a shadowing task the unattended message is processed at a semantic level. Four experiments are reported that deal with the question of how processing of the unattended message influences the difficulty of shadowing the attended message. Experiment I demonstrated that pupil dilation measures the difficulty associated with a shadowing task. In Experiment II it was shown that during shadowing of 20-item lists pupil dilation decreases as shadowing continues when either words or white noise are in the unattended channel. These results support the idea that it takes time for the attentional mechanism to focus on the attended message. In Experiments III and IV it was found that this decrease in difficulty of shadowing is much less when the attended and unattended messages come from the same stimulus category (letter-letter, digit-digit). The results indicate that, when the unattended message is from the same stimulus category as the attended message, it can interfere with the ability of the attentional system to focus on the attended message.