The inappropriate smile and zygomatic muscle activity

Long-term recording of activity of the zygomatic muscle, the most important mimic muscle involved in smiling, was performed in 22 disorganized type schizophrenic patients with inappropriate smiles and 15 normal subjects in two separate experiments. During inappropriate smiles, the zygomatic muscle exhibited waxing and waning bursts of activity with an amplitude of 75 to 120 microV, which could not be distinguished from the activity observed during usual smiling in normal subjects. However, the duration of such activity tended to be longer when compared to that in usual smiling by normal subjects as well as by schizophrenic patients. In contrast to usual smiles, inappropriate smiles decreased with personal contact. When asked about their thoughts during smiling shortly after inappropriate smiles, more patients reported that they thought of nothing at all or something not necessarily pleasant rather than something pleasant that would be expected to induce smiling.     

Constraints on using the dual-task methodology to specify the degree of central executive involvement in cognitive tasks

The dual-task paradigm has been used to examine the role of the central executive in various cognitive tasks. In these studies, performance decrements in primary cognitive tasks performed concurrently with secondary executive tasks have been interpreted as evidence for the involvement of the central executive in those primary tasks. In the present study, we examined the effects of different secondary tasks on performance of three psychometric visuospatial tasks. The decrement in performance of these tasks when they were paired with secondary executive tasks was smallest for the psychometric task considered to most heavily involve the central executive and largest for the task considered least demanding of executive mechanisms. We propose that, when applied to the assessment of central executive involvement, the prevalent simple dual-task logic does not always apply. Special conditions that limit the application of the dual-task methodology include two inherently related factors--a response selection bottleneck and a strategic tradeoff between primary and secondary tasks.     

Threshold Models for Comparative Probability on Finite Sets

Let succeeds be a comparative probability relation on the set ℬ(S) of all subsets of a finite state space S. This paper presents and discusses necessary and sufficient axioms for several threshold models of succeeds, whose general representational form yields a probability measure P on ℬ(S) and a bivariate set function Omega>/=0 on ℬ(S)xℬ(S) such that for all A, Binℬ(S), A succeedsB if and only if P(A)>P(B)+Omega(A, B). Several conditions such as skew-monotonicity and additive separability will be imposed on the functional form of Omega. Copyright 2000 Academic Press.     

Choice reaction time of elbow flexion and extension during passive elbow motions

The effect of passive elbow motions on electromyographic reaction times (EMG-RTs) of the biceps brachii for elbow flexion and the triceps for elbow extension was investigated in 8 normal subjects, using a choice-RT task, in which the subject was uncertain about the response direction to perform until the arrival of response signal after the passive motion started. Compared to the static condition, choice EMG-RTs shortened only when the direction of passive and response movements was the same. It seems that passive motions act as prior information on direction of movement in the choice-RT task.     

Relative contributions of expressive behavior and contextual information to the judgment of the emotional state of another

This study used a technique for assessing the relative impact of facial-gestural expressions, as opposed to contextual information regarding the elicitor and situation, on the judgment of emotion. In Study 1, 28 undergraduates rated videotapes of spontaneous facial-gestural expressions and separately rated the emotionally loaded color slides that elicited those expressions. The source clarities of the expressions and slides were matched using correlation and distance measures, and 18 expressions and 9 slides were selected. In Study 2, 72 undergraduate receivers were shown systematic pairings of these expressions and slides and rated the emotional state of the expresser, who was supposedly watching that slide under public or private situational conditions. Expressions were found to be more important sources for all emotion judgments. For female receivers slides were relatively more important in the public than in the private situation.     

Is Trait Rumination Associated with the Ability to Generate Effective Problem Solving Strategies? Utilizing Two Versions of the Means-Ends Problem-Solving Test

This study examined the relationship between trait rumination and the effectiveness of problem solving strategies as assessed by the Means-Ends Problem-Solving Test (MEPS) in a nonclinical population. The present study extended previous studies in terms of using two instructions in the MEPS: the second-person, actual strategy instructions, which has been utilized in previous studies on rumination, and the third-person, ideal-strategy instructions, which is considered more suitable for assessing the effectiveness of problem solving strategies. We also replicated the association between rumination and each dimension of the Social Problem-Solving Inventory-Revised Short Version (SPSI-R:S). Japanese undergraduate students (N = 223) completed the Beck Depression Inventory-Second Edition, Ruminative Responses Scale (RRS), MEPS, and SPSI-R:S. One half of the sample completed the MEPS with the second-person, actual strategy instructions. The other participants completed the MEPS with the third-person, ideal-strategy instructions. The results showed that neither total RRS score, nor its subscale scores were significantly correlated with MEPS scores under either of the two instructions. These findings taken together with previous findings indicate that in nonclinical populations, trait rumination is not related to the effectiveness of problem solving strategies, but that state rumination while responding to the MEPS deteriorates the quality of strategies. The correlations between RRS and SPSI-R:S scores indicated that trait rumination in general, and its brooding subcomponent in particular are parts of cognitive and behavioral responses that attempt to avoid negative environmental and negative private events. Results also showed that reflection is a part of active problem solving.     

Critical role of foreground stimuli in perceiving visually induced self-motion (vection)

The effects of a foreground stimulus on vection (illusory perception of self-motion induced by a moving background stimulus) were examined in two experiments. The experiments reveal that the presentation of a foreground pattern with a moving background stimulus may affect vection. The foreground stimulus facilitated vection strength when it remained stationary or moved slowly in the opposite direction to that of the background stimulus. On the other hand, there was a strong inhibition of vection when the foreground stimulus moved slowly with, or quickly against, the background. These results suggest that foreground stimuli, as well as background stimuli, play an important role in perceiving self-motion.     

Synchronization error in bilateral simultaneous flexion of elbows.

Using 7 left- and 7 right-handed subjects, the difference in time between left and right arms in the initiation of bilateral simultaneous flexion of elbows (synchronization error) was measured under three conditions: response to a sound stimulus with a warning signal, response to a sound stimulus without a warning signal, and self-initiated trial (option). The absolute value of synchronization errors depended upon experimental conditions. In conditions 'with warning' and 'option' the dominance shown in performance of left-handed subjects was the mirror-image of that shown by the right-handed subjects. The right biceps muscle responded faster in left-handed subjects and vice versa. Right-handed subjects showed rather a constant value in their dispersion of synchronization errors.     

A simple device for detecting saccades and judging their intervals

A simple device is described with which the occurrence of saccades can be detected and their intervals classified by reference intervals determined by experimental requirements. The device reliably detects saccades of greater than 2 deg.