Effects of three levels of arousal on 3-back working memory task performance.

This study investigated how three levels of arousal affected performance of a 3-back working memory task. Ten female and ten male university students participated in this experiment. With pictures selected from a group test, three levels of arousal were induced--i.e., tense, neutral, and relaxed emotions. Each subject was run through the procedure three times, once for each arousal level. The procedure consisted of six phases for each arousal condition: (1) Rest 1 (2 min), (2) Picture 1 (presenting emotion arousing photos for 2 min), (3) 3-back working memory task 1 (2 min), (4) Picture 2 (presenting emotion-arousing photos for 2 min), (5) 3-back working memory task 2 (2 min), and (6) Rest 2 (2 min). The skin conductance level of electrodermal activity was also measured during all phases of the experiment. The accuracy rate of 3-back working memory task performance was the highest at a neutral emotional state, followed by relaxed and then tense emotional states. There were no significant differences in reaction time.

Development of the Real-Time Subjective Emotionality Assessment (RTSEA) system.

A new Real-Time Subjective Emotionality Assessment (RTSEA) system was developed for this study. The system is composed of two parts: an emotionality input and evaluation parts. An experiment was conducted in order to investigate the effectiveness of the RTSEA system. The present study compared Galvanic Skin Response (GSR) with the RTSEA by presenting 28 subjects with pictures that aroused either positive or negative emotion. Following the experiment, a subjective assessment using a questionnaire was given to the same subjects. According to the correlation coefficients, changes of the RTSEA had strong correlations with the changes of the GSR. Also, the questionnaire results showed marked similarity to the average responses of the RTSEA. In conclusion, the most remarkable characteristic of the present system is that it not only assesses the average emotionality when stimuli are presented, but also shows the trend of change in emotionality over time.

Ambient air monitoring of PCDD/Fs and co-PCBs in Gyeonggi-do, Korea.

We started the monitoring for PCDD/Fs in ambient air and soil in August 2001, and co-PCBs in January 2002. Decreasing of PCDD/Fs and co-PCBs levels in ambient air were observed. The higher PCDD/Fs levels were found in winter and lower in autumn. We found that the industrial incinerators influenced the PCDD/Fs levels in ambient air. In the 2,3,7,8-substituted PCDD/Fs concentration profiles, the three major congeners occupied 67% of the total mass. In case of co-PCBs, PCB#118, #105 and #77 were observed as the main congeners. Five cluster groups discriminated by ratio of four components, O(8)CDD, 1,2,3,4,6,7,8-H(7)CDD, 1,2,3,4,6,7,8-H(7)CDF and O(8)CDF, were obtained from HCA (hierarchical cluster analysis).

Young adult drivers' sensitivity to changes in speed and driving mode in a simple vehicle simulator.

The study was done to check replication of changes in sensitivity with a simple simulator as had been obtained in an experiment using the real road situation. Another purpose was to control simulator sickness which could have confounded data from testing with a simulator or in actual driving. Sensitivity of the drivers (72 healthy young adults, M age = 24 yr., SD = 5) while performing the driving task was measured in terms of subjective ratings of simulator sickness and affect, and physiological measures (i.e., galvanic skin responses and skin temperature) at different driving speeds and in driving mode conditions, using a simple vehicle simulator. Analysis showed measures of drivers' state, including simulator sickness, physiological indices, and subjective reports, increased with driving speed (30 --> 90 -->120 km/hr.) and driving mode change from the regular speed to sudden increasing to sudden decreasing speeds. Particularly, the results suggest that the increased autonomic nervous activation induces increase of rated simulator sickness. Based upon the same tendency in change of the simulator sickness and physiological state with driving speed and driving mode conditions, it was concluded that, if the results obtained from the simulator experiment can be generalized to the real situation, the simulator sickness must be considered a confounding factor. The results also suggest that the changes in human sensitivity are dependent upon aspects related to speed of a vehicle and driving mode.

Physiological evaluation on emotional change induced by imagination.

In this study, emotional changes were induced by four imaginations--pleasantness, unpleasantness, arousal, and relaxation. They were induced using situations or pictures, as stimuli for imagination, selected on the basis of subjective evaluation and were examined by analyses of the physiological signals of the central and autonomic nervous systems whether the intended emotions were appropriately achieved, and whether these emotional changes could be distinguished from the analysis of physiological signals. While participants were asked to recall each situation (for experiment 1--free recall) or picture (experiment 2--forced recall) of the four imaginations, Electroencephalogram (EEG) in the area of Fz and Cz, Electrocardiogram (ECG), Galvanic Skin Response (GSR), Skin Temperature (SKT), and Respiration (RSP) were measured. The analysis of the EEG revealed that three emotional states were classified by values of alpha/(alpha + beta) and beta/(alpha + beta) and the autonomic nervous system responses, particularly the average interval of R-R and RSP. The results suggest that the values of alpha/(alpha + beta) or beta/(alpha + beta) in the areas of Fz and Cz and the average interval of R-R and/or RSP can be reliable parameters to measure some of the emotional states.

Psychophysiological evaluation of simulator sickness evoked by a graphic simulator.

The present study investigated the effects of simulator sickness, as an important bias factor on evaluation of emotional changes under the controlled condition of driving a car for 60 min at a constant speed (60 km/h) in a graphic simulator. Simulator sickness was measured and analyzed every 5 min using both subjective evaluation and physiological signals. Results of the subjective evaluation showed there was a significant difference between the rest and the driving conditions 10 min after the main experiment started and that the level of difference increased linearly with time. Analysis of the central and the autonomic nervous systems showed the significant differences in delta, theta, alpha and beta bands of an electroencephalogram (EEG), skin temperature, and the R-R interval between the rest and the driving conditions after about 5 min from the start of driving. In particular, there was the highest correlation between parameter of theta and subjective evaluation, and thus theta was considered an effective physiological parameter for numerically evaluating simulator sickness. The results indicate that physiological changes due to simulator sickness can be a bias factor in evaluation of human sensibility.