Human physiological benefits of viewing nature: EEG responses to exact and statistical fractal patterns.

Psychological and physiological benefits of viewing nature have been extensively studied for some time. More recently it has been suggested that some of these positive effects can be explained by nature's fractal properties. Virtually all studies on human responses to fractals have used stimuli that represent the specific form of fractal geometry found in nature, i.e. statistical fractals, as opposed to fractal patterns which repeat exactly at different scales. This raises the question of whether human responses like preference and relaxation are being driven by fractal geometry in general or by the specific form of fractal geometry found in nature. In this study we consider both types of fractals (statistical and exact) and morph one type into the other. Based on the Koch curve, nine visual stimuli were produced in which curves of three different fractal dimensions evolve gradually from an exact to a statistical fractal. The patterns were shown for one minute each to thirty-five subjects while qEEG was continuously recorded. The results showed that the responses to statistical and exact fractals differ, and that the natural form of the fractal is important for inducing alpha responses, an indicator of a wakefully relaxed state and internalized attention.

The impact of flicker from fluorescent lighting on well-being, performance and physiological arousal.

In working environments all over the world, fluorescent tubes are by far the dominating light source. Still, there have been very few studies on the impact of the non-visible flicker from fluorescent tubes. The purpose of the study was to compare the impact on subjective well-being, performance and physiological arousal of fluorescent light powered by conventional and high-frequency ballasts. Thirty-seven healthy males and females were subjected to either condition in a laboratory office on two separate occasions with 1 week in between. Although the methodology was quite extensive, only a few general effects were observed. However, when the light was powered by the conventional ballasts, individuals with high critical flicker fusion frequency (CFF) responded with a pronounced attenuation of EEG alpha waves, and an increase in speed and decrease in accuracy of performance. These results may be understood in terms of heightened arousal in the central nervous system in response to the pronounced light modulation caused by the conventional ballasts. In order to alleviate this potential stress source, it is recommended that fluorescent lighting be powered by electronic high-frequency ballasts of good quality.

The impact of daycare environments on children's mood and behavior.

This study examined the influence of different environmental features at nine daycare centers on 74 children's (42 boys and 32 girls) emotions in relation to their individual traits. The environments were predominantly assessed by semantic scales, and the children's emotions using a structured observational technique. Hierarchical regression analysis revealed that the activation level as well as the control of the behavior were related to the individual traits of the children, whereas the directedness and the hedonic tone of the behavior were related to the environment and the situation (meal or free play). Of special interest is the result that extrovert children displayed higher levels of control than the more introvert children. The most important quality of the physical daycare environment was unity, whereas intensity and familiarity were to most salient qualities of the social environment.

Psychologic tests in the evaluation of psychic changes after myelography with metrizamide.

The possibility of using psychologic tests to demonstrate psychic changes following myelography with metrizamide was investigated in 15 patients. The tests were made before and after the examination. The results revealed psychic changes of cognitive nature to occur both at 6 and at 24 hours after myelography. Of the tests used determination of the reaction time gave most significant results. Subjectively the patients considered themselves better 24 hours after the examination than after 6 hours. This was not confirmed from the test results--an observation indicating the sensitivity of the test instruments used. Thus, these appear to be well suited to study cognitive changes caused by the contrast media used in this particular type of examination. Since the tests are repeatedly performed, the effect of habituation and of learning cannot be avoided. However, when applied in groups of patients, in whom the effects of different contrast media are compared, the disadvantages of these specific effects can be neglected.

Psychic changes following myelography with metrizamide and iohexol. A comparative investigation with psychologic tests.

Based upon the results of repeated psychologic tests, psychic impairment following myelography has been studied in 60 patients. Thirty of these had lumbar myelography with metrizamide and 30 with iohexol. Psychic impairment was noted in both groups, although with a higher frequency and much more marked in the group which had metrizamide myelography. For this type of examination iohexol is thus to be recommended.