In the course of an experimental investigation 16 volunteers were exposed intermittently to the EM-radiation of a GSM-mobile phone in a single blind test. The mobile phone was placed at the left and right side of the head alternatively. The values of the SAR were higher than those of normal used mobile phones, caused by the chosen mode of operation. The SAR-values exceeded the values recommended by ICNIRP for exposure of the general population, but they were lower than those re-commended for occupational exposure. The influence of EM-radiation on cognitive performances was observed recording the numbers of identified signals, single and multiple reaction-time on demands for visual attention. The influence of the field on psychological basic activity was examined altering the autokinetic illusion during a rest situation. It was tested by analysis of variance whether the distribution of behavioural data was depending on the kind of field exposure (field and non-field, left and right side of application). In addition to that, the contrast during change between neutral and field-influenced situation was investigated. The results of the study show the possibility of an activation of brain structures caused by the pulsed EM-field. A very subtle, positive influence on the concentration performance and a better information processing were found. It has to be pointed out, that all observed and statistic significant effects were very weak in the behaviour parameters compared with those effects, which have been found as a result of learning and training. The subjects were not able to detect or perceive the EMFs and no influence on health and well-being could be found.