48 healthy males (right-handed) were divided into three groups: 1) exposure to the left side of the head, 2) exposure to the right side of the head, 3) sham exposure. All partcipants performed a spatial working memory task (that required either a left-hand or a right-hand response; 12 blocks of 50 trials). By averaging the reaction times separately for each block, the time course of the radiofrequencyirradiation effect could be assessed.
During the first two time blocks, the average reaction time of the right-hand responses [matching condition] was significantly longer under left-side exposure than under right-side exposure and sham exposure averaged together. This result confirms an effect of exposure on reaction times. Left-hand responses [mismatching condition] showed the same pattern, but it was non-significant. The participants failed to judge which phone was operating during the experiment. Although the present results confirmed some findings from the previous study (e.g. time dependency of reaction times), differences between the present results and previous findings may be due to the following factors: exposure duration, responding hand, side of exposure, and differences in the cognitive tasks. These factors may have major influence on the detection of radiofrequencyirradiation effects.