Materials and Methods

Subjects
16 males and 8 females participated in the study and were paid A$10, age ranged from 19 to 48 years (mean = 27.5) and twenty were right-handed. Subjects reported no hearing deficits or neurological history, gave written informed consent and were free to withdraw from the study at any time without penalty. The study was approved by the local ethics committee.

Procedure
On arrival at the laboratory, subjects completed an informed consent form followed by demographics and personality questionnaires. They were fitted with EEG recording apparatus and seated in a sound attenuated recording booth where an EMF stressor (EMF) and an EMF attenuator (EMFatt) were attached. Subjects then performed a 3-minute auditory discrimination task after which the subject sat resting for two minutes with their eyes open (Resting EEG). This five-minute EEG protocol was repeated four times, and this twenty-minute series of tasks was performed three times, each with a different background condition (resulting in a total EEG recording time of sixty minutes). The three background conditions were ‘EMF’, consisting of exposure to an active MP, ‘EMFatt’, consisting of concurrent exposure to an active MP and Q-Link, and ‘CONTROL’, consisting of neither MP nor EMFatt. Condition order was counterbalanced across subjects, and subjects were unaware of which condition they were engaged in (single-blind). Further to this, immediately before and after each twenty-minute series of tasks, the Thaya Activation-Deactivation Adjective Check List (AD-ACL; Thaya, 1967) was administered. Subjects were continuously monitored throughout the experiment via closed circuit television.

Discrimination Task
Each discrimination task consisted of ninety 70 dB binaural tones, of which half were 1100 Hz [High] and half were 1000 Hz [Low]. Tone duration was 60 ms, with a variable interstimulus interval of 2 +/- 1 s, and stimuli were presented through speakers positioned approximately 1.5 m in front of the subject. Subjects were asked to respond as quickly and accurately as possible to the target tones with a button press. Target-frequency and response-hand were constant within subject and counterbalanced and randomly assigned between subjects. A trial block was given prior to the testing session to familiarise subjects with the task. Behavioural measures obtained were accuracy and reaction time, and to encourage peak performance throughout the session, after the practice block subjects were offered monetary reward (A$20) to perform at least as accurately and fast during the remainder of the session as they did in the practice block.

Materials
To enhance ecological validity, a standard Nokia 5110 mobile phone was used as a receiver to generate EMF (900 MHz EMF, 217 Hz pulse rate; 0.577 ?s pulse width; estimated maximum power 250 mW; actual emissions during experiment not measured). This was positioned 5 cm radial to the subject’s scalp midway between Oz and Pz, using a non-metallic external bracket. To reduce variability due to changes in signal strength, a standard script was employed that was sent by a phone in another room. The standard script consisted of spoken extracts from a radio play. These were not audible to the subject, but were played during each condition. The Q-Link was powered by 240 V mains with a 9 V D.C. transformer, and was positioned over the subject’s chest (left sternum) using a comfortable chest-strap and operated from a separate room. The position of EMF and EMFatt were constant throughout the experiment.

Con’t