Apparatus
Participants were seated 57 cm from a 29 X 51 cm 60Hz LCD monitor. Head position was stabilized with a chin rest. The experiment was programmed in Python on open source PsychoPy software (Peirce, 2007). EEG data was recorded continuously from 64 scalp electrodes arranged according to the extended international 10-20 system. We used the BioSemi active-two EEG system, sampling at 512 Hz. To control for eye movements and blinks bipolar HEOG and VEOG were monitored online. These external channels were not included in any analyses.