Brain wave data were recorded through the Netstation v.4.4 software package (EGI, Inc.) and EGI high impedance amplifiers, sampling at 250 Hz (EGI, Inc. Series 300 amplifier). The online filters were set at .1–100 Hz. All electrodes were referenced to Cz for recording and then re-referenced offline for data analysis. All impedances remained at or under 40 kΩ as indicated by impedance measures made immediately before and after the test session. The E-prime v.2.0 (PST, Inc.) software package controlled the stimulus presentation. Each child’s EEG and behavior were continuously monitored across the session so that stimulus presentation occurred only when the child was sitting still and looking at the monitor.
