Planned contrasts to test for pharmacological versus expectancy effects showed that ERN amplitude for errors was significantly smaller in alcohol group (M = −4.14 µV) compared to the average of control and placebo groups (M = −5.56 µV), t(957) = 2.34, p = .02, consistent with a pharmacological effect. The control group (M = −5.20 µV) did not differ reliably from the average of placebo and alcohol groups (M = −4.99 µV), t < 1, p = .76.
