Figure 1.

Results showed a main effect of Drug (A), where averaged across blocks and order, response bias was significantly higher in the nicotine relative to the placebo condition. There was also a trend-level Drug x Order interaction (B), which was driven by higher response bias in the nicotine relative to the placebo condition in those who received the placebo first, but not in those who received nicotine first. Furthermore, response bias in the placebo condition was higher for those who received nicotine first relative to those who received the placebo first. *p < 0.05.