The infusion consisted of 100% dehydrated ethanol and saline, mixed to a 6.0% ethanol (v/v) solution and delivered by a dual-channel infusion pump. Participants submitted “drink” requests by pressing an electronic button; each request triggered the pump to deliver a volume calculated to raise aBAC by 7.5mg% over 2.5 minutes. During alcohol delivery the electronic button deactivated and additional requests could not be made. The CASE software generated instructions on a computer screen to guide participants during the experiment, conveying whether the “bar” was open or closed at a given point. At the onset of the session, instructions prompted participants to self-administer four successive priming doses (raising aBAC to ~30mg% in 10 minutes). A mandatory 5-minute waiting period ensued, during which participants completed post-priming subjective questionnaires. The CASE software specified a descending aBAC slope rate of −1mg%/minute during wait periods (resulting in aBAC of ~25mg% at the conclusion of the initial priming/waiting period). The ad libitum phase began at 15 minutes and lasted until 120 minutes.
