consumed and dipper presentations per bout. The second study examined continuous access home-cage drinking and operant self-administration of ethanol under limited (30-min) access conditions (Samson et al., 1998). These authors reported that during initiation of ethanol drinking in the home-cage the order of magnitude for ethanol intake was AA~HAD1=HAD2>P; after employing a sucrose-fading procedure the order of magnitude for ethanol intake was P~HAD1>HAD2~AA; and the order of magnitude for ethanol self-administration under fixed-ratio four (FR-4) limited access operant conditions was HAD1>P=HAD2>AA. Again, these findings indicate some significant differences in the reinforcing effects of ethanol under limited access conditions.
