Therefore, despite the ease with which home-cage drinking tests can be conducted, the reinforcing effects of ethanol cannot be readily observed under home-cage access conditions. Essentially, an examination of the reinforcing properties of ethanol, and its disruption, requires an evaluation of the amount of effort, or work, a subject is willing to put forth in order to obtain access to ethanol. Operant procedures provide an elegant method to measure this effort and work. Operant testing allows for increased sensitivity of measurement as it pertains to ethanol self-administration and the effects of pharmacological challenges on these measurements. Thus, measurements in latency to drink (lick), changes in response rate across time, and changes in the level of effort exerted to obtain ethanol can be evaluated in the operant setting. In addition, the operant procedure is tailor made to examine cue-induced ethanol-seeking behavior, whereas home-cage procedures do not allow for easy assessment of this behavior. The fact that motor activity and food intake are rarely measured in operant experiments indicates that specificity of drug effects cannot always be determined, although the presence of
