Free parameters from the exponential demand equation used to quantify the operant alcohol self-administration. A) Mean (±SEM) α values representing the elasticity of demand, the rate of change in the number of reinforcers earned with increases in cost (FR). B) The intensity of demand, reinforcers that would be earned at no cost, described by mean (±SEM) Q0 values. *, **, and *** correspond to p<.05, p<.01, and p<.001 using Fischer’s LSD test.