According to the Multiplicative Hyperbolic Model of reinforcer value (MHM), the value of a reinforcer is an increasing hyperbolic function of its size. In addition it is generally accepted that in the case of soluble reinforcers such as sucrose, value is an increasing function of molar concentration. The present experiment examined the interaction between size and concentration on the effectiveness of sucrose reinforcers in an operant choice paradigm. Rats were trained under an adjusting-magnitude schedule in which a response on lever B delivered a fixed volume of a sucrose solution, while a response on lever A delivered a 0.8-M sucrose solution, the volume of which, q_A, was adjusted according to the rats’ choices. When B was preferred in a given block of trials, q_A was increased in the following block; when A was preferred, q_A was reduced in the following block. The concentration and volume of B (c_B, q_B) were varied across six phases of the experiment and the corresponding indifference magnitudes of A (q_A(50)) were measured. Log q_A(50) increased and q_B/q_A(50) declined as approximately linear functions of log c_B, consistent with the supposition that reinforcer value was determined by multiplicative combination of hyperbolic expressions representing concentration and volume.

根据强化物价值的乘法双曲模型（MHM），强化物的价值是其大小的递增双曲函数。此外，人们普遍认为，在可溶性增强剂如蔗糖的情况下，价值是摩尔浓度的递增函数。本实验在操作选择范式中检验了蔗糖强化剂的大小和浓度之间的相互作用。大鼠在调整幅度计划下进行训练，其中杠杆 B 的响应提供固定体积的蔗糖溶液，而杠杆 A 的响应提供 0.8 M 蔗糖溶液，其体积q _A根据取决于老鼠的选择。当 B 在给定的试验块中是首选时，q _A在下一个试验块中增加；当 A 是优选的时，q _A在下面的块中减少。B ( c _B , q _B )的浓度和体积在实验的六个阶段中变化，并测量了相应的 A ( q _{A(50) ) 的无差异幅度。}Log q _A(50)增加，而q _B / q _A(50)下降，近似为 log c _B的线性函数，这与强化物值由代表浓度和体积的双曲线表达式的乘法组合确定的假设一致。