Instrumental responding following reinforcer devaluation

In two experiments, hungry rats were given instrumental lever-press training for an appetitive reinforcer and, in addition, were exposed to another type of food which was not contingent on lever pressing. In the first experiment, exposure to each type of food was on separate days, whereas in the second experiment rats were exposed to each type of food in strict alternation within each session. Subsequently, a food aversion was conditioned to the reinforcer for the experimental group and to the non-contingent food for the control group. In both experiments, animals with an aversion to the reinforcer responded less in an extinction test than animals with an aversion to the non-contingent food. Subsequent reacquisition tests confirmed that the aversion to the non-contingent food in the control group was of comparable strength with that to the reinforcer in the experimental group. The results were discussed in terms of whether the reinforcer is encoded in the associative structure set up by exposure to an instrumental contingency.     

ARGUMENT TO BLISS: THE EPISTEMOLOGY OF THE SUMMA THEOLOGIAE

The essay examines intellectual virtue in the Summa theologiae, taking it as an interpretative key to the epistemology of the Summa theologiae as a whole. Because Aquinas blurs the line between the acquired and the theological virtues, and between virtues and the gifts of the Spirit, it becomes impossible to maintain the distinction between the realms of nature and grace, or between natural reason and revealed truth: grace permeates the most ordinary activities of human reasoning. This reading of the Summa theologiae raises questions about many contemporary debates, particularly those concerning natural law.