Locke, McCann, and Voluntarism

Abstract: Locke scholars continue to disagree over how he analyzed natural laws, real essence-power relations in physical substances. Some say he regarded them as emanations, necessitated by the corpuscular structure of real essences; for others his laws are adventitious, imposed on substances by God and contingent on divine alterable will. The second view has been increasingly favored in recent years, assisted no doubt by Edwin McCann's potent case for it in Lockean Mechanism (1985). The present article, whose authors are sympathetic to the necessitarian reading of Locke, argues against McCann's exegesis.     

Conditioned suppression of drl responding: Effect of ucs intensity, schedule parameter, and schedule context

In Experiment I, groups of rats were trained to press a lever for food reinforcement on differential reinforcement of low rate (DRL) schedules which differed in parameter value. A stimulus which terminated with either a 0.5-mA or 2.0-mA electric shock was then superimposed upon each DRL baseline. In general, the magnitude of conditioned suppression was an inverse function of DRL schedule parameter and a direct function of shock intensity. Experiment II demonstrated that the rate of responding maintained by the DRL component of a multiple DRL-extinction schedule decreased during a stimulus preceding a 0.5-mA shock, whereas the rate of responding maintained by the DRL component of a multiple DRL-variable interval schedule showed little change or increased slightly during a stimulus preceding a 0.5-mA shock.     

Learning to perceive the relative mass of colliding balls: the effects of ratio scaling and feedback

The theory of direct perception holds that competent observers are able to detect optical patterns that specify the relative mass of colliding balls. Heuristic theorists, on the other hand, claim that judgments of relative mass are based on variables that do not specify relative mass. We contrasted these views with an experiment in which participants were given feedback on their ratio-scaled estimates of the relative mass of simulated colliding balls. Correlations between judged relative mass and various kinetic and kinematic measures of the collisions revealed that (1) judgments of relative mass become more accurate with feedback, (2) different observers use different variables, (3) during training, many observers change which variables they use, (4) before training, observers tend to use nonspecifying variables or combinations thereof, (5) after a minimal amount of training, at least some observers seem to detect mass-specifying information, and (6) the judgments do not support a generalization of the heuristic model of Gilden and Proffitt (1989, 1994). These findings suggest that direct perception of relative mass is a skill that can be developed through appropriate training.     

Interresponse times in serial recall: effects of intraserial repetition

The authors examined the effects of intraserial repetition on multitrial serial learning of random consonant lists, analyzing both learning rates and perfect trial interresponse times (IRTs). Lists varied along 3 dimensions: list length, presence or absence of a repeated element, and lag between repeated elements. After achieving a forward-recall criterion on a given list, participants (N = 20) attempted backward recall. At small lags, IRTs between the repeated elements were very short (compared with IRTs from identical positions in nonrepetition lists). At larger lags, the IRT to recall the second repeated item was substantially longer than in control lists. These results reveal a latency analogue of the Ranschburg pattern seen in accuracy data. A Ranschburg pattern was also found in participants' learning rates. These results both generalize the Ranschburg phenomenon and present further challenges to theories of serial order memory.