Background Economy type is an important determinant of reinforcer value. This study
investigated the effect of open and closed economies on demand and preference for …

Progressive ratio (PR) schedules have been widely used to study motivation to work for a
reinforcer. After a post-reinforcer pause, subjects engage in pressing a lever until a …

Here we present a novel effort-based task for laboratory rats: the weight lifting task (WLT).
Studies of effort expenditure in rodents have typically involved climbing barriers within T …

Duration schedules of reinforcement for continuous behavior abide by several preexisting
operant behavioral economic equations for reinforcer cost, otherwise known as price, and …

Response force is a fundamental dimension of behavior. Yet, little is known about its
functional significance for learning. The present review examines the behavioral effects of …

We investigated the duration of lever pressing by rats when the delivery of appetitive
reinforcers was contingent upon response duration. In the first experiment, response …

When reinforcement schedules demand that rats depress a lever for a minimum period of
time, most lever presses will meet reinforcer requirements, but others will be much shorter …

Rats responded under a procedure in which relatively short lever-press durations produced
1 food pellet and longer presses produced 4 food pellets. Because duration is a continuous …

We compared two progressive schedules of reinforcement in which rats received access to
sweetened condensed milk for depressing and holding down a response lever. Duration …

In 2 experiments, we investigated the utility of a progressive-duration schedule as an assay
for measuring drug effects. In both experiments, rats responded on a schedule of …