I just read the BF Skinner discovered partial reinforcement on accident! Pretty neat.

"B. F. Skinner (1956) discovered this (then) surprising effect quite by accident. Early in his career, Skinner began his study of lever pressing by rats for food. One Saturday, he found he did not have enough food pellets made to last the weekend. He wanted to keep up the daily training of the rats, but making pellets was a long, tedious task. (In those days researchers made almost everything for themselves. Now they buy most of their supplies and equipment from commercial manufacturers.) So he decided to spread out the remaining pellets by reinforcing only the first response that occurred after one minute had passed since the last reinforcer had been delivered. To his surprise, not only did his supply of pellets last, but the pressing behavior become stronger, steadier, and much more resistant to extinction, not weaker and less regular as one might expect."

When it comes to schedules of PARTIAL (INTERMITTENT) reinforcement, here's a handy chart and more to think about ... :) .

* NOTE: Giving pop quizzes is a good example of a variable interval schedule.

If the teacher starts making the quizzes more predictable (more fixed-interval) (for example, once a week on Fridays), students will begin to show the stop-start work pattern that characterizes the fixed-interval schedule- that is they won't work hard for most of the week; then towards the end of the week they will start cramming for the quiz. On the other hand, if the quizzes aren't predictable, the students have to be prepared/be studying at all times.

* Fixed schedules show less persistence and faster response extinction than variable schedules.

* Ratio schedules generate high rates of responding, because the faster the subject works, the sooner it earns the next reinforcer.