Questions: Valeria is conducting an experiment in which she reinforces a rat with a food pellet for pressing a lever every 3 minutes. This is considered reinforcement. negative ratio continuous partial

The answer is the last one: partial reinforcement.

Explanation for each option:

1. Negative reinforcement: This involves removing an unpleasant stimulus to increase the likelihood of a behavior. In Valeria's experiment, the rat is receiving a food pellet, which is an addition of a pleasant stimulus, not the removal of an unpleasant one. Therefore, this is not negative reinforcement.

2. Ratio reinforcement: This refers to reinforcement based on the number of responses. For example, a fixed ratio schedule might reward a rat after every 5 lever presses. In Valeria's experiment, the reinforcement is based on time (every 3 minutes), not the number of lever presses, so it is not ratio reinforcement.

3. Continuous reinforcement: This occurs when every instance of a desired behavior is reinforced. In Valeria's experiment, the rat is not reinforced every time it presses the lever, but rather every 3 minutes, so this is not continuous reinforcement.

4. Partial reinforcement: This involves reinforcing a behavior only some of the time. Since Valeria is reinforcing the rat every 3 minutes rather than after every lever press, this is an example of partial reinforcement.

In summary, Valeria's experiment uses a partial reinforcement schedule, as the rat is reinforced at intervals rather than continuously.