In classical conditioning, how can the connection between the conditioned stimulus (CS) and the conditioned response (CR) be strengthened?

In classical conditioning, the connection between the conditioned stimulus (CS) and the conditioned response (CR) is strengthened when the CS precedes the unconditioned stimulus (US). This is critical because for effective conditioning to occur, the CS should act as a signal that predicts the occurrence of the US, allowing the organism to associate the two.

When the CS occurs before the US, it creates an anticipatory response in the subject. For example, if a bell (CS) is rung before food (US) is presented to a dog, over time, the dog learns to associate the sound of the bell with the arrival of food, leading to salivation (CR) even when the food is not presented. This timing is essential for establishing the learning association, as the CS must signal the impending occurrence of the US for the learning process to be effective.

The other timing options—having the CS follow the US, occur simultaneously with the US, or happen after the CR—do not effectively establish this predictive relationship. When the CS follows the US, there is no opportunity to create an association, and when they occur simultaneously, the organism may not clearly identify the CS as a predictor of the US, preventing the establishment of a strong conditioned response. Therefore