Watson was astonished and impressed by the work done by Thorndike on animal research, but he thought of his law of effect as unnecessarily mentalistic approach. Watson contributed much to the theory of behaviorism. He also said that conditioning associates events with time and helps in the establishment of contiguity. Applying the principles of contiguity and frequency, Watson explained the concept of learning.
His explanation was closer to the approach followed by Pavlov and Bechterev, rather than Thorndike. He stressed on the observation that making an attempt or a trial leads to a correct response.
This can be interpreted in a way that the frequency of making a correct response as compared to incorrect one is higher, and also, the more number of times a response is made, the higher are the chances that they will be made again. This is the law of frequency.
Watson came out with the law of recency. This theory suggests that the final response made by an organism will be the one made by the same organism in the next situation.
In the classical conditioning situation explained by Watson, the conditioned stimulus (CS) and the unconditioned stimulus (US) get associated as they happen at the very same time. This is the law of contiguity. Watson also interpreted that learning is an outcome of mechanical arrangement of stimuli and responses.