Who is commonly attributed for discovering the law of effect

Edward Thorndike.

Explanation:

Law of effect is a principle of psychology that states that responses that produce a satisfying effect in a particular situation is likely to occur again in that situation, while the one that produced a discomforting effect is less likely to happen again.

This was proposed by Edward Thorndike in 1898 to address behavioral conditioning. He was an American psychologist famous for his work on comparative psychology and the learning process that brought about the theory of connection ism.

Edward L. Thorndike

Explanation:

He was an American psychologist whose work on animal behaviour and the learning process led to the theory of connectionism, which states that behavioral responses to specific stimuli are established through a process of trial and error that affects neural connections between the stimuli and the most satisfying responses