Robert Gagné was an educational psychologist known for his theory of instruction called the "Conditions of Learning". The theory proposes that there are different types of learning (intellectual skills, cognitive strategies, verbal information, motor skills, attitudes) which require different instructional conditions. Gagné identified eight types of learning (signal, stimulus-response, chaining, verbal association, discrimination, concept, rule, problem solving) and nine events of instruction that are effective for different types. The theory provides guidance for designing instruction to optimize learning. However, it has been criticized for not accounting for self-learning or discovery-based learning.