Burrhus Skinner (1904-1990) was a behavioural theorist whose work was mostly based on experiments carried out on rodents. He believed that animals and people were essentially the same, but that people were simply capable of more sophisticated learning. His argument was that all behaviour is linked to nurture and that behaviour is intrinsically linked to punishment and reward. By punishing negative behaviour and rewarding desirable behaviour an animal or person will learn to behave in the expected way. Skinner, however, prioritised reward over punishment, and advocated breaking things down into achievable steps with plenty of positive reinforcement and reward for each step. His work also influenced education by encouraging the repetition of the same type of sum or word.