Behaviorism also relied on another idea, that all human behaviour was learned. Behaviorists believed that behavior could be explained by classical or operant conditioning. This is learning as a result of influences from past experiences. However, behaviourists denied the importance of inherited behaviours, instincts (inherent inclination of a living organism), or inherited tendency to behave. They did not believe, or ignored, the idea of heredity(passing of traits to offspring from parents), that something can come from a person's genes. This was the idea of the blank slate, that babies are born with a clean, empty mind. Humans, when born, are thought not to have mental experience or knowledge, and that everything is learned after they grow. The blank slate premise is opposed by modern evolutionary psychology.