Learning is defined as relatively permanent changes in behavior resulting from exposure or practice. There are several theories of learning, including classical conditioning (Pavlov's work with conditioning responses), operant conditioning (Skinner's work showing that behaviors are strengthened by consequences), and social learning (Bandura's theory of observational learning). Memory involves both short-term memory (limited to 7 items) and long-term memory (more permanent storage), and there are techniques like rehearsal and mnemonics that can help strengthen memory.