There are two main learning processes, operant conditioning and classical conditioning. Operant conditioning is a learning process where the frequency of a certain behaviour is modified according to the behaviour’s consequences. If the consequence is positive, it is called a reinforcement and will lead to a higher frequency of the behaviour that caused it. If the consequence is negative, it is a punishment and the behaviour will decrease in frequency. Classical conditioning is learning through association. It involves the association of an unconditioned stimulus to a conditioned stimulus. A conditioned stimulus is a stimulus that causes a reflex, uncontrolled reaction, for instance, a loud noise causes a stress/fear response as the heart rate and adrenaline increase. By consistently presenting an unrelated, uncontained stimulus, such as a water bottle, before generating a loud noise, over time the individual will develop an association between seeing a water bottle and hearing a loud noise. This will then cause the individual to present a higher heart rate and adrenaline concentrations every time they see a water bottle, even if it’s not followed by a loud noise.