Animals need to learn to survive. Learning is any process through which experience at one time can alter an individual’s behaviour at another tie. Experience is any effects of the environment that are mediated by the individual’s sensory system. Future behaviour is any behaviour that is not part of the individual’s immediate response to the sensory stimulation during the learning experience.

Classical conditioning is a learning process that creates new reflexes. A reflex is a simple, relatively automatic, stimulus/response sequence mediated by the nervous system. Habituation is a decline in the magnitude of a reflexive response when the stimulus is repeated several times in succession. Not all reflexes undergo habituation.

With classical conditioning, several things should be taken into account:

1. Unconditioned stimulus
   This is the original stimulus which should trigger the reflex
2. Unconditioned response
   This is the reflex
3. Conditioned stimulus
   This is the new stimulus
4. Conditioned response
   This is the reflex

A conditioned response can be extinguished when the same conditioned stimulus is represented each time, without showing the unconditioned stimulus (e.g: ringing a bell without presenting food repeatedly). This is called extinction. The mere passage of time following extinction can partially renew the conditioned response. This is called spontaneous recovery. A single pairing of the conditioned stimulus with the unconditioned stimulus can fully renew the conditioned response. The response is somehow inhibited. It can be disinhibited by the passage of time or the recurrence of the unconditioned stimulus.

Individuals don’t only react to the conditioned stimulus, but also stimuli that resemble the unconditioned stimulus. This is called generalization. The less a stimuli resembles the original conditioned stimulus, the weaker the conditioned response is. Generalization between two stimuli can be abolished if the response to one is reinforced while the response to the other is extinguished. This is called discrimination training. (e.g: dogs were given food when a bell of 1000 hertz is heard, but not given food when a bell of 700 hertz is heard). For humans, interpretation is important for classical conditioning. When they are shown several words and a conditioned response is learned, they also show a similar response to words that have the same meaning as the original words but not to words that look similar to the original words.

The school of thought known as behaviourism argued that science should avoid terms that refer to mental entities because such entities cannot be directly observed. They believed that psychology should focus on the relationship between observable events (stimuli) in the environment and observable behavioural reactions to those events (responses). Behaviourism argued that all of behaviour is in essence reflex-like in nature.

There are several theories of what is actually learned in classical conditioning:

1. Stimulus-response theory
   The new reflex is learned because a connection between the unconditioned response and the conditioned stimulus is learned. (e.g: rats that have a connection between a light and a loud sound should still freeze when the light comes on, even though they are habituated to the sound)
2. Stimulus-stimulus theory
   The new reflex is learned because a new stimulus represents the old stimulus.
   (e.g: rats that are conditioned to learn that a light signals a loud sound, which causes them to freeze. If they are habituated to the sound, they will not freeze at the sight of the light) This theory is cognitive because it holds that the observed stimulus-response relation is mediated by an inner, mental representation of the original unconditioned stimulus.
3. Expectancy theory
   Individuals learn to expect the unconditioned stimulus when presented with the conditioned stimulus. This causes the conditioned response.

There are three conditions needed for classical conditioning:

1. The conditioned stimulus must precede the unconditioned stimulus
2. The conditioned stimulus must signal heightened probability of occurrence of the unconditioned stimulus
3. Conditioning is ineffective when the animal already has a good predictor

The failure of conditioning is called the blocking effect. The already conditioned stimulus blocks conditioning to a new stimulus that has been paired with it.

Evaluative conditioning refers to changes in the strength of liking or disliking of a stimulus as a result of being paired with another positive or negative stimulus. (e.g: attractive women being placed in car commercials. Attractive women resemble arousal and the new product of the car company causes the same effect after a while, causing people to be more likely to purchase it) 

Drug tolerance refers to the decline in physiological and behavioural effects that occur with some drugs when they are taken repeatedly.

Operant responses are responses that operate on the world to produce some effect (e.g: asking for potatoes at dinner, a rat pushing a button to receive some food). They are also called instrumental responses, because they function like instruments or tools, to bring about some change in the environment. The process by which individuals learn to make operant responses is called operant conditioning or instrumental conditioning. Operant conditioning is the learning process by which the effect or consequence of a response influences the future rate of production of that response.

Animals often learn through a trial-and-error process, through which an individual gradually becomes more likely to make responses that produce beneficial effects. Thorndike formulated the law of effect: responses that produce a satisfying effect in a particular situation become more likely to occur again in that situation and responses that produce a discomforting effect become less likely to occur again in that situation.

Operant response is any behavioural act that has some effect on the environment. Reinforcer is a replacement for words such as satisfaction and reward and refers to a stimulus change that follows a response and increase in the subsequent frequency of that response. Conditioned reinforcers are reinforcers that have reinforcing value only because of previous learning, for example, money.

With operant conditioning, the individual generates behaviour that has some effect on the environment, whereas in classical conditioning a stimulus elicits a response from the organism. Operant conditioning can come without awareness of the conditioning and this shows us how people can learn motor skills. We are not aware of the conditioning, but certain behaviour gets reinforced, thus we show that behaviour (e.g: proper motor skills) more often.

If the never individual makes the desired response himself, he can never be reinforced. The solution to this problem is called shaping, in which successively closer approximations to the desired response are reinforced until the desired response finally occurs and can be reinforced. Operantly conditioned responses can be extinguished if the response is no longer reinforced. Just as with classical conditioning, there is no unlearning of the response and there can be a spontaneous recovery of responding and a single reinforced response following extinction can lead the individual to respond again at a rapid rate.

There is a difference between partial reinforcement, in which the response only sometimes produces a reinforcer, and continuous reinforcement, where the response is always reinforced. There are four basic types of partial reinforcement schedules:

1. Fixed-ratio schedule
   A reinforcer occurs after every nth response.
2. Variable-ratio schedule
   The number of responses required before reinforcement varies unpredictably around some average.
3. Fixed-interval schedule
   A fixed period of time must elapse between one reinforced response and the next.
4. Variable-interval schedule
   The amount of time required before the reinforcement varies unpredictably around some average.

The different schedules produce different response rates because individuals are striving to maximize the number of reinforced responses and minimize the number of unreinforced responses.

Positive reinforcement occurs when the arrival of some stimulus following a response makes the response more likely to occur. The stimulus is also known as a positive reinforcer. Negative reinforcement occurs when the removal of some stimulus following a response makes the response more likely to occur. The stimulus is also known as a negative reinforcer. An individual will work toward a positive reinforcer (money, food) and work to move away from a negative reinforcer (electric shocks, loud noises). Punishment is the opposite of reinforcement. It is the process through which the consequence of a response decreases the likelihood that the response will recur. Positive punishment occurs when the arrival of a stimulus (electric shocks) decreases the likelihood of that response. Negative punishment occurs when the removal of a stimulus (taking away food, money) decreases the likelihood that the response will occur again. Reinforcement always increases the likelihood of the response and punishment always decreases the likelihood of the response.

The overjustification effect is a decline in response because the reward presumably provides an unneeded extra justification for engaging in that behaviour. This causes individuals to show the behaviour for an external reward, not for its own sake. They start perceiving the task as work and when they no longer receive a reward for the task, why would they continue to do the task?

The primary purpose of play is to provide a means for young animals to practice their species-typical behaviour. There are five pieces of evidence for this theory:

1. Young animals play more than adults do of their species
2. Species of animals that have the most to learn play the most
3. Young animals play most at those skills that they need to learn
4. Play involves many repetitions
5. Play is challenging

Learning can be divided at least roughly into two broad categories: learning to do (skill learning) and learning about (information learning). Exploration is used to learn about the environment and it differs from play learning because it is not used to learn any skills. Latent learning refers to learning that is not immediately demonstrated in the animal’s behaviour.

Observational learning is learning by watching others. Children learn important social behaviours (social learning) through a process of vicarious reinforcement, the ability to learn from the consequences of other’s actions.

Imitation is copying the observed individual. Stimulus enhancement refers to an increase in the salience or attractiveness of the object that the observed individual is acting upon. Goal enhancement refers to an increased drive to obtain rewards similar to what the observed individual is receiving (e.g: a kitten seeing its mother pressing a lever for food pellets may become attracted to the lever (stimulus enhancement) and motivated to eat food pellets (goal enhancement).

With stimulus and goal enhancement, the individual is not imitating the observed individual, but rather learning quickly, because of the increased attraction to a stimulus and motivated to obtain the same rewards.

Chimpanzees learn by emulation, which involves observing another individual achieve some goal, then reaching that same goal by their own means. With emulation individuals are more focussed on the goal than the means used to achieve it. Humans have mirror neurons; when we observe an individual, the same neurons that become active in the observed individual become active in ourselves. Gaze following is the reflexive action in which humans follow another person’s eyes to look at the same object the other person is looking at.

Food aversion is different from classical conditioning because with food aversion there is a much longer delay between the unconditioned stimulus and the conditioned stimulus. than with classical conditioning. Food aversion fails to occur if the gap between tasting the food and the induction of illness is less than a few minutes. In classical conditioning, almost every stimulus can serve as the conditioned stimulus, but with food aversion learning the stimulus must be a distinctive smell or taste. Some animals are prepared to make associations between food and nausea, so-called prepared behaviours. Unprepared behaviours are behaviours that are acquired through the normal processes of operant conditioning and usually take repeated trials to acquire. Contraprepared behaviours are behaviours that are impossible or difficult to learn despite extensive training. This shows that there are some biological constraints on learning.

There are a couple of evolutionary rules that omnivores use to determine what is safe to eat:

1. Eat what your elders eat
2. Remember the smell and taste of a food

Imprinting happens with animals such as chickens, that imprint on a moving object as soon as possible after they hatch.