The simplest form of learning that occurs is called habituation, this is when we gradually become used to a stimulus over a short period of time, we learn to ignore it. For example, the ticking of a clock might grab your attention at first, but it will slowly filter out of your awareness, same goes for birds chirping outside, cars on the road or even strange smells. This type of basic sensory learning is important because it helps screen out sensory information that doesn’t require our immediate attention.
Learning theory in psychology is the foundation of the behaviorist perspective, and the bulk of this post will cover the behavioral concepts of classical and operant conditioning, known together as associative learning. About 2,500 years ago the philosopher Aristotle proposed a set of laws of association to account for memory and learning. The two most important laws were:
- the law of contiguity, which stated that two events will connect together in the mind if they are experienced close together in time, such as thunder and lightning, or marriage and divorce (heh).
- the law of similarity, which suggests that objects that resemble each other, such as two people who look alike, are likely to become associated.
Classical conditioning was the first type of learning to be studied systematically. In the late nineteenth century, the Russian psychologist Ivan Pavlov (1849-1936) was studying the digestive systems of dogs when he came upon a curious discovery. Like humans and other animals, dogs salivate when presented with food, which is a natural reflexive response. But Pavlov noticed that if he rang a bell every time the dog was presented with food, it would eventually salivate at the sound of the bell, without the presence of food being necessary. As Pavlov had discovered, what happened is the dog had learnt to associate the sound of the bell with food, and the reflexive response of salivating had actually transferred to the sound of the bell. This phenomenon is called classical conditioning and it is not only restricted to dogs and saliva, but is open to any situation where learning takes place as a result of two stimuli being associated with a certain response, such as being afraid of any body of water after having a near death drowning experience in an ocean.
Pavlov’s Model – An innate reflex such as salivation to the sight of food is an unconditioned reflex. Conditioning is a form of learning, therefore an unconditioned reflex is a reflex that occurs naturally, without any prior learning; it is instinctual, such as withdrawing a hand that touches something extremely hot. The stimulus that produces the response in an unconditioned reflex is called an unconditioned stimulus (UCS). In the case of Pavlov’s dog, the UCS was the food. An unconditioned stimulus activates a reflexive response without any learning having taken place, which is why the reflex is considered to be unlearned, or unconditioned. An unconditioned response (UCR) is a response that does not have to be learned. In Pavlov’s experiment the UCR was salivation.
Shortly before presenting the UCS (food), Pavlov presented a neutral stimulus (the bell) that normally doesn’t elicit the reflex in question (salivating). After the neutral stimulus (bell) had been paired with the UCS (food) several times, the sound of the bell alone came to evoke a conditioned response (salivation. A conditioned response (CR) is a response that had been learned. By pairing the UCS (food) with the sound of a bell, the bell became a conditioned stimulus (CS) – a stimulus that through learning, has come to evoke a conditioned response. This initial stage of learning, in which the conditioned response becomes associated with the conditioned stimulus, is known as aquisition.
This discovery of classical conditioning was a breakthrough in psychology as it explains how learning takes place in a limitless amount of situations outside the laboratory. If you’ve ever had a dog you’ll know that the act of picking up a leash prompts the dog to salivate and jump around, or maybe even sit patiently infront of you as it awaits the leash to be attached to it’s collar. This is because the dog has associated the leash with being taken outside for a walk, and classical conditioning has occured to reach this stage. Dogs aren’t born knowing that leashes equals going for walks, they learn this information.
Cat’s also react to the sound of tins being opened and will end up circling your feet until you feed them. Humans too are affected by classical conditioning, as most behaviours and phobias are learnt through conditioning. We aren’t born afraid of spiders or snakes, an encounter with these creatures has to occur (whether in real life or on a television) to condition us to be forever afraid of them. Likewise to be afraid of needles, one would need to have associated an injection with distress at some point in their childhood. Through the knowledge of classical conditioning, psychologists can just as easily make a person unlearn these conditioned responses and eventually break the association they have made with certain phobias.
Stimulus Generalisation and Discrimination – Once an organism has learned to associate a conditioned stimulus (CS) with an unconditioned stimulus (UCS) it may respond to stimuli that resemble the CS with a similar response. This phenomenon, called stimulus generalisation, is related to Aristotle’s principle of similarity. This explains how a traumatic experience with a common house spider can generalise itself to all spiders, including hunstmans, black widows, trap doors and tarantulas. It may even transfer over to insects similar looking to spiders, such as scorpions or crabs.
Stimulus discrimination on the other hand, is the opposite of stimulus generalisation. Discrimination occurs when an organism differentiates between two similar stimuli when these stimuli are not consistently associated with the same UCS. For example if you think back to your high school days, the sound of the lunch bell would evoke feelings of relief for class being over, and it might also follow with feelings of hunger, while the alarm clock bell that rings every morning wouldn’t evoke the same conditioned response, this is the result of us being able to discriminate between similar, but different stimuli.
Extinction – Extinction in classical conditioning does not refer to the wiping out of a species, but instead to the process by which a conditioned response (CR) is weakened by presentation of the conditioned stimulus (CS) without the unconditioned stimulus (UCS). Sound confusing? Basically extinction is when we unlearn to associate a conditioned stimulus with a conditioned response. In the case of Pavlov’s dog this would be the dog no longer salivating at the sound of a bell, this will inevitably occur if the bell is rung without any food being presented – after a while, the dog knows what’s up.
Factors Affecting Classical Conditioning – Several factors influence the extent to which classical conditioning will occur with an organism, these factors are the interstimulus interval, the individual’s learning history and the individual’s preparedness to learn.
Interstimulus interval is the time between presentation of the CS and the UCS. If too much time passes between the presentation of these two stimuli, then the organism is unlikely to associate them and conditioning is less likely to occur.
An individual’s learning history also plays a part in classical conditioning; an extinguished response is usually easier to be reconditioned a second time around because the stimulus was already associated with the response in the past. On the flip side, sometimes prior learning can hinder conditioning. For example if I had already conditioned you to salivate at the sound of a bell, and then I wanted to condition you to evoke the same response to the flashing of a light, if during our light flashing sessions I rang the bell at any intervals you would ignore the lights and salivate at the sound of the bell. This is known as blocking, which is the failure of a stimulus to elicit a CR when it is combined with another stimulus that already elicits the response.
A similar phenomenon occurs in latent inhibition, in which initial exposure to a neutral stimulus without a UCS slows the process of later learning the CS-UCS association and developing a CR. For example if a bell is rung repeatedly without any presentation of food prior to the commencement of the food/bell association sessions, the dog might take longer to make the association between the sound of the bell and food.
Prepared learning refers to the biologically wired readiness to learn some associations more easily than others. This can be best explained from an evolutionary point of view, as associations that encourage survival are more easily learned, for example animals that have survived eating something poisonous are much more likely to associate that particular stimulus with avoidance. Given this knowledge it’s no coincidence that humans are more likely to associate fears or phobias of spiders and snakes than they are flowers and ants. This is because we are biologically prepared to avoid these creatures due to their potentially life threatening nature.