formal study of psychology.
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6542 – Transcript
00:00:24 How people learn is a question older than the formal study of psychology.
00:00:29 Since the time of the ancient Greeks, philosophers and biologists have asked questions about how we acquire knowledge.
00:00:37 50 years ago, we thought we had the answer.
00:00:41 The radical behaviorist approach dominated psychology.
00:00:45 And the theories of classical and operant conditioning were thought to be a complete explanation of all learning.
00:00:52 This video shows how far current thinking has moved on.
00:00:57 It’s now generally accepted that mental processes play a very important part in learning.
00:01:03 And so-called cognitive explanations are currently being widely researched.
00:01:09 There have been many other attempts to explain learning processes apart from conditioning.
00:01:15 And we’ll look at most of these as they’ve all contributed something to the debate about the mechanisms of how we learn.
00:01:22 S Several questions arise continually in this study of learning and will do so throughout this video.
00:01:31 One concerns the difference between learning and memory.
00:01:35 It seems obvious that you can’t remember anything that you haven’t learnt.
00:01:40 And if you learn it, you have to store that information somewhere and be able to retrieve it.
00:01:46 The nature/nurture debate crops up as in most areas of psychology.
00:01:52 Which aspects of our behavior are innate and which are learnt?
00:01:57 You would have noticed when studying conditioning that most of the research has involved the use of non-human animals studied in
artificial situations in a laboratory.
00:02:09 And this raises two more questions.
00:02:13 Since Darwin’s theory of evolution, it has been widely assumed that what we find in non-human animals, we can apply to all species.
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00:02:23 Can the behavior of non-human species tell us anything about man’s behavior?
00:02:30 Darwinian theory predicts that there are similarities in learning between species due to our common evolutionary origin.
00:02:38 However, it also suggests that there are differences in learning between species due to unique adaptations to unique environments.
00:02:50 This raises another question.
00:02:52 Should any animal be studied in an environment which is not natural to their species?
00:02:59 Should we study natural behavior in the natural habitat of the species and sacrifice control over variables?
00:03:08 Or should we set up an artificial experiment where we can tightly control all the unwanted variables which may creep in?
00:03:18 Consider these questions as you’re watching.
00:03:21 And we suggest that they form the basis of a discussion later.
00:03:25 We’re also going to discuss the recent move from radical behaviorist explanations of learning to the cognitive behaviorist
explanations.
00:03:36 But first of all, we’ll look at some of the many and very different explanations of learning that have been put forward over the years.
00:03:45 Let’s just remind ourselves first about the basic behaviorists principles of classical and operant conditioning.
00:03:53 Classical conditioning occurs when a stimulus such as the sight, smell, or sound of food produces an automatic response or reflex,
such as salivation.
00:04:06 When another stimulus regularly occurs just before food, an association is made between the two.
00:04:15 This type of strictly stimulus-stimulus conditioning, sometimes named after the originator, Ivan Pavlov, has its own Pavlovian terms
to describe how a stimulus produces an automatic reflex.
00:04:32 Many people would find the sight of fresh cream cakes attractive and may salivate when seeing cakes displayed in a shop.
00:04:41 However, you may find just walking in the streets that the cake shop is in sufficient to make you salivate, even if the shop is closed.
00:04:52 In Pavlovian terms, cream cakes, the unconditioned stimulus, or US, produce salivation.
00:05:00 When cakes are frequency associated with a certain street called a conditioned stimulus, the streets alone will produce salvation,
which is now a conditioned response.
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00:05:12 In classical conditioning, the behavior, for example, salivating, is an automatic response emitted due to the pairing of two events.
00:05:23 In operant conditioning, on the other hand, new responses are learnt and maintained by reinforcement.
00:05:31 This is based on the law of effect, which says a behavior which is reinforced will be repeated.
00:05:38 A behavior which is not reinforced tends to die out.
00:05:44 Any naturally occurring behavior in humans and other animals is more likely to be repeated if that behavior produces a reward, such
as food, or in humans, money, promotion at work, or praise.
00:06:01 To go back to cakes, in operant conditioning, you may be rewarded with a cake for producing a certain behavior.
00:06:10 We brought these students cakes for helping us.
00:06:14 And according to operant conditioning theory, this will be instrumental in they’re being more likely to help us on another occasion.
00:06:23 The second half of the video will look at these processes again.
00:06:33 Psychologists who emphasized the importance of factors other than stimulus and response have come to be known as
neobehaviorists.
00:06:43 Tolman was a neobehaviorist who realized that other factors besides the stimulus could affect the response.
00:06:50 He argued, in contrast to behaviorists, that all behavior was go directed, that is in a sense of having a purpose, and that actual
mental processes determined a response.
00:07:04 Tolman’s work has been valuable in highlighting the cognitive aspects of learning, especially the difference between learning and
performance.
00:07:15 It is only in some situations that performance shows evidence of learning.
00:07:20 For example, pause the video and consider what knowledge you have and what you’ve learnt but are not actually demonstrating at
this moment.
00:07:32 What learning are you demonstrating?
00:07:45 Well, there would be a huge list of abilities and skills that you are unable to actually show while watching a video, such as your skill
in swimming, mathematics, social skills, or bungee jumping.
00:08:15 Equally, there’ll be many things that you are demonstrating that show learning of some kind, including almost anything that you are
unable to do at birth, such as sitting in an upright position and reading the pause message.
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00:08:30 Tolman introduced the notion of latent learning, which broadly refers to any learning not shown in behavior, that is, which is hidden or
latent at the time of learning and which takes place without reinforcement.
00:08:48 Tolman and his colleague Honzik showed this originally in 1930 in an experiment involving three groups of rats, which were placed
daily in a maze.
00:09:00 The rats in group A were given a food reinforcement if and when they reach the goal box at the end of the maze.
00:09:08 Group B were allowed to explore the maze but were not reinforced if and when they reach the end box.
00:09:17 Group C were treated in the same way as group B for the first 10 days but were given a reinforcement after that if and when they
reach the end box.
00:09:29 As we see in this graph, the reinforced group A clearly learnt to run the maze more quickly and made fewer and fewer mistakes.
00:09:38 Group B wandered around the names apparently aimlessly most of the time and never became any quicker at running through the
maze or finding their way to the goal box without error.
00:09:50 Group C made no progress during the first 10 days.
00:09:54 But as soon as reinforcement started, they increased their speed and reduced their errors dramatically.
00:10:01 A very important point here is that group C learnt more rapidly than group A had when and only when rewards were introduced.
00:10:13 Obviously, the rats in group C were learning about the spatial orientation of the maze during the non-rewarded days but only showed
actual learnt behavior when they had an incentive to do so.
00:10:27 The learning was only apparent in performance when reward was given.
00:10:32 This demonstrates latent learning, or what is now often called behaviorally silent learning.
00:10:40 Now, let’s see how good people are at describing routes.
00:10:45 When you get to the end of the road T-junction, turn right again.
00:10:50 Follow the road down to the first set of traffic lights.
00:10:52 Turn left, and you’re at the cathedral.
00:10:55 No problem.
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00:10:58 You go straight down here, and then you turn left.
00:11:02 And you go past the student union on the right.
00:11:07 And I think– I don’t know.
00:11:11 You’re going have to go carry on down, and you have to go ask somebody else there [INAUDIBLE].
00:11:18 Because I don’t actually know where it.
00:11:20 Is Thank you very much.
00:11:21 Can you show how to get [INAUDIBLE]?
00:11:23 Yes.
00:11:23 That’s quite simple.
00:11:24 You go down here.
00:11:25 You cross the road.
00:11:27 You go to the left of the students union.
00:11:30 And you continue along in a straight line.
00:11:32 And you’ll see the School of Architecture on your left-hand side.
00:11:35 Its description, it’s a white building with lots of glass on the roof.
00:11:40 Go straight down until you get to the next street.
00:11:44 And then, you see a park on your left.
00:11:46 And if you cross the park on the other side [INAUDIBLE].
00:11:51 These are buildings similar to this one.
00:11:54 And that’s it.
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00:11:54 Thank you.
00:11:56 Go [INAUDIBLE] straight up here.
00:11:58 Turn left and then cross where the other crossings are.
00:12:01 Then, walk through the university campus precinct.
00:12:04 Walk straight on, and you can see Oxford Road.
00:12:07 You’ll see the sports centre on your right.
00:12:10 Walk across there.
00:12:12 And then there will be a park up on square in front of you.
00:12:15 Turn left in front of the park.
00:12:16 Walk along Oxford Road and then turn right.
00:12:18 And you’ll see the [INAUDIBLE], the second building on the left.
00:12:23 Go to the top of the road.
00:12:25 Turn left until you come to Crown Street and turn right.
00:12:32 I think it’s there on your right.
00:12:38 Now pause the video and have a go at describing routes that you know.
00:12:48 As you would have noticed from the people that we asked and your own attempts were very heavily dependent on landmarks and
left/right directions.
00:12:59 Perhaps, the rats in the maze were learning a sequence of left or right turns based on muscular movements.
00:13:06 However, the reinforced rats still learnt the route quickly if the maze was rotated.
00:13:13 If the dead ends were moved to different locations, and even if the maze was flooded with water, and they had to swim, Tolman
concluded that learning in this case does not just involve the learning of a set of particular muscle responses but the formation of a mental picture of the layout of the maze.
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00:13:35 He called these cognitive maps.
00:13:40 This seems a reasonable explanation, although we can only infer this from the rat’s behavior.
00:13:46 The same can be said of humans, of course.
00:13:49 You may know how you represent a route or plan in your head.
00:13:54 But it’s difficult to explain it to someone else.
00:13:58 I mentioned myself just go walking through, and then I realized I got there, and I didn’t actually which way to go.
00:14:05 I visualize it as a map.
00:14:08 I see a picture, really.
00:14:10 I’m not very good on directions.
00:14:13 A colored picture.
00:14:14 Yeah, really.
00:14:17 I was like a sort of overhead view, sort of the layout of the university.
00:14:22 I sort of described to you as I walked down to it.
00:14:25 So you see it through you own eyes?
00:14:27 Yes.
00:14:28 The way I normally go, the way I’ve done it before, that’s what’s in your head.
00:14:31 Like a map [INAUDIBLE].
00:14:33 What kind of map?
00:14:36 A-to-zed type of map, like a road.
00:14:43 Pause the video now to discuss the way you mentally represent routes.
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00:14:49 You could also compare different people’s drawings of the same route.
00:14:59 I’m sure that you too found enormous variations in mental maps as well as drawings.
00:15:06 We can conclude from our small survey that humans use cognitive maps but in different forms.
00:15:14 Humans do demonstrate an enormous amount of latent learning about their environment.
00:15:26 A further approach to learning came from a gestalt school which originated in Germany.
00:15:31 Gestaltists such as Wolfgang Kohler in the 1920s took a holistic view, particularly of perceptual learning.
00:15:40 He emphasized the importance of the organization of information as a whole rather than being concerned with individual
constituents.
00:15:49 The whole is greater than the sum of the parts.
00:15:53 Now, what do you make of this?
00:15:56 Most people read this as The Cat, even though the H and A are structured in the same way.
00:16:06 They’re just interpreted differently due to the context.
00:16:10 First, the same perceptual unit can have a different meaning due to learning, depending on the gestalt or whole in which it is
embedded.
00:16:21 In his observation of animals, Kohler realized that not all learning was made up of many learned stimulus-stimulus, and response-
stimulus associations, or by trial and error learning, but appear to involve some form of insight.
00:16:40 In a typical experiment, a chimpanzee sees a piece of fruit out of reach outside his cage.
00:16:48 But also outside the cage is a stick which can be reached.
00:16:54 After trying to reach the food with his arm, the chimpanzee suddenly reaches for the stick and uses it to pull the food towards him.
00:17:04 Kohler noticed that the chimpanzee seem to inspect the whole visual field and then suddenly solved the problem, showing a so-
called aha reaction.
00:17:18 In another experiment, the chimpanzee has several boxes in his cage and some bananas hanging out of reach from the ceiling.
00:17:27 After jumping up and down a few times, the chimpanzee stopped activity, inspected the problem visually, then suddenly stacked
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boxes on top of each other, climbed up, and reached the bananas.
00:17:43 In all cases, there was a period of intense fruitless activity followed by a reflective period which was then followed by a sudden
solution to the problem.
00:17:56 Kohler called this insight learning.
00:18:00 The chimpanzee, he said, was thinking and using cognitive reasoning was putting two and two together just as humans often do.
00:18:14 Aha.
00:18:19 One important feature of insight learning seems to be that the animals have to have full sight of each individual piece of apparatus
required to solve the problem.
00:18:31 Also, the animal needs to become aware of the function and properties of each element of the problem situation and must be able to
mentally manipulate them until a solution is reached.
00:18:45 Of course, a human would be able to solve the problem without seeing the boxes.
00:18:50 They would judge the distance visually and think, ah, I need something to stand on and go and find something appropriate.
00:19:00 Kohler didn’t consider the effect of past experience.
00:19:04 But chimps’ performance can be improved if they’re given experience of playing with sticks beforehand.
00:19:12 However, prior experience doesn’t rule out the possibility that insight has occurred.
00:19:19 Similar work is shown that there may be innate factors involved.
00:19:24 Chimps given sticks and boxes do spontaneously fit sticks together, and stack boxes, and stand on them during play.
00:19:34 Younger chimps are being shown to fit sticks together more easily than older chimps.
00:19:40 There’d be many criticisms of this work, mainly because of the lack of controls used, such as several chimps in the same cage
during trials.
00:19:50 However, outside the laboratory, primates do seem to show some sort of reasoning and often look to us as if they are thinking.
00:20:03 Robert Epstein and BF Skinner replicated Kohler’s experiment at Harvard University using a miniature box made out of cardboard
and a tiny banana, which were placed in a small chamber with a feeder tray on the side.
00:20:19 They trained the pigeon using reinforcement techniques to perform each element of the behavior.
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00:20:27 This certainly shows that prior training has produced learning.
00:20:31 But it has also produced completely novel behavior, which the researchers suggest appears very similar to insight learning.
00:20:42 We’ll come back to this question later.
00:20:50 In the 1940s, Harry Harlow suggested that rather than there being different explanations for learning, trial and error learning and
insight learning are two phases of the same continuous process.
00:21:05 Animals, he says, have to learn to learn.
00:21:09 And they do this by initially using trial and error, followed by insight learning.
00:21:16 He called this learning sets and demonstrated it using rhesus monkeys.
00:21:23 A monkey was presented with two objects and was rewarded with a peanut or raisin for choosing the one designated as correct.
00:21:33 Let’s do a trial ourselves before we explain further.
00:21:38 You’ll see six sets of two shapes appearing on the screen briefly.
00:21:43 We decide which one of each set is correct.
00:21:47 You have to choose left or right for each set.
00:22:08 The answers were left, left, right, left, right, right, that is, the ones composed of straight lines.
00:22:19 Of course, you didn’t have the benefit of a peanut when you chose the right one.
00:22:23 But you do now have the benefit of experience.
00:22:26 So let’s try another one.
00:22:29 This time, we’ll take the one out of each of 10 sets which is correct.
00:22:34 And you have to work out why.
00:23:02 This was more complex involving two elements.
00:23:05 The correct ones were the largest one when the background was white and the smallest one when the background was blue.
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00:23:15 It’ll be no comfort to those of you who didn’t get the answer to know that monkeys are able to do this but only after a great deal of
experience with similar problems.
00:23:27 Kohler concluded that they seem to have acquired a general skill, which could be used for all similar problems, a learning set.
00:23:38 This has at least shown that experience plays an important part in learning to solve problems.
00:23:45 It also seems that the animals have used some form of cognitive representation by remembering what have gone on in previous
trials and applying some general rule during later ones.
00:23:59 Learning sets are an example of transfer of learning taking place.
00:24:05 Positive transfer is when knowledge or skill in one activity aids learning in another.
00:24:13 However, there might sometimes be a negative effect if the skills are sufficiently different, as in tennis and badminton.
00:24:22 Wrist action is primarily used in badminton, whereas in tennis, you have to learn to use your whole arm and shoulder.
00:24:33 Lateral transfer is where you use the same knowledge or skill but in different contexts.
00:24:40 Pause the video for a few minutes now and think of examples of positive, negative, and lateral transfer of learning in your life.
00:24:56 It’s quite difficult to judge the effective previous learning on the acquisition of similar skills.
00:25:03 It would seem that positive transfer may occur with driving, whereby once you can drive a car, you can transfer much of that learning
to another vehicle.
00:25:13 But does the ability to roller skate help or hinder when you use ice states for the first time?
00:25:27 Would knowledge of Spanish make it easier for you to learn Russian?
00:25:31 Or would it interfere with your learning?
00:25:35 We often make use of lateral transfer.
00:25:38 In fact, if we didn’t, we would have to relearn every new task from scratch.
00:25:45 One common form of lateral transfer is using the four rules of arithmetic in a wide range of situations and environments.
00:25:54 For example, applying mental arithmetic once learned in school, or in shopping, or at work, in order for any of these transfers to
work, the initial learning must be very thorough.
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00:26:11 Another approach to explaining learning comes from the social learning theorists who emphasize the role of observation in learning.
00:26:22 Albert Bandura has been working on his theory for the last 40 years.
00:26:27 He says that we learn through watching the behavior of others whom he calls models.
00:26:34 Parents and other admired adults are the most influential models and are closely observed.
00:26:42 If we observe a successful or rewarded behavior performed by someone we admire, then it’s likely we’ll learn and imitate.
00:26:52 As we noted with latent learning, there is a gap between what is learnt and what behavior is actually performed.
00:27:01 Reinforcement, however, may determine whether we imitate the behavior ourselves.
00:27:07 Bandura’s work has emphasized the importance of good role models, especially for children.
00:27:14 These pictures show one of his well-known Bobo doll experiments, where young children watched an adult showing various forms of
aggression towards a large inflated doll.
00:27:27 Later, when the children played in a room with the same Bobo doll, they imitated many of the adult’s actions– throwing the doll,
kicking it, and hitting it with a toy hammer.
00:27:41 Further work with adults on film and cartoon characters as models have shown the same results, which has disturbing implications in
a society where violent videos are so widespread and easily available.
00:27:56 We may be rightly concerned about the ethics of exposing children to violence deliberately.
00:28:01 But luckily, in these experiments, the imitation has not been seen after the children left the laboratory.
00:28:10 This doesn’t mean children do not learn long-lasting behaviors as a result of imitation but perhaps need to be exposed to it on
several occasions.
00:28:21 Observational learning demonstrates the learning performance distinction with imitation being the acting out of what is being learnt
and the evidence that what was observed has been learnt.
00:28:36 Social learning theory seems to explain how novel behavior can be produced and appears spontaneously without requiring
reinforcement.
00:28:47 This is in sharp contrast to operant conditioning where novel behavior is said to be shaped by reinforcement.
00:28:55 It also stresses the importance of cognitive processes in that people can predict the probable consequences of their behavior.
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00:29:06 Observational learning has been found in many non-human species too, and many anecdotal accounts of imitation have been
reported.
00:29:16 Unfortunately, very few examples of social learning in non-human species have been properly analyzed as yet.
00:29:25 Some experimental work has confirmed that observation does produce learning in rats.
00:29:32 Those who watch another rat in the laboratory making learned responses, such as bar pressing, acquire the response much quicker
when it’s their turn than animals who’ve had no observing experience.
00:29:47 For animals, observational learning obviously improves their chances of survival by providing a shortcut to learning new methods of
obtaining food or avoiding predators.
00:30:00 As with humans, it also helps to improve social cohesiveness.
00:30:12 Ethology is a major area of evolutionary science whose beginnings coincided with the flowering of behaviorism.
00:30:20 While the behaviorists were establishing the laws of association mainly in laboratories using small mammals and pigeons as
subjects, the ethologists were observing animal behavior in the wild.
00:30:34 They established that there are basically three factors governing the behavior of animals– sign stimuli, instinctively recognized cues,
motor programs, innate responses to cues, drive, controlling motivational impulses.
00:30:55 Konrad Lorenz, one of the founders of ethology as a science, found all of these factors in the egg rolling behavior of geese.
00:31:03 Geese build nests on the ground.
00:31:05 And sometimes, an egg rolls out of the nest.
00:31:08 When the goose notices this, she fixes her eyes on the egg, extends her neck, gets up, puts the underside of her beak on the far
side of the egg, and rolls the egg gently back into the nest with her bill.
00:31:22 Although this seems a natural kind of response to a common problem, it’s been found to be highly stereotyped and innate.
00:31:31 Any objects which is a similar shape regardless of color, and to some extent, size, can trigger off the same response.
00:31:41 Even beer bottles will get the same loving attention and may end up in the nest.
00:31:48 In this case, the shape is the sign stimulus, the egg rolling, the motor program, and the entire behavior controlled by a drive which
lasts for about two weeks after the eggs are hatched.
00:32:07 It now seems that most animals have fixed action patterns, that is, innate preprogrammed behaviors.
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00:32:15 They seem to need to act out these very specific behaviors in very particular ways to increase their chances of survival.
00:32:38 However, not all animal behavior is based on innate instincts, as we’ve already seen in insight learning in chimpanzees, the
formation of cognitive maps in rats, and of course, the many novel behaviors that can be learnt through classical and operant conditioning.
00:32:59 Even in the egg-rolling behavior, although much is fixed and happens in response to any stimuli of the appropriate shape, the goose
does adapt its behavior.
00:33:12 If the egg seems to be slipping out of place, she will move her beak to prevent it, that she seems to be reacting to the environment
as well as innate instincts.
00:33:24 These instincts have been shown to be so strong that they sometimes can’t be overwritten by conditioning techniques.
00:33:32 Keller and Marian Breland spent 14 years trying to condition animals to perform tasks which were not species-specific, that is, not an
actual behavior for that species, the various displays, exhibitions, and advertising campaigns.
00:33:49 The Brelands tried to use conditioning techniques with pigs who are famously easy to condition and have a ravenous appetite.
00:33:58 Their task for a shop window display was to pick up large wooden coins, walk across the shop window, and deposit them in a piggy
bank.
00:34:08 This Initially appeared to be successful with the pig learning the behavior and enjoying the food reinforcement.
00:34:15 But the behavior quickly declined into routine behavior using their snouts to detect food hidden underground or under debris, which
is their natural way of searching out food.
00:34:29 The Brelands used 38 different species totaling 6,000 individual animals and found the same problem, which has become known as
instinctive drift.
00:34:40 Learnt behavior, which is rewarded, sometimes seems to drift towards instinctive behavior.
00:34:48 This relates to what Seligman called preparedness.
00:34:52 He argued that rats don’t have to press levers for food in everyday life anymore than dogs encounter flashing lights and ringing bells
to signal foods in the real world.
00:35:04 To explain why some behaviors are more easily conditioned than others, Seligman said that organisms are biologically prepared to
learn certain things and biologically contra-prepared to learn others.
00:35:19 The degree of preparedness is assessed by the number of trials taken to learn a task.
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00:35:26 Animals, including humans, are prepared to learn actions which are closely related to their survival, for example, ways of finding food
or avoiding danger.
00:35:40 Garcia and Koelling’s experiments with rats discussed more fully in an early learning video showed that rats who had nausea linked
with a compound of flavour, light, and clicker avoided the flavour but not the light afterwards.
00:35:57 While those who had a mild electric shock paired with the same compound avoided the light and clicker afterwards but not the
flavour.
00:36:07 The taste is associated with nausea.
00:36:10 And the tone clicker are associated with the shock.
00:36:16 By evolution, the species has acquired a predisposition to learn that in the real world, foods make you ill, and external stimuli cause
you pain.
00:36:27 Whilst food doesn’t cause pain, an external stimuli don’t make you ill.
00:36:35 Thus, the species is predisposed to learn some stimulus-stimulus associations and contra-prepared to learn others.
00:36:44 Seligman has argued that in humans, many phobias are prepared behavior.
00:36:51 Irrational fears develop towards a small range of objects and situations, such as snakes, or spiders, darkness, heights, or in closed
spaces.
00:37:03 Specific phobias are learnt very quickly, usually with just one pairing of objects, such as snakes with traumatic experience.
00:37:12 And they can be difficult to extinguish.
00:37:15 It’s thought that possibly that these are evolutionary throwbacks which were once threats to our survival.
00:37:22 We rarely become phobic about pot plants or family pets.
00:37:27 But if gerbils threatened to take over the world, we may see new phobias developing.
00:37:33 Instinctive behaviors are obviously important for the survival of the species and relate to behaviors that improves the chances of
survival for the individual, such as finding food, detecting danger, choosing the right mate so that the whole species continues.
00:37:57 Another very vibrant area of research into learning is that pursued by neuroscientists who presume the brain must possess neural
mechanisms through which stimuli, actions, or ideas can be associated in various ways.
00:38:14 Research has already shown that the brain possesses an enormous number of different types of neurons with different types of
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synapses making different types of collections leading to many patterns of synaptic transmission.
00:38:30 Research has now moved on to look at plasticity, that is, the way in which synapses alter, how they change, and whether there’s any
causal connection between learning and the plasticity of synapses.
00:38:45 The last years of the 20th century have produced scientific evidence and laboratory experiments that changes in synapses exist
which are directly related to associative learning.
00:38:59 However, laboratory results may not be recording changes during natural behavior, a recurrent problem in neuroscience and when
working with animals.
00:39:09 In terms of understanding the mechanisms of learning, however, the potential of this approach is enormous and very important in
terms of application to real-world problems.
00:39:21 If we can understand the physiology involved in learning processes, we can help to treat many memory disorders and learning
difficulties.
00:39:31 We’ve looked at many widely differing approaches to and explanations of behavior.
00:39:37 And we’re now going back to the behaviorist theories of classical and operant conditioning to look at the recent developments in this
area.
00:39:52 Cognitive psychology, the study of mental processes, has made a revival in the last few decades.
00:40:00 With the advent of the computer, the information processing approach has become popular, and computers are often used as
models for the human mind in areas such as memory, perception, and attention.
00:40:14 Even more recently, there has been a revolution in thinking in learning theory with psychologists moving away from the traditional
behaviorist explanations towards cognitive ones.
00:40:28 The researchers at the forefront of this change in the UK are Anthony Dickinson, and Nicholas Macintosh, and their colleagues at
the University of Cambridge.
00:40:39 In the USA, Robert Rescorla, Allan Wagner, Leon Kamin, and many others are involved in equally exciting research.
00:40:51 The difference in interpretation between the behaviorist and cognitive view of observable behavior is described simply by Dickinson.
00:41:01 Suppose a rat was exposed to a series of trials, let’s say a light is paired with a mild electric shock.
00:41:09 Eventually, the rat is going to show signs of being frightened, such as crouching in a corner or freezing when the light comes on.
00:41:18 The question is what has the rat learnt?
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00:41:22 The behaviorists would answer that the rat has learned a new response, in this case, that of crouching or freezing, that is, the animal
is merely responding to a stimulus.
00:41:36 The cognitive psychologist, on the other hand, would be inclined to view any behavioral change as a sign of mental processes, that
is, of stimulus-stimulus learning having taken place.
00:41:51 Cognitive psychologists would argue that the rat has learnt to predict that the light means shock, and is, therefore, frightened by it.
00:42:01 It is, afterall, a natural innate behavior for a rat to freeze when frightened, not a learned behavior.
00:42:10 But how do we know there any new mental processes?
00:42:15 All we can see is the behavior.
00:42:18 As we saw with latent learning, we have to devise a way of showing that something has been learnt.
00:42:25 It is what we call behaviorally silent.
00:42:29 If, for example, we paired a tone with a light but represented no shock, there will be no behavioral change.
00:42:38 And the behaviorist would say that no learning had taken place.
00:42:43 However, Rescoria, among others, has convincingly shown that learning has actually taken place but is not being displayed.
00:42:54 This is known as sensory pre-conditioning.
00:42:59 After the tone has been paired with the light for several trials, a light alone is then paired with a shock.
00:43:08 If a rat is then presented with a tone, it shows a typical fear response, even though the tone has never been presented with the
shock.
00:43:18 It is thought that a mental representation of the tone/light association was made during the first stage but not acted on, because
neither of the stimuli were of any significance to the rat at the time.
00:43:34 When the light acquired significance because of the shock paired with it, the mental structure representing the tone as a predictor of
the light resulted in the tone also becoming fear-reducing, or as a human might see it– That light used to come on at the same time as the tone.
00:43:58 I got a bit of a shock when that light came on.
00:44:02 I might get a shock with the tone as well because they used to appear together.
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00:44:10 Dickinson argues that any observable change in behavior is related to mental processes.
00:44:18 This move towards cognitive explanations of learning has come about through a buildup of evidence which showed that cognitive
processes, such as predictability and expectancy occur in conditioning experiments, and therefore, affect the outcome.
00:44:36 In classical conditioning, the conditioned stimulus has been shown to have information value which depends on the extent to which it
reliably predicts an unconditioned stimulus.