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MCAT
Course: MCAT > Unit 11
Lesson 9: Learning- Learning questions
- Classical and operant conditioning article
- Classical conditioning: Neutral, conditioned, and unconditioned stimuli and responses
- Classical conditioning: Extinction, spontaneous recovery, generalization, discrimination
- Operant conditioning: Positive-and-negative reinforcement and punishment
- Operant conditioning: Shaping
- Operant conditioning: Schedules of reinforcement
- Operant conditioning: Innate vs learned behaviors
- Operant conditioning: Escape and avoidance learning
- Observational learning: Bobo doll experiment and social cognitive theory
- Long term potentiation and synaptic plasticity
- Non associative learning
- Biological constraints on learning
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Biological constraints on learning
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Want to join the conversation?
- My only problem with this experiment is they seem to change all the variable without keeping any of them constant, as in if you want to compare something, at least keep 1 of the variable constant.
My other problem would be, when she presents the scenarios, it's assumed that the rats KNOW the taste of the water in advance (Ex: for the follow up experiment, how does the rats know that water is sweeten to avoid it?) I guess she should have used something like fruit punch (so the rats can visually distinguish it).
Still thanks for the video tho!(18 votes) - My freshman year of college was my first experience with alcohol. I drank 10 Keystone lights while watching Ted and puked. I couldn't drink beer for over 18 months without wanting to puke.
This, my friends, is taste aversion.(14 votes)- My taste aversion is oranges in salad. never again lol, though now I'm pretty sure it was the stomach flu(2 votes)
- I don't know what she's talking about, I'm very afraid of CARS(12 votes)
- Are there any studies that test newborns' and young children's responses to certain stimuli, such as cars and snakes, in order to tell if they share the biological predisposition to be phobic of snakes and the like? There might be something unethical to that...but my thinking is that, if they don't share those predispositions, then maybe the development of phobias later on in life are due to some subtle and constant socialization to that effect. I.e., from the time you are a newborn, your parents constantly respond to spiders in a negative way, so that via observational learning you come to fear spiders. Thanks for any response!(8 votes)
- From what I understand there isn't. Or at least there isn't anything well done. Due mostly to ethical constraints and the inability to control for confounds or satisfactorily assess the dependent variables. People have tried, but because you can't control every aspect of a newborns daily routine the methodology for these studies are often inadequate to support the conclusions. In addition, just as an extension, even if we were to be able to exert full control over a newborns ever act, it's difficult to say that our act of control won't somehow affect the results. So it's kind of a lose-lose situation at the moment. And as a consequence we can't really support anything theories through our methods. But who is to say that someone won't produce an amazing piece of methodology in the future.(4 votes)
- At, rats developing aversion to water is more classical conditioning isn't it? 7:13(1 vote)
- This is more Operant Conditioning, because of the shocking being a positive punishment (ie: "the light and beeping is back, that means I shouldn't move to the water cause I'll get shocked like last time"),(7 votes)
- What is the name of the rat experiment? This is the first time I have come across it and would like to learn more!(3 votes)
- Is the portion about phobias at the end really a good comparison? Snakes are mostly dangerous when there is even only one in your environment, whereas a car is generally safe, even if you are surrounded by them. They do not pose the same threat, and the statistics on a population level are not a good way of comparing the two. What matters to an individual is not what happens to the entire species, but what happens to him. In this case, he is much more likely to be injured in the presence of a snake than in the presence of a car.(3 votes)
- Can this theory explain why people can develop social phobias? Certain people having a phobia of social interaction doesn`t seem like an evolutionary benefit to me.(2 votes)
- At the very end around, does she say that learning CAN or CAN'T be simply reduced down to classical and operant conditioning? 10:30(2 votes)
- if you slow it down atyou can hear her say can't lol :D 10:30(1 vote)
- Omg. Same thing happened to me with cilantro. I loved it and then one day I had cilantro juice followed by a vegan quesadilla stuffed with cilantro.... Now I absolutely despise it.(2 votes)
Video transcript
- [Lecturer] Researchers initially thought that all of learning
could be narrowed down to these two basic
processes of conditioning. Classical conditioning
and operant conditioning. So they thought that all learning was based on these principles and it applied across the board. However, researchers soon discovered that there seemed to be biological
constraints on learning. That animals seemed biologically prepared to learn different kinds of associations with different degrees of difficulty. And in the end what they discovered was that it was easier for animals to learn associations that are
part of their natural world, but much harder to learn
associations that are not. And I want to take a minute to look at one of the studies that
proved this to be true. But first I want to take a minute to talk about taste
aversion, and this is when an animal eats something and becomes sick and then learns to avoid that food because it's associated
with that bad experience. And this is something that
can happen to people too. In fact, it happened to me. I used to absolutely love cilantro, but I once got sick after eating
something with a lot of it and now even the smell of
it makes me want to gag. And if you have a food aversion like this, you may have noticed two things. The first is that they're
incredibly powerful and really hard to get over. And the second one is that
they don't always make sense. So I was eating a chicken dish with cilantro in it before I got sick. And even though I think
it is probably a lot more likely that I got food
poisoning from incorrectly prepared chicken than from the spice that was put on top of it, I wound up developing an aversion to the cilantro, and not the chicken. But more importantly, I want to note that my body connected the fact that I got sick with something that I ate. I didn't get an aversion
to eating in restaurants with green leather
seats, or wearing jeans, or eating at 7:30 p.m. My body seems to have naturally understood that nausea most likely resulted from the food that I consumed, and not any of the other factors that were going on around
me at the same time. And this actually makes a lot of sense. Because we are in fact far more likely to get sick from the food that we eat, and not the type of
pants that we're wearing. And because of this, that
association is learned far faster than others. So now let's talk about how researchers actually went about
studying this in a lab. So they started with a group of rats that they deprived of water and this was done in order
to make them thirsty. These rats were then transferred to a cage where water is available, so of course they're going to drink. But this isn't everyday tap water, this water has been sweetened. It is sugar water, and prior to this these rats had only ever had tap water, so the sugar is really novel to them and they're pretty excited about it. And when the rats go to drink
this very exciting sugar water a tone sounds and a light flashes, and these things all
happen at the same time. So these rats actually belong
to two different groups. For the first group, a
tasteless, odorless substance has been added to the sugar water that's going to make them violently ill. It's gonna make them physically ill. The other group has not
been given this substance. They just have plain sugar water, but sometime after they
finish drinking it, about the same time the rats in our first group are becoming ill, the rats in our second group start getting electric shocks from
the floor in their cage. And these are pretty painful shocks. It's not going to give
them any long term damage, but they certainly aren't pleasant. And after this, some
amount of time goes by where the rats are
deprived of water again. And the rats are then put
back into those same cages. They're put back in the same situation. So now half the rats in the first group, the group that got physically ill, and half the rats in the second group, the group that got an electrical shock, they're going to get sugar water again but this sugar water is presented without the light and the tone, so it has that same sweet taste but there's nothing external
that happens when they drink. The other half of each of those two groups gets plain tap
water, not sugar water. But now whenever they
drink this tap water, they see the flashing light and they hear the tone sound just like before. So we wind up with these four groups. We have rats that were made
sick in the first part, who are then given sugar
water in the second part. Rats who were made sick
in the original group who are then given plain tap water but with the external stimuli. We also have the rats that
were given electrical shocks, and now they're being
given sugar water again. And finally we have rats that were given those electric shocks
and now they're being presented with tap water
along with lights and sounds. So we have these four groups
and our main question is which of these rats are
going to develop an aversion, and what are they going
to develop an aversion to? Okay, so let's look at
this first group here. So these are the rats who
are made violently ill after drinking the tainted sugar water and they were then
exposed to the sugar water again in part two. Do you think these rats,
these water deprived very thirsty rats will
drink the sugar water after having been made ill by it? And the answer is no, they
do not drink this water. They've developed an aversion to it and they're not going to
drink the sugar water again, theoretically because
they've made the connection that that is what made them
sick the previous time. And all right, let me get a second color for my second group. These guys will be yellow. All right, so we know that the rats made the connection that
drinking sugar water made them sick and so they didn't want to drink it the second time, but remember that that's not the only
thing that happened. The rats also heard this tone beeping and they also saw this light flashing, and so of course it's also possible that that led to them being ill. And that's what we're
testing in the second group. So these are rats who were
made sick the first time, and now when they go to drink the water, which is now plain tap
water, they're going to hear that tone and
see that light again. Do you think that this
is going to be enough to stop them from drinking the
water when they're thirsty? So will these rats show
the same type of aversion to the external stimuli as
they did to the sugar water? And it turns out that they don't. They do not develop an
aversion and they will drink, and why might this be? Well it's actually the exact same reason as before in the example about myself and my aversion to cilantro. I developed an aversion to food and not other external stimuli. And it's the same thing with these rats. In a rat's natural world, you get sick when you eat something unpleasant. They don't get sick like that when it's a certain temperature or a certain type of day
or even after an injury. So even though in this case the rats got sick after being
exposed to both sugar water and these external
signals, they only learned to associate getting
sick with a novel food and not with a novel
environmental factors. All right, so now let's
talk about the rats who got shocked instead
of being made sick. So these are rats who
also drank sweet water and saw the novel environmental stimuli so they heard the beeping and
they saw the light flashing, but then instead of getting
sick a short time later they actually get electrical
shocks to their feet. And then a short time later,
they're returned to these cages and they're either given sweet water without these environmental stimuli, or they're given tap water but with the beeping
and the flashing lights. So which of these two groups do we think is going to develop an aversion and what are they going to develop an aversion to? And let's actually start talking about group four over here. So these are the rats
who were given tap water on the second part, and also heard the beeping and saw the lights. So now our question is, will these rats refuse to drink the tap water in the presence of the
light and the sound? And it turns out that the answer is yes, they do develop an aversion. They do not drink the water. And let's talk about why this might be because this might seem
a little bit weird. It makes sense to us that the rats who were made sick by the water wouldn't drink that water a second time, but why would the rats
after getting shocked on their feet develop an aversion to these novel environmental signals? So obviously electric
shocks are not really something that a rat's
going to come across in its daily life, but
it is possible that it's going to get physically
injured in some way. And when a rat does get
injured in the real world it is most likely due to the fact that it interacted with
something in its environment, and not because it ate something strange. And as you might have
been able to guess by now, other rats in group three, so the rats that are
shocked in the first part of the experiment and
then given sugar water in the second part, they
don't show this aversion, because as I said eating
food in the real world doesn't really result in physical injury, and so these rats don't
immediately associate the two. And so what this study showed, and the reason why this
study was so important, is that it showed that not
all associations were equal. That animals didn't
naturally make associations in all circumstances. Instead, the rats were
learning to avoid the things that would have been dangerous
to them in the real world, so when they got sick to their stomachs, they associated that with food. And when they got shocked
when their feet were injured, they learned to associate that
with an environmental change. And so contrary to what
the behaviorists thought, what Pavlov and Skinner thought, the rats seemed to have
come into the world prepared to learn certain things. Prepared to learn that
if you get physically ill it's probably because
of something you ate, and if you get injured it's probably because of something
that's in your environment. And what this means is that we have some kind of biological predisposition. We are predisposed through evolution to learn some associations
better than others. There is also other evidence that there might be a biological evolutionary
influence on learning. I think a great example
of this is phobias, or more specifically what we do and don't develop phobias of. We are much more likely to develop phobias to things that were
threatening to our ancestors than we are to develop phobias of things that might actually injure
us in the modern world. So it's fairly easy for
someone to develop a phobias for snakes or spiders or heights, but very unlikely that someone's going to develop a phobia to cars
and electrical outlets. And really you are much
more likely to be hurt by a car than by a snake these days. Much, much more likely but learning to avoid things
like snakes and spiders would have conferred an
evolutionary advantage to your ancestors. In much the same way that it would have been adaptive to learn to
avoid foods that made you sick. But compared to snakes and spiders, cars are still very new. So new that even though
they are actually a threat, there's no biological
predisposition to avoid them. So really the takeaway from all of this is that associations that are adaptive, those that confer some kind
of evolutionary advantage, are learned much faster than associations that don't rely on those
biological principles. And because of this, because of these biological predispositions, we know that behaviorism
can't provide the whole story. That learning can't simply be reduced down to classical and operant conditioning.