So, the name Ivan Pavlov rings a bell
it's because his experiments are among the most famous in the history of
psychology. His work contributed to the foundation of the behaviorist school of
thought that viewed psychology as an empirically rigorous science, focused on
observable behaviors and not unobservable internal mental processes.
Even though today we view psychology as the science of both behavior and mental
processes, Pavlov's influence was tremendous. His research helped pave the path for more experimental rigor and behavioral
research right up to the present day. Born in 1849 in Russia, Pavlov was never
much for psychology. After giving up on his original aspiration to become a
Russian Orthodox priest like his father, he instead earned a medical degree and
spent nearly 20 years studying the digestive system, earning Russia's first
Nobel Prize in his mid-50s for his research expanding our understanding of
how stomachs worked. He didn't study human stomachs, though, because the
procedures were terrible and cruel. He studied dog stomachs. And while
researching those dogs, he noticed how the animals would salivate at a mere
whiff of their dinner. At first, he found all that slobber annoying, but soon
started to suspect that this behavior was actually a simple but important form
of learning. For us scholars of psychology, we can define learning as the
process of acquiring, through experience, new and relatively enduring information
or behaviors. Whether through association, observation, or just plain thinking,
learning is what allows us to adapt to our environments and to survive. And as
Pavlov began to discover, it wasn't only humans who learned. Soon enough, he was
turning out his famous series of experiments in which he paired the
presence of meat powder -- yummy -- which got the dogs to drooling, with lots of
different neutral stimuli. Things that wouldn't normally make you drool, like a
certain sound or shining a light or a touch on the leg. Then Pavlov observed,
after several of these pairings, a dog would start to drool just at the sound
or the light or the touch, even if there wasn't any slobber-inducing meat powder
around. Animals, he found, can exhibit associative learning. That's when a
subject links certain events, behaviors, or stimuli together in the process of
conditioning. This may be the most elemental, basic form of learning a brain
can do, but that doesn't mean that the processes behind conditioning
are, or ever were, obvious, or, for that matter, simple. In fact, the research that's gone into how we're
conditioned by our environments has helped shape the science of psychology from
a still-kinda-subjective thought exercise into the more rigorous
discipline we know today. And it starred some of psychology's most
notable, and often controversial, figures including Pavlov, BF Skinner, and that guy who
trained kids to be terrified of furry animals. [INTRO MUSIC] Okay, I'm not a licensed dog trainer
(do they license dog trainers?), but I can break down for you the sequence of steps
in Pavlov's famous experiment to help you get a sense of how conditioning
works. First, before conditioning, the dog just drools when it smells food. That
smell is the unconditioned stimulus and the slobbering, the unconditioned or
natural response. The ringing sound, which at this point means nothing to the dog,
is the neutral stimulus, and it produces no drooling. During conditioning, the
unconditioned stimulus -- the food smell -- is paired with the neutral stimulus -- the
bell sound -- and results in drooling. This is repeated many times until the
association between the two stimuli is made in a stage called acquisition. By
the time you get to the after-conditioning phase, that old neutral stimulus has become a
conditioned stimulus, because it now elicits the conditioned response of drooling.
Sounds super simple, right? If you have a dog, you've probably seen it
tap-dance at the sight of a leash, but in Pavlov's day, this whole series of steps hadn't
really been studied in a lab setting, or even thought about in scientific terms. Pavlov's work
suggested that classical conditioning, as this kind of learning came to be known,
could be an adaptive form of learning that helps an animal survive by changing its behavior
to better suit its environment. In this case, a bell means food, and food means
survival, so get ready! Not only, that but methodologically, classical conditioning
shows how a process like learning can actually be studied through direct
observation of behavior in real-time, without all those messy feelings and
emotions. This is something Pavlov especially appreciated, given his disdain
for "mentalistic concepts" like consciousness and introspection,
championed by Freud. Behaviorist psychologists like Pavlov's younger
American analogs, BF Skinner and John B Watson, also embraced the notion that
psychology was all about objective, observable behavior. In his 1930 book,
Behaviorism, he argued that given a dozen healthy infants, he could train any one
of them to be a doctor, artist, lawyer, or even a thief, regardless of their talents,
tendencies, or ancestry. Woah there, Watson! Thankfully, no one
gave him any infants. In his most famous, and yes,
controversial experiment, Watson conditioned a young child dubbed "Little Albert" to fear a white rat. Maybe
that doesn't sound so bad, but he accomplished this by pairing the rat
with a loud scary noise over and over. And then demonstrated that the terror could
branch out and be generalized to include other furry white objects, like bunnies,
dogs, and even fur coats. So yeah, that would not fly today, obviously. But Watson's
research did make other psychologists wonder whether adults, too, were just holding tanks
of conditioned emotions. And if so, whether new conditioning could be used to undo old
conditioning. Like, if you're terrified of rollercoasters, but you made yourself
ride one ten times a day for two weeks, would your fears fade? For the record, recent
exploration has revealed that the boy known as "Little Albert" sadly died a few
years after these experiments, while Watson eventually left academia and got
into advertising, where he put all that associative learning to lucrative use. So
that's classical conditioning, but we've also got another kind of associative
learning: operant conditioning. If classical conditioning is all about
forming associations between stimuli, operant conditioning involves
associating our own behavior with consequences. The kid who gets a cookie
for saying "please," or the aquarium seal that gets a sardine for balancing a ball
on its nose -- they've both been trained with operant conditioning. The basic
premise here is that behaviors increase when followed by reinforcement or reward,
but they decrease when followed by punishment. And the most well-known
champion of operant conditioning is American behaviorist, B.F. Skinner. He
designed the famous operant chamber or "Skinner Box" -- a confined space containing
a lever or button than an animal can touch to get some kind of reward (typically food),
along with the device that keeps track of its responses. Okay, time for a debunking break.
Other than maybe Freud, no other figure in psychology seems to be as shrouded in
lore and misinformation as B.F. Skinner. So I'm just gonna tell you straight that no,
Skinner never put any kids in the box, and no, he didn't raise his children without
love or affection. And his daughter didn't hate his guts until the day she committed suicide.
Deborah Skinner is alive and well and she loved her dad plenty. Skinner did, however, invent something called an "Air
Crib" -- a climate-controlled box with a window on the front that was meant to
keep babies warm and safe while their moms ran around doing their 1950s lady thang. It's not
exactly where I'd like to spend the night, but it wasn't remotely the same as the Skinner Box.
No one knows where all these myths came from, but being a somewhat controversial guy,
Skinner had a lot of haters. Some of whom were probably happy to perpetuate misinformation.
But back to the rat in the box. Basically, the box provided an observable stage to demonstrate
Skinner's concept of reinforcement, which is anything that increases the
behavior that it follows. In other words, you push
the lever, you get a snack, and then you want to keep pushing the lever.
But most rats aren't gonna push a lever for no reason. I mean, there aren't food dispensing
levers in the natural environment. So operant conditioning behavior requires shaping. Maybe
you give the rat a little nibble of food each time it gets closer to the bar,
then only when it touches the bar, until little by little, in a series of successive approximations to the desired
behavior, you reward them only when they do the thing you're trying to shape them
to do. In everyday life, we're all continually reinforcing, shaping, and refining each other's
behaviors, both intentionally and accidentally. We do this with both positive and negative
reinforcement. Positive reinforcement obviously strengthens responses by giving
rewards after a desired event, like the rat snack after the lever push, or getting a cookie when
you say please. Negative reinforcement is a little trickier -- it's what
increases a behavior by taking away an aversive or upsetting stimulus, like, say, you get in your car and it does that infernal
beeping thing until you fasten your seat belt. The car is reinforcing your seatbelt-wearing by
getting rid of that horrible beeping. And it's good. You should wear your seatbelt.
It's important to recognize here that negative reinforcement is not the same as punishment. Punishment decreases a
behavior, either positively, by, say, getting a speeding ticket, or negatively,
by taking away a driver's license. But negative reinforcement removes the punishing event to
increase the behavior. So pain killers negatively reinforce the behavior of swallowing them by
ending the headache. So by now, hopefully, you're getting the picture. There are things that we want
and things that we don't want, and we can be taught by way of those impulses to behave
certain ways. But it's worth pointing out that the conditioning is way more complex than
just the cookie in the beeping car. For one thing, ending annoyance or getting a cookie are types of primary reinforcers. You
don't have to learn that; they just make innate biological sense. Beeping is annoying; cookies are
delicious. So there are other kinds of reinforcers that we only recognize after we learn to associate them
with primary reinforcers, like a paycheck is a conditioned reinforcer.
We want money because we need food and shelter, which are still the primary drivers, plus
just as there are different kinds of reinforcers, so are there various reinforcement schedules. Like, those box rats were getting continuous
reinforcement when they got a treat every single time they hit the
lever, so they picked it up pretty quickly. But if one day, the rat chow doesn't come, that connection quickly dwindles
and the rat stops hitting the lever. This is a process called extinction, and it is important
because that's how real life works. Outside of a Skinner Box, you're not gonna get
continuous reinforcement. All of life is a series of partial or intermittent reinforcements
that only occurs sometimes. Learning under these conditions takes longer, but it holds up
better in the long run, and is less susceptible to that extinction. So, say a
cafe gives out a free cup of coffee for every 10 you buy, while another shop
pours a free double shot every Tuesday morning, and yet another has a free
coffee lottery that customers win at random. These are all different kinds of
intermittent reinforcement techniques that get customers coming back for more.
Now, Pavlov, Watson, and Skinner's ideas were definitely controversial, as well as
the whole scary rat experiment, plenty of folks disagreed with their insistence
that only external influences and not internal thoughts and feelings shaped
behavior. It was clear to many of the behaviorists' rivals that our cognitive
processes -- our thoughts, perceptions, feelings, memories -- also influence the way
we learn. We're gonna talk about how these other things factor into learning
next week, when we look more at conditioning, cognition, and observational
learning. And yeah, also watch kids beat the face off blowup dolls. Today, though,
you learned how associative learning works; the essentials of behaviorist
theory; the basic components of classical and operant conditioning, including
positive and negative reinforcement; and reinforcement scheduling. Thanks for
watching this, especially to all of our Subbable subscribers who make this whole
channel possible. If you'd like to sponsor an episode of Crash Course, or
get a special laptop decal, or even be animated into an upcoming episode, just
go to subbable.com. This episode was written by Kathleen Yale, edited by Blake
de Pastino, and our consultant is Dr. Ranjit Bhagwat. Our director and editor
is Nicholas Jenkins, the script supervisor is Michael Aranda, who is also
our sound designer, and the graphics team is Thought Café.