Here's the normal pattern of dopamine release.

It looks something like a roller coaster

because in biology,

what goes up must come down.

It could be food,

sex or even water when you're thirsty.

So,

let's say you're hungry.

Dopamine starts rising.

Then you think about a burger

and it rises more.

When the burger is sizzling,

dopamine's going way up.

It peaks right about at your first bite

then you take some more bites

then it starts to drop off,

and finally drops back down to normal levels

and you're full.

This graph could also represent

masturbating or having sex

and the peak would be right about at orgasm.

However,

I really want to point out

that the experience of orgasm

is probably driven by other neurochemicals

called Opiate,

not dopamine.

So,

dopamine drives you toward orgasm

but

the feeling of orgasm arises from something else.

The rise of dopamine levels

could also represent anything new or novel,

because dopamine loves novelty.

A new car,

a just released movie,

the latest gadget,

we're all hooked on dopamine.

You can have a spike of dopamine

just by ordering dessert

even though you haven't finished what's on your plate.

Dessert is something new.

In fact,

dopamine surging in your reward circuitry

can override your feelings

of what's called satiety or fullness

regardless of what your rational brain may think

about overeating

or even watching porn.

As with everything new,

the thrill fades and dopamine levels drop.

Now,

back to the Coolidge Effect.

So,

dopamine is what is behind the Coolidge effect.

If you look at our little graphs here,

we have a female rat #1,

female rat #2 and

dopamine level.

What's happening is

that the reward circuitry of the male

is squirting less and less dopamine

in each copulation with female #1.

And eventually,

the male can no longer copulate,

because there's not enough dopamine.

Dopamine is behind libido.

Then you dropped in female #2

and the male gets another squirt of dopamine

which surges his libido

and he goes back to work.

This is what's behind the Coolidge effect

and it's also why you click on to new videos

while you're watching porn:

to get another big squirt of dopamine

with something novel.

Ok.

Let's give another nickname for dopamine.

Let's call it the molecule of addiction.

It's because changes in your brain

that lead to addiction

caused by changes in dopamine level.

Cocaine,

alcohol,

nicotine,

they all feel different

but all of them flood the reward circuitry

with dopamine.

All addictive chemicals and activities

raise dopamine levels.

It's what makes them potentially addictive.

Of course,

you need continued use of the addictive substance

or activity

to cause physical changes that lead to addiction.

Here's an odd thing.

We've mentioned it before.

Dopamine is released

in response to expectations,

rather than actual levels of pleasure.

It's the drive to get it,

it's the craving,

but as I've mentioned,

the actual pleasure of eating or orgasm

is probably opioids.

Those are morphine-like chemicals

being released in the brain.

Dopamine is wanting it,

Opiates are liking it.

Addictions are basically chasing after dopamine.

So,

what happen is

addiction is wanting more but liking it less.

Speaking of wanting

and the power of the reward circuitry,

here's an experiment.

We have a rat

and you see there's a wire

and then this electrode

that's actually going to the reward circuitry

of the rat.

And the rat has its little paw on lever

and whenever he hits the lever

it sends just enough electricity

to the reward circuitry to stimulate it.

Now,

what will happen is

this rat would just keep hitting the lever

and hitting the lever thousands of times an hour

until it drops.

It won't stop to eat,

sleep,

have sex or even take care of the pups.

It will give up everything

just to press that lever.

As we know,

this behavior

is not unlike some serious drug addicts.

Here's another experiment.

They take the same rat

and then they have an electric grid

between the lever and the rat

so the rat has to feel painful shock

in its little paws

to go over to the lever and press it.

Well,

the rat will actually cross the bridge

and endure the shock

but if you take the rat

and put it in electric grid between them and food,

they will not cross the electric grid.

They will not undergo shock to eat food,

they would rather starve.

Here's more experiment

to show the power of dopamine

in your reward circuitry.

If you take rats and block their dopamine,

they have absolutely no motivation.

They're not even eat.

They won't walk over to the food dish

and they'll starve to death.

But they still like food.

If you drop food into their mouth,

they eat it and show little rat's smiles,

they just have no motivation to go get it.

They lie around.

They won't have sex either.

The male rat shows no signs of libido.

The key point is

you need the right level of dopamine

to function normally.

It does lots of important jobs.

Dopamine gives you that positive outlook,

good attitude,

keeps you motivated, keeps you happy.

Incidentally,

many psychological problems

involved dopamine imbalances,

including addictions.

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