Unit 5: States of Consciousness

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So have you ever been driving on a completely familiar route?

Maybe, you know, you're commuting home from school or work and suddenly you're pulling into your driveway, but you have absolutely no conscious memory of the last three miles.

Oh, highway hypnosis.

It is incredibly common and honestly a little terrifying when you think about it.

Right.

Or, well, maybe you play a sport like pick up basketball, you're on the court, and before your conscious mind can even process the thought like, Peter is going to intercept this, your body has already adjusted and completed a bounce pass.

Yeah, your reflexes just take over.

Exactly.

And it's incredibly frustrating when you try to think it, but it really highlights this wild, almost unsettling illusion of conscious will.

I mean, the psychologist Daniel Wegener actually demonstrated this beautifully in a lab.

Oh, the computer mouse experiment.

That is a classic.

Yes.

So he set up this experiment where people thought they were co -controlling a computer mouse with a partner, but, you know, the partner was actually in on the experiment.

They were confederate.

Exactly.

And even when that partner deliberately stopped the mouse on a predetermined square on the screen, the actual participants fully believed, I mean, they genuinely perceived that they had caused it to stop there.

It completely shatters our sense of being the sole captain of the ship, doesn't it?

That experiment really exposes the massive gap between what our brains are doing automatically behind the scenes and what our conscious minds are, you know, taking credit for after the fact.

We just walk around feeling like we were making every single decision.

We do.

But so much of our behavior is generated entirely unconsciously, which really brings us to the core of what we are tackling today, because what exactly is consciousness?

It's a big question.

It is.

It's a concept that is, to psychology, what the concept of life is to biology.

It's totally fundamental, yet incredibly slippery to actually pin down.

And mastering that slippery concept is our mission for you today.

So consider this, your personalized one -on -one tutoring session from the Last Minute Lecture Team.

We are going to dive deep into the states of consciousness.

Right.

We're breaking down every core concept, theory, and study from the AP psychology curriculum for this unit.

Exactly.

Specifically focusing on how our awareness changes when we sleep, when we dream under hypnosis, and when psychoactive chemicals enter the brain.

The goal here is for you to walk away with total college -level mastery of this material.

But to really understand consciousness, I feel like we have to look at how psychologists have struggled just to define it.

Because didn't the entire field basically just give up on studying consciousness for a few decades?

They absolutely did, which is such a fascinating quirk of psychology's history.

I mean, if you go back to the very early days, say around 1887, pioneers like George Trumbull had explicitly defined psychology as the description and explanation of states of consciousness.

So it was all about introspection, right?

Like looking inward.

Exactly.

But by the first half of the 20th century, the behaviorist movement staged this massive takeover.

Their argument was, well, it was purely practical.

You simply cannot scientifically measure an inner feeling or a subjective state of mind.

Because you can't see it.

You can only measure observable behavior.

Right.

So they essentially treated the mind as a black box.

You have an input, you have a behavioral output, and whatever conscious experience happens inside that box, it doesn't matter to science.

That is so wild.

I mean, they actually likened consciousness to car's speedometer, right?

Yeah.

The psychologist, Martin Seligman, later put it perfectly.

A speedometer doesn't make the car go.

It just reflects what's happening.

It's basically a byproduct.

So by the 1960s, psychology had practically lost consciousness entirely.

It just rebranded itself strictly as the science of behavior.

Exactly.

Which seems completely counterintuitive to me.

I mean, how can you have psychology without the inner human experience?

So what finally brought it back?

Neuroscience.

The cognitive revolution of the 1960s was fueled by these massive leaps in brain imaging and mapping.

Oh, so they finally had the tech.

Right.

Suddenly, researchers didn't have to rely on subjective introspection anymore.

They had tools like EEGs to actually map exact brain activity to specific mental states.

Like sleeping, dreaming, and drug use.

Yes.

They could literally see the biological footprint of consciousness in action.

So psychology essentially regained its consciousness.

And today, the working definition is simply our awareness of ourselves and our environment.

But that awareness isn't just one single stream, right?

Because this leads into the concept of dual processing, the two -track mind.

We are constantly processing information that we aren't even slightly aware of.

The two -track mind is essential to this unit.

We have a conscious, deliberate track and an unconscious,

automatic track, and they are running in parallel all the time.

Right.

Think of it like learning to ride a bike.

When you first learn, it requires intense, conscious, selective attention.

You're hyper aware of your balance, the pressure on the pedals, your grip.

You're entirely in what William James called the continuous stream of consciousness.

Every single action takes deliberate mental effort.

But once you master it, the process shifts entirely to the unconscious track.

You just ride on complete autopilot.

And the beauty of that is it frees up your conscious mind to wander.

You can plan what you're going to eat for dinner or just enjoy the scenery while your body does the complex work.

That mechanism shifting well -learned tasks to automatic processing is just an evolutionary masterpiece.

Conscious processing is slow and sequential, which is great for new problems.

But automatic processing is incredibly fast and can handle multiple streams of data at once.

And our stream of consciousness naturally flits between these different states of awareness all day.

We have our waking awareness.

We might daydream, but eventually we inevitably succumb to the most powerful altered state of all.

Sleep.

Right.

Which is not just a random switch that gets flipped when we get tired.

The transition from our waking stream of consciousness into sleep is deeply, relentlessly biological.

It is entirely governed by rhythmic tides.

And the most prominent of these is the circadian rhythm, which is our 24 -hour biological clock.

So our bodies don't just maintain a static baseline all day.

Not at all.

Our body temperature actually rises as morning approaches, it peaks during the day, and then it takes a notable dip in the early afternoon.

Which perfectly explains why so many cultures have a tradition of afternoon siestas.

Exactly.

And then the temperature drops again right before sleep.

And your cognitive performance rides that exact same wave.

Your sharpest thinking and most accurate memory occur right at your daily peak in circadian arousal.

Which is why taking a major exam during that mid -afternoon dip can feel so brutal.

Oh, absolutely.

But you know, if you've ever pulled an all -nighter, you know how powerful this rhythm really is.

You hit this wall of absolute crushing grogginess around 4 a .m.

where you feel like you can't even form a sentence.

But then, almost miraculously, you get a second wind around 7 a .m.

or 1 a .m.

Yeah.

You haven't slept, but your body thinks, oh, it's morning, time to ramp up the temperature and go.

Right.

And to really understand that 4 a .m.

wall versus the 8 a .m.

second wind, we have to look at the biological mechanics of light.

Light is essentially the master timekeeper.

Okay, break that down for us.

So morning light hits your retina, and that visual input triggers signals to a tiny, 20 ,000 cell cluster located in the hypothalamus.

This cluster is called the suprachiasmatic nucleus, or SCN.

SCN.

Okay, so the eye tells the SCN that the sun is up.

What does the SCN do with that?

The SCN is the control center.

It sends a message directly to the pineal gland to decrease its production of melatonin, which is your primary sleep -inducing hormone.

So melatonin levels drop and you wake up.

Exactly.

At night, as the ambient light fades, the SCN recognizes the darkness and allows the pineal gland to ramp that melatonin production back up.

It floods your system and makes you drowsy.

This mechanism is so fascinating because it perfectly explains why modern teenagers are so notoriously difficult to wake up in the morning.

We can basically blame Thomas Edison.

You really can.

Our ancestors' biological clocks were perfectly attuned to the rising and setting sun.

When it got dark, melatonin went up.

But the invention of the artificial light bulb completely hijacked that ancestral rhythm.

By staring at bright screens and bathing ourselves in artificial light late into the night, young adults are actively tricking their SCN.

The brain thinks the sun is still up, so melatonin production is heavily delayed.

You're essentially pushing your biological body toward a 25 -hour day.

It is a profound disruption of a deeply ingrained biological cycle.

But, you know, once sleep does finally overtake us, what actually happens to our consciousness?

It fades, right, as different parts of the brain's cortex stop communicating with one another.

It does fade, but the sleeping brain is far from quiet.

It's not just emitting a flat dial tone.

Instead, we pass through a very distinct, highly active 90 -minute cycle of sleep stages.

I am obsessed with the story of how this 90 -minute cycle was actually discovered.

It wasn't even that long ago, like 1952.

Right, Eugene Asurinsky.

Yeah, so he was a graduate student at the University of Chicago, and he was testing out this EEG machine.

He had been repairing it and needed a test subject, so he literally hooked up his 8 -year -old son, Armand.

As one does.

Exactly.

So he tapes these electrodes near Armand's eyes.

And as the boy slept, the machine started tracing these massive, wildly erratic, deep zigzags.

Asurinsky genuinely thought the machine was broken.

Because it looked like the brain of someone who was wide awake and panicked.

Exactly.

But as he watched over the night, he realized these fast, jerky eye movements were happening alongside highly energetic brain waves.

He actually woke his son up during one of these wild periods, and Armand immediately reported having a vivid dream.

That accidental late -night observation was the discovery of REM, or rapid eye movement, sleep.

Incredible.

And that single moment completely revolutionized sleep research.

Following that, Nathaniel Kleitman, who was working with Asurinsky,

pioneered the modern sleep lab procedures that we still use today to understand the brain's nighttime activity.

And the setup for that is quite specific.

Very.

They place electrodes on a volunteer's scalp to detect the electrical brain waves.

They place them near the corners of the eyes to detect those rapid eye movements.

And they place them on the chin to detect muscle tension.

Okay.

So let's map this out for you guys listening.

If you are a subject in one of these sleep labs, let's walk through what the EEG graph shows from the moment you hit the pillow.

Good idea.

So when you are just lying in bed awake, but totally relaxed with your eyes closed, your brain is emitting these relatively slow, regular waves called alpha waves.

You are awake, but your consciousness is relaxing.

Then, in an unremembered moment, you slip over the edge.

You enter stage one sleep,

your breathing slows down, and your brain waves shift from those smooth alpha waves to a much more irregular pattern.

And stage one is where some of the most bizarre psychological phenomena happen.

This is the stage for hypnagogic sensations.

Oh, these are fascinating.

Yeah.

These are those sudden, terrifying feelings of falling, where your whole body suddenly jerks awake, or you might feel like you're floating weightlessly.

And it's interesting because people who claim to have been abducted by aliens almost always report being floated off their beds or pinned down shortly after falling asleep.

Which perfectly aligns with the biological reality of stage one hypnagogic hallucinations.

Exactly.

And what's remarkable is how quickly that perceptual door closes.

Sleep researcher William Dement demonstrated this transition almost instantaneously.

Oh, the strobe light study.

Yes.

He took a sleep deprived young man, taped his eyes open, which sounds intense, but it was necessary for the study, and asked him to press a button every single time a strobe light flashed in his face.

The man was pressing it reliably, until suddenly he missed a flash.

When Dement asked why, the man insisted there hadn't been a flash at all.

But the EEG told the real story.

Right.

The man had fallen asleep for exactly two seconds.

In that tiny window, the brain's perceptual filter slammed shut, completely blocking out a bright strobe light flashing just six inches from his open eyes.

Two seconds to completely sever consciousness from the environment.

That is wild.

Now, stage one is brief.

Soon after, you sink down into stage two.

This lasts about 20 minutes.

And if you look at the EEG graph here, you see these highly distinct formations called sleep spindles.

Sleep spindles?

What are those?

They are sudden, tight bursts of rapid, rhythmic brainwave activity.

Once you see those, you're clearly demonstrably asleep.

Interestingly, while sleep talking can technically happen in any stage, this spindle -heavy stage two is where it's most likely to occur.

From there, the descent continues.

You transition through stage three and sink into the deepest sleep of all, which is stage four.

Right.

And stages three and four are characterized by massive, slow -rolling brainwaves called delta waves.

Stage four lasts for about 30 minutes, and it is the hardest stage to wake someone from.

If a thunderstorm rolls through or an alarm blares and you sleep right through it, you are firmly in delta sleep.

Children spend a lot of time in deep delta sleep, which is why it's so incredible.

Yes.

Instead of staying in deep sleep,

your brain essentially throws it in reverse.

You ascend back up through stage three, back through stage two.

But, and here's the trick, you don't wake up.

Instead, you enter the most fascinating state of all, REM sleep.

Which is often called paradoxical sleep.

Right.

Why is it a paradox?

Because the state of your body is in total contradiction.

Internally, you are in a state of high arousal.

Your brain waves speed up and become rapid and sawtooth, looking very much like they did in stage one when you were just barely asleep.

And your heart rate rises, your breathing becomes irregular, and of course, your eyes are darting around wildly under your clothes lids.

Furthermore, the body actually becomes sexually aroused in this stage for both men and women, regardless of whether the content of the dream is actually sexual.

So internally, your systems are firing on all cylinders.

Right.

Externally.

Externally, you are a statue.

You are completely calm.

What's happening is your brain's motor cortex is highly active, firing off commands to run, jump, or throw a punch in your dream.

But the brainstem steps in, acting like a roadblock.

So it blocks those motor messages from reaching the rest of the body.

Exactly.

So aside from an occasional minor twitch in a finger or facial muscle,

your physical body is essentially paralyzed.

Which is a brilliant evolutionary protective mechanism.

I mean, if that brainstem roadblock wasn't there, we would be jumping out of bed and acting out every single wild dream, injuring ourselves immediately.

Absolutely.

So that's one full cycle.

As the night progresses, this 90 -minute cycle repeats.

But the architecture of the graph changes.

Right.

The deep stage four sleep gets shorter and eventually disappears entirely as the night wears on.

Meanwhile, those REM periods, where we do our most vivid dreaming, get longer and longer.

By the time morning arrives, about 20 to 25 % of your total night sleep has been spent in that paralyzed, highly active REM state.

Understanding this biological cycle immediately forces us to confront the next major question for this unit.

How much of this do we actually need?

And what are the physical and psychological costs when we don't get enough?

First off, we have to destroy the universal eight hours for everyone rule.

That's a total myth.

Yes, sleep needs are highly individualized.

Genetics play a massive role in dictating your personal baseline.

Researchers Wils Webb and Scott Campbell conducted studies looking at twins.

They found that identical twins have strikingly similar sleep patterns and durations.

Fraternal twins who share less genetic overlap do not.

Culture and environment are huge variables as well.

If we look at the historical data, North Americans sleep significantly less today than they did a century ago.

Oh, without a doubt.

The combination of Edison's light bulbs, the demands of shift work, and the infinite scroll of the internet has fundamentally altered our cultural baseline.

But just because we can sleep less doesn't mean our bodies adapt to it without a penalty.

We accumulate sleep debt.

And William DeMint's research highlights a terrifying fact.

The brain keeps an accurate ledger of your sleep debt for at least two weeks.

That ledger is unforgiving.

Right.

If you only sleep five hours a night, Monday through Friday, you have a massive deficit.

You cannot just pay it off with one marathon 12 -hour sleep session on Saturday.

The brain demands consistent repayment.

So what happens when that debt remains unpaid?

The immediate consequences are obvious.

Decreased concentration, a depressed mood, and general irritability.

But the biological effects occurring under the hood are staggering.

Like what?

Well,

chronic sleep deprivation aggressively suppresses the immune system, making you far more susceptible to illness.

And arguably, most surprisingly, it is heavily linked to the modern obesity epidemic.

Let's unpack that mechanism, because it's so important for you to understand.

It's not just that you're too tired to exercise.

It is a very specific chemical cause and effect.

Right.

When you are severely sleep deprived, your body increases the production of a hormone called ghrelin.

Ghrelin is your hunger -arousing hormone.

It tells your brain, we need calories immediately.

And at the exact same time, sleep loss decreases the production of leptin, which is the hunger -suppressing hormone that tells you when you're actually full.

But it gets worse.

Lack of sleep also dramatically increases the release of cortisol, which is a stress hormone.

One of cortisol's primary functions in a stressed state is to stimulate the body to synthesize and store fat, particularly around the midsection.

So you are chemically driven to overeat by the ghrelin, you lack the stop signal from the leptin, and your cortisol is priming your body to turn every calorie into stored fat.

It's a perfect biological storm for weight gain.

Beyond our own bodies, sleep debt is a massive public safety hazard.

Oh, the traffic data.

Yes.

Researcher Stanley Coren looked at massive sets of traffic accident data, specifically surrounding the daylight savings time shifts.

The data is impossibly clear.

In the spring, when we spring forward and society universally loses just one hour of sleep, there is a massive statistically significant spike in traffic accidents on the following Monday.

People are driving to work slightly more impaired.

Conversely, in the fall, when we fall back and gain an extra hour of sleep, the accident rate notably drops.

That one single hour literally saves lives.

Given all these vital functions and severe consequences,

psychologists have proposed five major theoretical frameworks to explain the evolutionary and biological why behind sleep.

Why did we evolve to spend a third of our lives unconscious and vulnerable?

Theory number one is simple.

Sleep protects.

This is an ecological niche argument.

If you are a distant human ancestor, your vision is terrible in the pitch black.

Right.

Trying to hunt, gather, or travel at night is incredibly treacherous.

You are far better off retreating to a cave and staying completely out of harm's way.

And if we look across species, this holds up perfectly.

Animals with a high need to graze to get enough calories, and a poor ability to hide like horses or cows, sleep only about three or four hours a day.

But animals like bats, who can hide safely in dark, inaccessible caves, sleep up to 20 hours a day.

Sleep keeps them hidden when they don't need to be active.

Theory number two posits that sleep recuperates.

It physically restores and repairs brain tissue.

Because when you are awake, your high waking metabolism produces toxic byproducts, including free radicals, which are damaging to neurons over time.

Sleep acts as a biological cleaning cycle.

It gives resting neurons the time they need to repair themselves, clear out the toxins, and prune away unused neural connections to keep the system running efficiently.

Theory three is that sleep makes memories.

It reactivates the hippocampus and actively rebuilds and cements our fading memories of the day's experiences.

There is an incredibly elegant experiment that proves this.

Researchers had participants try to memorize the specific locations of picture cards on a grid.

While they were studying, the researchers exposed them to the distinct scent of roses.

Okay, I love this study.

Later that night, while the subjects were deeply unconscious in slow wave delta sleep, the researchers pumped that exact same rose scent into the bedroom.

And the scent acted as a trigger.

Exactly.

It reactivated the hippocampus while they slept.

The next day, the participants who received the scent chew during slow wave sleep remembered the card placements with almost perfect accuracy, far outperforming the control group.

The brain was actively consolidating the memory while unconscious.

Theory four suggests that sleep feeds creative thinking.

It helps the brain discern connections among novel pieces of information.

So it's not just about memorizing facts, it's about integration.

Right.

Research shows that even 15 -month -old infants, if they are given a puzzle or tested on recalling relationships among new words, perform significantly better if they've just had a nap.

The unconscious brain solves problems.

And finally, theory five, sleep aids the growth process.

During that deep stage four delta sleep, the pituitary gland actively releases growth hormone.

Which is critical for physical development.

It explains why infants and children spend so much more time in deep sleep.

As we age and stop growing physically, we spend less and less time in deep sleep and release less of this hormone.

So sleep is essentially a gentle tyrant that we must obey for our physical and mental survival.

But we have to acknowledge that for millions of people, sleep is not a peaceful restorative retreat.

It is a source of intense nightly struggle.

Let's examine the major sleep disorders.

The most common is insomnia, which is recurring wakefulness, or the inability to fall and stay asleep.

Now, a huge misconception here is how insomniacs perceive their own struggle.

Right.

Researchers have found that insomniacs typically overestimate how long it takes them to fall asleep by about double.

And they underestimate how long they actually slept by half.

That distortion of perception makes perfect sense though.

The waking moments in the dark feel agonizingly long and stressful, so those are the memories that stick.

Whereas the periods of light sleep are forgotten.

The problem is how people treat it.

The most common quick fixes, prescriptions, sleeping pills, and alcohol actually aggravate the problem fundamentally.

Right.

Because alcohol is a depressant, people think it helps them sleep.

But what it actually does is severely suppress REM sleep.

You might pass out, but you aren't getting the restorative cycles.

You wake up feeling groggy and terrible the next day, which leads to a vicious cycle of needing more caffeine to stay awake, and then more pills or alcohol to force yourself to sleep the next night.

Psychologists strongly recommend behavioral fixes over chemical ones.

Regular exercise in the late afternoon, aggressively avoiding caffeine past early afternoon, drinking a warm glass of milk.

Wait.

Milk actually works.

It does.

It provides raw materials for the manufacturing of serotonin, a neurotransmitter that facilitates sleep.

And above all, maintaining a ruthlessly strict, regular sleep schedule, even on weekends.

Then there is narcolepsy, which is a terrifying and dangerous disorder characterized by sudden, overwhelming attacks of sleepiness.

These attacks might last less than five minutes, but the person can collapse directly from a waking state straight into REM sleep, bypassing all the other stages.

And because REM comes with that muscular paralysis we discussed earlier, the person loses all muscle tension and simply drops to the ground.

It's important to clarify that narcolepsy is a biological brain disease, not just someone being excessively tired.

Researchers have linked it to a specific genetic abnormality.

There is a neural center in the hypothalamus that produces a neurotransmitter called orexin, also known as hypocritin, which is directly linked to alertness.

Narcoleptic patients have a relative absence of this brain center.

It's a hardware issue.

Another incredibly prevalent disorder is sleep apnea.

Apnea literally translates to with no breath.

People with this disorder intermittently stop breathing while they're asleep.

Their airway collapses.

They are basically suffocating for up to a minute or so until their decreased blood oxygen levels trigger an alarm in the brain, waking them up just enough to furiously snort in some air before falling back asleep.

And this cycle repeats hundreds of times a night.

They completely destroy their deep, slow -wave sleep because their body is constantly jerking them into a lighter stage just to keep them alive.

The scary part is they usually have absolutely no conscious ideas happening.

They just wake up feeling utterly exhausted and depressed.

Their partners, however, certainly hear the deafening intermittent snoring.

Apnea is heavily associated with obesity,

and the most common highly effective treatment is wearing a CPAP machine, a mask -like air pump that provides continuous positive airway pressure to literally force the airway open all night.

Finally, we must differentiate between two often confused childhood phenomena,

nightmares and night terrors.

Nightmares are simply bad dreams, and they occur during early morning REM sleep, just like regular dreams.

Night terrors, however, are entirely different.

They happen during stage four NREM non -REM sleep, usually in the first few hours of the night.

If you've ever seen a child have a night terror, it is horrifying.

They might sit up, scream, and appear absolutely terrified.

Their heart rate can double, but they are entirely asleep.

Because it happens in NREM sleep, they rarely wake up fully and almost never have any memory of the event the next day.

Sleepwalking and sleep talking are also primarily stage four NREM phenomena.

They are largely harmless, the person is not acting at a dream, and because they are tied to deep sleep, these behaviors tend to diminish naturally as children grow older, and the proportion of stage four sleep decreases.

But if sleepwalking isn't acting at a dream, what exactly is happening when we do dream?

Let's move into the inner theater of consciousness.

When you think about dreams, the cultural perception is always these wild, surreal, psychedelic adventures.

But the data shows that our dreams are remarkably mundane and surprisingly negative.

Eight in ten dreams contain negative events or emotions.

We dream about failing at a task, being attacked, being pursued, or experiencing social rejection.

And despite what movies suggest, explicit sexual overtones are surprisingly rare.

Only about one in ten dreams for men and one in thirty for women feature sexual content.

Our inner theater is also constantly pulling in real -world data.

We incorporate environmental stimuli directly into the narrative.

Willard Dement and Edward Wolpert ran a classic, somewhat cruel but brilliant study where they lightly sprayed cold water on the faces of sleeping participants while they were in REM sleep.

When they woke them up immediately afterward, those subjects were significantly more likely to report dreaming about a waterfall, a leaky roof, or being caught in a sudden rainstorm.

The brain seamlessly weaves the physical sensation of the water into the hallucinated story.

But there's a hard limit to what the sleeping brain can do with outside stimuli.

Absolutely cannot learn new, complex information while asleep.

All those schemes about learning a foreign language by playing a tape under your pillow completely scientifically debunked.

In fact, our memory encoding shuts down just before we sleep.

Anything that happens in the five minutes right before you fall asleep is totally lost from memory.

It's why you can't remember the exact moment you drifted off.

So if we aren't learning new, external information, why do we dream?

What is the function?

Psychologists debate five major theoretical frameworks to explain this.

Let's start with the most famous, and frankly the most controversial, Sigmund Freud.

Freud proposed the wish -fulfillment theory in 1900.

He argued that dreams provide a psychic safety valve to discharge unacceptable feelings.

He divided every dream into two layers.

First is the manifest content, which is the literal storyline you remember running through a forest, finding a key, etc.

Second is the latent content, which consists of the hidden, unconscious, and often highly erotic or aggressive wishes that would be too threatening to your conscious mind to express directly.

So your conscious mind disguises them.

To Freud, a gun, a snake, or a sword in a dream wasn't just a random object.

It was a disguised, latent representation of male anatomy.

But modern science has largely discarded Freud's theory.

The biggest issue is that it's completely unfalsifiable.

If you tell a Freudian analyst, no, the snake just represents a snake, they'll say, aha, your denial proves the latent sexual conflict.

You can't test it.

As many modern researchers note, there is zero scientific backing for these universal symbols.

Sometimes a cigar is just a cigar.

The second framework is the information processing theory.

This is much more grounded in neuroscience.

It suggests that dreams help sift, sort, and fix the day's experiences into our memory storage.

REM sleep is crunching the data.

Robert Stickgold, a prominent researcher, emphasizes this by warning against sleep bulimia.

This is the incredibly common student habit of depriving yourself of sleep all week to study, and then binge sleeping for 12 hours on the weekends to make up for it.

The data shows it doesn't work.

You need that daily REM sleep to integrate your daily memories.

If you skip it, the memories degrade.

Brain scans of rats running mazes prove this beautifully.

If you look at a rat's brain while it's learning a new maze, specific areas buzz with activity.

When that rat goes to sleep and enters REM, those exact same brain areas buzz again in the exact same patterns.

The rat is literally rerunning the maze in its sleep, burning the route into its memory.

Theory three is the physiological function theory.

This strips away the psychology and focuses on the biology.

It posits that the intense brain activity associated with REM sleep provides necessary periodic stimulation to preserve and develop the brain's neural pathways.

And the developmental data supports this perfectly.

Think about infants.

Their neural networks are developing at an explosive, unprecedented rate.

And consequently, infants spend an absolutely massive proportion of their total sleep time in REM sleep compared to adults.

The developing brain demands that physiological stimulation to build the hardware.

Theory four is perhaps the most fascinating from a neurological standpoint,

the activation synthesis theory.

This proposes that dreams are fundamentally meaningless.

They are just the brain's attempt to make sense of random biological noise.

Here is how it works.

During REM sleep, the brain stem is just firing off random neural static.

But at the same time, the limbic system, specifically the amygdala, which handles raw immersion like fear and aggression, is highly active.

Meanwhile, the frontal lobes, which handle logic, reason, and inhibition, are basically shut down and idling.

So your brain is being bombarded with intense emotional surges and random visual signals, and your logical center is offline.

Your brain, being a meaning -making machine, tries its best to weave this chaotic static into a coherent story.

Boo!

You are suddenly running from a monster made of spaghetti.

It's activation from the brain stem, synthesized by the cortex.

Finally, theory five is the cognitive development perspective.

Some researchers see dreams simply as a natural reflection of brain maturation and cognitive development.

Dreams aren't random static, but they aren't hidden Freudian messages either.

They draw on our waking concepts and our expanding knowledge.

Which explains why children's dreams change as they grow.

Kids under age nine typically have dreams that are more like a static slideshow.

They are just observing disconnected images.

They aren't active, complex story participants yet, because their waking cognitive abilities haven't matured to that level.

But regardless of which of these five theories you find most compelling,

the fundamental biological need for REM sleep is undeniable.

Researchers have demonstrated a phenomenon called REM rebound.

If you put a subject in a lab and continually wake them up, right as the EEG shows them entering REM sleep, essentially starving them of just that specific stage, they will build up a massive REM deficit.

Once you finally leave them alone and allow them to sleep uninterrupted, they won't just sleep normally.

They will plunge back into REM sleep much faster than usual, and they will spend a significantly larger portion of the night in that state.

The mammalian body physically demands REM.

Okay, we've explored the naturally shifting tides of consciousness through sleep and dreams, but what happens when consciousness is altered deliberately?

This brings us to hypnosis.

Hypnosis has this massive pop culture baggage of swinging pocket watches and magical mind control, but psychology grounds it firmly in observable social and cognitive science.

The working definition of hypnosis is simply a social interaction in which one person suggests to another that certain perceptions, feelings, thoughts, or behaviors will spontaneously occur.

The critical thing to understand is that the power of hypnosis does not reside in the hypnotist.

They don't have magical energy.

The power resides entirely in the subject's openness to suggestion.

To measure this, researchers use simple tests like the postural sway test.

If you stand perfectly still with your eyes closed, and I repeatedly suggest to you, you are swaying back and forth, you are falling forward, most people will eventually sway a little bit.

The people who are considered highly hypnotizable, about 20 % of the population, are simply individuals who have a profound capacity to become deeply absorbed in imaginative activities.

They can focus their attention so intensely that they ignore outside distractions.

But this naturally raises massive ethical and practical questions about memory and coercion.

Can a police officer use hypnosis to help a traumatized witness perfectly recall the license plate of a getaway car?

Or could a sinister hypnotist force you to commit a crime against your will?

The scientific consensus on both fronts is a resounding, unambiguous no.

Let's tackle memory first.

Hypnosis does not work like a truth serum or a video playback machine.

When hypnotists attempt age regression, trying to take adults back to their childhood memories, the subjects don't actually revert.

They just act how they believe a child would act.

They often outperform real children, for example, by writing in block letters but with perfect adult spelling.

They're role -playing.

And the danger is much worse than just bad role -playing.

Hypnotists can easily, albeit unintentionally, plant pseudo -memories.

Because the subject is in such a highly suggestible state, if the hypnotist asks a leading question, like, did you hear loud noises when the man approached?

The subject's brain will actively weave that suggestion into a fabricated memory.

They will wake up fully believing they heard a loud noise.

This phenomenon is exactly what drove the massive UFO abduction craze in the 1980s.

People were hypnotized to retrieve lost time, and the hypnotists fed them suggestions of aliens, creating incredibly vivid, completely false memories.

It is so notoriously unreliable that most Supreme Courts totally ban hypnotically refreshed testimony from trials.

As for coercion, can hypnosis make you do something terrible?

The textbook details a genuinely brilliant classic experiment by Martin Orne and Frederick Evans that answers this.

They took hypnotized subjects and gave them a horrifying command.

They asked them to plunge their hand into what looked like a vat of fuming, dangerous acid, and then they told them to scoop some up and throw it directly into a researcher's face.

Which sounds completely unethical.

But there was invisible glass protecting the researcher and the acid was harmless.

But the subjects didn't know that.

And the terrifying result.

The hypnotized subjects actually did it.

They threw the acid.

So case closed, hypnosis is mind control, right?

Not quite.

Because Orne and Evans used a control group.

They took a group of unhypnotized people, asked them to simply pretend they were hypnotized, and gave them the exact same commands in the exact same laboratory setting.

The unhypnotized control group also threw the acid.

The experiment conclusively demonstrated that the dangerous behavior was driven entirely by the authoritative context of the laboratory, not by magical hypnotic mind control.

People will obey authoritative figures in legitimate contexts, like scientists in white coats, whether they are hypnotized or not.

The power is in the lab coat, not the trance.

So if it doesn't enhance memory and it doesn't control minds, is hypnosis useless?

Actually, no.

Post -hypnotic suggestions, suggestions made during hypnosis to be carried out after the subject is no longer hypnotized, have genuine, measurable, therapeutic value.

They work remarkably well for treating obesity, asthma, and stress -related skin sores.

However, it's worth noting they perform very poorly for breaking deep chemical addictions like smoking or drug use.

But the most staggering application of hypnosis is pain relief.

The analgesic effect is undeniably real.

Nearly 10 % of people are highly hypnotizable enough that they can undergo major surgery with absolutely no general anesthesia.

They use only hypnosis and a mild local anesthetic.

There is a famous Belgian medical team that has successfully performed over 5 ,000 surgeries using this exact method, resulting in faster recovery times and fewer complications.

So how is that possible?

How can the brain ignore a scalpel?

Psychologists debate two major theories of how hypnosis actually works.

First is the social influence theory.

This is the idea that hypnotic phenomena are an extension of everyday social behavior.

The subjects are essentially caught up in playing the role of a good hypnotic subject.

They trust the hypnotist.

They want the experiment to succeed.

And like an incredibly talented actor who becomes fully immersed in a dramatic part, their thoughts and behaviors naturally conform to the role they are playing.

They aren't faking it.

Their deep immersion produces the experience.

The second theory is championed by researcher Ernest Hilgaard, and it's called the divided consciousness theory.

Hilgaard argued that hypnosis is more than just social role -playing.

It causes an actual dissociation, a split between different levels of consciousness.

Hilgaard demonstrated this with a brutal ice water bath experiment.

If you plunge your bare arm into a bucket of freezing ice water, it hurts instantly.

Within seconds, it becomes agonizing.

But under hypnosis, Hilgaard suggested that the sensation of the cold stimulus is dissociated or split off from the emotional suffering of the pain.

So the hypnotized subject leaves their arm in the ice water and reports feeling no pain.

Modern brain imaging actually supports Hilgaard's dissociation theory.

If we look at Pete's scans of people under hypnosis for pain relief, the sensory cortex of the brain, the part that receives the raw physiological input from the freezing water or the scalpel, is still lighting up.

The body is feeling the stimulus,

but the pain processing regions of the brain, which generate the conscious suffering, are quieted.

Hypnosis essentially uses selective attention to block our conscious awareness of the pain.

Ultimately, researchers like Kilstrom and McConkie suggest that we don't have to choose between these two theories.

They offer a unified account.

Hypnosis is likely a complex mix of both intense social influence and everyday cognitive dissociation.

That perfectly transitions us to the final major section of our journey through consciousness, psychoactive drugs.

We are moving from altering consciousness via social suggestion to altering it via physical chemicals.

Psychoactive drugs are chemicals that fundamentally alter our perceptions and moods right at the neural synapses.

But before we get into the specific drugs, we need to establish the foundational rules of engagement.

How does the body react to foreign chemicals?

The most foundational concept is tolerance.

Tolerance is neuroadaptation.

When you repeatedly flood your brain with a psychoactive drug, your brain chemistry adapts to offset the drug's effect in order to maintain its natural balance.

Because of this adaptation, the user requires larger and larger doses to achieve the exact same initial high.

And once that neuroadaptation occurs, if the user suddenly stops taking the drug, they experience withdrawal.

This is the body screaming for the chemical balance it has adapted to.

Withdrawal can involve extreme physical pain,

intense nausea and tremors, which indicates physical dependence on the drug.

But there's also psychological dependence, where the user might not have physical tremors, but the drug has become a vital, inescapable coping mechanism to relieve negative emotions or stress.

When these dependencies merge into a compulsive, relentless craving for a substance, despite severe adverse consequences to the user's life, that is addiction.

When discussing addiction, the psychological community has to work hard to debunk three pervasive, culturally ingrained myths.

Myth number one is that addictive drugs quickly and inevitably corrupt.

We have this cultural narrative that if you try crack cocaine or heroin once, you are instantly hooked for life.

But the epidemiological data tells a different story.

Medical patients routinely receive high doses of highly addictive opiates like morphine for post -surgical pain.

Yet they very rarely develop a lifelong addiction.

Even with highly addictive street drugs like cocaine, long -term studies show that only about 15 % of people become truly addicted within 10 years of their first use.

It is highly dangerous, but instant, inescapable corruption is a myth.

Myth number two is that therapy or clinical intervention is always required to overcome addiction.

Now, obviously, therapy, rehab and support groups like AA are incredibly helpful and save lives.

But treating addiction strictly as a permanent, inescapable medical disease can actually undermine a person's self -confidence and their belief in their own agency.

The data proves that people can and do quit on their own.

Most of America's 41 million ex -smokers who beat one of the most chemically addictive substances on Earth managed to quit voluntarily on their own without formal treatment programs.

And myth number three is the creeping tendency to apply the concept of addiction to all repetitive, pleasure -seeking behaviors.

We hear people say they are addicted to the internet, shopping, gambling or sex.

While these behaviors can absolutely be destructive and compulsive, stretching the strict biological disease model of addiction to cover everything can become a dangerous, all -purpose excuse for bad behavior.

It blurs the line between a biological chemical dependency and a behavioral lack of self -control.

With those rules established, let's break down the three major categories of psychoactive drugs.

Depressants, stimulants and hallucinogens.

Let's start with depressants.

These are drugs that calm neural activity and physically slow down body functions.

And the absolute biggest one is alcohol.

We need to immediately dispel the most common misconception about alcohol.

Alcohol is not a stimulant.

Right.

People think it's a stimulant because you go to a party, you have a few drinks and suddenly you're loud, talkative and dancing.

You feel stimulated.

But that is an illusion.

Alcohol only makes you feel that way because it is actively depressing and slowing down the higher cortical areas of your brain that control judgment, restraint and inhibitions.

It is taking the brakes off your behavior, not pressing the gas pedal.

Precisely.

Alcohol lowers inhibitions, slows neural processing and severely disrupts memory formation.

One of the main reasons heavy drinkers black out is because alcohol heavily suppresses REM sleep, which we know is crucial for fixing the day's memories into permanent storage.

Furthermore, the physical effects on the biological hardware are profound.

Prolonged excessive drinking physically destroys brain tissue.

MRIs comparing the brains of women with and without alcohol dependence show literal brain shrinkage, a reduction in brain mass in the heavy drinkers.

Women are particularly vulnerable because they generally possess less of a specific stomach enzyme that digests and breaks down alcohol before it reaches the bloodstream.

But the truly fascinating thing about alcohol is that its effects on human behavior aren't purely chemical.

They are heavily psychological.

The power of expectation is massive.

If you think you are drunk, you act differently.

To prove this, researchers Abrams and Wilson at Rutgers University ran a classic, highly clever study.

They brought men into a lab and gave them drinks.

Half got alcohol, half got a non -alcoholic placebo.

But, and here's the brilliant trick, they deceived the subjects.

Half the men thought they were drinking alcohol, regardless of what was actually in their cup.

So you have sober men who believe they are intoxicated.

What did they do?

The researchers had all the men watch an erotic movie.

The men who simply thought they had consumed alcohol, even if it was tonic water, reported feeling guilt -free and experienced strong sexual fantasies.

Their belief that they were drinking gave them the psychological permission to release their inhibitions.

It proves that alcohol disinhibits us through a powerful combination of both physical chemistry and mental expectation.

Other major depressants include parbiturates, which are tranquilizers like nembutyl and syconol.

These are often prescribed to induce sleep or severely reduce anxiety by depressing central nervous system activity.

However, they become incredibly lethal when mixed with alcohol because the combined depressive effect on the body systems is too great.

The autonomic nervous system just stops telling the heart and lungs to work.

Then we have the opiates, which include heroin and medically prescribed painkillers like morphine.

The biological trade -off a user makes with opiates is absolute torture.

Here's what happens at the neural level.

When a user floods their system with artificial opiates, it feels incredibly euphoric and kills all pain.

But the brain is efficient.

It realizes, oh, we have plenty of opiates here, and it completely stops producing its own natural painkillers, which are called endorphins.

The factory shuts down.

If the user then stops taking the artificial heroin, their system is completely devoid of opiate receptors.

They have zero natural painkillers left to handle even basic everyday discomfort, leading to a period of agonizing, excruciating withdrawal until the brain can slowly restart endorphin production.

Moving to the second broad category,

stimulants.

These do the opposite.

They excite neural activity and rapidly arouse body functions.

Under this umbrella, we have methamphetamine, which triggers an aggressive release of the neurotransmitter dopamine, leading to enhanced energy and a massively elevated mood.

But the long -term cost is severe.

Over time, meth permanently damages the dopamine receptors, depressing the brain's baseline dopamine levels and leaving the user with permanently depressed functioning and an inability to feel normal joy.

Then there is caffeine, which is the world's most widely consumed psychoactive substance.

It blocks specific sleep -inducing chemicals and lasts about three to four hours.

But we really need to talk about nicotine.

Nicotine is terrifying.

To illustrate the danger, psychologists use a stark, chilling analogy.

Imagine cigarettes were totally harmless, except that one in every 25 ,000 packs contains a cigarette filled with literal dynamite instead of tobacco.

If that were the case, based on global daily consumption rates, that would result in over 10 ,000 explosive violent deaths every single day.

We would ban them immediately.

Society wouldn't tolerate it for a second.

Yet the actual slow -motion deaths caused by tobacco -related illnesses approximate that exact number.

The World Health Organization predicts an unfathomable one billion tobacco -related deaths in the 21st century.

It's a staggering public health crisis, driven entirely by how perfectly nicotine hacks our biology.

The mechanism is fiercely aggressive.

A hit of inhaled nicotine reaches the brain in just seven seconds faster than intravenous heroin.

Once it hits the brain, it triggers an explosion of neurochemicals.

Ebenephrine and norepinephrine boost alertness and arousal, while dopamine and opioids rapidly calm anxiety and reduce sensitivity to pain.

It is an incredibly powerful, perfectly engineered neurochemical reward.

But researchers recently discovered an incredible insight into nicotine addiction by looking at brain injuries.

They found that patients who suffered a stroke or damage to a very specific prune -sized region of the frontal lobe called the insula, which is the area that heavily lights up during drug cravings, instantly lost the urge to smoke.

They could have been chain -smoking for 30 years, but with the insula damage, they could quit immediately with zero cravings.

It highlights exactly where the physical addiction lives in the brain.

The next major stimulant is cocaine.

Cocaine offers a very fast, intense 15 to 30 -minute rush of euphoria.

To understand why, we have to visualize the neural synapse.

Normally neurotransmitters like dopamine, serotonin, and norepinephrine are released into the synaptic gap to pass a message, and then they are sucked back up by the sending neuron in a process called reuptake.

Cocaine acts like a blockade.

It physically blocks the reuptake valves.

Imagine a vacuum cleaner trying to suck up dirt, but someone put duct tape over the hose.

Because these feel -good neurotransmitters are trapped in the synapse, they just keep firing and firing, continuously hitting the receptors and creating an intense rush.

But the problem is, the supply isn't infinite.

When the cocaine eventually washes away and the duct tape comes off, all those neurotransmitters get vacuumed back up, leaving an absolute void.

There is an immediate, crashing depletion of dopamine and serotonin.

The craving to get that rush back is terrifyingly strong.

In animal studies, caged rats given cocaine will fight each other relentlessly.

Monkeys will press a lever up to 12 ,000 times until they are exhausted and starving, just to get a single hit of cocaine.

The final prominent stimulant we must cover is ecstasy, or MDMA, which actually doubles as a mild hallucinogen.

Ecstasy acts as both a stimulant and a massive serotonin releaser.

It floods the brain with serotonin and blocks its reabsorption, creating a profound feeling of euphoria and social connectedness.

However, the long -term biological cost is incredibly steep.

Repeated use physically leeches brain serotonin and actually damages the serotonin -producing neurons themselves.

This leads to long -lasting, potentially permanent depressed moods, heavily impaired memory, and because it's usually taken at crowded, hot -dance raves, a severe risk of potentially fatal dehydration.

This brings us to the third and final category, hallucinogens.

These are psychedelics that actively distort perception and evoke vivid sensory images without any actual sensory input from the environment.

Your brain hallucinates the reality.

The most historically famous synthetic hallucinogen is LSD, which was accidentally created and first ingested by Swiss chemist Albert Hofmann in 1943.

Research over the decades has shown that the visual progression of an LSD trip is actually quite predictable across users.

It almost always starts with simple geometric shapes like cobwebs, grids, or spirals.

As it intensifies, those shapes transition to more meaningful, complex images, often layered over the actual environment.

Finally, the trip often peaks with profound feelings of separation from the physical body, which can cause either deep spiritual euphoria or severe panic.

And here's where it gets incredibly fascinating.

These LSD hallucinations are strikingly almost perfectly similar to near -death experiences.

People who survive cardiac arrest and are revived often report seeing a tunnel of intense light, experiencing a rapid replay of old memories, and having out -of -body sensations where they float above their physical form.

Some view this as spiritual proof of the afterlife.

But hallucinogen researcher Ronald Siegel points out a biological reality.

A brain under extreme physiological stress, like severe oxygen deprivation during a heart attack, fires off neural static and hallucinates in the exact same visual pattern as a brain heavily dosed with LSD.

The tunnel of light is a biological byproduct of the visual cortex shutting down from the outside in.

Finally, we must look at marijuana, which is classified as a mild hallucinogen.

Its main active ingredient, THC, relaxes the body and disinhibits behavior much like alcohol.

But biologically, it acts very differently.

Alcohol is flushed from the system within hours.

THC, however, is fat soluble and lingers in the body for a month or more.

This creates a very unique phenomenon, a reverse tolerance effect.

Regular heavy users might actually need less of the drug to get high than occasional users because the THC from their previous use is already lingering in their system.

But the cognitive disruption of marijuana is significant.

It heavily impairs motor coordination and reaction time, and it severely disrupts memory formation, interfering with the recall of events that happened just minutes prior.

However, scientists recently discovered something that changes how we view it.

The human brain naturally possesses cannabinoid receptors.

This discovery implies that our bodies naturally produce our own internal THC -like molecules that help control pain and regulate mood.

This biological reality is exactly why marijuana has proven therapeutic applications for managing chronic pain, reducing nausea in chemotherapy patients, and treating severe weight loss.

Now, looking at all these drugs, their immense dangers, and their allure, we have to ask the ultimate question.

Why do people use these dangerous substances in the first place?

To explain drug use, psychologists rely on the biopsychosocial approach.

Behavior is never caused by just one factor.

Let's break that down, starting with the biological influences.

Genetics matter deeply when it comes to addiction vulnerability.

The data is clear.

We see much higher addiction concordance rates in identical twins than in fraternal twins.

If your identical twin struggles with alcohol, your risk is significantly higher.

Researchers have also identified behavioral traits in youth that predict future risk.

Boys who are naturally fearless, highly impulsive, and under -aroused at age six are statistically much more likely to abuse drugs as teenagers.

They are seeking external stimulation.

In animal labs, researchers have even engineered mice that overproduce a specific brain chemical called NPY.

These NPY -rich mice are highly sensitive to alcohol sedating effects, so they naturally drink very little of it.

Biology sets the baseline risk.

But biology isn't destiny.

We must layer on the psychological influences.

Heavy drug use is strongly, consistently correlated with feelings that life is meaningless and directionless.

Significant stress, a sense of failure, and untreated depression are massive drivers.

Many people use psychoactive drugs to temporarily dull the acute pain of self -awareness.

It's a coping mechanism for psychological suffering.

And finally, perhaps the most immediate trigger for teens and young adults.

Social cultural influences.

The environment and peer norms dictate behavior in profound ways.

If we look at the data from the 2003 ESPED survey of European teenagers, the variance is staggering.

It found that marijuana use among 15 -year -olds in the prior 30 days was 0 % in Romania, but a massive 22 % in Britain.

And within the U .S., African -American teens consistently report sharply lower rates of drinking, smoking, and cocaine use compared to other demographics.

The cultural environment, the community norms, and religious boundaries strongly dictate the behavior.

And we also have to account for the false consensus effect.

University students notoriously and vastly overestimate how much their peers are actually drinking or smoking.

Because they only see the loud parties, they assume everyone is constantly binge drinking.

They drink heavily to fit into a norm that doesn't actually exist.

But social networks aren't just negative.

They can be a massive force for good.

There was a huge 32 -year study by Christakis and Fowler following 12 ,000 adults.

They mapped out their social connections and found a powerful network effect when it came to health behaviors.

People tend to quit smoking in clusters.

If your spouse, your sibling, or your close friend quit smoking, your personal odds of quitting skyrocket.

You influence each other's behavior.

This comprehensive biopsychosocial view gives us clear, actionable avenues for prevention.

It tells us we need to educate youth on the long -term biological costs of temporary chemical pleasures.

We need to boost their psychological self -esteem and sense of life purpose.

And we need to inoculate them socially against peer pressure by actively teaching them refusal skills so they know exactly what to say when a drug is offered.

We have covered an incredible amount of ground today in this tutoring session.

We've traced the history of how psychology views the mind.

We've explored the relentless biological rhythms of sleep, the bizarre, hallucinated landscape of dreams, the mechanics and limitations of hypnosis, and the profound chemical alterations caused by psychoactive drugs.

But I want to leave you with a final, provocative thought.

We started this deep dive talking about the illusion of conscious will, how your physical body reacts on the basketball court before you even consciously decide to move.

Exactly.

Now think about everything we've unpacked since then.

If your vivid memory of a dream, your profound experience of pain under a hypnotist's suggestion, or your very perception of color and reality on a hallucinogen can all be fundamentally completely altered by a shift in a biological brainwave, a quiet whisper in a lab, or a single molecule sneaking across a neural synapse.

Well, who is the you really in charge behind the steering wheel of your consciousness?

Are we the deliberate driver of the car?

Or, as the behaviorists argued, are we just the speedometer watching the journey unfold and taking credit for the ride?

It's something to mull over the next time you feel yourself drifting off into the darkness of sleep.

It truly is the ultimate enduring question of human psychology.

Thank you so much for joining us for this intensive deep dive.

On behalf of the Last Minute Lecture Team, we sincerely wish you the absolute best of luck mastering this material and crushing your AP studies.

Keep questioning, keep exploring the mechanics of your own mind, and above all else, make sure we get a good night's REM -filled, biologically restorative sleep before your exam.

See you next time.