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How Your Brain Sees, Smells, and Decides: Sensation vs Perception · Professor Peterson’s Psychology Classroom

0:05
Welcome to Professor Peterson's Psychology Classroom,
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connecting the science of human behavior to everyday life.
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Here's Dr. Curtis Peterson.
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All right, so what we have for today is we're
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going to start on our discussions about sensations and perceptions.
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Um, and again, uh, to kind of bring this to
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the broader area of what we're, we're trying to build in this class,
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which is in a sense a thinking human
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being, is that we've talked about
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the— if we look at it from a computer model, we looked at the CPU
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in the last section, uh, where we looked at the
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brain system, the nervous system. It's a system that receives information,
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and then it's going to organize it in some organic
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way, and then we have some type
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of output, which is our perceptions,
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right? But to give this even more
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clear definition,
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um,
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we can say that sensations,
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uh, is sensations, uh, is established
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by the sense organ, uh, where a certain type of
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stimuli is detected from the external
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world, and then that stimuli is then
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transmitted into some other region
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of the brain where it's then processed.
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All right, so when we're talking about sensations,
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we're talking about just the raw wavelength
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sound waves, um,
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feeling of temperature, uh,
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taste in our mouth. All of those things are
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then getting centralized in the brain And it's developing
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kind of this output, which we
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call perceptions, which is really that processing
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organization. It's the interpretation of that sensory
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information in the brain. Okay,
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and these processes result in our internal
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neural representation of the physical stimuli.
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When we want to think about it from a brain perspective.
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This then, so when
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we talk about the brain,
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how our sensory systems then get it into a code,
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as you would say, that the brain can
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understand it, this is what's known as transduction.
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Okay, transduction is a process by which
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sensory receptors change physical
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stimuli into signals that are eventually sent
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to the brain. So, for example,
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it will take wavelengths. These sensory
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receptors detect those wavelengths,
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and they transfer those wavelengths based on the sensory
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receptor into electrical chemical impulse that
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then is transmitted to usually
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the occipital and the temporal areas of the brain for
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further processing. Okay, so that
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is the sensation part when
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we go from receiving physical energy into
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electrical chemical energy.
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And then when it gets sent to the correct areas of the brain,
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that's where we start transmitting it into a
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perceptual event. Okay.
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And this kind of is one of those really clear examples
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of, of the basic sensory stimuli.
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So if we have like a physical stimuli such as
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a traffic light that turns green,
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That wavelength is a physical stimulus.
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It really has no meaning. It's just
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green wavelengths that are going towards an organism.
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That light in and of itself is meaningless.
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Okay, that— but when that light
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then is detected, the light waves go on and go back to
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the back of the eye, and they're detected by the sensory receptors.
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It recognizes a green wavelength
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and then puts that into a certain neural package,
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as if you want to think about it that way,
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and sends that electrical impulse
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first to the thalamus. Okay, remember when we
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talked about this, when we kind of talked about Freud's theory?
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Everything is— all information except for,
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um, auditory information goes through the limbic system
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first. And this is important, uh,
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because when we're at a green light, right,
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um, we want to be able to react to it
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without the information needing to go clear to the frontal
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cortical areas of our brain and for us to physically
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state Oh, it's green now, I can push the gas,
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right? So that limbic system that holds those
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conditioned stimulus responses,
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those award-punishment responses,
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it's important for it to hit there first. Okay,
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then it's transmitted to the occipital lobe,
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mainly the cortical areas of the brain. And this
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is where I stated in the last section, your mom was right. We do
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have eyes in the back of our head because it's transmitted
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back to here where then it is organized
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and put into a perceptual package that then could be delivered
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to what we see. Okay. And then
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that information travels into our spatial
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area of the brain that makes us realize where we are in traffic.
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Helps us stay in the lanes we need to stay in, our motor
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and sensory responses. Are we pushing on the gas enough
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or not enough? Is the car in front of us going or
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not going? And then to the frontal cortical area where we're
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making the decision, okay, I'm past Ajo
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Drive, how do I get to Mission? Okay, or something
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like that. It's a Tucson example.
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So, um, and so that's kind
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of how these systems work. And the point
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I want to make is, uh, it's these areas that
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give us our conscious perception. It's this
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area that starts the reaction process.
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All right, and so an individual who,
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for example, has, uh,
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is for— how I'll put it this way— someone who has
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a lot of stress and cognitive load in the frontal
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cortical area of the brain, okay?
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Their limbic system might respond to the green
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light, which means go, and you may push on the gas,
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but because you're so cognitive loading, you won't maybe
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notice the car in front of you who hasn't started to go.
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Okay, and I think we all have
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experienced that type of event in our life, uh,
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but usually, you know, we'll notice that it's because we're either focusing on
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something else that we think is more important, or we're
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very stressed, and that's where a lot of those mistakes can happen.
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Okay, so this is
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kind of the process, and we will note that this does
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have some processing time. All right,
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is it's usually a person will sit at a green light when it
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actually turns green for anywhere between 5
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to 15 seconds. This sometimes
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annoys individuals that are in a hurry and are hyper-aware
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of what's going on, and we question, why isn't this person going?
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Because we ourselves are very hypervigilant.
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Um, and so that's kind of speeding that process up,
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uh, but, uh, we need to remember these processes
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in normal transmission take a
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bit of time to have the full conscious perceptual
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ability to really say, okay, I'm going, I'm doing all
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of these things. So just to learn a few patient
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remarks. Uh, plus you will notice
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that as individuals ages,
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ages, uh, staying at the green light,
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uh, gets longer and longer and longer. I, I don't know
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anyone who hasn't experienced as a younger person
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being behind an elderly person and
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the light will turn green and we're there at 20 seconds,
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30 seconds before they get going.
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Please note that this is not a fault of the
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individual. This is the fault of that slowing cognitive
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system as we age. So I hope that
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provides a little more patience.
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Um, just to kind of review some of the areas that
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deal with sensory information is
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this cortex right here that is in green. This is the temporal
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lobe. That really deals mostly with primary
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auditory processing. And you'll notice that it is
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significantly larger than the other areas that we're going
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to talk about. Now, you'll notice
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that it says primary auditory cortex right here,
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right? But then this whole area is green.
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Well, when we think about the different ways we listen
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as human beings, we listen through reading,
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writing, thinking.
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And if you ever notice, when you talk to yourself, you hear a voice.
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You don't see words.
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If you do, I'd really like to
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dissect your brain. Someday. Uh, no, I'm just kidding.
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Uh, we do— human beings have a
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very complex language
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system, and the different ways
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that we process language is
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largely the reason this is the whole temporal lobe,
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but the area that first receives actual
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auditory information from the ears is this
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area right here. Okay, and then we have
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in the back, we have the occipital lobe that represents
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the whole yellow, and the primary visual cortex
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that processes vision, visual stimuli. And I want
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to be careful here, what it's processing is,
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am I receiving a green wavelength signal,
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a red wavelength signal?
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What is it that is that primary signal?
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Okay. And then it is these other areas, the whole entire yellow
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area that then start to put the picture together. Okay.
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And one of the ways that we know this
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is the primary visual cortex is studies dealing
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with people who are colorblind. These are individuals wherein parts
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of their primary cortex, they might not
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have a receptor area or neurons that
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light up to certain colors. So then the brain
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has to fill it in with a different color. Okay.
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So this is kind of gives us the picture and according
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to current research, this is kind of a 2D picture.
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Because it's not until it starts to combine the auditory information,
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which there we hear distance and balance,
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and the parietal lobe, which really
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deals with our perception in time and space,
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where we are. Okay,
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so if it wasn't the combination of these systems
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I have one of my on-campus students here that I recognize. He's probably about
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8 feet away from me. If I didn't have my
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parietal lobe, it would look like he was right in front of me. There would
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be no spaces between us, which would
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be really weird. Okay, so that's kind of the combination
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of the parietal lobe and the occipital lobe. And then of
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course, what's butted up against these before we get into the frontal lobe
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area is our pro— our,
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our somatosensory cortex,
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which is then reacting to all the
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areas of the body that need to react to
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this stimuli. All right,
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so, uh, and then we get into the frontal cortex,
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um, and there's some interesting areas in here. Of course,
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this is where we believe the areas of consciousness arise.
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This is where our higher thinking arises.
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This is where we stop behaviors
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that we initially initiated
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but decided were a bad idea. This is
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where, um, the, the area that
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is most compromised when we drink things like alcohol,
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and we start making not very good decisions.
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Um, but one of the interesting things about the
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frontal lobe is I mentioned
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the system— one of the systems that
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is closely related to it is our olfactory system. Okay,
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now the most interesting thing about the olfactory
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system in the state of science is
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it is one of the most understudied areas
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in the human sensory system,
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mainly because humans didn't want to think
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that they were— that we're animals and we respond to things like
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pheromones and things like that.
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But when we get to social psychology,
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We will find that the olfactory system plays a
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huge role in who we're attracted
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to, who we will respond to,
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um, and how we will actually
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really engage in the world. Okay,
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we'll do some interesting studies about the attraction
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of, for example, I'll just give one example that
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kind of shows where we'll be heading to this in social psychology.
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There was a study where they gave,
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I think it was a football team, cleaned laundered
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shirts to exercise during football exercise.
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Okay, and then they turned those t-shirts into the experimenter,
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and they also had then just clean laundered
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t-shirts Uh, in 2 kind of separate boxes
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with holes in it, so you couldn't see what was in the box, but smell
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was able to get out. Okay, and then they put girls in
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2 booths and they
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showed pictures of men ranging
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from, you know, sizes,
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shapes, Haircuts,
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ethnicity, you name it. They showed pictures,
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but they were the exact same pictures in both booths.
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So you would assume the rating of attraction, if it was based
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on visual cues and your own personal,
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uh, you know, preferences, that the
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ratings would average out to be the same. You wouldn't see
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any average differences between people who were randomly assigned
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to one booth versus the other. But interestingly,
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the women in the sweaty football t-shirts
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room actually rated the exact same,
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uh, pictures much higher in attraction,
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right? And this was interesting because Further
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research went on to show that the only thing that you
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needed in one booth versus another is testosterone.
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So in later experiments, they took a little bottle of testosterone
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and just kind of put it in the booth versus the other
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one that didn't. And they found that women
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in the booth with the testosterone,
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regardless of seeing the same pictures, would rate those men,
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those men as more attractive. Okay,
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the sweat example, the reason they narrowed that down is because the one
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thing that men sweat when they sweat that is
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common between all men is testosterone.
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Okay, we all might discrete different other
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chemicals that give us a different smell based on our sweatiness,
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But the common chemical in all of them is always testosterone.
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So that's how that got narrowed down to that. My point
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being is we're finding more and more the
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importance of smell in the human experience, even to
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things such as men for women who they'll potentially
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be attracted to. Okay.
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And the other area that I want to focus on is our gustatory
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cortex. So this is our taste cortex, okay?
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And again, the interesting thing that I think for—
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from a psychological perspective about this area of the brain is
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its reactivity, okay? If you have a quick
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disgust response to food,
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Um, that, you know, you're going to find this kind of interesting,
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you know, because we can measure it by that area of your brain lighting
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up. So we can tell you, yeah, you gag quickly.
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Okay, or if you have a low
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gagging reflex— let's use that term, low gagging reflex—
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we tend to find that the people with low gag
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reflexes are not that picky about who they
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will mate with. However, people with
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a very, very strong gag reflex are
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very, very picky about who they
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will intimately be involved with.
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So again, going to the social psychology perspective,
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we will see that some of these sensory inputs that we may
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not be aware of— who would guess that I gag very
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quickly to something I don't like means that I'm a
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picky person? But these are some of the
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kind of interesting things we're finding out about sensory
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response systems. Okay,
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so there's a view of the brain systems
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and the receptor systems, uh,
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let's move on to some notions
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of, uh, what amount of stimuli
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is necessary for us to respond
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to a stimulus. Okay,
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and there's, uh, 2 types of methods
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that we use. Okay, one is what's called
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the absolute threshold. Okay, this is the
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smallest amount of physical stimuli required to
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detect a sensory input at least half of
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the time when it's present. So it's like at that very minimum
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level that we detected about half of the time.
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Difference threshold is the minimal difference
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in physical stimuli required for us to detect
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a difference between that
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sensory input. Okay,
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so if I put a 5-pound weight
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on your hand, how much more weight would I need
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you— need to add in order for you to feel a
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difference in the amount of weight that you're holding?
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Okay, so that's difference threshold.
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All right. And so,
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this is kind of an example of absolute threshold. So, we have
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the stimulus intensity, and we have
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how much one detects it. And we can see that it's kind of this,
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kind of almost an S-curve.
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And we see that around about half of the intensity is
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where we detect it the most, and then beyond
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that, the detection rate gets higher and higher. So that's an example of
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absolute threshold. The— so
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that's for hearing. This is kind of the absolute threshold for human
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beings in some different sensory detections.
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So we can detect a teaspoon of sugar
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in about— in 2 gallons of water. Uh, we can,
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uh, smell a drop, which is kind of interesting. Just one drop
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of perfume diffused into the entire
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volume of 6 rooms about half the time.
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Um, so when you're spraying that spray
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around, just remember it's being detected a
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lot further than you— I think you might hope. Uh,
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touch. This is also kind of an interesting one.
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A fly's wing falling on your cheek from a distance
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of about 0.04 inches away. You can feel that.
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Hearing. You can hear a tick of a clock at
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about 20 feet under quiet conditions. And probably the
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one that I think is absolutely cool. Is if there is
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no interference, meaning there's no pollution,
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there's no other lighting that's coming in,
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is we can see a single candle flame flicker
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from about 30 miles away.
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So that's kind of, uh, that I, I think that's kind of a something
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to— it blows my mind that we actually have
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that kind of visual acuity. It's kind of some cool stuff.
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Okay, uh, I want to— I want to go
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back to a
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difference in threshold, and I want to note very much in
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psychology we have very few laws because
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very few of what we say can really— I mean, we use averages
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and probabilities and whatnot, and we have very few
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laws. The one law we probably have
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shown to be very consistent is something called Weber's
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Law. It also can be known as Weber's
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Law, depending— the W in
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German is the, so it's Weber's Law.
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And what Weber found
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is that the ability to detect differences
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in sensory input is not the amount,
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it's the percentage. All right,
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so this is one of my most clearest examples. Let's say to
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tell the difference in your weight, your physical weight,
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it's— here, I'll write it out.
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It's 5%.
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So in order to tell that you're losing weight,
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you have to lose 5% of your
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weight. Okay,
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so let's take 2 people. I can
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draw these. We have a person that
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is 100 and one that
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is 300 pounds.
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And let's say these guys are friends and they're like, we're gonna start
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exercising, we're gonna start doing this, and our first
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goal is to lose,
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let's say, 10 pounds.
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Okay, so 10 pounds is the goal. So this person
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is going to be 290 at the end.
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This one's going to be 90 pounds at the end.
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Now, at the end of this, you would assume because they
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both lost the same amount of weight, they both feel very
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rewarded. For losing that amount. Okay,
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but let's apply Weber's Law.
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5% of 100 pounds is
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5 pounds. Okay,
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so in order for this person to feel a change in their
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weight, they only have to lose 5 pounds,
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which is 95 pounds.
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However, for the 300 person to feel the
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difference in their body, 5% of 300
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is 15%.
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So this person, in order
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to feel the success would
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need to lose and weigh down to 285
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pounds. So when the 2 individuals
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get to their 10-pound goal, the only
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one that's going to feel it is this person.
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And this person is probably going to go, why is he so happy? I don't
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feel like I've lost a thing. Okay.
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So again, if we— Weber's law says
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a change in stimuli has to do with the percentage,
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not the amount. Okay, so keep that in mind.
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Okay, so that's the different— that's some examples of threshold
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and changes in
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weight. Uh, and the other kind
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of thing that goes along with these differences is sensory adaptation.
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And this is our decrease to sensitivity to constant
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levels of the same stimuli. Okay, when we
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get to attention, we're going to find
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out that humans don't have very good sustained
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attention. Okay. I hope you
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guys feel like you're engaged in this lecture.
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You're here, you're listening to what I say,
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you're looking at the slides going, geez, I get this.
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But if I were to ask you, let's say on Monday,
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recall my lecture from
29:59
Thursday, you may only be able to
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recall about 10 minutes of our entire time together.
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Okay, uh, a lot of times I know I
30:11
got frustrated with this. Um, I go and
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I, I listen to an instructor or a professor
30:18
or a speaker, and they make these really awesome
30:22
claims, and I get excited to go home and tell
30:26
my family or tell my spouse or tell
30:30
a friend and call them up. And have you ever noticed you really
30:33
can't really reproduce the
30:39
coolness of what you just heard? All right,
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this is due to what we call sensory adaptation.
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When our brain is inundated with the same stimuli
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that area of the brain, the neurons that are processing
30:57
that information get burnt out. And so
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it has to turn on the neurons that are next to
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it until it's able to fire again.
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And so sensory adaptation is
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one, our sensory system just starts— stops firing
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to any unimportant information. We stop
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processing it altogether. The other part
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of it is, is that we shift attention every about 10 to 15
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seconds. Okay, so every 10 to 15 seconds,
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let's say you listen to this part of the lecture
31:39
for 10 to 15 seconds. I'd be willing, if I could look
31:43
inside your mind, you would be going I wonder what I'm doing
31:46
for lunch. And then you take a few seconds and you'd
31:50
come back. And you may do it not even aware
31:54
that you're doing it. Okay. And so this is kind of sensory
31:58
adaptation. And when we get to the attention section,
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what really interrupts our ability to really attend
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to a specific stimuli for an extended period
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of time. Okay, this is also part of what's
32:15
called the cocktail effect. Okay,
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you ever find it interesting that sometimes you can walk in a crowded
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room, let's say a party, a cocktail party— that sounds fancy,
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um, or a, a party of some type— and there's
32:30
lots of sensory noise coming at you, right?
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But then you hear your name.
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Out of all that sensory information, you heard your
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name and you orient and you notice
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a person saying your name, come over here.
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And what do you do? You go over there.
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And has ever anybody ever realized when you're having a
32:57
kind of an introductory or even an important
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conversation or an exciting conversation, in a very crowded,
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loud room, all of that crowded noise goes
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to the background. And it's not
33:12
quite, but it's almost like you two are in the room
33:17
by yourselves. Okay, this is an example
33:21
of sensory adaptation and attention. Okay,
33:27
is that you're recognizing an important stimuli You're
33:31
responding to it, and then you're going to focus on that stimuli.
33:36
And as you do that, your adaptation system
33:39
is starting to weed out anything that's not currently important
33:44
to you. Okay,
33:47
so those are some examples of,
33:50
of stimuli and detection and how we can put things to the background,
33:54
to the foreground, even when there's immense amount of stimuli coming
33:58
towards us.
34:02
All right, so let me— and
34:10
in the book it goes over some of these really cool kind of
34:14
objects, but what I want to kind of end
34:19
with for at least this lecture today is
34:23
the notion of bottom-up versus top-down processing.
34:28
Bottom-up is when the body is
34:33
responding to,
34:37
uh, very important sensory signals from
34:41
your sensory system and is using your sensory system
34:45
to primarily respond to that
34:49
environmental stimuli. Okay, probably the best answer,
34:53
uh, um, example of this is
34:57
when you put your hand on a hot stove. All right,
35:01
you're not usually going to sit there and think, oh,
35:05
this is really hot, I should move my hand before
35:08
it gets burnt. Okay, that's bottom-up processing.
35:12
It's when the higher area of your brain says,
35:16
you know what, I'm not getting involved in this, you need to
35:20
respond very quickly. Okay,
35:22
top-down processing is when
35:28
your experience, your memories,
35:35
your learned behaviors provide
35:41
the— how should I say this— the
35:46
information that you want your sensory system
35:50
to pay attention to. Okay, so it's saying
35:54
pay attention to this stimuli and not this
35:57
stimuli. Okay,
36:00
some good examples of how these
36:04
2 systems work today is,
36:08
uh, one, one of them is subliminal stimuli.
36:13
The other one is priming, priming.
36:17
And the other one, which we will get again in more
36:21
detail on social psychology, is something we call the confirmation
36:25
bias. Okay, so how
36:29
these 3 work. So you probably have heard the idea, you know,
36:33
subliminal messages. It's put at the lowest
36:37
level of a message to try and influence your behavior.
36:40
It became really popular when there was a
36:44
Beatles record that if you played it backward, it said something
36:48
about the devil, those kinds of things. And during
36:52
that time, psychologists really got interested. Does subliminal
36:56
messaging really work? Okay,
36:59
so I'll give a grocery store example for
37:03
this one. So they would, uh, just below the level
37:07
of awareness Uh, they'll play the,
37:10
the store music, and they would play a subliminal message saying,
37:15
uh, buy more Coke. Okay, buy more Coke,
37:19
uh, it's cheaper today. Um, and so they gave
37:23
commands to do something, all right?
37:28
And the question is, is did people buy more Coke? And the answer was
37:32
no. All right, so don't worry about somebody
37:37
telling you that you need to, um,
37:40
become a more extremist to something because they command
37:45
you to at the subliminal level. Now,
37:49
however, where does subliminal messaging
37:53
really work? Okay, while it won't
37:57
influence your rational thinking It
38:01
does actually can influence your emotional thinking and
38:07
your emotional perception. So I'll give the
38:11
Coke example again. So they're playing the music,
38:14
and in the message it says stuff
38:19
like Coca-Cola is happy,
38:22
um, Coca-Cola is going to give us a good day.
38:26
Um, one good Coke
38:30
tastes really good today. Okay,
38:33
notice that appeal. It's appealing to the emotional areas,
38:37
not the rational areas of the brain.
38:40
Does that influence purchasing behavior? The answer is yes,
38:43
because if there's a sign too on the Coke display
38:47
that says happy people drink Coke, you're having a congruent
38:51
emotional experience with the product.
38:54
And therefore you may purchase it more.
38:57
Okay, hence there's a lot of restrictions and rules
39:00
about subliminal messaging. How does this work more
39:04
in modern times? And subliminal messaging— if
39:09
you go to, for example, your favorite store
39:13
and they have the corporate box music
39:17
playing, you'll notice that in that store
39:21
They play probably what would have been your favorite
39:25
music during your teenage transition
39:29
into adolescent years. Okay,
39:32
um, why?
39:36
Because it is that era of our life where we
39:40
tend to have a lot of music appreciation,
39:45
and we identify— we start to identify with what genre
39:48
of music we're going to play. And what genre are we
39:52
going to choose? What's available during that time of
39:57
age and development. Okay, so, you know,
40:01
uh, if we think about Walmart,
40:05
Walmart, uh, plays music. If they're
40:09
playing the, uh, the, the music that Walmart
40:12
wants them to play— there's some Walmarts that don't—
40:17
but if they're playing the music They're going to play the music
40:22
that, uh, was the music of anyone
40:26
from the age of 35 to 55 when
40:31
they were in their teen years.
40:34
So they'll play music basically from the '80s,
40:38
'90s, and early 2000s. Okay,
40:42
why? Because those are the individuals that tend
40:46
to have— tend to be
40:50
able to purchase more at Walmart
40:55
than other age groups, and they're the ones that are more likely
40:59
to shop at Walmart. Okay,
41:04
some other examples. If you go to Hot Topics, their age
41:08
group will play music that's only about 5 or
41:11
10 years before them when they were in those years. Okay,
41:16
so notice that one experiment you can do if you
41:19
ever want to experiment on this is when
41:23
you go grocery shopping, if you want to lower your ticket
41:27
amount that you spend at the grocery store,
41:31
listen to something in your, uh, phone or
41:35
your, your earbuds that you don't
41:39
really want to listen to. So maybe your last
41:42
math lecture. For some of you, it may be this lecture.
41:47
Listen to something that just really is not
41:51
interesting to you. And I'm willing to bet
41:55
that your purchase amounts will
41:59
go less and less and less until you get irritated
42:03
enough to take them off. Okay, this is an example of
42:07
top-down processing.
42:10
Um, and how those areas of the
42:14
brain that appeal to emotionality and those kinds of things can
42:17
tell your sensory receptors and your,
42:21
uh, sensory cortex, hey, I really
42:25
want to respond to these things.
42:28
The other one is priming effect, and this is another
42:33
example of top-down processing. Okay, and I think
42:37
I've already given some examples dealing with morality and
42:40
social psychology on this, um,
42:44
but I'll give kind of 2 experimental examples.
42:48
Okay, one experiment is that we bring
42:52
individuals in and we have them either read
42:55
a book about a child who does something right,
42:59
so a moral positive book reading.
43:04
And then we have someone that reads something morally
43:09
nonjudgmental, okay? And long before
43:13
then, we measured their moral aptitude, okay?
43:16
Measure high in moral decision-making, low in moral decision-making
43:21
at some other period in time. And then after that,
43:25
we have them play a game. Where on
43:29
a screen, the screen— the
43:33
experimenter asks you to hand score and
43:38
compare it to the screen after. The screen is always going
43:42
to give you less points than what the person hand
43:46
scores. All right,
43:49
your score is based— will base the
43:54
amount of money the experimenter is going to give you at the end
43:57
of the experiment. So the higher the score, the more money you
44:01
get. Okay, if moral aptitude
44:05
was the way we're going to judge
44:09
our world, it should be the person— people who measured high
44:14
in moral fortitude who should do less cheating
44:18
than the individuals who scored lower. But those scores actually
44:22
had nothing to do with it. The individuals who
44:26
read a book earlier in the day about a child doing something morally
44:30
right were more likely to say, hey, the computer gave
44:34
me a smaller score than what I found. It was
44:38
the people who read a neutral thing that it
44:41
didn't matter where you scored on moral fortitude,
44:45
they tended to cheat at a higher rate.
44:48
Regardless of their moral attitude
44:53
or fortitude. Okay, why? Because both groups were primed differently.
44:59
Another example of priming that deals with visual stimuli
45:05
is we would give a— we'd
45:11
have people read something and we related it to exercise.
45:16
That if you read more, we tend to exercise more.
45:20
Okay, so we— but the true experiment
45:24
is, is again, we'd randomly assign individuals into
45:29
2 different groups. One, people would read a story about urban living.
45:33
Uh, other people would read a book about rural,
45:37
rural, uh, reading,
45:40
and then we go time how long they exercised, really didn't matter.
45:44
But then we asked them to do a quick visual experiment while
45:48
they were there. And what we did is we took a picture of
45:52
some people around a campfire and
45:56
flashed it for 1 second and simply had them write
46:00
down what they visually saw in the quick picture.
46:04
Okay, and again, You would think
46:07
same visual stimuli, everyone should write down if the visual
46:11
stimuli is a one-to-one thing, right?
46:15
But it's interesting that the people who read
46:19
about the urban living tended to put one of those
46:23
barrel fires in the thing instead of a campfire.
46:27
The white people turned either as bums
46:30
and dirty or black. There was a guy holding
46:34
a cup. The cup was replaced with a gun,
46:38
and there was a dog in the original picture that no one in the
46:43
urban— who read about the urban setting even saw. Okay,
46:47
the people who read about the rural thing got
46:51
everyone's race right. There was no gun, there was just a
46:55
cup of coffee, they would say, and they noticed the dog. And they
46:59
noticed that it was an actual campfire. Okay,
47:02
this is an example of priming and what we
47:07
visually will process and see. Okay,
47:10
so we have an example of things we've heard,
47:14
and then a game we physically interact with,
47:18
and a visual example of priming. Okay,
47:22
probably the last example of priming that we'll get to today
47:27
is kind of a fun experiment, and I'm giving
47:30
the very simple version of it. But in an experiment,
47:34
they had students, and these students were in a closed
47:38
campus, so it was a controlled environment.
47:42
And the experimenters would have subjects come in and
47:47
take a quick personality assessment
47:51
of some type. It was a bogus assessment. It really didn't measure anything.
47:56
But then under the table or somewhere else, they would kind of flip
48:00
a coin. Okay, the people who got heads were told
48:04
that they were going to have a wonderful day. There was
48:08
a lot of positivity coming to them. The other people were
48:12
told that, you know what, you're,
48:15
you're pretty sad today. Uh, you're,
48:18
you're— I don't think your day is going to turn out the way you hope.
48:22
Okay, so bogus test.
48:26
Randomly assigned but told 2 different
48:30
things about how their day was going to go. During the
48:33
day, they had purposely set up that all the individuals
48:37
in the experiment would receive the same amount of positive information
48:42
and negative information. Okay, and then
48:47
at the end of the day, they would have the participants come in and report,
48:49
how did you experience your day? Okay,
48:53
the people who were going to have a positive day reported
48:57
hearing all the positive things they heard.
49:02
They did report 1 or 2 of the negative
49:05
things that people said. Okay, so in that group, there was
49:09
a little bit of processing beyond you're going to
49:13
have a great day. In the people who said they were going to
49:16
have a bad day, they recalled zero
49:21
positive things happening during their day, and they reported
49:25
all 10 of the negative things that happened
49:29
to them during the day. Okay, this is what I call the
49:34
morning effect, okay, where when we wake up
49:37
and maybe we wake up in a good mood, we get our cup of coffee,
49:42
the traffic is really light, it's going to work.
49:45
We— the kids were ready to go. He got them dropped off
49:49
and everything's just going well. Has everybody noticed when you have mornings like
49:54
that, your day seems better? But then you
49:58
wake up and the house is a mess,
50:01
uh, you spill your coffee all over yourself,
50:05
the kids are awry, you get out late,
50:09
traffic is horrible. Have you noticed when you have mornings like that,
50:12
your day ain't so good? Okay,
50:16
that's priming by experience.
50:20
Okay, so those are different top-down
50:24
ways that our experiences can
50:28
tell our sensory stimuli what you want
50:32
to respond to. Okay,
50:36
not your stimuli, your receptors, I should say. Okay,
50:40
um, the other one is something that's a really
50:44
top-down, heavy top-down process that
50:47
we'll talk about when we get to social psychology,
50:52
and that's the confirmation bias. This is
50:56
where we have the tendency to pay
51:01
attention to information that confirms our
51:05
beliefs, attitudes, and ideas and ignore information
51:10
that is counter to our beliefs,
51:13
attitudes, and ideas. Okay,
51:17
and literally, uh, our sensory system—
51:21
we're so— if we're so determined
51:25
that our belief system is right, our sensory system
51:29
actually does not even pick up information from
51:34
something that is counter to it. All right,
51:37
so an example of this is, um, they would have individuals
51:42
come in and tell us about their attitudes or their political
51:46
view or something like that,
51:50
and then we'd have them hear some type of media that
51:55
falsifies their belief Um, uh,
52:00
or, or, or does, okay,
52:03
something, maybe a thing on the radio or
52:07
an announcement over a speaker if we're going to do this experiment at school or
52:11
something like that. And one of the interesting things is, is individuals
52:16
who have a strong belief system,
52:20
uh, when we ask, hey, did you hear that announcement about
52:24
XYZ, about 50% of participants
52:28
would say no, they don't ever remember hearing
52:32
anything like that. They had no sensory experience
52:38
of any counter-information to what they believed.
52:43
Um, and it's, and it's kind of interesting when we
52:47
do these kind of experiments on on the—
52:51
this type of, uh,
52:55
social process. Um,
52:58
and so that's something I'm going to leave that topic for right now
53:03
because there's a lot more to say about it when we get to social psychology.
53:07
But what I want us to realize now in the sensation and perception
53:12
process, we can hold things so strongly
53:16
that we actually tell our sensory system to completely
53:21
ignore any sensory system that is objectable
53:25
to what we truly strongly
53:30
believe. And it's kind of an interesting
53:33
thing, but it gets a lot more complex,
53:37
and we'll talk a lot more about that when we get to the social
53:41
psychology section. All right, I think that is what I wanted
53:44
to get through, uh, today.
53:48
Thank you for joining us for this Psychology Explained.
53:51
I hope you'll join us in later episodes where we can— we'll continue
53:56
to investigate the human mind and psychology.