All right.
I'm going to start out with a challenge for you.
I'm going to show you a series of shapes,
and I want you to count the number of yellow stars
that you see.
Also, count the number of red X's that pop up on the screen,
so that's two separate numbers, one
for how many yellow stars you see
and one for how many red X's come up on the screen.
All right.
So that was probably a challenging task
because you had to count two different things
and I kept talking to you while you were trying to do that.
That's an example of divided attention, which
we'll talk about in just a second.
But first, you probably want to see how you did.
So let me show you everything you just saw.
All right, this is everything that popped up on your screen.
There were 15 yellow stars and 13 red X's, and also one smiley
face.
Don't worry it if you didn't see this guy.
We'll talk about that later.
But now that you have a good example of how
limited a resource your attention is,
let's talk more about it.
When you're paying attention to something,
that means that you're concentrating on it
at the exclusion of the other stimuli in the environment.
A lot of times, though, we try to divide our attention
and do multiple things at once.
So maybe you watch TV while studying,
or try to count yellow stars while trying to count red X's.
The thing is, as you just saw, attention
is a limited resource, and we can't split it all that well
when it comes to complicated stimuli.
So if you're trying to do two things at once,
you usually end up switching between those tasks
rather than doing them simultaneously,
even if you're switching so fast you can barely tell.
So think back to when you had to count the yellow stars
and the red X's.
You couldn't really do that at the same time.
You had to kind of flip back and forth.
When you switch, or if you do just
intend to focus on one thing at a time,
you're exercising your selective attention.
You can think of selective attention like a flashlight
beam on some aspect of your environment.
You can move the flashlight around,
depending on what you want to focus on,
but at any given moment, it's illuminating
one particular area of interest, and everything else
is just kind of dimmer.
So the question is, what causes your flashlight beam
to swing around and focus on one thing or another?
There are two types of cues that can direct our attention,
exogenous and endogenous.
Exogenous cues are external to any goals we might have,
meaning we don't have to tell ourselves
to look for them in order for them to capture our attention.
They include things like bright colors or loud noises,
because you can be in the middle of a gripping conversation
and have every intention on focusing on it,
but a loud noise will still cause your focus to shift.
And with salient visual cues, the ones that really stand out,
this is called the pop-out effect.
Something just pops out at us, like a yellow circle
amidst a bunch of green circles.
Endogenous cues, on the other hand,
are more internalized and higher order,
meaning they involve the internal knowledge
to understand the cue in the first place,
and the intention to follow it.
Take an arrow, for example.
If you didn't know what an arrow meant,
then you wouldn't know to follow it.
It's just some random lines on a piece of paper.
But because you have the internal knowledge
of what an arrow is, you can carry out
an intention to look where it's pointing.
One really good example of selective attention
is the cocktail party effect, which you've probably
experienced yourself multiple times.
And this is your ability to attend to one voice even amidst
many others.
And it most commonly occurs when you hear your own name
amid those voices.
So, for example, picture the last time
you had a big family dinner, and you're
at one end of the table talking with someone,
and then Grandma down at the other end of the table
says your name.
And even though you haven't been listening
to grandma's conversation, you instantly
swing your flashlight beam of attention
down to hear what she's saying about you.
And if you had to guess what type of cue
your name was in that situation, endogenous
or exogenous, what would you say?
If you said endogenous, then that's right.
Because it was the meaning of your name
that drew your attention to when Grandma said it.
All right.
So now we know that different cues draw our attention
to certain stimuli, whether we want them to or not.
But what happens to all the stuff
we're not paying attention to?
Scarily enough, we experience something
called an inattentional blindness, which
means that we're not consciously aware of things that happen
in our visual field when our attention is directed elsewhere
within that field.
So think back to that smiley face
from our demo in the beginning.
Because you were focused on yellow stars and red X's, you
might have missed the smiley face, especially
because he kind of blended in with the yellow stars.
And that's a minor example, but inattentional blindness
happens in more important situations too.
For example, can you say exactly where
the nearest fire extinguisher is?
If you're like most people, you probably go by this every day
when you're going to your home or office or wherever you are,
but very few people actually pay attention
to where things like fire extinguishers are,
even though they're bright red and they
can be necessary for our survival.
Usually your attention is directed elsewhere,
so you fail to notice the fire extinguisher.
Closely related to inattentional blindness
is change blindness, which is when
we fail to notice changes in the environment.
Now be careful, because the difference
between change blindness and inattentional blindness
is subtle but important.
Inattentional blindness means that you miss something
right in front of you, while change blindness means
that you fail to notice a difference
between a previous state and a current state,
like when you don't notice when your mom gets a haircut
or you get back to your room and don't
notice that furniture or books are in a different place.
And this is actually very common as well, so
don't feel bad if it happens to you.
In fact, there's one really good example
when a researcher stopped people on a busy street
and asked for directions.
And part way through when the people were giving
their directions, a large bookcase was carried
between them and the researcher, and he swapped
places with a different person.
And almost no one noticed.
And very few people even noticed when the new person
was a different race or gender.
So it was just a great example of our limited attention
and our ability to focus on one thing
to the exclusion of everything else.