Chapter 5. Linking Attention and Memory

I want to move now to attention and memory and I'm going to treat attention and memory together. We are fascinated with memory and, in particular, it's particularly interesting when memory goes wrong. It's particularly fascinating what happens in cases of amnesia. So for example, I need a volunteer who is willing to do a little bit of acting, a very little bit, an incredibly little bit. [a student volunteers] Excellent. Okay. So well, you just stay there. So pretend you have amnesia. Okay? What's your name?

Student: I don't know.

Professor Paul Bloom: Perfect. I'm really glad you said that. That's the wrong answer because you don't have total amnesia. You still remember English. Okay. It's very clever. Okay. So you couldn't have lost all your memories. You have English. You [pointing to a different student] — So we'll do you. What's your name? Oh. He looks puzzled but he still maintains bowel and bladder control so he hasn't forgotten everything. [laughter] Now, I always lose the third volunteer in that demo.

So, what I'm saying is that memory is a hugely broad concept. It includes autobiographical memory, which is what we standardly think. That's a perfectly rational response. When I say somebody's losing their memory, "Oh. I have a movie about somebody losing their memory," you don't imagine a person in diapers. You imagine the person walking around, having sex with cool people and saying, "Where am I?" And [laughter] so what you imagine is you imagine them losing their autobiographical memory, their sense of self. But of course, knowing English is part of your memory and knowing how to stand and knowing how to chew and swallow are all things that you've learned, that you've — that have been molded by experience.

There's another distinction which is going to come in regarding amnesia, which is there's broadly two types of amnesia. They often run together, but one type of amnesia is you lose your memory of the past. Another type of amnesia — That's the Matt Damon amnesia. Another type of amnesia though is you lose the ability to form new memories. And here's a film of a man who had exactly this problem. [film playing]

He was a world-renowned choir director and he suffered viral encephalitis which led to brain damage which destroyed most of his temporal lobes, his hippocampus, and a lot of his left frontal lobe. It could be — It could have been worse in that he retains the ability to talk. He seems to be — He's not intellectually impaired. He just can't form new memories and so he lives in this perpetual "now" where just nothing affects him and he feels — This has not always happened. There's more than one of these cases and it doesn't always happen like this, but he feels continually reborn at every moment. And we'll return to this and then ask what's going on here. But there's a few themes here.

I want to, before getting into detail about memory, I want to review some basic distinctions in memory when we talk about memory. So crudely, you could make a distinction between sensory memory, short-term memory, which is also known as working memory, and long-term memory. Sensory memory is a residue in your senses. There's a flash of lightning. You might see an afterimage. That afterimage is your sensory memory. There's somewhat of a longer echoic memory for sounds. So as somebody is talking to you even if you're not paying attention you'll store a few seconds of what they're saying, which is sometimes, when somebody's talking to you and you're not listening to them and they say, "You're not listening to me." And you say, "No. You were talking about — " and pick up the last couple of seconds from echoic memory. There's short-term memory.

Anybody remember what I just said? If you did, that's short-term memory — spans for a few minutes. And then there's long-term memory. Anybody know who Elvis is? Do you know your name? Do you know where you live? Your long-term memory store that you walk around with and you're not going to lose right away. When we think about amnesia in the movie sense, we think of a certain loss of long-term memory associated with autobiographical personal events.

There is a distinction between implicit and explicit, which we'll talk about it in more detail. But explicit, crudely, is what you have conscious access to. So, what you had for dinner last night. You could think back and say, "I had this for dinner last night." Implicit is more unconscious. What the word — what certain word — what the word "had" means, how to walk, how to ride a bicycle, that you might not be able to articulate and might not even be conscious of but still have access to.

There's a distinction between semantic memory and episodic memory. Semantic memory is basically facts, what a word means, what's the capital of Canada, and so on. Episodic is autobiography, is what happened to you. That Yale is in New Haven is semantic. That you went on vacation away from New Haven last week, it would be episodic. There is encoding stores and retrieval, which refers to different levels of what happens in memory. Encoding is getting the memory in, as when you study for a test or you have an experience. And storage is holding the memory. And retrieval is getting the memory out.

Finally, retrieval is often broken, conveniently, into recall versus recognition, where recall is when you just pull it out of memory and recognition is when you recognize what corresponds to something in the past. Anybody remember what color tie I had on two days ago? Oh. Okay. Well, that would be impossible to remember but if I asked you, "Is it purple or is it orange?" that would be much easier. [laughter] Now, you could break up, crudely, the memory into stages. So you start that sensory memory is just the stuff that comes in leading to short-term memory, leading to long-term memory. And this stage theory is something which we'll discuss in more detail. But this leads us to the issue of attention.

How do you get memory from your sensations, from what you're hearing? I'm speaking to you. You're hearing me. How does it ever get in to the other systems? What decides what's remembered and what's not? There's all sorts of things happening to you now. The seat of your chair is pressing against your butt. You wouldn't say, "Oh. I want to remember this forever. The seat's pressing against my butt." [laughter] Your neighbor is exuding a certain sort of smell. You're thinking about something. Your eyes follow him. Not everything gets in memory. You'd go mad if you tried to remember everything. You can't. So, what determines what gets into memory? Well, one answer is "attention does."

And attention is — could be crudely viewed as a flashlight, a spotlight on experience that willingly zooms in on something and makes it memorable. Attention has certain properties. Some things come from attention — to attention effortlessly and automatically. Here's an example. You're going to see an array of letters here. One of them's going to be green. When you see the green one, please clap. [laughter] No, not this green one. [laughter] There's going to be another slide. Okay. You're ready now. [students quickly find the one green "x" amongst a background of black "x"s. Okay. Now find — Not that "o" [laughter] but there's going to be an "o." When you see it clap. [students quickly find the "o" amongst a background of "x"s] Okay. Sometimes it's work. Find the red "o." [students are much slower at finding the red "o" amongst a background of black "o"s and red "x"s] [laughter] It's harder.

Sometimes attention is involuntary. I need a volunteer. And all I want to do is I want to show you colors on the screen and I'd like you to name the colors as they come out. [pointing at a student] Do you want this?

Student 1: I'm colorblind.

Professor Paul Bloom: Oh. [laughter] The first one is easy. See. This is — You have to just go down the colors [on the slide are a series of different colored rectangles. The student must name the colors]. Anybody? Okay.

Student 2: Red, green, blue, black, green, blue, red, blue, black, red.

Professor Paul Bloom: Excellent. [applause] Okay. Now these. These will be words but just name — Okay, you. Just name the colors. [this slide contains color words that are written in the same color that they spell. Again, the student must name the color of the font]

Student 3: Green, red, blue, black, blue, red, green, black, red, blue.

Professor Paul Bloom: Perfect. Now, we'll go back to you, same deal, words. [now the slide contains a list of color words that are written in a different colored font then what they spell. The student must name the font color.]

Student 4: Red, blue, green —

Professor Paul Bloom: No, no, no. Huh uh. Don't — I know you can read. The colors.

Student 4: Okay. Sorry. Okay. Blue, green, red, green, black, green, blue, black, red, [laughter] blue, black, red, black. [the student struggles to name the color of the font without accidentally saying the name that is written]

Professor Paul Bloom: Very good actually. [laughter] That's known as the Stroop effect. Being an expert reader, as you are, your knowledge of reading, your attention to what the words meant, subverted your desire to do the task. You couldn't make that go away even if you wanted to. If somebody gave you $1,000 to read this as fast as you read this, and as fast as you read this, you'd be unable to. You can't block it.

There is some work — There are some interesting discoveries about attention. I have a demonstration here. I'd like people actually — It's important — Some of you may have seen this before. It's important for you to be silent throughout it. What you're going to see is you're going to see two teams of basketball players. One of them is going to have white T-shirts. The other one will have black T-shirts. They'll be passing balls back and forth. What I'd like you to do is count in your head how many passes the white team does with the ball. [the video shows several people passing a basketball back and forth while, at one point, a person in a gorilla suit walks across the scene] [laughter] What number did people get? Okay. Did anybody notice anything unusual? [laughter] Did anybody not notice anything unusual? Okay. Some people did not notice anything unusual. Those who didn't see anything unusual, watch this again and just watch it. [laughter] About 50% of people when counting, who have never seen this before don't notice anything. But then when you're not counting it's kind of obvious what you're missing. [laughter] And this is one demonstration among many of the fact that when you're attending to something you have a very small window of attention and you lose the focus on other things.

Here's another different example. I'd like people to watch a movie and pay attention very closely to what happens in the movie and try to remember this. [The movie shows a conversation between two people. Each time the camera cuts from one angle to the next something about the scene changes.] How many of you noticed something odd in that movie? How many of you didn't? Okay. Now, everybody look at the scarf, the color of the plates and the food, among other things. [the same movie plays again] The phenomena, in general, has been called "change blindness." And what it is is we tend to be — when there's a focus of attention focused in a certain way, we tend to be oblivious to other things that go on in the environment. Often it is, in fact, quite difficult when there's a change in scene to notice what changes and what stays the same.

So, in this final demo, there's just going to be two pictures flicking. Could you clap when you see what's different between the two pictures? [applause] [laughter] I myself am terrible at these and so I have a lot of sympathy. How many people never saw it? [laughter] Good. That's very impressive. [laughter] One more time with a different one. [applause] Did anybody not see it? Be honest. I'll give you another try. [applause] Okay. I'll put you out of your misery. [laughter] This is work by Dan Simons and it's part of an extraordinarily interesting body of work on what's known as "change blindness." And what this means is, the phenomena is, we have a very narrow focus of attention and huge changes can happen that we are oblivious to. This is why, in movies, there are so many — so much difficulty with continuity changes.

Dan Simons is also famous for having brought this outside of the laboratory in some classic experiments and I'm trying to get the film corresponding to them. What he did was that he did this great study in the Cornell campus where he was — where what happened is they would get some unsuspecting person walking through campus and some guy would come over and say, "Excuse me, Sir. I'm lost. Could you help me with directions?" And have a map and then the person would say, "Sure." And then there'd be two construction workers holding a door. And these guys were going to rudely bump between these two characters and then the experimenter gets switched with another guy. So now, when these two guys walk away, the subject is standing there with an entirely different person. [laughter] What's interesting is nobody notices. [laughter] They notice if the person changes sexes. "Didn't you used to be a woman?" [laughter] And they notice if the experimenter changes races, but most other changes they're oblivious to.

There's another experiment. I think Brian Scholl did this one but it may have been Dan Simons where what happens is a subject comes in to the lab. They say, "If you're going to do an experiment with us, you need to sign the human subject form." Hands him the form, the experimenter. The subject signs the form. The experimenter takes the form and says, "Thank you. I'll put it down here." Goes down here and then a different person pops up. [laughter] People don't notice. And there's a certain level on which we're oblivious to changes. What's weird is we don't see — we don't think we are. We think we see the world as it is and we don't know — notice that when we're attending to something; everything else gets blanked out.

And so about 50% of people who have never seen this demo before, the gorilla demo, they don't notice the gorilla. And there's — you couldn't imagine anything more obvious. The gorilla study was actually done a very long time ago. And it was originally done in a different way but I'll show it to you just because this is the original study and now that you all know what to expect — Oh, not that one. Oops. [demo playing] Nope. [demo playing] That's actually — If you looked at that quickly, it's a current Yale professor. Oh. I'm never going to get my DVD back. Anyway, I'll show you the other demo on — next week. I will. [laughter]

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