In this video I begin describing the 4 stages of Piaget’s theory of cognitive development: sensorimotor, preoperational, concrete operational, and formal operational. Then I provide details of the sensorimotor stage along with more recent research suggesting that infant understanding of the world may be more detailed than Piaget proposed.
Infant demonstrating the A-not-B error: https://www.youtube.com/watch?v=lhHkJ…
Scientific American Frontiers video with Renee Baillargeon: https://www.youtube.com/watch?v=b1tQO… Video explaining the mark test (or rouge test) for self-consciousness: https://www.youtube.com/watch?v=d0wKP…
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Video Transcript
Hi, I’m Michael Corayer and this is Psych Exam Review. In this video we’re going to start looking at Piaget’s stages of cognitive development. So Jean Piaget proposed four main stages that children move through and these were the sensorimotor stage, beginning at birth and lasting until about age 2; followed by the preoperational stage beginning around age 2 and lasting until about age 6; then the concrete operational stage which lasts from about age 6 to age 11; and then finally the formal operational stage which begins sometime around age 11 and continues for the rest of life.
So in this video we’re going to look at the sensorimotor stage in detail and we’re also going to consider some related research that came after Piaget. So the main idea of the sensorimotor stage is that during this time infants are learning how to take in and interpret sensory information and they’re learning control over their body movements. So this is why it’s called the sensorimotor stage; those are the two main tasks that infants have to figure out during this stage.
And in the process of understanding sensory information Piaget thought they need to understand the concept of object permanence. So this is the idea that just because you can’t see something, it continues to exist. It doesn’t mean that it’s gone. This is why you can play peek-a-boo with a very young infant and it’s endlessly entertaining, you know, and say your face is gone and then magically you’re back, and then you’re not there anymore and then you’re back, and of course this game is very boring for anybody over about the age of 2. But at this age the idea is the infant doesn’t understand that when the infant can’t see your face, you’re still there, right? So this is the idea of object permanence and Piaget thought you could see this in an error that children make called the A not B error. So the A not B error is the idea that you can teach a child to find an object in the same location, so you have a ball here and you repeatedly hide it in the location A. So I keep putting the ball into this box here and the child can’t see it when it’s in the box. But they watch me place it there and I teach them to reach into the box and get the ball. And so when I hide the ball in the box, then when they look for it they’ll reach into A, right? So I teach them that first. Then they watch me place the ball in location B. So I place it here into B and then, strangely enough, what the child will do is reach for location A to find it. This is why it’s called the A not B error. They’ll reach where they found it before, not where they watched it go. And this suggests that they don’t understand that the ball continues to exist and it’s inside Box B here. It’s like they think “if you don’t know where the ball is, well it just sort of magically is inside this location here, and that’s where you reach for it.” So that’s the A not B error and young infants will make this error but as they move out of the sensorimotor stage they stop making this error.
Now this is not the only way to interpret this error, this idea that they don’t understand that the object continues to exist. And so some other research has raised some different interpretations of this type of error. So another interpretation has to do with the idea that the child or the infant has learned this motor pattern; when you want the object, they’ve learned this particular motor pattern. They’re figuring out how to control their body and so they have this pattern for reaching to location A and so one thing is that they don’t have the ability to inhibit that pattern yet. You know, so this newly learned motor pattern and they’re not able to inhibit that sort of reflexive reaching for A and to try something new. They’ve never done this new motor pattern that involves reaching to B. So another interpretation of this is that it’s, it’s about really inhibition of a learned pattern, right? Stopping your arm from doing the thing you’ve just practiced, you know, ten times.
And this relates to the idea that young infants are still developing what’s called executive function. This is something that we continue to develop for a very long time up until probably about age 25 or so. We’re increasing our ability to control our own behavior and this is referred to as executive function and this would relate to the idea of inhibition of certain patterns. And we have patterns and we’re able to control them, so they don’t just happen on their own almost automatically.
Another way of thinking about this A not B error and the idea of object permanence is using studies that rely on the techniques I talked about in the previous video of habituation and preferential looking. That maybe we can find other evidence that infants actually understand more than we initially suspected. This brings us to a study by Renee Baillargeon, Elizabeth Spelke, and Stanley Wasserman looking at five month olds and showing them possible and impossible versions of events. And so in the possible version of the event, of the event, this panel here, the child will be watching from over here, so the child is looking in this direction, and they see this panel get lifted up and then it falls all the way over. It rotates 180 degrees here, until it’s laying flat again over here. And that’s the possible event. It’s pretty boring. So you have the child watch this a bunch of times until this habituation occurs, right? Where the child gets bored; they stop staring at this event because they’ve seen it a bunch of times and it’s pretty boring. And then once they’re habituated to this boring version of the event, the possible version, now the researchers switch it to an impossible version of the event.
So now it’s the same thing this plank is going to rotate but there’s a box, or an object in the way here, and so the infant watches as this panel goes up and comes back and then, unbeknownst to the infant, the object is secretly taken away. And so the plank continues its rotation all the way till it’s flat again. This is the impossible version; it seems to have passed through this other object, right? This other object has disappeared. Now as this is rotating, when it gets fully vertical here, the infant can’t see the object anymore. So if they really had no understanding of object permanence, then that would mean they wouldn’t be surprised that it continued to rotate all the way. Because as far as they’re concerned that object is gone. But what happens, what Baillargeon, Spelke, and Wasserman found, is that the infants will scrutinize this event. They’ll stare at this longer, right? Before they habituated to the boring version, they don’t really care they don’t pay much attention to it. Then they see this where this rotates all the way through and this object disappears and the five month old infants stare at this. They seem surprised and this suggests that they actually understand more about how the physical world operates then Piaget initially proposed.
Now some other demonstrations have found similar ways that infants might actually understand more than we initially suspected and research by Karen Wynne has suggested that infants as young as about five months old have a sense of number. So they can appear to count the things that they’re seeing. So you show them to objects and then you hide them behind a screen and then you remove one of the objects, so the child sees the object get taken away, and then when the screen goes back down there’s still two objects there. And again, infants will stare at this impossible event. They’ll be very surprised by it, you can see the surprise on their faces. And I’ll post some links in the video description where you can see some videos of children doing these types of tasks; the A not B error tasks, and also these experiments where infants will stare at these impossible events. They seem surprised by them and that suggests they actually understand.
Another related concept here that emerges around this same time period, sometime around 18 months to about 2 years of age, is children begin to show self–concept. They seem to be able to begin to recognize themselves as an object rather than just a subject experiencing consciousness. And the way that this is demonstrated is, what’s called, is in what’s called the Mark Test. So this is a test where a mark or some rouge is placed on an infant’s face without them knowing and then they interact with a mirror. The idea is if they reach for their own face, then that means they understand that the face they’re seeing in the mirror is actually the body that they actually are. And so if they reach for their own face to wipe away this mark or this rouge then that suggests they have at least a basic sense of self concept and self consciousness. And this is something that I explained in more detail in a video in the unit unconsciousness, so I’ll post a link to that video in the description box as well.
Ok, in the next video we’ll start looking at Piaget’s next stage which is the pre-operational stage. I hope you found this helpful, if so, please like the video and subscribe to the channel for more. Thanks for watching!
