now a long time ago people used to think that children were just miniature versions of adults and that they thought in pretty much the same way but then this guy piaget came along and he figured out that children actually reason quite differently in fact he believes that children are actively constructing their understanding of the world as they grow so that as their bodies grow their minds grow as well and he thought that this happened generally in different stages so i want to tell you about psja's four stages of cognitive development so first we start out with zero to two years and at this point children children are said to be in the sensory motor stage so this word kind of makes sense sensory just comes from the senses so he said children gather information about the world with their eyes so through sight smell taste hearing and touch so that's why whenever you see a baby zero to two years they're always touching stuff and putting in their mouth and then the motor part is that they are very active as they discover how to use their senses they also discover how to move their bodies around and this helps them explore the world and learn what they're capable of and the main task or awareness that develops during this time is object permanence this just means that infants don't recognize that objects still exist even though they can't see them so for example if you give an infant a toy or something say you have a nice ball for them and you take it away they won't look for it because they don't understand that it still exists so the next stage occurs from about age two to right around six or seven years now the reason i'm being a little wishy-washy on the years is because these are really just general guidelines it's not really hard and fast rules of when these stages happen the next stage is the pre-operational stage the operational part just means mental operation so imagining things or mentally reversing actions things like that and the thing to notice about this phase is that this is really when children start to develop and engage in pretend play and they'll begin to be able to use symbols to represent things what you might notice is that around age two is also when children learn to talk and so as they learn that words symbolize objects that starts to help them into the pre-operational stage and understand the idea of symbols children of this age are very egocentric and that's that's not a bad thing they're not just arrogant and bragging all the time they just don't understand that other people have a different point of view than they do so if you're ever watching tv with a child like a five-year-old say and they might sit down right in front of you and not understand that you can't see through them because they can see also sometimes kids will try to hide from you at this stage by covering their eyes the whole i can't see you you can't see me idea so then once they get to about age seven to about age 11 years old then they are in the concrete operational stage and again remember operational means mental operations and now they can do concrete operations so this is where children learn the idea of conservation so if you know a little kid and you want to see what stage of development they're in then you can do this little test it's pretty fun it's easy you take two identical glasses and pour the same amount of water in them and show them to the child and say which one has more and kids will tell you they'll have the same amount and then right in front of the child so that she sees you you take one of those glasses and pour it into a short fat glass and then you take the other one and pour it into a tall skinny glass and then right away ask the child again okay which one has more and up until concrete operational the child is going to say the tall skinny glass has more because the water is higher but once they reach the concrete operational stage and understand that the amount of water doesn't change just because the glasses are different sizes then they'll tell you that they both still have the same amount of water even though they look different so that's a fun little test and at this stage children can also begin to reason about mathematics so they'll be able to understand that 8 plus 4 equals 12 and then that must mean that 12 minus 4 equals 8. so moving on up children from about age 12 and up are in what piaget called the formal operational stage and that's when children are able to reason about abstract concepts and think about consequences of potential actions so they're able to reason out what might occur and also piaget thought that this is where really sophisticated moral reasoning began to take place and at this point children are reasoning more like adults and they continue to develop that over time now later developmentalists have come along and figured out that these stages aren't quite so discreet as piaget may have originally thought children don't always develop these abilities within the certain age brackets but they do tend to progress in a predictable fashion and thanks to piaget now we know that children are more than just miniature adults so go find a child and see what stage they're in test psja's theory yourself