Developmental Psychology Essay Question
“Piaget explained preoperational children’s (2-7 years) failure on conservation problems in terms of a lack of understanding of the principle of invariance. Evaluate this claim with a specific focus on the methodological factors outlined by Roazzi and Bryant (1997).”
As a result of his experiments into the development of children’s mental abilities, Jean Piaget theorised 4 stages of intellectual development. He claimed that his research strongly suggested that children in the second stage of his development model, the pre-operational stage, consistently failed at ‘conservation tasks’ due to an inability to understand the concept of invariance.
Perhaps the most renowned of all Piaget’s conservation tasks was the ‘water conservation task’, whereby children were shown two glasses that were equal in the capacity of water they held, but different in dimensions: one was short and wide (glass A), the other tall and thin (glass B). When given glass A containing a certain amount of liquid and asked to pour an equal amount of liquid into glass B, children who had not yet reached the third stage, the concrete operational stage, were unable to do this accurately as they were unable to move past the visual stimulus of the height of the water and grasp the rather more abstract concept that the taller, thinner glass B would need a higher measure of liquid to equal the volume of liquid in glass A.
This is, essentially a description of the principle of variance. Once the child has grasped that the height of the liquid between the two glasses is not necessarily consistent with the volume of liquid between the two glasses, they have grasped the principle of invariance. In more general terms, to understand the principle of invariance, a child must understand that although the appearance of something (height of water) has changed, this does not necessarily mean that the thing itself (volume of water) has changed.