Children aged about four suddenly become capable of recognising that an object can be described differently depending on how it is viewed.
This apparently simple skill requires cognitive changes that are not far enough advanced until then. A project carried out by the Department of Psychology at the University of Salzburg with support from the Austrian Science Fund FWF reached this finding.
The research could also contribute to an improved understanding of developmental disorders such as autism and attention impairment.
Children aged under four are good at classifying objects, meaning that they can cope with a complex world. They effortlessly sort objects such as red apples by colour or shape. However once it has been described as an apple, the classification seems to be final. It is neither necessary nor possible to see it as red. Understanding that an object can be two things at the same time calls for a major cognitive leap forward.
Research by a team led by Dr. Daniela Kloo and Prof. Josef Perner at the Department of Psychology at the University of Salzburg has shown that this developmental jump takes place at about four years of age. As Dr. Kloo was able to determine through experiments with playing cards, beyond this age children are able to describe an object in more than one way, for instance as an apple and a red object.
The question for Dr. Kloo was whether younger children are at all capable of discriminating between simultaneously perceived object properties. The answer: "By making a simple change to the experimental situation we were able to show that three-year-olds do actually use the categories red and apple at the same time - but only if the two attributes do not belong to the same object. When we used cards with, for instance, a red circle or a colourless apple, the three-year-olds were able to sort the red circle by colour and the apple by shape. This provided us with an elegant proof that children in this age group are capable of discriminating between sets, but that object-set-shifting is difficult for them."