ABSTRACT
An IV with two levels Imagine that we have a test which is given to children to see whether they can sort a set of pictures into two groups according to a particular aspect of the pictures: for example, the relevant aspect might be shape and the two groups might be angular (such as squares and triangles) and round (such as circles and ovals). We present each child with 11 of these sorting problems and note how many that child sorts successfully. We might have devised a training technique which gives children experience with such sorting tasks with the training materials being different from those on which the children will be tested. We might then compare the sorting ability of children who have received such training with children who have not.
