It was hypothesized that the ability to form verbal concepts would increase with age. A test for verbal concept formation was developed and administered to 668 boys and girls between the ages of four and nine. By varying sentences that describe nonsense figures four variables were systematically explored: (a) type of description, (b) complexity of sentence, (c) number of sentences, and (d) relationship between sentences. Results indicate consistent improvement as age increases (p < .01). Four-year-olds had difficulty with negations, relations, and indirect descriptions. Combinations of positive and negative information were most difficult. The children often used an inadequate strategy of directly associating the unknown word with a high content word.