The length-difficulty relation in serial memorization of words, pictures, and snowflakes

Arrays of 3, 6, 9, or 12 items were studied until they could be ordered from memory without error. A power function described the relation between array size and study time for words, pictures of objects, and pictures of snowflakes. Under two payoff conditions, the exponents for words and snowflakes were around 2.3 and for pictures, 2.0.