Subjects and design. Subjects were selected from three age groups
in the same population. Forty-eight second graders and 48 fifth graders
participated from Preston Elementary School, Rialto, California. The
young adult sample was composed of 48 high school juniors and seniors
who volunteered from classes at Cajon High School, San Bernardino,
California. Equal numbers of male and female students were randomly
assigned to each of two orders of arranging the stimulus items on the
display matrix. Within each age group, equal numbers of subjects were
presented with the same 16 stimulus items in one of three forms; these
were (a) the objects alone, (b) the objects plus a verbal label for each,
or (c) the verbal labels alone. Stimulus type was thus varied between
subjects.