Abstract

Development of automatic activation of addition knowledge was examined in two experiments with elementary school children in grade l and 3. In Experiment 1, addition problems (e.g., 4+2) were followed by three kinds of probes: sum(e.g., 6), neutral number(e.g., 7) or one number presented in the problem(e.g., 4). Delays between the problem and the probe were 120msec, 180msec, 240msec, 480msec, and 960msec. In Experiment 2, problems were preseneted without + sign (e.g., 4 2). Subjects decided whether the probe number was presented in the problem or not. Children in grade 1 and 3 rejected sum probes more slowly than neutral probes only at delay 120msec and 180msec in Experiment 1 and only at delay 120msec, 180msec and 240msec in Experiment 2. Children rejected sum probes less accurately than neutral probes only in Experiment 2. These results imply that automatic activation of addition knowledge develops much earlier in Korean children than in children from Western countries.