Two batteries were designed, one for Time 1 and one for Time 2. Each took cumulatively about 50 min, but the tasks were interspersed with other activities. The mother was usually in the room, busy with questionnaires. The tasks were based on a review of past research (e.g., Campbell et al., 1982; Maccoby et al., 1965; Milich & Kramer, 1984; Olson et al., 1990; Reed et al., 1984) and on the analysis of the content of temperament concepts and questionnaire items. The tasks assessed delaying, slowing down motor activity, suppressing/initiating activity to signal (go-no go), lowering voice, and, at Time 2, cognitive reflectivity. Each task involved multiple trials. Typically, midway through each task, the experimenter reminded the child of the relevant rule, independent of the child's performance. For each task, the final inhibitory control score was the aggregate of all trials.

Inhibitory control battery:

Delaying: Snack delay, Tongue, Home gift, Lab gift, Dinky toys

Slowing down motor activity: Turtle-and-Rabbit/Accuracy and Slow-Down, Walk-a-line-slowly, Telephone poles, Circle

Suppressing/initiating activity to signal ("go-no-go"): Tower, Bear-and-Dragon/Bear and Dragon, Pinball

Lowering Voice: Whisper