Fig. 3.

Schematic of a single trial. During the exposure period, an experimenter handed the item (pipe or pencil) to the participant's left hand. The participants were explicitly instructed to hold the item as they would normally, but also so they were able to view both the item and their hand in the mirror system throughout the entire period. After the exposure period, a 5-second urge rating period followed during which participants were asked to respond on a scale of 0–10 via right-handed button press to the statement, “Please rate your level of urge to use marijuana right now.” The trial ended with a washout period during which the experimenter took the item away from the participant. The visual presentations and timing of each event (in seconds) are illustrated.