Lejuez, CW; O'Donnell, J; Wirth, O; Zvolensky, MJ; Eifert, GH

Journal of the Experimental Analysis of Behavior [J. Exp. Anal. Behav.], vol. 70, no. 1, pp. 79-86, Jul 1998

Four college students were exposed to a Sidman avoidance procedure to determine if an avoidance contingency involving 20% carbon dioxide-enriched air (CO sub(2)) would produce and maintain responding. In Phase 1, two conditions (contingent and noncontingent) were conducted each day. These conditions were distinguished by the presence or absence of a blue or green box on a computer screen. In the contingent condition, CO sub(2) presentations were delivered every 3 s unless a subject pulled a plunger. Each plunger pull postponed CO sub(2) presentations for 10 s. In the noncontingent condition, CO sub(2) presentations occurred on the average of every 5 min independent of responding. Following stable responding in Phase 1, condition-correlated stimuli were reversed. In both conditions, plunger response rate was high during the contingent condition and low or zero during the noncontingent condition. Furthermore, subjects avoided most CO sub(2) presentations. However, CO sub(2) presentations did not increase verbal reports of fear. Overall, the results from the present study suggest that CO sub(2) can be used effectively in basic studies of aversive control and in laboratory analogues of response patterns commonly referred to as anxiety.