Lejuez, C. W., O'Donnell, J., Wirth, O., Zvolensky, M. J., & Eifert, G. H. (1998).
Avoidance of 20% carbon dioxide—enriched air with humans.
Journal of the Experimental Analysis of Behavior,
70, 79-86.
Four college students were exposed to a Sidman avoidance
procedure to determine if an avoidance contingency involving 20%
carbon dioxide—enriched air (CO2) 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, CO2
presentations were delivered every 3 s unless a subject pulled a
plunger. Each plunger pull postponed CO2 presentations
for 10 s. In the noncontingent condition, CO2
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 CO2 presentations. However,
CO2 presentations did not increase verbal reports of
fear. Overall, the results from the present study suggest that
CO2 can be used effectively in basic studies of
aversive control and in laboratory analogues of response patterns
commonly referred to as anxiety.
Key words: anxiety, avoidance, carbon dioxide—enriched air,
laboratory analogue, Lindsley plunger pull, self-report, humans