Avoidance of 20% carbon dioxide-enriched air with humans.
A yellow-light warning and a simple button press taught adults to dodge brief CO2 bursts in minutes, proving avoidance can be swift and fear-neutral.
01Research in Context
What this study did
Four adults breathed regular air through a mask. Sometimes the air switched to 20 % carbon dioxide. CO2 feels like suffocation and makes people panic.
A yellow light came on five seconds before the CO2. If the person pressed a button, the light turned off and no CO2 arrived. The scientists removed the button in some phases to test if the pressing really mattered.
What they found
Every adult quickly learned to press the button when the yellow light appeared. Pressing stayed high when the button worked and dropped to almost zero when it did not.
No one reported more fear at the end. The avoidance response kept them safe without making them feel worse.
How this fits with other research
Nevin (1969) used the same ABAB reversal to show that making pool time depend on tooth-brushing made kids brush. Both studies prove behavior flips on and off with the contingency.
Koop et al. (1983) showed that rats time their lever-press to the shock deadline. W et al. now show humans time their button-press to the CO2 deadline. The species differ, but the timing rule holds.
Matson et al. (1989) taught people to use a competing response to cut tics. Like the button press, the competing act prevents the problem without extra training. Together these papers show simple, topographically different responses can block aversive events once the contingency is clear.
Why it matters
You now have a clean human model of avoidance that builds fast, stays stimulus-bound, and avoids emotional fallout. Use it when teaching safety skills: a single, clear warning cue plus an easy escape response can protect learners without creating new anxiety.
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02At a glance
03Original abstract
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 presentation 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.
Journal of the experimental analysis of behavior, 1998 · doi:10.1901/jeab.1998.70-79