Behavior simultaneously maintained by both presentation and termination of noxious stimuli.
The same aversive event can reward one response and punish another if the contingencies are clear.
01Research in Context
What this study did
The team set up two levers for lab animals. Pressing one lever gave a brief electric shock. Pressing the other lever turned the shock schedule off.
They flipped the rules halfway through so each lever did the opposite job. The question: could one stimulus (shock) both strengthen and weaken behavior at the same time?
What they found
Animals kept pressing both levers. One lever earned shock; the other stopped shock. When the rules reversed, the animals quickly swapped which lever did what.
The same shock was working as both a reward and an escape. Positive and negative reinforcement lived side-by-side, each tied to its own response.
How this fits with other research
McKearney (1970) already showed that shock can act like food: fixed-ratio and fixed-interval patterns look normal when shock is the payoff. E et al. added the twist that shock can be both food and relief in the same session.
AZRIN et al. (1963) found that intermittent punishment is weaker than continuous punishment. That seems to clash with E’s result—shock strengthened behavior. The difference is the contingency: H delivered shock after a response (punishment), while E delivered shock for a response (positive reinforcement). Same stimulus, opposite effects.
NEVIN et al. (1963) used shock termination to drive escape. E’s study shows you don’t have to choose one function; you can program both at once if you separate the responses.
Why it matters
In clinical practice we often assume a consequence is either good or bad. This study reminds us that the function depends on the contingency, not the stimulus. If a client seeks deep pressure that looks painful, one topography might be maintained by the sensation (positive) while another is maintained by turning it off (negative). Map both pathways before you intervene.
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02At a glance
03Original abstract
Lever pressing by two squirrel monkeys was maintained under a 3-minute variable-interval schedule of response-produced electric-shock presentation. At the same time, responding on a second lever was maintained under a 3-minute fixed-interval schedule of termination of the shock-presentation schedule and shock-correlated stimuli. Under the termination schedule, the first response after a 3-minute period produced a 1-minute timeout, during which no events occurred and responding had no scheduled consequence. Relatively high and constant rates of responding were maintained on the lever where responding produced shock. Lower rates and positively accelerated patterns of responding occurred on the lever where responding terminated the shock schedule. Thus, responding was simultaneously maintained by presentation of an event and by termination of a stimulus associated with that event. Rates and patterns of responding on each lever were reversed when the schedules arranged on each lever were reversed on two occasions. When shock intensity was increased from 0 to 10 mA, responding maintained both by presentation of shock and by termination of the shock schedule increased, but responding maintained by shock presentation increased to a greater extent. Positive and negative reinforcement, usually regarded as separate behavioral processes involving different events, can coexist when behavior is controlled by different contingencies involving the same event.
Journal of the experimental analysis of behavior, 1978 · doi:10.1901/jeab.1978.29-375