There are some terms and concepts from behavioral psychology’s past that have found themselves buried in time. Tucked away in a journal here or there but largely forgotten. The older research that tracked rates of behavior following “noxious stimuli”, for example- A phrase we don’t use anymore.  Time has also changed the fascination with respondent conditioning and effects that just two (or more) paired stimuli somewhere along the line could change responding for a lifetime. Powerful principles, which with progress now seem so mundane. Somewhere in there, we have the pre-aversive stimulus.

The pre-aversive stimulus had a great role in early behavioral science animal research to describe responding patterns, but the concept easily applies to humans as well. A pre-aversive stimulus, simply put, is the stimulus that reliably precedes an aversive stimulus. Have you ever heard the term avoidance responding? Some people may call that “escape-maintained behavior” in the field but it is effectively just that- engaging in behavior (responding) to avoid a stimulus that was aversive in the past. Running away. Getting away. Dodging it. What signals that, then? The pre-aversive stimulus. It goes even further. Just through respondent conditioning, the pre-aversive stimulus can take on features of the aversive stimulus and become a conditioned aversive stimulus itself. Then there’s another pre-aversive stimulus that could reliably precede that, and with enough second-order conditioning, you could get messy (over)generalization and find all sorts of related stimuli as aversive. Generalized Anxiety Disorder theoretically works on this same principle. It’s not hard to see how this kind of thing can tangle up a person’s life- whether they are able to realize it and vocalize it or not.

Wait! Isn’t a pre-aversive stimulus just a kind of S^D?

Let’s not jump to any conclusions and mistake a pre-aversive stimulus for an S^D just yet. They have some things in common. They’re both stimuli (but so is almost everything else). They can both be considered antecedent stimuli when we look at the framework of the avoidance responding that sometimes follows them. They signal something. All good comparisons- but here’s a big distinction if you don’t remember: A discriminative stimulus (S^D) signals reinforcer availability for a specific type of response.

The per-aversive stimulus does not necessarily have to.

In some situations, you could conceptualize a case for negatively reinforced behavior, but that might muddy the definitions of both terms being used concurrently. They speak to different phenomena even though they could describe one particular stimulus. The big difference is that the cue for available reinforcement is not necessary for a pre-aversive stimulus. It is simply a stimulus that has commonly preceded something aversive, or bad.

Example: An individual has been stung by a wasp before. Maybe several times if they were unlucky. Prior to the stinging, they heard the buzzing around a wasp nest.

That buzzing could likely become a pre-aversive stimulus, and through respondent conditioning, a conditioned aversive stimulus itself in the future.

In the research, pre-aversive stimuli tended to evoke “anxiety” in respondents- which was quasi-operationalized to the term conditioned emotional response (CER), also called conditioned suppression. That’s an important distinction to keep in mind. Here, a pre-aversive stimulus appears to suppress or decrease responding- not signal reinforcement for a response like an S^D would.

Like freezing near a wasp nest when buzzing is heard. The usual comfortable walking pace (response) is suppressed in the presence of the buzzing sound (pre-aversive antecedent stimulus).

Anxiety! Conditioned Emotional Responses! Conditioned Suppression!

Respondent conditioning research has some fascinating lessons that are just as relevant today as they were decades ago. Sometimes in the day to day practice of behavior analysis- things get oversimplified for the sake of ease of practice.

Behavior goes up? Reinforcement is at work.

Behavior goes down? Punishment is at work.

To a degree, those definitions work. Even with our wasp nest example earlier, those initial stings could absolutely punish some future walking behavior. But we can’t forget about the little things- the little preceding stimuli that have so much to do with the actual phenomenon. The buzzing didn’t punish the walking. Don’t forget the antecedents. Don’t forget the respondent conditioning. Taking the time to examine just one more step explains the process so much more clearly.

What conditioned pre-aversive stimuli appear to evoke conditioned emotional responses in your day to day life? Do you see conditioned suppression of behavior, as a result, that would have otherwise been there? What pre-aversive stimuli could be “tagging on” to the effects of an aversive stimulus you’re aware of? Does it evoke any avoidance behavior?

Too simple? Laurence Miller ‘s (1969) work on compounding pre-aversive stimuli might whet your broader research appetite. Citation below.

Thoughts? Comment! Question! Like!

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