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Solomon's "Opponent Process" Theory

Common patterns underlie all addiction, indeed all hedonic or pleasure-seeking behavior. These patterns are described in Richard Solomon's opponent process theory of acquired motives.

As noted on the previous page, acquired motives and learned preferences are both labels for behaviors that resemble addictions but lack the harmful effects of many drug addictions. Solomon's theory applies to both types.

We discussed Solomon's opponent process theory in Chapter 9, in the context of pleasure and pain as motivating forces. Here we elaborate on its relevance to addiction.

graph showing the most mentions of opponent process theory in 1985
The phrase "opponent process theory" peaked in 1985.

First, a caveat. This is an older theory. We can turn again to Google's n-gram service (which counts how often words and phrases are used in English-lang­uage books) for an operational definition of scholar­ly interest in the topic. Meantions of opponent process theory peaked around 1985, over 30 years ago.

However, interest in the topic never disappeared. It continues to be mentioned at about half the peak rate.

The theory was not disproved or rendered obsolete. Rather, it became taken for granted by experts. To those unfamiliar with it, it can be a surprising and persuasive con­ceptual framework for studying acquired motives, so we will examine it here.

Solomon discovered two components in every reaction to an emotional situation. The first component he called the A reaction. It is short-lived and intense.

For example, while receiving an award, you may feel great joy. That occurs at the moment you are handed a medal or certificate. A response of pleasure is probably accompanied by neural activity in the dopaminergic areas of the brain.

The A reaction is quick, almost simul­taneous with emotional experience. The B reaction is slower and starts to occur when the A stimulus is no longer present.

The B reaction is opposite in hedonic tone from the A component. In other words, if the A reaction is pleasurable, the B reaction is unpleasurable.

The B response is slower to build and slower to decay. An hour after getting an award, you may feel a bit let down, but the feeling gradually disappears, and you go back to normal.

How are the A and B components different, in Solomon's theory?

Solomon called the B reaction hedonic contrast because it is opposite in sign (positive or negative) from the A reaction. The reaction to happiness, when it is over, is sadness.

The reverse is also true. For example, a mild illness can make you feel bad, but when it is over and you feel healthy again, you might feel extra good.

Chapter 9 used the example of small children being irritable or crying on Christmas afternoon, after a morning of opening presents. Opening lots of presents causes an emotional high, and children can crash in the afternoon.

Hedonic contrast is a rebound reaction. Solomon conceived of it as the nervous system adjusting and getting back to a normal equilibrium.

What happens as an event is repeated?

The key to Solomon's theory is that the B component becomes larger as an event is repeated, while the A component becomes smaller. This can produce a complete reversal in the hedonic tone of an event (i.e. whether it is experienced as positive or negative).

An event that was once fun can become boring, even aversive, as the A compo­nent shrinks and the B component increases. An event that was terrifying can become fun.

Solomon used the example of parachute jumping. A beginning parachutist typically feels fear at the prospect of jump­ing out of a plane. This is the A response: a quick, intense response to the situation.

After making a jump, landing on the ground, and returning to the clubhouse, the beginner is typically talkative and excited, as if very happy. This is the B response, a rebound reaction to the earlier fear. Solomon put it this way:

During their first free-fall, before the parachute opens, military parachut­ists may experience terror: They may yell, pupils dilated, eyes bulg­ing, bodies curled forward and stiff, heart racing and breathing irregular.

After they land safely, they may walk around with a stunned and stony-faced expression for a few minutes, and then usually they smile, chatter, and gesticulate, being very socially active and appearing to be elated. (Solomon, 1980, p.693)

As the parachutist gains experience with repeated jumps, the A process (anxiety) diminishes. That is habituation, a predict­able reaction to repeated experience.

Meanwhile, the B response grows bigger. An experienced jumper may experience a high lasting eight hours after a jump.

Eventually the body adjusts and no longer reacts so strongly. A person requires a bigger dose or more extreme stimulus to get the same effect.

For example, a gambler requires a bigger bet to get the same high he once got from a small bet. A heroin addict requires larger doses of the drug. The parachute jumper gets bored with ordinary jumping and may want to try fancy variations.

This is called tolerance. When tolerance builds up, the excitement of the addiction starts to disappear. It becomes routine.

The addict may still enjoy the addicting event, yet at the same time it is no longer such a big deal. The thrill is gone, unless the dosage is increased, and even then the pleasure is not as great as it was in the beginning.

What is tolerance?

Drug addiction phenomena are explained with the opponent process theory. First an addictive event causes a large A reaction, for example, great feelings of joy, with possibly a mild depression as an aftereffect. (This is sometimes called the honeymoon period of an addiction.)

After repeated experiences, the joy is greatly reduced. Tolerance occurs; the body adjusts. The B reaction becomes stronger. Negative aftereffects such as cravings become stronger.

Soon, with some drugs, the addictive stimulus is badly needed, because the withdrawal period is intensely unplea­sant. Yet the drug experience itself is less enjoyable, almost routine. That is the end of the honeymoon.

When does the fun not go out of an activity? The short answer appears to be: When the A reaction (the immediate reaction) is not strong enough, or repeated often enough, to cause habituation and tolerance.

Moderate drinking (defined as the equivalent of a glass or wine, a beer, or a shot of liquor per day) does not cause tolerance. Probably this is because the pleasure obtained from a nightly beer or glass of wine is modest, not intense.

Similarly, a married couple with an established frequency of sex, satis­factory to both parties, does not be­come bored with that activity. They recover their appetite between encoun­ters, and (research shows) sexual frequency stays steady in happy couples from middle age to old age.

However, a young and infatuated couple may experience a terrific high at first, then tire of each other. Pam, Plutchik and Conte (1975) found a negative correlation between intensity of love feelings and the likelihood a young couple would still be together, six months later.

Maybe the ancient Delphic Oracle had the right idea. For happiness, strive for moderation in all things.

The opponent-process theory helps explain why people can learn to enjoy some peculiar things. The appeal of monster movies and horror movies is an example.

Horror movies are shocking at first, es­pecially to a youngster seeing one for the first time. However, after seeing a few more, the shock is not so unpleasant and people can become fans of horror movies.

Emergency Medical Service technicians can become addicted to the excitement of emergency runs. Some firemen admit to enjoying big fires. In each case, an event that is initially aversive produces a B reaction that grows with time until it is enjoyable, even addictive.

How does the opponent process theory explain enjoyment of horror movies? Fighting fires?

The act of giving blood can be addicting. This is a classic example of opponent processes at work. Before giving blood, first-time donors described their feelings as "uptight, skeptical, suspicious, angry, and jittery."

After the donation, they felt "relaxed, playful, carefree, kindly, and warmheart­ed." That is the rebound effect, the B reaction. The more times a person gives blood, the weaker are the negative effects and the more pronounced are the positive aftereffects. "They unconsciously acquire a positive response to blood donation" (Brittain, 1983).

Solomon's theory explains an important paradox about addictions. Greatest dependence (need for the drug) occurs after tolerance becomes strong, because the B reaction (which causes craving) increases in size at the same time the A reaction (which produces the thrill) is disappearing.

Consequently, an addiction may be most powerful at the same time as the addictive behavior is no longer thrilling. Hardcore heroin addicts testify that they need the drug just to feel normal. Yet they are the ones who have the hardest time quitting.

What paradox of hardcore addiction is explained by Solomon's theory?

Withdrawal syndromes occur with heroin, cocaine, nicotine, and alcohol. But exaggerated negative reactions do not seem to occur when non-drug, acquired motivations are discontinued (Sandvik, Diener, and Larsen, 1985).

For example, a very experienced parachute jumper may find a routine jump to be a "ho-hum" experience. That shows the person is fully habituated to the A reaction. But the jumper does not feel exaggerated withdrawal symptoms if required not to jump for a few months.

Something is different about drug addictions. Probably it is the fact that most addictive drugs mimic a particular neurotransmitter in the nervous system.

If a drug is taken constantly, the nervous system responds by shutting down production of transmitters mimicked by the drug. "Neurochemical system(s) on which the drug has its primary actions...undergo adaptations to chronic presence of the drug" (Koob, Caine, Parson, Markou, and Weiss, 1997).

Not only are transmitters resembling the drug produced less; antagonists of the transmitters may be produced (to clean up the excess of the drug coming into the system). That heightens withdrawal symptoms in hardcore drug addicts: they have created their own transmitter shortages.

This pattern does not occur with non-drug acquired motives, like giving blood or watching horror movies. So there is no exaggerated withdrawal syndrome for those acquired pleasures.

To explore whether the B reaction is a response to pleasure or some other aspect of an addictive drug, Vargas-Perez, Ting-A-Kee, Heinmiller, Sturgess, and Van Der Kooy (2007) studied the effect of eliminating the tegmental pedunculopontine nucleus (TPP). That is the brain structure mediating the reward­ing effects of opiates.

The researchers found that when the TPP was removed, no "B" reaction occurred (the animals did not experience the usual aversive effects of opiate withdrawal). Significantly, removing the TPP only blocked the pleasurable response to opiates; it did not alter opiate levels in the blood or the pain-killing effects of opiates.

The authors interpreted this finding as confirming Solomon's theory of hedonic contrast. Strong pleasure was required to produce an aversive rebound. Other affects of opiates were not involved.

Ettenberg (2004) studied the B response of rats who learned to run a maze to obtain intravenous cocaine. As the rats became habituated to their daily dosage, they developed ambi­valent behavior, because the B reaction was getting larger.

Behaviorally, this was shown by the rats stepping forward toward the goal box, then retreating, before going forward and getting an injection. Other evidence confirmed that 15 minutes after receiving intravenous cocaine, the rats were experiencing an aversive state (the B reaction).

Ettenberg found that administering oral alcohol or intravenous heroin greatly diminished the B reaction, eliminating the retreat behaviors on the runway. "It may therefore be that the high incidence of co-abuse of cocaine with either ethonol [alcohol] or heroin, stems from the users' motivation to alleviate some of the negative side effects of cocaine." (Ettenberg, 2004)

How did Ettenberg explain the tendency of cocaine addicts to get addicted to alcohol or heroin as well?

Peele and Brodsky (1975) applied the concepts of addiction to dysfunctional love relationships in the book Love and Addiction. To explain why people stay in bad relationships despite misery, they described a combination of tolerance and dependence much like drug addiction.

The analog to tolerance is the mutual boredom and lack of excitement that occurs in some relationships, after an initial chemical thrill wears off. A couple trying to recapture the intense pleasures of an early relationship (the honeymoon phase) may increase "dosages" of the relationship. The couple may start to spend all their time together.

At the same time, they may start to find each other's company increasingly unsatisfying. Yet they cannot quit. They start fighting all the time, but if they try to break up, they experience craving, miss each other, and get back together.

What pattern did Peele and Brodsky point out in Love and Addiction?

Fortunately this destructive cycle is not inevitable. Lasting love relationships tend to be based not only on chemistry but also other ingredients such as friendship and mutual interests. Those are not as vulnerable to habituation.


Brittain, J (1983, March). Addictive bloodletting. Psychology Today, p.24

Ettenberg, A. (2004) Opponent process properties of self-administered cocaine. Neuroscience and Biobehavioral Reviews, 27, 721-728.

Koob, G. F., Caine, S. B., Parsons, L., Markou, A., & Weiss, F. (1997) Opponent process model and psychostimulant action. Pharmacology Biochemistry and Behavior, 57, 513-521.

Pam, A., Plutchik, R., & Conte, H.R. (1975). Love: A psychometric approach. Psychological Reports, 37, 83-88.

Peele, S., & Brodsky, A. (1976). Love and Addiction. New York: Basic Books.

Sandvik, E., Diener, E., & Larsen, R.J. (1985) The opponent process theory and affective reactions. Motivation and Emotion, 9, 407-418. doi:10.1007/BF00992209

Solomon, R. L. & Corbit, J.D. (1974) An opponent-process theory of motivation: I. Temporal dynamics of affect. Psychological Review, 81, 119-145.

Solomon, R. L. (1980) The opponent-process theory of acquired motivation: The costs of pleasure and the benefits of pain. American Psychologist, Vol 35, 691-712.

Vargas-Perez, H., Ting-A-Kee, R. A., Heinmiller, A., Sturgess, J. E. and Van Der Kooy, D. (2007). A test of the opponent-process theory of motivation using lesions that selectively block morphine reward. European Journal of Neuroscience, 25, 3713-3718. doi:10.1111/j.1460-9568.2007.05599.x

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