Opponent process theory (OPT) is a psychological theory of emotion and motivation: it proposes that every strong emotional reaction is automatically followed by an opposite after-reaction, and that this opposite reaction grows stronger the more often the experience is repeated.
Note that this name is shared by a completely different theory. “Opponent-process theory” is also the name of Ewald Hering’s theory of colour vision. The two are easy to confuse.
Hering’s theory explains how the eye codes colour through antagonistic red-green and blue-yellow channels. It concerns sensory coding, not emotion, and has no connection to the ideas on this page.
Key Takeaways
- The Theory: Opponent process theory (OPT) proposes that the initial reaction to an emotional event is followed by an opposite, secondary emotional reaction.
- Origin: Richard L. Solomon developed OPT, also called the opponent process theory of acquired motivation. A stimulus that first causes displeasure can, over time, become pleasurable, and vice versa.
- Affective Balance: Every emotional process has an affective balance, either negative or positive, that is immediately followed by an opposing “opponent process.”
- Repetition Effect: The opponent process (the b-process) strengthens with repeated exposure. The original a-process itself stays roughly the same; what weakens is the felt reaction, because the strengthening b-process cancels out more of it each time.
How it Works: A- and B-Processes
Opponent process theory (OPT) rests on a simple two-step pattern. An emotional event directly activates a process (x), which triggers a related response (y).
For simplicity, call the triggered process “process A” and the response it causes “process B.”
Process A is directly activated by the original event. It is followed by what psychologists call the opponent process, or process B, which produces the opposite emotional state.
What will occur is that during the first few exposures to an emotion-eliciting event, the opponent process mechanism can act to return someone to a state of emotional homeostasis or neutrality after having gone through an emotionally intense experience or episode.
With frequent repetition, this pattern shifts. The A-process response weakens while the B-process response strengthens.
On the first few exposures, this plays out in a predictable five-phase pattern, sometimes called the standard pattern:
- Peak: a sharp burst of primary feeling (State A) right after the event starts.
- Decline: the feeling fades a little as process B builds up underneath it.
- Plateau: a steady, lower level of State A while the event continues.
- After-reaction: when the event ends, process A switches off quickly, but the slower process B lingers unopposed, producing an opposite-feeling after-reaction (State B).
- Decay: State B gradually fades back to a neutral baseline.
One subtlety matters here. The a-process itself does not actually get weaker with repetition; it stays roughly constant each time.
What changes is the b-process. It starts sooner, grows larger, and lasts longer with use, so it cancels out more and more of the felt primary reaction. That growing b-process, not any decay in the original process, is what drives tolerance and withdrawal.
Motivation and Emotional States
Negative feelings can turn positive over time. OPT explains why.
The emotional value that is provided by the initial primary A-process will always be in direct contrast to the opponent B-process.
After repeated exposure to the same emotional event, the initial A-process reaction, first linked to positive feelings, weakens. The B-process reaction, in contrast, strengthens, starts sooner, and lasts longer, while the A-process itself grows shorter. That shift is the whole mechanism.
This leads to the feeling that comes after an intense “negative event” (B-process) becoming the prevailing emotional experience associated with a particular stimulus event.
One of the most common examples of this is the thrill of riding a rollercoaster or flying on a plane.
The initial experience could seem mind-boggling and terrifying (which leads to a negative emotional response such as feelings of anxiety or fear) but once the actual event occurs, people tend to want to seek that thrill that comes with the culmination of these types of activities.
The imbalance does not stay fixed either.
These states can change over time, along with their lasting effects. An initially pleasing experience, such as falling in love, can eventually give rise to negative feelings like jealousy or loneliness. It can also give rise to withdrawal: the lingering low that follows once a once-positive feeling fades.
This happens because things change over time. Both the original stimulus and the circumstances around it can shift.
It’s easy to love someone at first, or to be instantly drawn to them. But as you learn more about a person, and face problems together, your emotional response to them naturally becomes more realistic. Feelings evolve with familiarity.
The opposite happens with an initially negative experience, such as parachuting or rock climbing. Over time, it can give way to a prevailing sense of positive emotion. Fear fades with practice.
This happens because the original danger signal weakens each time the activity is repeated successfully. The more often someone succeeds, the weaker that negative response becomes.
The negative feelings are eventually replaced with positive ones. The relief and joy of having survived the ordeal replace the fear that came before it.
As a result, this theory is often used to explain puzzling behavior. It accounts for both addictive behavior and the withdrawal that follows when that behavior stops.
Examples
Solomon supported his theory with many real-world examples of opponent process effects. These examples helped it gain traction in the broader medical community.
These examples gave the theory credibility. They were also drawn from everyday events, making the theory easy for readers to relate to and understand.
The first two examples, love and drug use, involve events that create initially positive emotional states. The other two, parachuting and donating blood, are considered to create initially negative emotional states.
The logic repeats each time. With repeated exposure, the pattern is the same across all four examples. The A-process weakens while the B-process grows stronger.
Falling in Love
When falling in love, the initial happiness elicited from a certain stimulus (either the person or the concept of being with a companion) will change over time.
This occurs for two reasons: firstly, the person who elicited that response is subject to change in both appearance and manner.
Second, as time passes, the initial “buzz” of falling in love fades. The emotional response then changes, even though the stimulus, the person, stays the same.
An easier way to see this is an older couple. Their love may be completely real.
But after a lifetime together, it would be almost uncanny for their emotional response to that person not to have changed along the way.
Life changes: children, financial troubles, growing old. Even if some original feelings remain, this changing environment reshapes the emotional response over time.
Another manner in which one can view the OPT as useful is by observing separation anxiety in interpersonal relationships.
Think of an infant with their mother. Once the mother leaves the room, the infant is likely to crave the emotional comfort they felt while she was there.
Drugs
According to OPT, what drug addiction basically amounts to is the direct result of an unwanted pairing between the actual “buzz” or high that is experienced from the drug use and the subsequent emotional symptoms associated with withdrawal that come with the conclusion of the experience.
The initial “high” is very strong. But it weakens over time with continued drug use.
Contrastingly, the feelings of withdrawal (wanting to use the drug again) increase with the more the drug is consumed.
During the initial stages of drug usage, the high or “buzz” experienced is much more pleasurable than the high that comes with regular usage of the drug.
Vice-versa, the withdrawal symptoms from not utilizing the drug are very low at the beginning, but once the drug usage becomes common, the consequences of withdrawal become much more serious.
This explains why drug addiction is so hard to overcome. The initial buzz from first use decreases with continued usage, so the user needs more of the drug to feel that original positive response.
Withdrawal effects also grow worse as drug dependency increases. Eventually, the drug becomes necessary just for the person to function normally.
Not all of this tolerance is automatic, though. Shepard Siegel showed that much of it is classically conditioned.
The cues that reliably surround drug use, the room, the ritual, the people present, come to trigger their own compensatory reaction in advance, opposite to the drug’s effect.
Siegel (1975) demonstrated this directly. Rats given repeated morphine showed strong pain tolerance when tested in their usual drug-paired environment, but far less tolerance when tested somewhere new.
- Aim: Siegel, Hinson, Krank and McCully (1982) tested whether a tolerant animal is at greatest risk when a drug is taken somewhere the usual protective cues are missing.
- Method: Rats were made tolerant to heroin in one environment, then given a larger dose either in that same environment or in a new, unfamiliar one.
- Results: Rats given the dose in a novel environment died at roughly double the rate of those given the identical dose in the familiar, drug-paired setting (about 64% versus 32%).
- Conclusion: Drug tolerance is tied to context. When the setting fails to cue the learned compensatory response, a normally survivable dose can become fatal.
This is a compelling explanation for human overdose deaths at ordinary doses in unfamiliar settings. It shows that the opponent process behind tolerance is not purely automatic.
Parachuting
An experience that makes many tremble with fear before actually taking part in it.
- Aim: Fenz and Epstein (1967) set out to map how fear changes across the timeline of a parachute jump, comparing novice and experienced sport parachutists.
- Method: They measured physiological arousal (skin conductance, heart rate, and breathing rate) at several points across jump day, from arrival at the airfield to the moment of the jump and after landing.
- Results: Novices showed arousal that rose steadily to a peak at the moment of the jump. Experienced jumpers showed the opposite pattern: their arousal peaked early, then declined, so it was lowest right when the objective danger was highest.
- Conclusion: With experience, the fear response reorganizes itself and shrinks at the critical moment, while an opposing, self-regulating process develops and grows.
Solomon (1980) used this pattern to explain the jumper’s whole emotional journey. A first-timer feels terror in free-fall and a stunned relief on landing.
After many jumps, the terror fades into mild pre-jump tension. The after-effect, meanwhile, grows into a strong, hours-long high. That is why experienced jumpers come to jump for the rush that follows, not despite the fear that used to come first.
What ends up happening is that, given the intense fear and anxiety experienced beforehand, the feeling of making it out alive becomes almost euphoric.
As a result, once the individual turns the activity into something that they frequently do, what occurs is that most jumpers cease to be terrified.
In fact, the opposite happens. The rush felt after a successful jump is one people want to feel again, so they keep seeking the thrill rather than dreading it.
Donating Blood
At first, people report feeling anxious and nervous before beginning the process of donating blood.
Once the actual task is done, however, people report experiencing a sense of relief.
Research has shown something surprising. After enough donations, people stop feeling that initial anxiety.
Instead, they report a warm, positive emotional experience once the donation is over.
Implications of the Theory
Opponent process theory explains many different effects with one simple mechanism. The emotional response a stimulus first produces does not have to stay the reason a behavior continues.
The Cost of Pleasure: Marriage and Alcohol
Solomon (1980) called this pattern the cost of pleasure. An activity that starts out rewarding is increasingly kept up to avoid its growing, aversive aftermath, rather than for the fading pleasure itself.
Consider a couple who fell in love quickly. At first, love was the motivation for staying together.
Over time, though, the couple may stay together mainly to avoid separating their children or being lonely, even though the relationship itself has not changed.
The same pattern appears with alcohol. The initial buzz from drinking is strong, but it fades as tolerance builds with continued use.
The withdrawal that follows, however, does not fade. Just as loneliness can keep a marriage going, the fear of losing that buzz becomes the real motivator for drinking, rather than the original high.
The Benefit of Pain: Seeking Out Negative Emotions
The pattern also runs in reverse. Solomon (1980) called this the benefit of pain.
When an experience starts out unpleasant, its positive aftermath can become the real reward being sought.
Fear and anxiety can be sought out in a half-hearted attempt to reach the positive feelings that follow a stressful task. It is ironic: an initial pleasure creates avoidance motivation, while people pursue an initial negative emotion like fear to achieve approach motivation.
Bresin et al. (2010) found something similar. In their controlled experiment, physical pain reliably reduced prior negative affect once the pain episode ended. That is a genuine opponent-style relief effect. It helps explain why a stressful or painful experience can sometimes leave people feeling better once it is over.
Opponents of OPT
Solomon made many strides with his research. Still, some psychologists disagree with his opponent process theory.
The main point of contention is that researchers don’t necessarily agree that there will be an increase in withdrawal response after repeated exposure to a stimulus.
These examples of drug use and relationships showcase Solomon’s theory well. But they don’t account for external factors or the possibility of multiple experiences producing multiple emotional responses. That ambiguity is a real limitation.
What if a person or experience elicits multiple responses at once? It becomes hard to test OPT if people themselves aren’t sure what is causing their emotions. This is a fair criticism.
This theory is a useful way of explaining how people behave. But multiple, overlapping psychological responses are hard to account for, so OPT should not be treated as absolute. That nuance matters here.
Different processes and emotional responses are at play, with the possibility of multiple factors influencing what occurs.
The best way to use OPT is to remember that emotion and motivation are always changing. That makes the exact origin of a feeling hard to pin down in practice.
Critical Evaluation
Opponent process theory has held up well as a broad explanatory framework, especially for addiction, but it also has real limitations that later research has exposed.
Strengths
Three strengths stand out:
- Parsimony and Reach: a single mechanism links emotional habituation, drug tolerance, withdrawal, and acquired motivation, making sense of otherwise puzzling behavior such as repeatedly seeking out initially aversive experiences.
- Testable Predictions: unlike many emotion theories, OPT specifies a concrete time-course (the standard pattern) and a clear direction of change (process B strengthens with use), which can be tested against data.
- Productive Descendants: it seeded both Siegel’s conditioning model of tolerance and the allostatic neurobiology of addiction described below, and its core prediction has since been confirmed at the neural level.
Together, these three strengths explain why the theory has remained influential for decades. It is simple enough to state clearly, precise enough to test, and generative enough to have shaped the addiction neuroscience that came after it.
Limitations
Later work has also exposed real weaknesses.
- Under-Specified Mechanism: the original model describes the shape of emotional change over time but does not say what implements the b-process in the brain, leaving it vulnerable to circular reasoning until neuroscience gave it a physical basis.
- Underweights Learning: Siegel’s research (described above) shows tolerance is often cue-specific and learned, not the automatic, context-free process the original theory proposed.
- Neglects Appraisal: the model treats emotion as one hedonic quantity added up over time. It does not easily account for cognitive appraisal, context, or several emotions occurring at once.
- Uneven Support: the strengthening-with-repetition prediction is best supported in addiction. In other domains, such as exercise, direct tests have been only partially confirming.
No single limitation is fatal on its own, but together they explain why psychologists treat OPT as a useful framework rather than a finished, exact law of emotion.
Contemporary Research
Modern addiction neuroscience has given the b-process a physical identity.
Koob and Le Moal (2001) reframed the theory using allostasis: stability achieved through change in the regulatory set-point, not a return to a fixed baseline.
On this view, repeated drug use shifts the brain’s reward system into a chronically altered state. A standing negative mood builds up. Researchers call this hedonic dysregulation.
Epping-Jordan, Watkins, Koob and Markou (1998) measured this directly. The effect was large. Nicotine-dependent rats going through withdrawal needed roughly 45% more brain stimulation to register a reward.
That is a large, measurable deficit. It is not just an inferred one.
Koob’s (2015) synthesis, The dark side of emotion: the addiction perspective, ties this together.
It organizes addiction into a three-stage cycle: binge/intoxication, withdrawal/negative affect, and craving. Compulsive drug-seeking, it argues, is increasingly driven by relief of this manufactured negative state. It is not driven by the original reward.
This review sits high in the hierarchy of evidence for the framework. Even so, it has limits. It leans heavily on animal models and mainly biological explanations.
How OPT Compares to Other Theories
Classic drive-reduction theory explains behavior as the reduction of biological needs. It struggles with motives that run against homeostatic comfort.
OPT extends this idea dynamically. It adds a time-lagged overshoot that becomes a motive in its own right.
Arousal theory explains who seeks stimulation, and how much, but treats a person’s preferred arousal level as fixed.
OPT is complementary. It explains how the hedonic value of one fixed activity changes with experience, converting fear into a sought-after high.
Operant conditioning and incentive theories emphasize positive reinforcement by rewards.
OPT shifts the weight to negative reinforcement instead: behavior maintained by relief of an aversive opponent state. Modern addiction neurobiology treats this as central to the shift from casual to compulsive use. The two accounts are usually seen as complementary, not competing.
Further Information
- Solomon, R. L. (1980). The opponent-process theory of acquired motivation: the costs of pleasure and the benefits of pain. American Psychologist, 35(8), 691.
- Solomon, R. L., & Corbit, J. D. (1974). An opponent-process theory of motivation: I. Temporal dynamics of affect. Psychological Review, 81(2), 119.
References
Bresin, K., Gordon, K. H., Bender, T. W., Gordon, L. J., & Joiner, T. E. (2010). No pain, no change: Reductions in prior negative affect following physical pain. Motivation and Emotion, 34(3), 280–287. https://doi.org/10.1007/s11031-010-9168-7
Epping-Jordan, M. P., Watkins, S. S., Koob, G. F., & Markou, A. (1998). Dramatic decreases in brain reward function during nicotine withdrawal. Nature, 393(6680), 76–79. https://doi.org/10.1038/30001
Fenz, W. D., & Epstein, S. (1967). Gradients of physiological arousal in parachutists as a function of an approaching jump. Psychosomatic Medicine, 29(1), 33–51. https://doi.org/10.1097/00006842-196701000-00005
Koob, G. F. (2015). The dark side of emotion: The addiction perspective. European Journal of Pharmacology, 753, 73–87. https://doi.org/10.1016/j.ejphar.2014.11.044
Koob, G. F., & Le Moal, M. (2001). Drug addiction, dysregulation of reward, and allostasis. Neuropsychopharmacology, 24(2), 97–129. https://doi.org/10.1016/S0893-133X(00)00195-0
Siegel, S. (1975). Evidence from rats that morphine tolerance is a learned response. Journal of Comparative and Physiological Psychology, 89(5), 498–506. https://doi.org/10.1037/h0077058
Siegel, S., Hinson, R. E., Krank, M. D., & McCully, J. (1982). Heroin “overdose” death: Contribution of drug-associated environmental cues. Science, 216(4544), 436–437. https://doi.org/10.1126/science.7200260
Solomon, R. L. (1980). The opponent-process theory of acquired motivation: The costs of pleasure and benefits of pain. American Psychologist, 35, 691–712.
Solomon, R. L., & Corbit, J. D. (1974). An opponent-process theory of motivation: I. Temporal dynamics of affect. Psychological Review, 81, 119–145.
