Opponent-Process Theory: The Emotional Equilibrium

Have you ever noticed how the excitement of a new relationship settles into a quieter, more familiar feeling over time? Or how people who are terrified of skydiving on their first jump eventually come to crave it? These aren’t coincidences – they reflect a consistent pattern in how our brains process and regulate emotion. Psychologist Richard Solomon gave this pattern a name and a framework: the opponent-process theory of emotion. First published in the journal American Psychologist in 1980, this theory offers a compelling explanation for why our emotional highs and lows shift so predictably over time – and why some experiences that start as frightening eventually become addictive.

The core idea: every emotion has an opponent 🔗

According to Solomon’s opponent-process theory, an initial emotional response (State A) to a stimulus is followed by an opposing secondary response (State B), with repeated exposures weakening State A and strengthening State B. In other words, your brain doesn’t simply let you feel a strong emotion and move on. It actively counteracts that emotion with its opposite in order to maintain psychological balance – a state known as emotional homeostasis.

This theory asserts that the brain avoids extremes of emotional experience by countering the stimulation it receives with an opposite or “opponent” reaction. Think of it as the brain’s built-in thermostat. When things get too hot emotionally, the brain turns on the cooling system. When things are too cold, it heats things up.

The A-process and B-process explained 🔗

The theory is built around two internal emotional processes that work in opposition to each other.

The A-process: your immediate reaction 🔗

The A-process is largely responsible for the initial, usually fast and immediate, emotional reaction to a stimulus. There is a peak response to any emotional stimulus which usually occurs rapidly, usually out of shock, but lasts only as long as the stimulus is present. In a physiological sense, the A-process is where the pupils dilate, the heart rate increases, and the adrenaline rushes. This initial reaction can be either positive (pleasure, joy, excitement) or negative (fear, anxiety, dread).

The B-process: the after-reaction 🔗

The B-process occurs after the initial shock or emotion and is evoked after a short delay. While the A-process is still in effect, the B-process starts to rise, ultimately leveling out the A-process’s initial spike in emotion. Once the B-process has ended, the body returns to homeostasis and emotions return to baseline.

The B-process is always the emotional opposite of the A-process. If the A-process is euphoria, the B-process is a comedown. If A is fear, B is relief. A stimulus that initially inspires displeasure will likely be followed by a pleasurable after-feeling and vice versa.

What happens with repeated exposure? 🔗

Here is where the theory becomes especially powerful. The A-process and B-process don’t stay the same strength forever. After repeated exposures, the State A response weakens and the State B response strengthens. Because these states change over time, the later acquired effects are often referred to as States A′ and B′ to indicate change over time.

This shift explains a great deal about human behavior. The b-process appears after the a-process has terminated and is sluggish in onset, slow to build up, slow to decay, and gets larger with repeated exposure. Thus, the affective dynamics of opponent-process theory generate new motives and new opportunities for reinforcing and energizing behaviour.

Over time, the emotional experience associated with a stimulus transforms: what once felt intensely positive may become routine, and the “after-feeling” – the B-process – can become the dominant emotional driver of behavior. These inhibitory processes get stronger when stimulation of a primary emotional response is sufficiently intense, sustained, and frequent. They become evident only when the stimulus and the primary processes are absent, and typically last for some time afterwards.

Real-world examples of the theory in action 🔗

Solomon supported his theory with four key examples drawn from everyday life: love and attachment, drug use, parachuting, and blood donation. Each of these illustrates the core principles of the theory in a concrete way.

Skydiving: from terror to thrill 🔗

It was found that beginners have greater levels of fear than more experienced skydivers, but less pleasure upon landing. However, as the skydivers kept on jumping, there was an increase in pleasure and a decrease in fear. The A-process (fear) weakens with experience, and the B-process (exhilaration and relief) strengthens – eventually becoming the primary reason people keep jumping. This is why activities that terrify novices become deeply rewarding pastimes for veterans.

Drug addiction: from pleasure to dependency 🔗

The theory offers one of the clearest frameworks for understanding addiction. The initial “high” experience – which is very strong – weakens over time with the continued usage of the drug. Contrastingly, the feelings of withdrawal increase with the more the drug is consumed.

According to opponent-process theory, drug addiction is the result of an emotional pairing of pleasure and the emotional symptoms associated with withdrawal. At the beginning of drug or any substance use, there are high levels of pleasure and low levels of withdrawal. Over time, however, as the levels of pleasure from using the drug decrease, the levels of withdrawal symptoms increase.

Neuroscience research backs this up. The initial, rewarding effects of drugs of abuse are followed by the emergence of a negative emotional state each time a drug is experienced, including the first. Negative emotional symptoms of withdrawal are therefore an intrinsic component of daily drug exposure and likely contribute to the development of dependence. At this stage, a person is no longer taking the drug to feel good – they’re taking it to avoid feeling terrible. Counteradaptive processes such as the opponent b-process, which are part of the normal homeostatic limitation of reward function, fail to return to within the normal homeostatic range.

Love and interpersonal attachment 🔗

The theory also applies to romantic relationships. Think of a couple that fell in love very quickly. At first, the motivation for staying in that relationship was love, but after time, chances are that the couple will choose to remain together for the purposes of not separating the children or not being lonely. The initial rush of passionate love (A-process) fades with time, and the deeper B-process – a quieter attachment, comfort, and fear of loss – becomes the primary emotional bond holding the relationship together.

Blood donation: discomfort to dedication 🔗

Research has shown addiction to altruism through habitual blood donation , where first-time donors may feel anxious or faint, but regular donors often report a sense of calm or even satisfaction afterward. The initial negative A-process diminishes, and the positive B-process – a warm, rewarding after-feeling – grows stronger, motivating continued donation.

The three core phenomena: contrast, habituation, and withdrawal 🔗

Solomon identified three key emotional phenomena that underpin the theory, outlined in his original 1980 paper:

Affective contrast refers to the way an emotional state is followed by its opposite. Strong pleasure is followed by a dip; intense fear is followed by relief.

Hedonic habituation (tolerance) describes how the intensity of the A-process diminishes with repeated exposure. Frequent repetition of the unconditioned stimulus often gives rise to affective or hedonic habituation (tolerance). You simply don’t feel the same intensity as you once did.

Withdrawal (abstinence syndrome) emerges when the stimulus is removed after habitual exposure. After frequent repetition of these stimuli, a withdrawal or abstinence syndrome often emerges directly following stimulus termination. The B-process, now stronger than ever, persists in the absence of the original stimulus – and this lingering emotional state becomes a powerful motivator to seek out the stimulus again.

The concept of “savings”: emotional memory 🔗

Solomon also identified a phenomenon he called “savings” – a particularly interesting dimension of the theory. Although opponent processes can be weakened or faded away by avoiding the stimulus for an extended period of time, that does not mean they leave no memory traces. Studies show that these opponent processes are more quickly reactivated the next time they are re-stimulated. Reflexes and emotional reactions build up more quickly when reactivated than they did with the initial stimulation.

This helps explain why relapse is so common in addiction recovery. Even after months of abstinence, a person can be quickly pulled back into old emotional patterns because the B-process – and its motivational pull – is reactivated faster the second time around.

Tolerance and why “more” is never enough 🔗

One of the theory’s most practically significant implications is its explanation of tolerance. A person requires a bigger dose or more extreme stimulus to get the same effect. 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.

Repeated use of the substance will continue to strengthen the opponent process, but the feelings gained through the initial process will remain constant. This dynamic explains tolerance – the increase in the amount of drug or substance needed to overcome the opponent process that is increasing in strength. The initial high hasn’t changed, but the counterforce has grown – and so more is needed just to feel what was once easily achieved.

Criticisms and limitations 🔗

Like all psychological theories, the opponent-process theory has its critics. The relevance of this theory for affective experiences in general – beyond physical stimuli and addictions – has yet to be fully demonstrated. Research has confirmed habituation to emotional stimuli, but some predicted effects, like exaggerated withdrawal responses after habituation, have not always been observed in controlled settings.

Additionally, the theory doesn’t account for external factors, nor does it fully address situations where multiple experiences elicit multiple emotional responses simultaneously. Human emotions are rarely triggered by a single, isolated stimulus – we’re complex beings navigating layered social and psychological environments.

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. This suggests that addictive substances operate through additional neurochemical mechanisms – like mimicking neurotransmitters – that go beyond what the opponent-process model alone can explain.

Why the theory still matters 🔗

Solomon’s theory has been verified experimentally with animals and humans, and provides a framework that has been used to explain behaviors and emotional experiences in areas as diverse as addiction, thrill-seeking, love, job satisfaction, and cravings for food or exercise. Its core insight – that emotions don’t operate in isolation, but in dynamic pairs that shift with experience – remains highly relevant in addiction neuroscience, clinical psychology, and behavioral research.

Understanding this theory can also carry practical value in daily life. Recognizing that the initial intensity of a positive or negative experience will change over time – and that an opposing emotion is always waiting in the wings – can foster greater emotional self-awareness. It can help explain why the thrill of a new job fades, why grief follows intense joy, or why someone might find themselves craving what was once a frightening experience.

What do you think? Can you think of an experience in your own life where your emotional response shifted dramatically with repeated exposure – something that once made you anxious or thrilled that now feels routine or even comforting? And do you think the brain’s instinct to balance out emotional extremes is ultimately helpful to our well-being, or does it rob us of the ability to sustain genuine happiness?

References

1. https://psychology.iresearchnet.com/social-psychology/social-psychology-theories/opponent-process-theory/
2. http://people.whitman.edu/~herbrawt/classes/390/Solomon.pdf
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC2607326/