Psychology of Learning

Module 03: Unlearned Adaptive Behaviors

Part 3: Opponent-Process Theory & Motivation

Looking Back

In Parts 1 and 2, we explored unlearned behaviors and proto-learning processes—reflexes, tropisms, fixed action patterns, habituation, and sensitization. We saw how dual-process theory explains that opposing processes operate simultaneously, with behavior reflecting their combined influence. Now we extend these ideas to emotional experiences through opponent-process theory, which proposes that emotions involve opposing processes (a-process and b-process) that determine emotional experiences and explain phenomena like drug tolerance, addiction, and thrill-seeking.

Defining Emotion

“There is no way that someone could convince me to skydive!” Those were your thoughts before your friend convinced you to try it. Now you’re making your tenth jump and wondering why you were ever afraid. What happened? Why did your emotional response to skydiving change so dramatically?

Before answering, we need to define emotion—a surprisingly difficult task. Emotions have three basic components (Plutchik, 2003):

Cognitive: Thoughts, beliefs, and expectations. These determine the type and intensity of emotion experienced. Your interpretation of a situation—whether you perceive threat, opportunity, loss, or gain—shapes your emotional response.

Physiological: Internal changes in arousal level. During emotional experiences, heart rate changes, blood pressure shifts, pupils dilate or constrict, respiration alters, and hormones release. These bodily changes prepare you for action.

Behavioral: Outward signs of emotions. Facial expressions, body posture, gestures, and tone of voice communicate emotional states to others. These displays serve social communication functions.

What Elicits Emotions?

Some type of stimulus triggers emotions—either external or internal. External stimuli are stimuli received from the environment through sense organs. The sound of footsteps behind you on a deserted street late at night may elicit fear (Schachter & Singer, 1962).

Internal stimuli are stimuli produced by the nervous system and internal organs. Thoughts, memories, and physiological states can trigger emotions. Remembering an embarrassing moment can elicit shame; hunger pangs can produce irritability (Cannon, 1927).

We can now define emotions: Emotions are physiological changes and conscious feelings of pleasantness or unpleasantness, aroused by external or internal stimuli, that lead to behavioral reactions. The key point is that emotions have behavioral consequences—they influence what you do (Plutchik, 2003).

Emotions & Evolution

Research by Paul Ekman has shown that facial expressions of emotions are universal and even occur in infants born blind and deaf. By showing photographs to people around the world and asking them to identify depicted emotions, Ekman identified six basic emotions recognized everywhere: anger, disgust, fear, happiness, sadness, and surprise (Ekman, 1973). Thus, emotional display and recognition appear to be traits passed from generation to generation.

This fits with John Watson’s early observations that even newborn infants show three basic emotions: fear, love (or contentment), and rage. More modern work by developmental psychologists has expanded this list, showing that infants naturally develop increasingly complex emotional repertoires as they mature (Izard, 1977).

Adaptive Functions of Emotions

Why do emotions exist? Dating back to Charles Darwin’s The Expression of Emotion in Man and Animals (1872), researchers have contended that emotions have adaptive value. Emotions increase the chance of survival by providing readiness for action (Plutchik, 2003).

Anger intimidates others, influences them to do what you wish, energizes you for attack or defense, and spaces participants in a conflict. Fear quickly drives blood to large muscles, making it easier to run. When surprised, you raise your eyebrows—this response allows your eyes to collect more visual information about the unexpected event.

These adaptive responses evolved over millions of years when immediate physical responses to threats were crucial for survival. The problem is that our fast-paced society has changed dramatically, while evolutionary change hasn’t caught up. Emotions like anger that prepare us for fight or flight may be counterproductive in modern contexts where physical confrontation is inappropriate (Plutchik, 2003).

Plutchik’s Emotion Wheel

Robert Plutchik (2003) developed an influential model describing relationships among emotions using a three-dimensional circumplex, analogous to a color wheel. The cone’s vertical dimension represents intensity, and the circle represents degrees of similarity among emotions. Eight primary emotion dimensions are arranged as four pairs of opposites: joy-sadness, trust-disgust, fear-anger, and surprise-anticipation.

Just as primary colors can mix to create secondary colors, primary emotions can combine to create complex emotions. For example, joy + trust = love; fear + surprise = awe; sadness + disgust = remorse. The notion that emotions come in opposing pairs becomes central to opponent-process theory.

The Opponent-Process Theory of Emotion

Why did fear decrease and excitement increase with repeated skydiving jumps? Richard Solomon’s opponent-process theory provides an elegant explanation (Solomon, 1980; Solomon & Corbit, 1974).

The opponent-process theory of emotion recognizes emotions as pairs of opposites (fear/relief, pleasure/pain) and proposes that when one emotion is experienced, the other is suppressed. Repeated presentations of an emotional stimulus are sufficient to change a person’s reaction to that stimulus (Solomon, 1980).

Solomon and Corbit (1974) examined fear and relief in skydivers before and after their jumps. Beginners experience extreme fear as they jump, which is replaced by great relief when they land. But with repeated jumps, the fear decreases and the post-jump pleasure increases dramatically. Experienced skydivers feel mild anxiety before jumping and intense euphoria afterward. This pattern explains various thrill-seeking behaviors—the emotional rewards grow with experience.

The a-Process & b-Process

The opponent-process theory assumes that an emotional response is composed of two separate, sequential reactions: the initial emotional reaction (called the a-process) and the aftereffect of the opposite emotion (called the b-process). These processes operate according to specific principles (Solomon & Corbit, 1974).

When you first jump from a plane, you experience intense fear (a-process). This fear remains strong throughout the fall. When you land safely, relief and mild euphoria replace fear (b-process). The a-process (fear) parallels sensitization, and the b-process (relief) parallels habituation—similar opponent processes operate in both domains.

Or consider drug use: A person taking amphetamine initially experiences a “rush” and feelings of euphoria (a-process). However, when the drug’s effects wear off, euphoric feelings are replaced by depression and tiredness (b-process). The pleasurable initial state inevitably gives way to an unpleasant opposite state.

Characteristics of a-Process & b-Process

The a-process and b-process have distinct characteristics that explain how emotional responses change with repeated experiences:

a-process characteristics: Fast-acting—develops rapidly when the stimulus appears. Remains at maximum strength as long as the eliciting stimulus is present. Decays rapidly when the stimulus is terminated. Doesn’t strengthen with repeated experiences.

b-process characteristics: Elicited by the a-process—the initial emotion triggers the opponent emotion. Slower to develop than the a-process. Becomes stronger with repeated presentations. Occurs sooner with repeated presentations. Slower to decay than the a-process.

These characteristics explain why emotional experiences change so dramatically with repetition. The a-process stays constant, but the b-process strengthens, begins earlier, and lasts longer with each repetition.

Changes with Repeated Experience

On the first skydive, the a-process (fear) develops rapidly when you exit the plane and decays rapidly when you land safely. The b-process (relief) develops slowly, has less strength than the fear, and decays slowly. You experience intense fear during the jump and mild, brief relief after landing.

After many jumps, the a-process still develops rapidly and strongly when you jump and decays rapidly when you land. But due to repeated presentations, the b-process now develops more rapidly and more strongly than on the first jump. The b-process continues to decay slowly.

The net result: The amount of fear you experience when jumping is substantially reduced and lasts only briefly—the strengthening b-process opposes and cancels much of the a-process. However, the euphoria after landing is stronger and longer-lasting. Experienced skydivers report feeling “high” for hours after jumping. The strengthened b-process dominates the emotional experience (Solomon & Corbit, 1974).

Recent research continues to support opponent-process theory. Poole and colleagues (2020) examined opponent processes using visual afterimage responses to emotional faces. They found that individuals characterized by conflicted shyness (high shyness combined with high sociability) showed stronger opponent processes to both positive and negative emotions—perceiving negative afterimages after viewing happy faces and positive afterimages after viewing angry faces. This suggests that opponent processes may relate to individual differences in personality and emotional regulation.

Applications: Drug Tolerance & Addiction

Tolerance occurs when repeated drug use requires increasing doses to achieve the same effect. Opponent-process theory explains this: the pleasurable a-process remains constant, but the unpleasant b-process strengthens, requiring higher doses to overcome it (Solomon, 1980).

With repeated drug use, users need more drug to feel the same euphoria because the opponent process (depression, dysphoria) has strengthened. Meanwhile, the opponent process itself becomes the problem—when the drug wears off, the strengthened b-process produces intense withdrawal symptoms. Users take drugs not just for pleasure but to avoid the horrible feelings when the drug is absent.

This explains why addiction is so difficult to overcome. Even after the drug clears the system, the strengthened b-process persists. Former addicts experience depression, anhedonia (inability to feel pleasure), and intense cravings—manifestations of the strengthened opponent process no longer balanced by the drug’s effects (Solomon, 1980).

Motivation: Another Hypothetical Construct

Having discussed emotions, we should briefly distinguish them from motivation—another internal process that influences behavior.

Motivation is a three-step internal process: (1) Activation—motivation energizes behavior; (2) Direction—motivation directs or guides behavior toward a goal; (3) Maintenance—motivation maintains behavior until the desired goal is achieved. Like learning, motivation is a hypothetical construct we infer from behavior (Hull, 1943).

Motivation involves goal-directed behavior based on feedback systems. A comparator compares actual input (current state) with reference input (desired state). When a discrepancy exists, the system activates behavior to reduce the discrepancy. For example, when you’re hungry (actual state) but want to feel full (reference state), the discrepancy motivates food-seeking behavior.

Distinguishing Motivation from Learning

If motivation and learning are both hypothetical constructs that we infer from behavior, what distinguishes them? The major distinction concerns the time required for behavioral change. When learning is involved, behavioral change is gradual and occurs through practice. You don’t learn to play piano in one session—it requires repeated practice. When a motivational state is created, behavior changes much more rapidly and doesn’t require practice. A hungry person immediately seeks food without practicing food-seeking (Hull, 1943).

Another process that changes behavior but isn’t considered learning is extinction—the gradual reduction or elimination of a learned behavior when reinforcement is discontinued. While extinction results from experience (withholding reinforcement), it doesn’t add new behaviors to the organism’s repertoire; instead, it removes behaviors. Learning, by definition, expands what an organism can do. Extinction reduces behavioral potential rather than creating it. We’ll examine extinction in detail when we study operant conditioning, but it’s important to recognize that not all experience-dependent behavioral changes constitute learning in the strict sense.

Some motives, such as hunger, thirst, or sexual arousal, are physiological motives—based on biological needs. Other motives are psychological motives, based on cognitive or social needs.

Cognitive dissonance is a motivational state that occurs when a person has two incompatible thoughts. This discomfort motivates behavior to reduce the inconsistency—for example, changing beliefs or rationalizing contradictions (Festinger, 1957). Cognitive dissonance theory predicts we’ll be motivated to reduce discomfort from incompatible thoughts, sometimes leading to surprising outcomes like stronger commitment to choices after making them.

Looking Forward

We’ve completed our survey of unlearned adaptive behaviors, proto-learning processes, and opponent-process theory of emotion. These foundations prepare us for Module 04, where we’ll study classical conditioning—the first type of true learning we’ll examine in detail. Classical conditioning builds directly on the reflexive and emotional responses we’ve studied, and we’ll see how conditioned emotional responses develop, how drug tolerance involves conditioned compensatory responses, and how phobias and preferences are learned through associative processes.