Richard Solomon

Introduction

Richard Lester Solomon (October 2, 1918 – October 12, 1995) was an American experimental psychologist who shaped the study of learning and motivation for half a century. In a career spanning Harvard and the University of Pennsylvania, he directed the classic experimental analyses of avoidance learning in dogs, helped originate the research program that produced the theory of learned helplessness, and, with John Corbit, proposed the opponent-process theory of acquired motivation (1974), which explains why pleasures fade, why pains dull, and why people return to skydivers' drop zones and lovers' quarrels. He was elected to the National Academy of Sciences and the American Academy of Arts and Sciences, received the Society of Experimental Psychologists' Warren Medal, and — through a research seminar that trained leaders including Martin Seligman and Robert Rescorla — populated an entire subfield of psychology with his intellectual descendants.

Early Life and Education

Solomon was born in Boston into a family he described as orderly and intense, run by a hard-driving CPA father and a mother who stressed manners and responsibility. He was a lukewarm student in the Newton and Brookline public schools, grading high only for teachers he liked — most importantly Tyler B. Kepner, a history teacher whose demand for analytical thinking and whose personal encouragement he credited with sending him to college at all.

At Brown University he took a joint major in economics and psychology, wrote an honors thesis under Joseph McV. Hunt, and graduated summa cum laude in 1940. The Brown department — then home to Walter Hunter, Harold Schlosberg, Donald Lindsley, Carl Pfaffmann, and Lorrin Riggs — convinced him to stay for graduate work in Schlosberg's laboratory. He completed a master's degree in 1942, then spent the war as a research psychologist with the Office of Scientific Research and Development, working on perceptual–motor systems for the B-29 bomber's defensive fire control; one redesign earned him a patent, which he donated to the government. He returned to Brown and received his Ph.D. in 1947.

The war work is a useful corrective to the picture of Solomon as a pure learning theorist. He spent the decisive years of the 1940s solving a human-factors problem — how to get a gunner to track a target under stress — rather than running conditioning experiments, and the problems he took up afterwards, about how motivational states acquire control over behaviour, are continuous with that.

Academic and Professional Career

After a year teaching at Brown, Solomon joined Harvard's Department of Social Relations as an assistant professor in 1947, rising through the ranks to full professor in the 1950s. At Harvard he became known both for experimental work — the "new look" in perception, conditioning, and motivation — and for unusually inventive interdisciplinary courses that wove philosophy, anthropology, and social psychology together with learning theory.

In 1960 he was recruited by Robert Bush to the young, experimentally ambitious psychology department at the University of Pennsylvania, where he held joint appointments in psychology and the Institute for Neurological Sciences and became the first James M. Skinner University Professor. He retired from Penn in 1984, by which time he had published some 65 papers and supervised 35 doctoral dissertations. His weekly research seminar, in which undergraduates, graduate students, and postdocs together dissected journal articles and experimental designs, became legendary; Judith Rodin, who took his undergraduate course and later became Penn's president, called him "a brilliant scientist, an extraordinary mentor, and a very humane and gentle person." Among the honors beyond his Academy elections were a Guggenheim Fellowship, the Monie A. Ferst Award of Sigma Xi, a Brown University Distinguished Achievement Citation, and editorship of Psychological Review from 1959 to 1964.

Major Contributions to Psychology

Avoidance Learning and the Fate of Fear

From the early 1950s, Solomon's laboratory ran the systematic studies of avoidance learning in dogs that defined the field. In the standard shuttlebox paradigm, a warning signal precedes shock unless the dog jumps a barrier in time. Solomon and Lester Wynne showed that after a few traumatic trials, dogs continued to avoid even when shocks were discontinued — "partial irreversibility" — which they interpreted as conservation of anxiety: fear responses, once acquired, persist because successful avoidance prevents the fear from ever being disconfirmed. Related work with Leon Kamin and Wynne on extinction after traumatic conditioning, and with Turner on dogs' acquisition of punishment-avoidance, set the empirical agenda for two-factor theories of avoidance that combined Pavlovian fear with instrumental escape.

From Pavlovian Conditioning to Learned Helplessness

Solomon's laboratory pioneered the experimental machinery for studying how Pavlovian conditioned states interact with instrumental behavior — transfer-of-control and conditioned-emotion procedures that turned conditioned fear into a measurable instrument. It was within this program, in the mid-1960s, that experiments in which dogs were exposed to inescapable shock first produced the profound escape-learning impairment that Seligman and Steven Maier developed into the theory of learned helplessness — one of the most consequential lines of research in twentieth-century psychology, born in Solomon's lab.

The Opponent-Process Theory of Acquired Motivation

With Corbit, Solomon proposed in 1974 that every affective event triggers two opposing processes: a fast primary process (a-process) that follows the stimulus, and a sluggish opponent process (b-process) that rises to cancel it and outlasts it after the stimulus ends. With repetition, the opponent grows stronger: the first parachute jump is terror followed by exhilaration, the hundredth is exhilaration with a lingering afterglow; early drug euphoria shrinks while withdrawal deepens. The theory recast addiction, thrill-seeking, attachment, and craving as timing phenomena — the costs of pleasure and the benefits of pain, as his 1980 summary put it.

Experimental Design as a Contribution

Solomon treated design itself as a scientific contribution. The Solomon four-group design — his pretest–posttest control-group innovation published with Marilyn Lessac in 1968 — remains a standard tool for separating testing effects from treatment effects in developmental and educational research.

Major Publications

Solomon, R. L., & Wynne, L. C. (1953). Traumatic avoidance learning: Acquisition in normal dogs. Psychological Review, 60, 417–434.
Solomon, R. L., Kamin, L. J., & Wynne, L. C. (1953). Traumatic avoidance learning: The outcomes of several extinction procedures with dogs. Journal of Abnormal and Social Psychology, 48, 291–302.
Solomon, R. L., & Lessac, M. S. (1968). A control group design for experimental studies of developmental processes. Psychological Bulletin, 70, 145–150.
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, 35, 691–712.

Impact and Legacy

Solomon's laboratory produced the concepts and the personnel of modern learning-motivation research: learned helplessness theory grew from his dogs, and his students and postdocs — Rescorla in associative learning, Seligman in helplessness and later positive psychology, and dozens of others — carried his standards into departments across the field. The opponent-process framework remains a standard reference point in motivation, addiction, and emotion research, and it anticipated later neuroscientific work on opponent neural systems in reward and withdrawal.

The theory has also drawn sustained criticism:

Extrapolation outran the data. The theory's most vivid applications — veteran parachutists, distance runners, lovers separated and reunited — rested on anecdote and small studies rather than the parametric rigor Solomon demanded elsewhere. Critics within behaviorism noted that affective states in humans are inferred from self-report, not measured with the precision the theory's timing predictions require.
The b-process was never directly isolated. The opponent process is a theoretical construct inferred from response dynamics; direct, independent measurement of the postulated opponent state — as opposed to fitting curves to behavior — proved elusive, leaving the theory closer to metaphor than mechanism in many eyes. It also predicts a specific temporal signature — a-process habituating with repetition while b-process strengthens and lengthens — and that signature does not appear for all stimuli or all affective responses, which makes the theory hard to state as a general law rather than a description of some cases.
Addiction applications were superseded. Solomon's account of tolerance and withdrawal as opponent-process dynamics was later eclipsed in addiction science by neuropharmacological models such as incentive-sensitization theory, which located the mechanisms in dopaminergic systems rather than in generic affective opponents, and which explained features (like wanting without liking) the 1974 theory did not anticipate.
The avoidance account was challenged. The "conservation of anxiety" interpretation of persistent avoidance was disputed by cognitive and safety-signal accounts — including work by his own former students — showing that avoidance can extinguish without terrifying trials when animals are given safety information, undermining the claim that fear is conserved because avoidance prevents its disconfirmation.
The animal work could not be done now. The avoidance experiments used intensities of shock chosen precisely because they were traumatic, and the learned-helplessness experiments depended on dogs being unable to escape it. Both programmes belong to a period before institutional animal-care review, and the procedures as described would not be approved today. This is not a criticism of Solomon by the standards of his time — he was working within the norms of 1950s American experimental psychology — but it is a reason the foundational findings cannot be directly replicated, and the field has had to reconstruct them with milder procedures and different species.
Credit for learned helplessness is shared and disputed. The impairment was first produced in Solomon's laboratory, and the theory was developed by Seligman and Maier; the standard citation honours the latter. Historians of the field have noted that this is the normal outcome when a discovery emerges from a lab rather than from a hypothesis — the director's contribution is the apparatus, the paradigm and the permission to pursue an anomaly, which is exactly what is hardest to cite — and also that Solomon's own theoretical commitments, which were about acquired motivation rather than about cognition, meant he was not the person to develop what his dogs had shown.
The four-group design is honoured more than used. The design Solomon published with Lessac requires double the participants of a standard pretest–posttest study and assumes that pretest and treatment do not interact. Because it doubles cost for a check that is often assumed rather than tested, it remains a methodological reference point that most researchers cite and few actually run.

The opponent process was taken in, renamed, and given a mechanism. This is the part of the legacy Solomon did not live to see. Koob and Le Moal's hedonic allostasis model of addiction, set out in 2001 (Neuropsychopharmacology 24:97–129), is built explicitly on the a-process/b-process skeleton, including Solomon's central move that repeated use converts reward-seeking into relief-seeking. The difference is that the b-process is no longer an inferred affective opponent but two identified classes of neuroadaptation: within-system changes such as downregulation of mesolimbic dopamine, and between-system changes such as the recruitment of corticotropin-releasing factor and other stress systems that the drug never touched at first. The successor model also claims something Solomon did not, that the opponent reaction fails to return to baseline after the drug stops and instead drags the hedonic set point below where it began, which is why it accounts for protracted withdrawal and relapse better than a time course alone. Contemporary summaries in addiction medicine treat the scheme as standard background — Gibson, Pearce, Thomas and Thurber's 2025 chapter on the neurophysiological foundations and clinical applications of opponent-process theory restates it without any gesture back to the 1974 paper. So the objection that the b-process was never isolated has been met, at the cost of replacing a general theory of affect with a domain-specific pharmacological mechanism that keeps Solomon's timing and little of his ambition.

It has also escaped into popular advice, with the usual losses. Anna Lembke's Dopamine Nation (2021) carried the pleasure–pain balance, citing Solomon's 1980 paper, to a mass readership, applying it to smartphones, online shopping and pornography rather than to heroin and parachute jumps — precisely the kind of extrapolation beyond his own evidence that critics had flagged in his lifetime, minus the parametric discipline he demanded in the laboratory. The specific claim that ordinary non-drug rewards recruit the same escalating opponent process as opioids remains asserted more than demonstrated.

Solomon's own response was characteristic of his seminar: the theory was a heuristic to be tested and improved, not a monument. He died in Philadelphia on October 12, 1995, aged 77, shortly before Rescorla's biographical memoir for the National Academy of Sciences appeared, recording a career that few experimental psychologists have matched for rigor, breadth, or progeny.

Learn More

Opponent-Process Theory — the full statement of the theory of acquired motivation.
Martin Seligman — Solomon's student, whose learned helplessness research began in his laboratory.
Robert Rescorla — Solomon's student and colleague, successor to his chair at Penn.
Michel Cabanac — whose concept of alliesthesia makes pleasure depend on the body current state rather than the stimulus
All Psychologists — browse the full biographical collection.

References

Solomon, R. L., & Corbit, J. D. (1974). An opponent-process theory of motivation: I. Temporal dynamics of affect. Psychological Review, 81(2), 119-145.