The Impact of Behaviorism on Understanding Animal Minds

For most of human history, the question of whether animals think, feel, or have inner mental lives seemed almost self-evident. Watch a dog mourn a dead companion, or observe a crow bending a wire into a hook, and the inference feels natural: something is going on inside. But in the early twentieth century, science made a sharp turn. Under the influence of a school of thought called behaviorism, the inner lives of animals were effectively ruled out of scientific bounds – not because evidence against them was found, but because scientists decided such questions could not, in principle, be studied. Understanding how and why that happened reveals as much about the sociology of science as it does about animals themselves.

Before behaviorism: Darwin, Romanes, and the case for animal minds 🔗

The story begins, as so many things in biology do, with Charles Darwin. Darwin’s emphasis on continuity between humans and other animals opened the door to a serious scientific study of animal psychology. If humans evolved from earlier organisms, the mental faculties of humans could not be absolutely severed from those of other animals. Darwin argued explicitly in The Descent of Man (1871) and The Expression of the Emotions in Man and Animals (1872) that emotions, memory, and even basic reasoning were not exclusively human endowments. This was a radical claim at the time, and it set the stage for the first systematic inquiry into animal minds.

George John Romanes (1848-1894), Darwin’s close friend and intellectual protégé, took that torch and ran with it. In his 1882 book Animal Intelligence, Romanes reported dozens of accounts of complex cognitive behaviors across species ranging from scorpions to elephants. His broader project, as he put it, was to do for the mind what Darwin had done for the body – to trace the gradual and continuous development of mental life across the animal kingdom. Romanes distinguished between intelligence (individually acquired adaptations marked by conscious choice) and reflexes or instincts (fixed by heredity), using this distinction to trace the evolution of behavior from unicellular organisms upward.

His method, however, was his undoing. Romanes relied heavily on anecdote – stories collected from naturalists, pet owners, and travelers. He tended to over-ascribe human traits to animals, treating a scorpion’s recoil from flames as evidence of deliberate suicide, and a fox’s behavior as reflecting vindictive planning. His approach, sometimes called anthropomorphism – attributing human characteristics to non-human animals – was, in intent, a well-meaning effort to argue for continuity between human and animal minds. But it lacked the empirical discipline that science was coming to demand.

Morgan’s Canon: the first brake on animal mentalism 🔗

The first major corrective came not from behaviorism but from within comparative psychology itself. C. Lloyd Morgan (1852-1936), a British psychologist who had followed Romanes’s work closely, published An Introduction to Comparative Psychology in 1894. In it, he articulated what became known as Morgan’s Canon, described by scholar D.A. Dewsbury as perhaps the most quoted statement in the history of comparative psychology. The canon states that animal behavior should never be interpreted as the product of a higher psychological process if a simpler one can account for it.

Morgan himself observed his terrier carefully and argued that what observers took to be intelligent gate-opening was, on closer inspection, the product of repeated trial and error rather than any conscious plan. The canon was not, in Morgan’s original formulation, a denial of animal minds – he was careful to add that complex interpretations remain valid when a species has shown independent signs of high intelligence. But as the Stanford Encyclopedia of Philosophy notes, Morgan’s Canon functions as a default preference for simpler explanations akin to Ockham’s Razor, and in subsequent decades, it was widely applied in ways that went well beyond what Morgan intended, functioning as a near-total prohibition on attributing mental states to animals.

Watson’s manifesto and the behaviorist turn 🔗

It was John B. Watson who transformed this methodological caution into a full philosophical program. Watson’s 1913 manifesto proposed abandoning introspective attempts to make consciousness a subject of experimental investigation, focusing instead on behavioral manifestations of intelligence. In a landmark paper often called the “behaviorist manifesto,” Watson argued that psychology had been held back by its preoccupation with subjective mental states – states that could not be directly observed, measured, or controlled. Watson described the purpose of psychology as predicting behavior from a given stimulus, or identifying the stimulus that caused a given reaction. Consciousness, feeling, intention – these were expelled from the scientific vocabulary.

Watson’s position led, scientifically, to the ignoring of consciousness and the declaration that making consciousness a special object of observation was illegitimate. He proposed that psychology should study only observable, measurable behavior. Watson’s approach assumed that the human mind is a tabula rasa at birth and saw no fundamental distinction between human and animal behavior, believing both could be studied the same way. Animals, in this framework, became convenient experimental subjects – not because their minds mattered, but because their bodies could be manipulated under controlled conditions.

Pavlov, Thorndike, and the laboratory animal 🔗

Watson did not create behaviorism from nothing. He built on the work of two important predecessors. Ivan Pavlov, the Russian physiologist, had demonstrated through his famous conditioning experiments with dogs that complex behavioral responses could be produced, extinguished, and transferred through careful manipulation of stimuli – all without any reference to what the dog was thinking or feeling. Pavlov’s classical conditioning showed that a previously neutral stimulus (a bell) could, after repeated pairing with food, produce the same salivation response as the food itself. For Watson, this was exactly the kind of rigorous, objective, replicable science that psychology needed.

Edward Thorndike contributed another key piece. Thorndike placed hungry cats and dogs in enclosures from which they could escape by performing a simple act such as pulling a cord. Their behavior suggested to him that they did not possess the power of rationality. He argued that what appeared to be intelligence was, on careful analysis, the mechanical result of “trial and error” – responses that produced satisfying outcomes were repeated; those that did not were abandoned. Thorndike wrote that most books about animal behavior gave not a psychology but a eulogy of animals – a pointed criticism of the Romanes tradition. Using Morgan’s Canon, he concluded that inferring reason, insight, or consciousness in animals was simply unnecessary to explain what he observed.

Skinner and the hardening of behaviorism 🔗

If Watson opened the door, B.F. Skinner (1904-1990) cemented it shut. It was not until 1945 that Skinner proposed that covert behavior – including cognition and emotions – is subject to the same controlling variables as observable behavior, forming the basis of his philosophy called radical behaviorism. Skinner did not deny that internal states like thoughts and emotions existed; he insisted they were simply more behavior, shaped by the same environmental reinforcements and punishments as any other response. Skinner hardened behaviorist strictures to exclude inner physiological processes along with inward experiences as items of legitimate psychological concern.

Skinner’s operant conditioning chamber – the Skinner box – became the central tool of mid-century animal research. In it, a rat or pigeon could press a lever to receive food, and the precise rates and patterns of this lever-pressing under different reinforcement schedules were studied exhaustively. For Skinner, behavior could be explained by reference to its functional relation to the environment and to the animal’s history of environmental interaction. Neurophysiological and neurobiological conditions merely implemented these functional relations without serving as independent sources of explanation. The animal’s inner experience – whether pressing the lever felt like anything, whether the rat was anxious or curious – was simply not a scientific question.

The cost: what behaviorism erased 🔗

The consequences for the understanding of animal minds were profound. The comparison of animal intelligence and human intelligence disappeared as a psychological topic until its revival late in the twentieth century. Decades of potential research into animal cognition, emotion, and consciousness were effectively suspended. Animals in the laboratory became input-output machines: stimuli in, responses out, with the intervening territory of experience cordoned off as unscientific.

This erasure happened despite the fact that Darwin and Romanes had already assembled substantial evidence – however methodologically imperfect – suggesting that animals displayed behaviors strongly consistent with memory, problem-solving, social bonding, and emotional response. The behaviorist movement did not refute this evidence; it simply reclassified the questions as illegitimate. As one analysis in Frontiers in Psychology notes, the anthropomorphic, anecdotal approach adopted by Darwin and Romanes – considered “unsound” by modern standards – nevertheless helped instigate the experimental studies conducted by Morgan and Thorndike, sparking a revolution in the psychological study of animals. The tragedy is that the revolution it sparked then turned back and suppressed the very questions that had motivated it.

The philosophical machinery behind the denial 🔗

Behaviorism’s rejection of animal consciousness was not simply a matter of scientific fashion. It rested on a specific philosophical commitment: that science can only deal with publicly observable, measurable phenomena. This position, rooted in logical positivism, held that statements about unobservable inner states were not merely uncertain – they were meaningless. If you cannot in principle design an experiment to test whether a rat is conscious, the claim that it is conscious is not a scientific hypothesis at all.

One defining aspiration of behaviorism was to free psychology from having to theorize about how animals represent their environment internally. This effort seemed worthwhile because behavior-environment connections appeared far clearer and more experimentally manageable than internal representations. The commitment to empirical rigor, in other words, was genuine – but the price was a conceptual framework that made it impossible, by definition, to ask whether animals have minds. The question was not answered; it was forbidden.

Cracks in the edifice: the cognitive turn 🔗

Behaviorism’s dominance began to crumble in the late 1950s and 1960s. The successful “cognitive revolution” of the 1960s styled itself a revolt against behaviorism, even though the computational processes cognitivism hypothesized were public and objective – not the sort of private subjective processes Watson had banned. Researchers studying language, memory, and problem-solving found that there was an enormous collection of experimental data that simply could not be made sense of unless internal information-processing mechanisms were posited. The brain, it turned out, was not merely a relay station between stimulus and response.

For animal cognition specifically, the revival came even later. By the 1970s and beyond, ethologists and comparative psychologists began systematically revisiting questions about animal minds – this time with better experimental designs and more rigorous methods than Romanes had employed. Research on primate language, tool use in corvids, self-recognition in mirrors, and emotional responses in elephants and cetaceans began to restore scientific credibility to the idea that animal consciousness is a genuine phenomenon worthy of study. In July 2012, a prominent group of neuroscientists gathered at Cambridge and signed a declaration concluding that non-human animals possess the neuroanatomical, neurochemical, and neurophysiological substrates of conscious states, along with the capacity to exhibit intentional behaviors.

What the behaviorist turn teaches us about science 🔗

The behaviorist episode in the study of animal minds is a revealing case study in how methodological commitments can shape – and distort – scientific inquiry. Behaviorism’s insistence on observable behavior as the only legitimate subject of psychology was, in many respects, a genuine advance: it demanded rigor, replicability, and precision. But it also demonstrates how a philosophical choice about what counts as real science can silently rule out entire categories of question before a single experiment is run.

Darwin and Romanes were wrong in their methods – they relied too heavily on anecdote and too readily attributed human mental states to animal behavior. But the questions they were asking – do animals think? do they feel? are their minds continuous with ours? – were the right questions. Behaviorism answered those questions not by finding evidence against animal consciousness, but by declaring the questions themselves inadmissible. Although behaviorism as an avowed movement may have few remaining advocates, its methodological mark remains wherever experimental rigor in psychology requires the “operationalization” of variables. The ghost of Watson still haunts how scientists design experiments, write papers, and frame hypotheses about the minds of other species.

What do you think? If science can only study what is directly observable, does that mean questions about animal consciousness are permanently beyond its reach – or do we simply need better methods? And given what we now know about animal cognition and neuroscience, was the behaviorist suppression of these questions a costly detour in the history of science, or a necessary phase that ultimately strengthened the field?

References

1. https://www.sciencedirect.com/science/article/pii/S1631069109003114
2. https://en.wikipedia.org/wiki/George_Romanes
3. https://connect.springerpub.com/content/book/978-0-8261-6235-9/chapter/ch01
4. https://neurobiotaxis.livejournal.com/8028.html
5. https://en.wikipedia.org/wiki/C._Lloyd_Morgan
6. https://en.wikipedia.org/wiki/Animal_cognition
7. https://plato.stanford.edu/entries/cognition-animal/
8. https://iep.utm.edu/behaviorism/
9. https://www.simplypsychology.org/behaviorism.html
10. https://en.wikipedia.org/wiki/Behaviorism
11. https://plato.stanford.edu/entries/behaviorism/
12. https://www.psywww.com/intropsych/ch08-animals/early-comparative-psychology.html
13. https://pmc.ncbi.nlm.nih.gov/articles/PMC4812110/