Is Psychology a Science?

Psychology is a science because it employs systematic methods of observation, experimentation, and data analysis to understand and predict behavior and mental processes, grounded in empirical evidence and subjected to peer review.

Science relies on empiricism: the idea that all knowledge comes from sensory experience rather than reason alone. John Locke founded this view, arguing that observation, not intuition, is the only real source of knowledge.

Empiricism contrasts with rationalism, which holds that knowledge can come from reason and logical argument alone. This experience-based approach became the foundation of the scientific method, driving the growth of physics and chemistry in the 17th and 18th centuries.

This experience-based approach became a method of inquiry. It used careful observation and experiments to gather facts and evidence.

The nature of scientific inquiry may be thought of at two levels:

1. That to do with theory and the foundation of hypotheses.

2. And actual empirical methods of inquiry (i.e. experiments, observations)

The prime empirical method of inquiry in science is the experiment.

The key features of the experiment are control over variables (independent, dependent, and extraneous), careful, objective measurement, and establishing cause and effect relationships.

Features of Science

The Scientific Process

Before the twentieth century, science largely used induction. Researchers made discoveries through accurate observation, then formulated theories based on the regularities they observed.

Newton’s Laws are an example of this. He observed the behavior of physical objects (e.g., apples) and produced laws that made sense of what he observed.

The scientific process is now based on the hypothetico-deductive model proposed by Karl Popper (1935).  Popper suggested that theories/laws about the world should come first, and these should be used to generate expectations/hypotheses, which observations and experiments can falsify.

As Popper pointed out, falsification is the only way to be certain:

‘No amount of observations of white swans can allow the conclusion that all swans are white, but the observation of a single black swan is sufficient to refute that conclusion.’

Darwin’s theory of evolution is an example of this. He formulated a theory and tested its propositions by observing animals in nature.  He specifically sought to collect data to prove his theory / disprove it.

Thomas Kuhn argued that science does not progress gradually towards truth. Instead, a field holds one paradigm until anomalies pile up that it cannot explain, which triggers a shift to a new paradigm.

Kuhn’s own standard says a field only counts as a mature science once its practitioners share a single paradigm.

By that test, psychologists disagree about which description fits best. Some call psychology pre-paradigmatic, since it has never reached that consensus. Others see a candidate paradigm, such as cognitive psychology, already dominant. Still others describe it as multi-paradigmatic: several coexisting frameworks that have not displaced one another.

There are many conflicting approaches, and the subject matter of Psychology is so diverse; therefore, researchers in different fields have little in common.

Psychology is really a very new science, with most advances happening over the past 150 years or so.  However, it can be traced back to ancient Greece, 400 – 500 years BC.  The emphasis was a philosophical one, with great thinkers such as Socrates influencing Plato, who in turn influenced Aristotle.

Plato argued that there was a clear distinction between body and soul. He also believed strongly in the influence of individual differences on behavior.

Plato played a key role in developing the notion of “mental health,” believing that the mind needed stimulation from the arts to keep it alive.

Aristotle, by contrast, firmly believed that the body strongly affected the mind. You might call him an early biopsychologist.

Psychology as a science took a “back seat” until Descartes (1596 – 1650) wrote in the 17th century. He believed strongly in the concept of consciousness, maintaining that it was consciousness that separated us from animals.

He did, however, believe that our bodies could influence our consciousness, and that the interactions between them began in the pineal gland. We now know this is probably not the case.

From this influential work came other important philosophies about psychology, including the work by Spinoza (1632 – 1677) and Leibnitz (1646 – 1716).

But there still was no single, scientific, unified psychology as a separate discipline (you could certainly argue that there still isn’t!).

When asked, “Who is the parent of psychology?” many people answer, “Freud.” Whether this is fair is open to debate. But ask who the parent of experimental psychology is, and few people would answer the same way. So, where did modern experimental psychology come from, and why?

Psychology took so long to emerge as a scientific discipline because it needed time to consolidate.  Understanding behavior, thoughts, and feelings are not easy, which may explain why it was largely ignored between ancient Greek times and the 16th century.

But researchers eventually tired of years of speculation, theory, and argument.

Bearing in mind Aristotle’s plea for scientific investigation to support theory, psychology emerged as a scientific discipline in the late 1800s.

Wilhelm Wundt developed the first psychology lab in 1879.  Introspection was used, but systematically (i.e., methodologically). It was really a place from which to start thinking about how to employ scientific methods to investigate behavior.

The behaviorists were the classic movement to adopt these strategies. They relied on controlled laboratory experiments and rejected unseen or subconscious forces as causes of behavior.

And later, cognitive psychologists adopted this rigorous (i.e., careful), scientific, lab-based approach.

Psychological Approaches

Psychoanalysis has great explanatory power and understanding of behavior. Still, it has been accused of only explaining behavior after the event, not predicting what will happen in advance, and being unfalsifiable.

Some have argued that psychoanalysis functions more like a religion than a science. It is not alone in facing the unfalsifiability charge: evolutionary theory faces the same criticism, since it can explain any outcome as something that evolved that way.

Like other theories that are hard to refute, however, the possibility remains that psychoanalysis is actually right.

Kline (1984) argues that psychoanalytic theory can be broken down into testable hypotheses and tested scientifically. For example, Scodel (1957) postulated that orally dependent men would prefer larger breasts (a positive correlation) but, in fact, found the opposite (a negative correlation).

Freudian theory could explain this finding through reaction formation: the subject shows exactly the opposite of their unconscious impulse. Even so, Kline points out that no significant correlation would have refuted the theory.

Behaviorism builds parsimonious, or economical, theories of learning from a few simple principles: reinforcement, behavior shaping, and generalization. These principles explain behavior ranging from language acquisition to moral development.

Behaviorism advanced bold, precise, and refutable hypotheses, such as Thorndike’s law of effect. It also rested on a hard core of central assumptions, especially environmental determinism, an assumption that held until cognitive and ethological theorists mounted overwhelming criticism against it.

Behaviorists firmly believed in determinism and orderliness.

They therefore made fairly consistent predictions about when an animal would respond, though they admitted that perfectly predicting any one individual was impossible.

The behaviorists used their predictions to control behavior in both animals, such as training pigeons to detect life jackets, and humans, through behavioral therapies. Skinner even described a behaviorist-controlled society in his book Walden Two (1948).

Cognitive psychology – adopts a scientific approach to unobservable mental processes by advancing precise models and conducting experiments on behavior to confirm or refute them.

Full understanding, prediction, and control in psychology are probably unobtainable. Environmental, mental, and biological influences on even the simplest behavior are too complex for every extraneous variable to be controlled.

You will see, therefore, that there is no easy answer to the question, “is psychology a science?”. But many approaches of psychology do meet the accepted requirements of the scientific method, whilst others appear to be more doubtful in this respect.

Alternatives to Scientific Psychology

However, some psychologists argue that psychology should not be a science. There are alternatives to empiricism, such as rational research, argument, and belief.

The humanistic approach (another alternative) values private, subjective conscious experience and argues for the rejection of science.

The humanistic approach argues that objective reality is less important than a person’s subjective perception and subjective understanding of the world. Because of this, Carl Rogers and Maslow placed little value on scientific psychology, especially using the scientific laboratory to investigate human and other animal behavior.

A person’s subjective experience of the world is an important and influential factor in their behavior.

Only by seeing the world from the individual’s point of view can we really understand why they act the way they do. This is what the humanistic approach aims to do.

Humanism is a psychological perspective that emphasizes the study of the whole person. It looks at human behavior through the eyes of the person doing the behaving, not just the observer.

An individual’s behavior, on this view, is connected to their inner feelings and self-image.

The humanistic approach in psychology deliberately steps away from a scientific viewpoint. It rejects determinism in favor of free will, aiming for a unique, in-depth understanding rather than prediction and control.

It does not have an orderly set of theories, although it does share some core assumptions.

It is not interested in predicting and controlling people’s behavior – the individuals themselves are the only ones who can and should do that.

Miller (1969), in Psychology as a Means of Promoting Human Welfare, criticizes the controlling view of psychology. He argues that understanding should be the field’s main scientific goal, asking who would do the controlling and whose interests it would serve.

Humanistic psychologists rejected a rigorous scientific approach to psychology because they saw it as dehumanizing and unable to capture the richness of conscious experience.

In many ways, the rejection of scientific psychology in the 1950s, 1960s, and 1970s was a backlash to the dominance of the behaviorist approach in North American psychology.

Common Sense Views of Behavior

In certain ways, everyone is a psychologist. This does not mean everyone has had formal training in psychology.

People have common sense views of the world, of other people, and of themselves. These common-sense views may come from personal experience, from our upbringing as a child, and through culture, etc.

People hold common-sense views about many aspects of psychology.

These include the causes of their own and others’ behavior, the personality traits people possess, what others should do, and how to raise children.

Informal psychologists acquire common-sense knowledge in a rather subjective (i.e., unreliable) and anecdotal way.  Common-sense views about people are rarely based on systematic (i.e., logical) evidence and are sometimes based on a single experience or observation.

Racial or religious prejudices may reflect what seems like common sense within a group of people. However, prejudicial beliefs rarely stand up to what is actually the case.

Common sense, then, is something that everybody uses in their day-to-day lives, guides decisions and influences how we interact with one another.

Common sense is not based on systematic, scientific evidence, so it can mislead. It may even lead one group to treat others unfairly.

The Objectivity Problem

Psychology faces a challenge that physics and chemistry do not: the object being studied can notice it is being studied, and react to that fact. A participant might guess a study’s hypothesis and change their behavior accordingly, something no rock or chemical compound can do.

Experimenter Bias

Experimenter bias occurs when what a researcher expects shapes what they unwittingly communicate, which then shapes how participants behave. No one has to handle the data dishonestly for this to happen.

Aim: Rosenthal and Fode (1963) tested whether an experimenter’s expectations could influence the outcome of a study, even without any dishonesty.

Method: Students were told they were testing rats bred to be either “maze-bright” or “maze-dull,” although the rats were actually standard lab rats assigned to groups at random.

Results: Students who believed their rats were “maze-bright” reported faster maze learning than students who believed their rats were “maze-dull,” even though the rats did not actually differ.

Conclusion: An experimenter’s expectations can unintentionally bias the results, even in a tightly controlled study.

Rosenthal and Jacobson (1968) later found the same effect in real classrooms. Teachers were told certain students would soon show an “intellectual growth spurt.” Those randomly chosen students then showed bigger IQ gains than their classmates.

The Pygmalion effect, as this finding came to be known, shows that an expectation can become a self-fulfilling prophecy.

Demand Characteristics

Demand characteristics are cues in a study’s setting, instructions, or the experimenter’s manner that let participants guess the hypothesis being tested. Once participants think they know what a study is about, they often change their behavior. Sometimes this helps confirm the hypothesis; sometimes it deliberately sabotages it.

Orne (1962), who coined the term, argued that participants actively try to work out what an experiment is really testing, then adjust their behavior accordingly.

This makes demand characteristics one of the hardest sources of bias for researchers to eliminate. Even careful debriefing afterwards cannot undo behavior participants have already changed.

Together, experimenter bias and demand characteristics show that psychology’s objectivity problem is not just philosophical. It is a practical, well-documented pattern that researchers must actively guard against in every study design.

Limitations of Scientific Psychology

Despite having a scientific methodology worked out (we think), some further problems and arguments doubt psychology is ever a science.

Limitations may refer to the subject matter (e.g., overt behavior versus subjective, private experience). They may also refer to objectivity, generality, testability, ecological validity, ethical issues, and philosophical debates, etc.

Science assumes that there are laws of human behavior that apply to each person. Therefore, science takes both a deterministic and reductionist approach.

Science studies overt behavior because it is objectively observable and measurable. This lets psychologists agree on what they observed, so evidence can be collected to test a theory about people.

Scientific laws are generalizable, but psychological explanations are often restricted to specific times and places. Because psychology studies (mostly) people, it studies (indirectly) the effects of social and cultural changes on behavior.

Psychology does not go on in a social vacuum. Behavior changes over time and in different situations. These factors, and individual differences, make research findings reliable for a limited time only.

Are traditional scientific methods appropriate for studying human behavior? When psychologists operationalize their IV, it is highly likely that this is reductionist, mechanistic, subjective, or just wrong.

Operationalizing variables means defining and measuring a specific variable for use in a study. For example, a biopsychologist might operationalize stress as an increased heart rate.

Doing this may remove researchers from the human experience of what they are studying. The same problem applies to causality.

Experiments aim to show that X causes Y. But this deterministic view ignores extraneous variables, and the fact that a different time or place might remove X’s influence altogether. This raises the issue of ecological validity.

Objectivity is impossible. It is a huge problem in psychology, as it involves humans studying humans, and it is very difficult to study people’s behavior in an unbiased fashion.

A general philosophy-of-science problem compounds this: a theoretical standpoint always influences the researcher, as Freud’s own case shows. The observer and the observed belong to the same species, which creates problems of reflexivity.

A behaviorist would never examine a phobia in terms of unconscious conflict. Likewise, Freud would never explain a phobia as behavior acquired through operant conditioning.

This particular viewpoint that a scientist has is called a paradigm (Kuhn, 1962). Kuhn argued that most mature scientific disciplines have one predominant paradigm that the vast majority of scientists subscribe to.

Psychology, by contrast, has several competing paradigms: psychoanalytic, biological, cognitive, and humanistic, among others. As discussed above, psychologists disagree about whether this makes the field pre-paradigmatic, multi-paradigmatic, or simply in a period of normal science under a candidate paradigm.

Verification (i.e., proof) may be impossible. We can never truly prove a hypothesis. We may find results supporting it for years, but we will never be 100% confident it is true.

It could be disproved at any moment. The main driving force behind this objection is Karl Popper, the famous philosopher of science and advocate of falsificationism.

Take the famous Popperian example hypothesis: “All swans are white.” How do we know for sure that we will not see a black, green, or hot pink swan in the future? So even if there has never been a sighting of a non-white swan, we still haven’t really proven our hypothesis.

Popper argues that the best hypotheses are those which we can falsify – disprove. If we know something is not true, then we know something for sure.

Testability: much of psychology’s subject matter, such as memory, is unobservable and cannot be measured directly. So many variables influence human behavior that it is impossible to control them all effectively.

The Replication Crisis

Since replicability is one of the criteria a science must satisfy, psychology’s own replication record offers a direct empirical test of whether the field lives up to its scientific claims.

Aim: The Open Science Collaboration, a large multi-site group of researchers, set out to measure directly how reproducible published psychology findings really are.

Method: The team selected 100 studies from three top psychology journals and attempted to replicate each one as closely as possible, using larger sample sizes than the originals so that low statistical power could not explain any failures.

Results: Of the 100 original studies, 97% had reported a statistically significant result, but only 36% of the replications did.

The replicated effects were roughly half the size of the originals.

Conclusion: A large share of psychology’s headline findings do not survive an honest, well-powered attempt to reproduce them, and even when they do, the true effect is usually smaller than first reported (Open Science Collaboration, 2015).

The finding sparked a wider reform movement.

Ioannidis (2005) had already argued that low statistical power and flexible analysis choices make many published findings, across many fields, likely to be false. Munafò et al. (2017) later proposed concrete fixes, including pre-registration, larger samples, and open data, aimed at raising psychology’s reproducibility rate.

So, are we any closer to understanding a) what science is and b) if psychology is a science?

Unlikely. There is no definitive philosophy of science and no flawless scientific methodology.

When people use the term “scientific,” they generally share a rough sense of what it means. But once we break the term down, as we just have, the picture gets far less certain.

What is science? It depends on your philosophy.

Is psychology a science? It depends on your definition.

So why bother asking, and how do we conclude all this?

Slife and Williams (1995) have tried to answer these two questions:

1) We must at least strive for scientific methods because we need a rigorous discipline. If we abandon our search for unified methods, we’ll lose a sense of what psychology is (if we knew it in the first place).

2) We need to keep trying to develop scientific methods suitable for studying human behavior. The methods adopted by the natural sciences may simply not be appropriate for us.