To what extent should psychology be considered a science?

Science and psychology

Broadly speaking, science is concerned with the objective, logical study of the material world based on fact, and not opinion or intuition.  It can be defined as a systematic approach that is grounded in logic and which aims to produce data that can be measured, tested, analysed, and reproduced (Lilienfeld, 2010; Lindberg, 2010). Science encompasses all of our accumulated knowledge and discoveries about the universe. Though it featured early on in human history, namely ancient Greece, it has been argued that scientific thought did not reappear again until the European enlightenment because of the difficulties faced by humans in overriding automatic and intuitive modes of thinking (Lilienfeld, 2010).

Psychology on the other hand, is arguably a relatively new domain that has been studied as a distinct discipline in its own right for only a couple of hundred years (Danziger, 2013). Psychology is a multi-faceted and wide-ranging subject that focuses on the study of the mind and behaviour (Henriques, 2004). Many different perspectives have contributed to the study of psychology including behaviourism, developmental and cognitive approaches. The role of psychology as a science has been debated for over one hundred years and continues to generate controversy (Lilienfeld, 2010; Zittoun, Gillespie, and Cornish, 2009). Thus, the following work will discuss to what extent psychology should be considered a science. To achieve this aim, evidence in support of psychology as a science will be considered and evidence against this supposition will be examined. The work will conclude with a summary and analysis of the question under review.

In support of psychology as a science

Evidence that provides support for the idea that psychology is a science will now be examined. Science is grounded in the empiricism paradigm which postulates that observations and experiences, or data derived from the senses, are the primary way of gaining knowledge (Hjørland, 2005). Thus, empirical methods are used to obtain factual information that all can agree on and which is immune from the influence of any researchers (Hjørland, 2005). In the scientific approach, double-blind experiments should be utilised wherever possible and subjectivity reduced to the bare minimum (Hjørland, 2005). This is because the research ideal in science is to assume that all observations are neutral and not effected by any knowledge, bias, culture, or opinions of the researcher (Hjørland, 2005).

As per the scientific tradition, research in psychology predominantly relies on collecting objective empirical data from participants, for example through questionnaires, performance tasks, experimentation, or observation. Therefore, it can be argued that psychology is a science because many researchers use the scientific method of hypothetico-deductivism. Hypothetico-deductivism is a methodology which places emphasis on hypotheses verification or rejection through statistical analyses and significance testing (Haig, 2005). Consequently, in many psychological disciplines the researcher must test a theory or hypothesis by making observational predictions which can be empirically tested (Haig, 2005). The data needs to undergo direct statistical analyses, and if the data supports the predictions made at the outset then the result is viewed as confirming the theory in this instance. On the other hand, if the predictions are not supported by the data then this particular study is viewed as disconfirming the theory under question (Haig, 2005).

Predictability in empirical research is important because in this way, researchers can estimate or forecast future behaviour from their results. Another important feature of psychology as a science is that extraneous variables should be controlled as much as possible, and any research conducted should be amenable to replication by other researchers (Hjørland, 2005; Lilienfeld, 2010). In this way, cause and effect can be more clearly determined, and if different researchers consistently find the same results then it is more likely that the results are valid and reliable. Consequently, a theory or treatment should only gain acceptance if other investigators are able to provide empirical support for it (Haig, 2005; Hjørland, 2005; Lilienfeld, 2010). Accordingly, in parallel with the scientific domain, it can be argued that a major goal of research in psychology is to successfully identify empirical phenomena which subsequently lead to explanation and theory construction (Haig, 2005).

Behaviourism is one dominant example of empiricism and scientific thought in psychology. It should be noted that behaviourism in its original form is now considered outdated and too simplistic to account for the complexity of human behaviour. Nevertheless, it has been contended that it facilitated the focus on scientific principles and was the precursor to experimental research in areas such as cognitive, clinical, and developmental psychology (Costall, 2006; Moore, 2011). The foundation of behaviourism is the premise that behaviours are derived from learned associations between a stimulus and a response (Moore, 2011; Padoa-Schioppa, 2008). In other words, behaviourism proposes that all behaviours (including feelings, thoughts, and actions) are a result of events external to the individual and that organisms respond to stimuli in automatic ways and following universal laws (Hjørland, 2005).

It is clear that behaviourism is a highly scientific approach. Indeed Skinner, a prominent behaviourist, stated in relation to research "it is science or nothing" (1971, p. 160).  Behaviourism posits that psychology should be studied scientifically with attention focused on observable behaviours rather than internal processes (Moore, 2011). Behaviourism is often regarded as a direct reaction to the unscientific and introspective nature of psychoanalysis, a perspective which dominated psychology in the early 20th century (Costall, 2006; Moore, 2011). Comparatively, behaviourism's major strengths were that it was highly objective, was applicable to both humans and animals, and was highly replicable (Hjørland, 2005; Moore, 2011).

Another perspective that provides support for psychology being a science is the cognitive approach. It has been argued that the cognitive approach replaced behaviourism as the dominant paradigm in psychology (Costall, 2006; Gardner, 2008). Cognitive psychology returned focus to the importance of mental processes rather than concentrating solely on environmental factors as behaviourism had done (Gardner, 2008). The basic premise of cognitive psychology is to examine how mental processes contribute to human emotions, behaviour, and thinking (Gardner, 2008). Nevertheless, although investigating unobservable phenomena may seem unscientific, cognitive psychology continues to use the rigorous experimental methods and robust statistical analyses of behaviourism (Gardner, 2008). Therefore, in line with the hypothetico-deductive method cognitive psychologists develop precise theoretical hypotheses and then conduct well-controlled experiments in order to confirm or reject them (Gardner, 2008; Haig, 2005). By applying scientific methods researchers in the cognitive discipline are able to investigate complex systems such as information processing, language, attention, memory, and the effects of brain injury on cognition (Gardner, 2008).

Against psychology as a science

Hitherto evidence in support of psychology as a science has been examined; now arguments which contradict this notion will be considered. One important factor to consider when determining the scientific nature of psychology is that due to the complexity of brain function and human behaviour, control of all extraneous variables is almost impossible. For instance, in a study examining the relationship between depression and eating habits a psychologist would not be able to truly control for a person's childhood experiences. In addition, much of the research in psychology does not employ double-blind procedures, even in studies of a clinical nature where it would be advantageous to do so (Lilienfeld, 2010). It is also likely that a researcher can never be completely certain that their hypothesis is true because psychological processes occur in the mind and are not readily accessible.

It is interesting that although the hypothetico-deductive approach to research is held in great esteem by many scientists and psychologists, it has also been heavily criticised (Haig, 2005). It has been argued that approaching research using the principles of empiricism means that the role of language and culture in psychological processes tend to be neglected (Hjørland, 2005). Furthermore, the nature of empirical studies means that generalisations are made by studying one population which may not be representative of all groups (Hjørland, 2005). It can be difficult to reconcile psychology with science when human behaviour varies across situations and over time. This means that testing an individual at one particular instance and situation is unlikely to provide an absolute explanation of any behaviour.

It is evident that there is a division within psychology as to how scientific it should be, which is determined by one's perspective and priorities. For example, Lilienfeld (2010) strongly supports the idea that psychology should be a science but argues that a major threat to scientific psychology is the failure of empirical research to prevent or control confirmation bias. Confirmation bias is against scientific ideals because it involves the tendency for academics to look for evidence consistent with their hypotheses and to ignore, deny, or alter evidence that is in contrast to them (Lilienfeld, 2010).  Thus, psychology is hindered by the desire of researcher's to see what they want to see, and this has facilitated "dubious science, non-science, and even pseudoscience to take root and flourish in many quarters" (Lilienfeld, 2010, p. 282).

Another pertinent point is that not all areas of psychology adhere to strict methodological stipulations and are actually opposed to the idea of psychology being a science. For example, the humanistic psychology movement, which developed in the 1950s and 1960s partly as a reaction to psychoanalysis and behaviourism, emphasises the importance of an individual's subjective way of thinking and personal perception (Elkins, 2008). For humanist psychologists, science has little place in psychology because only by investigating subjective experience can a true understanding of behaviour be realised (Elkins, 2008). Thus, humanists do not support empirical research involving rigorous testing and control and instead champion the precepts of free will, richness of experience and subjective understanding.

Humanists acknowledge the importance of the therapeutic relationship and the focus on an individual's strengths (Elkins, 2008). Prominent supporters of humanistic psychology included Allport, Maslow, and Rogers (Elkins, 2008). Indeed, Carl Rogers developed client-centred therapy and was considered at one point the most influential psychologist in America (Elkins, 2008). Supporters of the humanistic perspective lament the dehumanising and deterministic nature of current psychology and humanism's fall from favour (Elkins, 2008). They point out that despite the dominance of objective and scientific psychology, humanistic ideas permeate mainstream psychology and therapy (Elkins, 2008). It has been argued that mainstream, scientific psychology continues to undermine humanistic psychology and does not acknowledge its contributions to theory and academic literature (Elkins, 2008).


In summary, the extent to which psychology should be considered a science is a complex area of debate. Evidence in support of psychology's scientific nature emphasises the benefits of conducting psychology research in line with the principles of hypothetico-deductivism such as greater control, replicability, and robust statistical analyses. Similar to science, in many areas of psychology objectivity is paramount, whilst subjectivity is frowned upon. For example, in the behaviourism and cognitive disciplines empirical research and the control of variables are highly important. Furthermore, some psychologists argue that psychology as a whole should be scientific and can be improved by following scientific principles (Lilienfeld, 2010). On the other hand, there are pitfalls to examining complex psychological processes in a scientific way such as difficulties with generalising findings to different populations, the practical impossibility of maintaining true control over all extraneous variables, and issues with conducting double-blind experiments.

In addition, it could be argued that psychology cannot be considered a science when confirmation bias remains so rampant in the field (Lilienfeld, 2010). Naturally, humanistic psychologists approach the debate from a different standpoint and wholly reject psychology as a science. They posit that mainstream psychology's emphasis on laboratory experiments and objectivity has come at the cost of truly understanding individual experience and free will. Therefore, humanistic psychologists do not believe that psychology benefits from being (or trying to be) a science; rather psychologists should try to understand human behaviour from the perspective of the individual (Elkins, 2008). Consequently, it seems that psychology can be considered a science to a large extent. Nonetheless, its focus on the processes of the mind and behaviour means that it should not ignore potentially valuable, yet subjective, areas of investigation. However, one views psychology as a subject it is likely that its scientific identity will continue to cause controversy.


Costall, A., (2006) 'Introspectionism' and the mythical origins of scientific psychology. Consciousness and Cognition, vol. 15, no. 4, pp. 634-654.

Danziger, K., (2013) Psychology and its history. Theory & Psychology, vol.23, no. 6, pp. 829-839.

Elkins, D. N., (2008) Why humanistic psychology lost its power and influence in American psychology: Implications for advancing humanistic psychology. Journal of Humanistic Psychology, vol. 49, no. 3, pp. 267-291.

Gardner, H., (2008)The Mind's New Science: A History of the Cognitive Revolution. New York: Basic Books.

Haig, B. D., (2005) An abductive theory of scientific method. Psychological Methods, vol. 10, no. 4, pp. 371-388.

Henriques, G. R., (2004) Psychology defined.Journal of Clinical Psychology, vol. 60, no. 12, pp. 1207-1221.

Hjørland, B., (2005) Empiricism, rationalism and positivism in library and information science. Journal of Documentation,vol. 61, no. 1, pp. 130-155.

Lilienfeld, S. O., (2010) Can psychology become a science? Personality and Individual Differences, vol. 49, no. 4, pp. 281-288.

Lindberg, D. C., (2010) The Beginnings of Western Science: The European Scientific Tradition in Philosophical, Religious, and Institutional Context, Prehistory to AD 1450. Chicago: University of Chicago Press.

Moore, J., (2011) Philosophy of science, with special consideration given to behaviorism as the philosophy of the science of behavior. Psychological Record, vol.60, no. 1, pp. 132-136.

Padoa-Schioppa, C., (2008) The syllogism of neuro-economics. Economics and Philosophy, vol. 24, no. 3, pp. 449-457.

Skinner, B. F., (1971) Beyond Freedom and Dignity. New York: Bantam.

Zittoun, T., Gillespie, A., and Cornish, F., (2009) Fragmentation or differentiation: Questioning the crisis in psychology. Integrative Psychological and Behavioral Science, vol. 43, no. 2, pp. 104-115.