Debates in Psychology: Psychology and Science


Describe the debate over what science is and how far psychology fits the definition.

Evaluate whether psychology should be called a ‘science’.

Compare the five approaches from units 1 and 2 according to how scientific their content and methods are.

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Psychology and Science 1

There are 5 criteria that can be applied when discussing whether a subject can be considered a science:

1.       The Hypothetico-Deductive Model

2.       Falsification

3.       Reductionism

4.       Paradigm

5.       Subject Matter

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Psychology and Science 2

The Hypothetico-Deductive Model

Karl Popper, a philosopher of science argued that the scientific method starts out with an idea about the world, a theory. That then, leads to a suggestion about what might happen under certain circumstances, a hypothesis.  This is then tested against reality, empirical data, to see if it works. If it does, more knowledge is added to the theory, if it doesn’t the theory is then amended or even discarded. This model is circular, with new data from research adding to and refining the theory.


If a subject uses this method of investigation, it can be considered a science.

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Psychology and Science 3


Popper also introduced the idea of falsification. Popper thought that nothing can be proven. A theory can be supported by evidence e.g. “all swans are white” is generally supported by observation. However, you cannot find all of the swans in the world and prove that all swans are white.

This means that theories can only be falsified e.g. a black swan falsifies the theory that all swans are white. If we continue to see all white swans then we can say the theory is well supported but never say is proven. Popper thought that to qualify as a science a subject had to develop theories that are able to be falsified if they are incorrect. If a theory can be tested and shown to be incorrect then it should be discarded.


If the subject develops theories that cannot be directly tested and falsified then it is not a science.

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Psychology and Science 4


In order to test hypothesis, they must be specific and measurable. Measurement of broad factors is reduced to measuring just one part in order to isolate the factors affecting the variable. This reduction of complex things down to simple parts is central to the scientific method e.g. to understand an organ of the body scientists will study individual cells. In order to understand the brain, smaller sections will be scanned. Variables are ‘narrowed down’ so they can be measured.


For a subject to be considered a science it needs to take a reductionist approach.

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Psychology and Science 5


Thomas Kuhn introduced the paradigm; a common unifying theory and an agreement within the subject about what to study and how. He said that sciences developed through three stages:

1.       Prescience – there are lots of different competing theories and research methods used within the subject.

2.       Normal science – there is one common paradigm.

3.       Revolutionary science – when one paradigm is being replaced by a new one.


For a subject to be considered a science it needs to have one paradigm.

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Psychology and Science 6

Subject Matter

Another way of defining whether a subject is a science is to look at the subject matter within the subject. There are some areas of study that are clearly ‘scientific’ in that they lend themselves to the methods outlined in the four criteria above. These areas are usually ones studied by subjects such as chemistry and biology such as genes and neurotransmitters. The defining feature of these areas of study is that they can be objectively measured.


For a subject to be considered a science it needs to study measurable subject matter. 

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Psychology and Science 7: How far can Psychology b

Hypothetico-Deductive Model

Psychology uses this method a great deal. For example, the Levels of Processing Theory leads to the hypothesis that participants will remember more words processed by meaning that by appearance. This can be tested by experiments and the results will strengthen the theory. In this respect psychology builds up a body of knowledge in a scientific way.

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Psychology and Science 8: How far can Psychology b


Some theories are falsifiable. For example, the Social Identity Theory predicts that people will be negative towards the out-group. If this does not happen the theory is falsified. (In psychology this may have to be done many times to check reliability).

Freud’s theory about id, ego and superego is impossible to falsify as it is not possible to show they are not there so not all psychology is scientific.

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Psychology and Science 9: How far can Psychology b


To use the Hypothetico-Deductive method a hypothesis must be specific and measurable. Many aspects of psychology are studied in this way, for example, a Learning Approach psychologist might measure stimulus-response learning.

The Psychodynamic Approach takes a more holistic view and uses the in-depth case study approach. As not all psychology is reductionist it is not all scientific.

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Psychology and Science 10: How far can Psychology


Psychology has many paradigms- all the main five approaches could be seen as having a separate paradigm and use different research methods so according to Kuhn’s criteria, psychology is still at the pre-science stage.

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Psychology and Science 11: How far can Psychology

Subject Matter

Some aspects of psychology are clearly scientific, for example, DNA, hormones, neurotransmitters and animal experiments. Other aspects are not easy to measure in an objective way, for example, emotions, opinion or the unconscious mind. In this respect some of psychology fits the criteria for a science and some does not.

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Psychology and Science 12: Should Psychology be a

Some argue that as research continues it will lead to a single paradigm emerging with methods that are objective and replicable.

Others argue that humans are so complex that they can never be studied in a truly objective way and with all the different approaches to psychology there will never be one single paradigm.

Many psychologists who take a more holistic approach argue that psychology should make no attempt to be a science. Using methods that are replicable and objective would lead to loss of validity.

They also argue that many aspects of humans will never lend themselves to this approach and we should study individuals in-depth to find out more about the human experience.  

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Psychology and Science 13: The Social Approach

Milgram used experimental methods as did Hofling et al (1966). Tajfel et al used laboratory experiments and Sherif used field experiments. When looking at behaviour, field experiments are a popular research method (e.g. Piliavin). Even when surveys are carried out (e.g. Adorno), questions are piloted and care is taken to gather at least some quantitative data. There are hypothesis and there is empirical testing.

Social psychology tends to be seen as non-scientific. However, there are elements of science such as in suggesting that societies evolved to have agents and followers (Agency Theory). Evolution Theory is part of science.

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Psychology and Science 14: The Cognitive Approach

Cognitive Psychology follows scientific research methods, including laboratory experiments, scanning and brain imaging. Craik and Tulving carried out a laboratory experiment with careful controls and Godden and Badderly carried out a well- controlled field experiment. There are hypotheses, empirical testing, and statistical testing with regard to the results.

Cognitive Psychology does contain biological principles. Memory and forgetting, for example, are about information processing, and, when considered in more depth, can involve scanning the brain and considering neuroscience.

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Psychology and Science 15: The Psychodynamic Appro

The Psychodynamic Approach is the least scientific because it focuses on case studies and unique research methods such as dream analysis and free association. Qualitative data is gathered, not quantitative data, and far from having controls over their behaviour, participants are required to generate data freely without control. There are no hypotheses to test using empirical data, more that data drives the analysis. Freud hoped to build a scientific theory so he made sure he could give examples and evidence for all his claims. For example, in the Little Hans study he only took notice of what Hans’ father said that had come directly from Hans, and he checked back with Hans where possible to see if his analysis was appropriate. However, the Oedipus Complex, unconscious, ego and id, are not measurable or testable, so the psychodynamic approach is seen as non-scientific. This, however, does not in itself make its conclusions wrong.

The Psychodynamic approach studies the unconscious and its power over conscious thoughts. As the unconscious is not empirically measurable, the subject matter of psychodynamic approach is not scientific – though Freud does talk about energy and instincts, which are biological aspects of the person.

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Psychology and Science 16: The Biological Approach

The Biological Approach uses laboratory experiments, PET scans, MRI scanning and uses EEG measurements. Hypotheses are rigorously set up, with clearly operationalized variables and empirical testing takes place to confirm or amend them.

The Biological Approach is clearly scientific, as it includes things like genes, hormones, brain lateralisation and synaptic functioning.

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Psychology and Science 17: The Learning Approach

Scientific research methods such as laboratory experiments and using animals were adopted from the start, with the aim of making the study of behaviour scientific. It was the Social Learning Theory that started to move away from such a strong scientific background, although, Bandura began with carefully planned experiments. He later considered motivation and memory, which are aspects of thinking. When he moved to look at such issues such as self-efficacy, which involves considering how far our feelings about being able to succeed affect our performance, the research methods and subject matter began to be less successful.

Learning Approach is behaviour, and only measurable and observable behaviour is considered in a bid to make the approach scientific. Particularly at first, the approached focused on stimulus and response – both of which can be observed and tested. By reducing behaviour to separate parts for study – such as a rat pressing a lever to get a reward of food – the subject matter was deemed to be scientific.

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Psychology and Science 18

Except for the psychodynamic approach, scientific methods are used as far as possible. Hypotheses are generated, empirical testing takes place and statistical testing is used to see how far any findings might be due to chance.

With regard to subject matter in general, social and psychodynamic psychology are thought to be the least scientific – at least to some extent – in that they look at brain and behaviour.

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