Features of Science (AQA A Level Psychology)

Theory construction & hypothesis testing

Theory Construction

• A theory is a set of principles that intend to explain certain behaviours or events e.g.

  • Social learning theory proposes that children learn via observation of role models

  • Localisation of function is the theory that specific brain regions/structures control or are specialised to different functions, e.g. the hippocampus and memory

• A theory can be constructed using empirical evidence gathered via research to support its central assumptions and principles as a theory cannot exist based on beliefs alone e.g.

  • Bandura (1961) designed a controlled observation in which children were exposed to an aggressive or a non-aggressive role model; the children were then tested for imitative acts of aggression

  • Maguire et al. (2000) used MRI scans to determine the volume of grey matter in taxi drivers' brains and found that spatial navigation may be localised to the posterior hippocampus

Hypothesis Testing

• A hypothesis is a prediction of what the researcher expects to find after conducting their research

  • A hypothesis must be objective and measurable e.g. "There will be a difference in the levels of aggression shown by children depending on whether they have been exposed to an aggressive model or a non-aggressive model"

• The study is then conducted following the hypothesis, i.e. what is the central focus of the study and how will the independent variable (IV) and dependent variable (DV) be operationalised in the study?

• When the study's findings have been analysed, a  clear decision can be made as to whether the null hypothesis can be accepted or rejected

  • If the null hypothesis can be rejected then the theory is strengthened as it means that the IV has affected the DV (a significant result)

The empirical method

• The empirical method involves using scientific methods to collect data (quantitative data only) in ways which are controlled by the researcher and which are replicable

• Empirical methods test hypotheses using methods gained from direct observation in a systematic way e.g.

  • Lab experiments are hypothetico-deductive as they involve:

    • controlled conditions

    • the manipulation of an IV

    • a replicable procedure

    • the generation of quantitative data that is easy to compare and analyse

  • The observational method is empirical as it is based on direct observation of behaviour as proposed by the behaviourists e.g.

    • Pavlov's original research into classical conditioning

    • Watson & Rayner's (1920) systematic conditioning of a phobia in an infant ('Little Albert')

• Methods which depend on individual subjective experience could not claim to be empirical e.g.

  • interviews depend on first-person narratives involving opinions, attitudes, feelings etc.

  • case studies generally use a range of qualitative methods such as interviews, and naturalistic observations in which there is no attempt to exert control on the procedure

Paradigms & paradigm shifts

• A paradigm is a set of shared assumptions and methods within a particular discipline which distinguishes science from non‐science (Kuhn 1962)

• Psychology is thus viewed as a pre‐science, (physics, biology and chemistry are science) as it has too much disparity between its various approaches (e.g. cognitive versus biological) e.g.

  • the cognitive approach argues that depression is the result of faulty thought processes

  • the biological approach argues that depression is the result of a neurochemical imbalance

Paradigm shifts

• A paradigm shift occurs when a field of study moves forward through a scientific revolution, generally when one or more scientists challenge an existing, accepted paradigm, which may, initially be ridiculed by the scientific community

• As time passes these new, revolutionary ideas gain traction as more scientists begin to challenge the old theory, adding more research to contradict the existing  assumptions

• A crucial point occurs at which the old paradigm is discarded for the new paradigm

Examples of paradigms and paradigm shifts in psychology

• Psychoanalytic theory (popularised by Freud) prevailed from the late nineteenth century and was at the forefront of  psychological thinking until behaviourism (around 1913) proposed the idea that all behaviour is learned from the environment

• The cognitive approach took over in the 1950s with its emphasis on mental processes and machine reductionism

Replicability

• Replicability refers to a piece of research which could be carried out again by the same or another researcher and which would be likely to show consistent results

  • This helps to increase the validity of the findings as they show that the IV has affected the DV

  • It also helps to increase the possibility of generalising the findings as the procedure can be repeated in different settings and with different samples

• Replicability is only possible if the original research has been designed in a way in which variables are controlled and there is great attention to detail in the design i.e. the procedure is unambiguous and precise

• The use of a standardised procedure is one way to ensure replicability as it eliminates sources of bias as all participants experience the same treatment per condition e.g.

  • Peterson & Peterson (1959) tested each participant over eight trials, using the same trigrams and 3-digit numbers in each trial

• Methods which generate qualitative data do not lend themselves to replicability e.g.

  • a case study based on one individual is not replicable as the data generated from it will only apply to that individual

  • an unstructured interview follows no set plan or outline which means that participant response will be different every time

Objectivity

• Objectivity involves using scientific methods to collect data (quantitative data only) in ways which are controlled by the researcher and which are objective

  • By doing so it is possible to obtain empirical evidence

• For a method to be objective it must strive to keep any personal, subjective or partial features or elements out of the research process

• Hypothetico-deductive methods are high in objectivity as they:

  • establish a controlled, neutral space in which to conduct research

  • involve the manipulation of an IV

  • involve a replicable procedure

  • generate quantitative data that is easy to compare and analyse

• Objectivity must be maintained while the procedure is being conducted

  • Researchers must strive to be neutral and professional with participants

  • Researchers must ensure that they do not indicate to participants what they expect to find as a result of the research

• Objectivity must be maintained when research findings are being analysed

  • The researcher must not use any forms of bias when dealing with their findings

  • They should not be swayed by their prejudices or preconceptions when analysing the findings

• Methods which are designed  the using subjective experience of individuals could not claim to be objective e.g. interviews, case studies

Falsifiability

• Falsifiability is the ability of a theory to be found to be wrong (i.e. false)

  • The emphasis is placed on being able to test the theory

    • If the theory is true then it should withstand testing

    • The theories which survive constant and continual testing are therefore the strongest

• Being able to falsify a theory or study means that scientific methods can be used to test it

  • This is why significance testing is based on either rejecting or accepting the null hypothesis as it is the hypothesis that states that there is no effect of the IV on the DV

• Some theories may not be false thus far but this does not mean that they are not false

  • The more these theories are tested and found to withstand the testing then the more scientific they are

• Theories which have been tested repeatedly using controlled methods are falsifiable e.g.

  • experiments on memory (e.g. Peterson & Peterson 1959)

  • localisation of brain function (e.g. Maguire et al., 2000)

• Some theories do not lend themselves to hypothesis-testing and are thus unfalsifiable (which makes them unscientific) e.g

  • psychodynamic theory as this is based on the therapist's subjective interpretations and untestable concepts (e.g. the unconscious mind)

  • the humanistic idea of self-actualisation as this will differ from person to person and has no agreed-upon criteria