research methods- features of science

empirical evidence

scientific evidence obtained by careful observation and experimentation

Paradigms

Paradigms:

• The philosopher Thomas Khun (1962) suggested that what distinguishes scientific principles from non-scientific principles was a shared set of assumptions and methods- a paradigm.

• Natural sciences have a number of principles at their core, e.g. the theory of evolution in biology or the standard model of the universe in physics.

• Psychology has too much disagreement with conflicting approaches to qualify as a science and is therefore a pre-science.

what is a paradigm

a set of shared assumptions and agreed methods within a scientific discipline

paradigm shift

Paradigm shifts:

• According to Kuhn, progress within an established science occurs when there is a scientific revolution. A handful of researchers begin to question the accepted paradigm, this gathers popularity from others, and eventually there is too much evidence to ignore.

• One popular example of a paradigm shift is the transition between the worldview of Newtonian gravity and the Einsteinian General Relativity Theory in 1919.

• Some people have applied the idea of paradigm shifts to Psychology- such as the movement from Wundt's early introspection ideas to the cognitive neuroscience ideas of today.

What is a paradigm shift?

A fundamental change in an accepted view or understanding of a concept

what is a theory

• A theory is a set of general laws or principles that have the ability to explain particular events

or behaviours.

• Scientists use both inductive and deductive methods when constructing theories.

inductive model

1) observation

2) testable hypotheses

3) conduct a study to test hypothesis

4) draw conclusions

5) propose theory

Deductive Model

- most common way of constructing theories

1) observations

2) propose theory

3) testable hypotheses

4) conduct study to test hypothesis

5) draw conclusions

hypothesis testing

Theories are modified through hypothesis testing.

• This is where the validity of theories is tested.

• A good theory must be able to generate testable expectations.

• These expectations are stated in the form of hypotheses.

• If 1 scientist fails to support a hypothesis, then the theory requires modification.

empirical methods - features of science

empirical methods: information is gained through direct experience or observation rather than beliefs or

reasoned argument.

People can make claims about anything- but the only way we can know if they are true is through direct testing- empirical evidenc

objectivity- features of science

Objectivity: an important aspect of empirical data is that it should be objective- not affected by the expectations of the researcher.

In order for data to be objective it should be measurable (operationalised variables) and collected in carefully controlled conditions (e.g. lab experiments).

The opposite of this type of data is subjective and this is not scientific.

Falsifiability - features of science

Falsifiability: Karl Popper (1934) argued that a key characteristic of science was falsifiability- the ability to prove something wrong. Even if a theory has been successfully tested and repeated- it was not necessarily true. It just had not yet been proven to be false.

Scientific theories should be, in principle, able to be proven wrong

replicability- features of science

Replicability: in order to demonstrate the validity of any observation it must be repeated.If the outcome is the same, this confirms the truth of the

original results.

In order to achieve replication,scientists must record their procedures very carefully so that someone can repeat it exactly.

This is different from testing reliability as psychologists in this case will use different people and a slightly different test to check for similarity.

A teacher has worked in the same primary school for two years.While chatting to the children,she is concerned to find that the majority of them come to school without having eaten a healthy breakfast. In her opinion,children who eat 'a decent breakfast' learn to read more quickly and are better behaved than children who do not. She now wants to set up a pre-school breakfast club for the children so that they can all have this beneficial start to the day.The local authority is not willing to spend money on this project purely on the basis of the teacher's opinion and insists on having scientific evidence for the claimed benefits of eating a healthy breakfast.

• Explain why the teacher's personal opinion cannot be accepted as scientific evidence. Refer to some of the major features of science in your answer. (6)

The teacher has not used empirical methods to support her argument. She claims that children who eat a 'decent breakfast' learn better but this is not based on any empirical evidence such as results from an experiment.

The teacher's idea is based on her own subjective opinion. Scientific data should be objective and not affected by the researchers own thoughts and opinions.The teacher has not conducted any controlled observations to test whether having a 'decent breakfast' is better making her claims very subjective.

The teacher has only experienced one school and so we can not be certain that these observations would be the same in another school. In order to achieve replicability the teacher would need to devise a carefully controlled procedure to use that could be repeated in other schools to check her claims and findings were valid.

A researcher believed that there is a biological basis to aggression in males. She predicted that there would be a significant difference between the levels of the hormone testosterone in aggressive males and the levels of the hormone testosterone in non-aggressive males. In order to test her prediction, the researcher statistically analysed the levels of testosterone in saliva samples from 20 aggressive males and 20 non-aggressive males.

Outline three ways in which the study described above could be considered to be scientific (3 marks).

The researcher has proposed a theory and then created a testable hypothesis by predicting a significant difference in levels of testosterone in aggressive and non-aggressive males (deductive model).

The researcher is using empirical methods in order to test her prediction by using measurements of testosterone from saliva and comparing these within the two groups.

As the researcher has carefully planned an experiment this means that it can be replicated in order to test the validity of the results.

A psychodynamic psychologist wished to investigate the function of dreams. He asked five friends to keep a 'dream diary' for a week by writing a descriptive account of their dreams as soon as they woke up in the morning. He interpreted the content of their dreams as an expression of their repressed wishes.

Referring to the study above, explain why psychodynamic psychologists have often been criticised for neglecting the rules of the scientific approach (Total 3 marks).

Interpretation of dreams is subjective and can be influenced by the thoughts and opinions of the psychologist, especially as the participants are his friends.

No empirical evidence to support that the dreams actually an expression of repressed wishes. Procedure was not carefully controlled or measureable which affects replicability.