How Science Works Learning Approach

For this section you need to be able to: a Describe and evaluate observation as a research method in psychology. b Identify, describe and apply the terms participant, nonparticipant, overt, covert, naturalistic observations c With regard to inferential statistics, identify, describe and apply i levels of measurement ii reasons for choosing a chi-squared (χ2) test, Spearman and Mann-Whitney iii how to compare the observed and critical value(s) to judge significance Note: with regard to inferential tests, no calculations will have to be carried out in the examinations and formulae do not have to be learnt. d Describe and evaluate the laboratory experiment method as it is used in general with human and with animal participants (including details specified for the Cognitive and Biological Approaches). e Describe and assess ethical guidelines for the use of human participants when carrying out psychological research (include details specified for the Social Approach).

All types of research involve some element of observation. It is not just observational studies that use observation. For example, when we use self report measures we observe the responses of the participants, when we carry out experiments we observe the behaviour of our participants and so on.

Observational studies are investigations where the researcher observes a situation and records what happens but does not manipulate an independent variable.

Observational studies therefore tend to be high in ecological validity as there is no intervention and if the observer remains undetected the method avoids problems with demand characteristics.

A main strength of observational studies is that they get to see how participants actually behave rather than what they say they do.

A further strength of observational studies is that they offer ways of studying behaviour when there are ethical problems with manipulating variables. For example there will be less ethical issues with carry out a naturalistic observation of school children compared to carrying out experiments on school children.

Observational studies are also useful as a starting point in research. For example the researchers may be investigating a new area of research in order to produce hypotheses for future investigations such as experiments.

On the other hand observational studies are difficult to replicate.

Observations do not provide information about what participants are thinking or feeling.

There is little or no control of extraneous variables in observational studies therefore we can not make cause and effect statements.

There is also the problem of observer bias with observational studies. This occurs if the observers ‘see’ what they expect to see.

A number of ethical issues can arise with observational studies including problems with a lack of informed consent and invasion of privacy.  However, note that the ethical guidelines state that observational research can take place where those observed could normally be expected to be observed by strangers. Canteen – OK. Toilet cubicles wrong.

Observations can also be very time consuming, require careful preparation and possibly training for the observers.

There are a number of different types of observations including non-participant, participant observations, overt, covert and naturalistic observations.

A non-participant observation is a type of observational study whereby the researcher does not join in with the activity being observed.

A participant observation is a type of observational study where the observer is also a participant in the activity being studied. This type of observation can be useful because it provides more insights about behaviour but does have a problem that the observer may lose some objectivity.

A covert observation is a type of observational study whereby the participants are not fully aware that they are being studied. The researchers may use one-way mirrors. This ensures that the participants are not aware they are being studied.

An overt observation is a type of observational study whereby the participants are aware that they are being studied.

Inferential Statistics

Inferential statistics allow us to make a conclusion related to our hypothesis.  As the name suggests inferential statistics attempt to make an inference about our data.  That is, which hypothesis offers the best explanation for our results?

When we carry out an experiment we have two hypotheses.  A null hypothesis which states that the results will be due to chance, and the experimental (alternate) hypothesis, which predicts that the results are due to the manipulation of the independent variable.

To assess the probability that the results are due to chance an inferential statistical test is used.   Inferential statistics tell us whether the difference between two sets of scores is significant or due to chance.

It is an academic convention that in A level psychology we accept the null hypothesis as the best explanation for out results unless there is a 5% probability (or less) of the results being due to chance.  5% probability is expressed as p<0.05 and if we find that the null hypothesis can be rejected we can be 95% confident of the conclusions.

The correct inferential statistic to use is firstly dependent upon the level of measurement our data is collected; either nominal, ordinal or interval data.

Nominal data are data in separate categories such as number of runners that finished a marathon.

Ordinal data are data that are ordered such as the order of runners that finished the marathon – first, second, third and so on.

Interval data are data that are measured using a public unit of measurement. For example this could be the times in which the runners finished the marathon.

If we have nominal data and we are looking at the differences between scores (such as males and females) the statistical test used is the chi square.  When a chi square is calculated this produces an observed value and if this is larger than the observed value taken from a table the results are said to be significant at the 5% level of significance.

Laboratory Experiments

An experiment is a research method used by psychologists which involves the manipulation of variables in order to discover cause and effect. It differs from non-experimental methods in that it involves the deliberate manipulation of one variable, while trying to keep all other variables constant.

A laboratory is any environment where variables can be well controlled.  Such environments are usually artificial but do not have to resemble a science lab at school.

The variable which is being manipulated by the researcher is called the independent variable and the dependent variable is the change in behaviour measured by the researcher.

All other variables which might affect the results and therefore give us a false set of results are called confounding variables (also referred to as random variables).

By changing one variable (the independent variable) while measuring another (the dependent variable) while we control all others, as far as possible, then the experimental method allows us to draw conclusions with far more certainty than any non-experimental method. If the independent variable is the only thing that is changed then it must be responsible for any change in the dependent variable.

Laboratory experiments allow for precise control of variables. The purpose of control is to enable the experimenter to isolate the one key variable which has been selected (the independent variable), in order to observe its effect on some other variable (the dependent variable); control is intended to allow us to conclude that it is the independent variable, and nothing else, which is influencing the dependent variable.

However, it must also be noted that it is not always possible to completely control all variables. There may be other variables at work which the experimenter is unaware of.

A confounding variable is a variable which has an unintentional effect on the dependent variable.  When carrying out experiments we attempt to control extraneous variables, however there is always the possibility that one of these variables is not controlled and if this affects the dependent variable in a systematic way we call this a confounding variable.

An extraneous variable is a variable which could effect the dependent variable but which is controlled so that it does not become a confounding variable.

It is argued that laboratory experiments allow us to make statements about cause and effect, because unlike non-experimental methods they involve the deliberate manipulation of one variable, while trying to keep all other variables constant. Sometimes the independent variable is thought of as the cause and the dependent variable as the effect.

Furthermore, experiments can usually be easily replicated. The experimental method consists of standardised procedures and measures which allow it to be easily repeated.

However laboratory experiments are not always typical of real life situations. These types of experiments are often conducted in strange and contrived environments in which people are asked to perform unusual or even bizarre tasks. The artificiality of the situation, together with the ‘unnatural’ things that the participants may be asked to do, jointly produces a distortion of behaviour. Therefore, it should be difficult to generalise findings from experiments because they are not usually ecologically valid (true to real life).

A further difficulty with the experimental method is demand characteristics. Demand characteristics are all the cues which convey to the participant the purpose of the experiment.   If a participant knows they are in an experiment they may seek cues about how they think they are expected to behave.

Another problem with the experimental method concerns ethics. For example, experiments nearly always involve deceiving participants to some extent and it is important to recognise that there are very many areas of human life which cannot be studied using the experimental method because it would be simply too unethical to do so.

Ethics are a set of guidelines which psychologists carrying out research should follow.  According to the ethical guidelines participants should be protected. That is, the experimenters should avoid psychological harm such as embarrassment, a loss of self esteem and changing a person.

Participants should not experience any greater risks than they would encounter in their everyday lives.  It is recommended that participants in experiments are effectively debriefed and that the participants are clear that they can withdraw from the study at any time.

In the learning approach animals, are used to study the mechanisms of learning, sometimes it is more advantageous to use animals instead of humans. For instance it is easier to isolate the stimulus and measure a response when using animals, and many ethical considerations are also reduced.

Ethics are a set of guidelines which psychologists carrying out research should follow.

The following list includes a summary of the ethical criteria proposed by the British Psychological Society for the conduct of research.

The British Psychological Society issued revised ethical principles in June 1990. In the conduct of their research, psychologists should always consider the following;

Consent; Have the subjects of the study made an informed consent to take part? Have the parents of child subjects given informed consent to the research procedures? Have payments been used to induce risk taking behaviour?

Deception; Have the subjects been deceived? Was there any other way to carry out the study other than by using deception? Have the procedures been approved by other psychologists?

Debriefing; Have the subjects been effectively debriefed? Has any stress caused by the procedures been removed?

Withdrawal from the investigation; Are the subjects clear that they can withdraw from the study at any time without penalty or scorn?

Confidentiality; Participants in psychological research have the right to expect that information they provide will be treated confidentially.

Protection of participants; Investigators must protect participants from physical and mental harm during the investigation.

Observational research; Unless the participants give the consent to being observed, observational research must only take place where those observed could normally be expected to be observed by strangers.

Giving advice; Psychological advice must only be given if the psychologist is qualified in the area that the advice is requested in.

Colleagues; Psychologists should take action if they believe that any of the above principles are being violated by a colleague.