- We've covered a number of the topics within research methods already in our GCSE psychology research methods content since there is significant overlap between GCSE and A-level. This section will look to cover both AS and A level psychology content for research methods.
The Experimental Method
The AQA AS/A level psychology specification states you need to know the following for research methods:
- Experimental method. Types of experiment, laboratory and field experiments; natural and quasi-experiments.
The experimental method is a scientific method that involves the manipulation of variables to determine cause and effect.
Participants are usually randomly allocated without bias to different testing groups which results in the groups being fairly similar. The procedures within the experiment should also be standardised, which means they are kept the same for all participants.
Within the experiment, the researcher will manipulate an independent variable (IV) to see if this has an effect on the dependent variable (DV). For example, the consumption of a stimulant such as coffee (IV) may be manipulated to see its effect on reaction time (DV).
Within an experiment, variables need to be operationalised so they can be manipulated and measure the effect. Some variables are more difficult to operationalise and in turn only allow one aspect of a variable to be measured. Without the ability to operationalise variables, the results will be unreliable and impossible to replicate to determine their validity.
Types of Experiment
Research methods for A level psychology identifies 4 different types of experiments we need to know about which are:
- Laboratory experiments,
- Field experiments,
- Natural experiments
We've covered many of these already in our GCSE psychology content which we have linked to at the beginning of this chapter (scroll to the top, in yellow) but for ease of use, we've copied over the main elements.
"Laboratory experiments are experiments that are conducted in a controlled setting, usually a research laboratory where participants are aware of being observed and part of a study.
Laboratory experiments tend to have high internal validity because researchers can control all the variables so the main differences between the experimental condition and control group are only the independent variable whose effect is being monitored. This allows researchers to more confidently assume that any differences between the conditions are due to the independent variable."
A field experiment is conducted in a more natural or everyday environment, unlike the laboratory experiment where the behaviour being measured is more likely to occur.
The field experiment can be conducted anywhere in real-world settings with researchers manipulating an independent variable to measure its impact on the dependent variable. A field experiment can include confederates that participants are unaware of also being involved to test their response in the field setting.
One key difference between a field experiment compared to a laboratory experiment, are participants may not be aware of being observed or studied. This is in an attempt to generate more realistic behaviour or responses from them that can generalise to real-world settings.
"A natural experiment is conducted when ethical or practical reasons to manipulate an independent variable (IV) are not possible. It is therefore said that the IV occurs 'naturally'.
The dependent variable (DV), may however, be tested in a laboratory, for example, the effects of institutionalisation in some form, which may occur naturally due to imprisonment or disruption of attachment through the care system and how it may affect psychological development such as intellect or emotional development.
Another good example of a natural experiment is the study by Charlton et al. (2000) which measured the effects of television. Prior to 1995, the people of St. Helena, a small island in the Atlantic had no access to TV however it's arrival gave the researchers to examine how exposure to western programmes may influence their behaviour. The IV in this case was the introduction of TV which was not controlled by researchers and something they took advantage of would be practically difficult to control. The DV was measures of pro or anti-social behaviours that were assessed through the use of questionnaires, observations and psychological tests.
These types of experiments would either impractical or unethical to implement and therefore cases where this occurs naturally due to normal circumstances may be examined through natural experiments."
In quasi-experiments, the independent variable (IV) is naturally occurring, similar to a natural experiment, however, the dependent variable (DV) may be measured in a laboratory. The key feature of a quasi-experiment is that the IV has not been created by anyone. An example where an IV might be occurring naturally would be a study of gender where males and females are compared.
Quasi-experiments are often used when it might be unethical to manipulate an IV and a common feature of such experiments is that random allocation of participants is not possible.
Strengths and Weaknesses of Quasi-Experiments
- A weaknesses of quasi-experiments is randomisation is not used with the samples. This limits the study's ability to draw a causal association between cause and effect but also rule out confounding variables which are more likely to occur. This would make results less reliable and difficult to replicate due to the lack of control over the IV.
- Another issue with quasi-experiments using non-random samples is this increases the possibility of having groups that are not comparable due to significant differences in the samples. This means the results may be due to these significant differences rather than the IV that is being measured which would mean study's lack internal validity and may not be measuring what they intended to.
- A strength of quasi-experiments is it allows researchers to test a naturally occurring IV that may be unethical to test in the context of an experiment. This avoids ethical issues that would prevent such an experiment from taking place.
- Another strength of quasi-experiments is they can be argued to be more realistic and have ecological validity as they look to test something that is naturally occurring. Therefore, the behaviours observed should also be more realistic and have validity.
The AQA AS/A level psychology specification states you need to know the following for research methods:
- Observational techniques. Types of observation: naturalistic and controlled observation; covert and overt observation; participant and non-participant observation.
During observational study, a researcher will watch or listen to participants engaging in whatever behaviour is being studied and record these observations. An important aspect of observations is they are often used in an experiment as a way to measure the dependent variable. Therefore, observations are less of a research method and more of a technique that is used in conjunction with other research methods.
There are different types of observational techniques that are used which we will explore.
Naturalistic and Controlled Observations
In a naturalistic observation, behaviour is studied in a natural situation where everything has been left as it would be normally without interference from the researcher. Examples of naturalistic observations might include children playing in their normal environment i.e. a nursery or an animal being observed in an environment that is natural to them such as a zoo (if raised in captivity) or the wild.
During such observations, researchers will normally take great care to not to intrude or interfere with the behaviour they are observing to ensure the behaviour is realistic.
Controlled observations involve variables in the environment being altered by the researcher which would reduce the 'naturalness' of the environment. This could therefore alter the naturalness of the behaviour being studied too. Participants are also more likely to be aware of being observed as the study may be conducted in a laboratory setting.
Controlled observations allow researchers to investigate the effects of one variable on another more directly (the IV on the DV) and also allows researchers to randomly assign participants to different groups for comparison.
Evaluating Naturalistic and Controlled Observations
- A strength of naturalistic observations is the behaviour observed is more realistic as it occurs in a natural habitat and therefore the findings are seen to be more valid and applicable to generalisation. Further strengths of naturalistic observation includes the ability to study something that may be unethical or difficult to setup as the independent variable is naturally occurring. For example, observing animals in their natural habitat would be difficult to setup in an artificial setting, or predatory behaviour animals engage in that might be deemed unethical to recreate.
- Weaknesses of naturalistic observation include the inability to manipulate variables which makes it difficult to establish causal relationships with certainty. As researchers are unable to isolate an independent variable on its own with naturalistic observations, it is possible that the dependent variable observed may be a consequence of other confounding variables that haven't been controlled for.
- Another weakness is the information gathered may be subjective and based on the researchers own interpretations and observer biases. As the study lacks control to isolate the independent variable, the researcher observes the behaviour and makes recording, sometimes against defined criteria. An issue with this is, it may still be subject to interpretations, mistakes and biases.
- A strength of controlled observations is they give researchers the ability to isolate an independent variable more directly through laboratory settings. This greater control allows researchers to measure how the IV affects the DV with greater certainty and limit extraneous variables from influencing the results.
- A weakness of controlled observations is they are less realistic and lack ecological validity due to the artificial setting which is normally a laboratory setting. This means the behaviour by participants may not be indicative of real world behaviour as the nature of the experiment is artificially setup.
- Another issue with controlled observations is the risk of demand characteristics. Observers are aware they are being observed and may engage in behaviour that either looks to please researchers and their expectations or be different to what would normally happen in the real world. Due to this, the results collected may not generalise to real world behaviour and be invalid.
Covert and Overt Observations
Covert observation refers to studies where participants are unaware that they are being observed by researchers. This might involve naturalistic experiments conducted in everyday environments for participants or animals.
Overt observation refers to studies where participants are aware they are being observed. This usually involved a controlled environment such as a laboratory setting.
Participant and Non-Participant Observation
Participant observation involves the observers/researchers becoming actively involved in the situation being studied to gain a more 'hands-on' perspective. An example of participant observation would be Milgram's Obedience study.
Non-participant observation means observers/researchers will not become actively involved in the behaviour being studied. An example of this would be Ainsworth's Strange Situation study.
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