Paragraph 1. Ethical Issues
Definition An ethical issue is a conflict between aims of researcher and the participants experience in a lab experiment.
Point Psycological harm is an issue as participants have been deceived: this is an issue that could appear in lab experiments. This may lead to other issues as they may not want to take part in furthur lab experiments.
Example In Milgrams study, the participants were not protected from harm- the participants showed signs of extreme stress and some even had seizures and uncontrollable laughing fits. Although they were debriefed, the harm might not have been undone.
Extra (A*) This means people may be reluctant to participate in other psychological research due to previous negative experiences in studies. E.G If the 'protection from harm' was broken, participants may suffer from psychological harm after the study, and as a result be put off participating again
Paragraph 2. Population Validity
Definition It is the extent to which results from lab experiemtns can be generalised to other groups of people in the total population.
Explain It is a disadvantage as individual differences are not taken into account when generalising the results of the lab studies.
Example A limitation of population validity in lab experiements was shown in Asch's study of conformity. He only used American male university students: this implies that the results of this study would be difficult to generalise to the rest of the population.
Extra (A*) A consequence of an experiement not having population validity is that it's results may not be credible; findings in one country may not be generalisable to another.
Paragraph 3. Demand characteristics
Definition Participants are often unaware they are taking part in lab experiments. They may then respond to the demand characterisis of the experiment by behaving differently from their natural behavious.
Explain It is wrong to regard the participant in a lab experiment as passively responding to enviomental stimuli and experimental psychology; this can make feelings invalid.
Example For Example in Milgram's experiment there may have been issues with demand characteristics, some participants may have figured out the true aim of the study and realised the electric shots were not genuine. For example, Orne and Holland claimed that the participant's in Milgrams studies were 'going along with the act'.
Extra (A*) Demand characteristics can be a major problem in experiments that alternative methods can be chosen, such as observations. These allow natural behavious to be studied without demand characteristics occuring therefore they are more valid.
Paragraph 4. Extraneous Variables
Definition Extranous variables are variables besides the IV that can effect the DV in a lab experiment.
Explain If extraneous variables are present, cause and effect relationships can't be established- making the resuklts less internally valid in the lab study.
Example In Loftus and Palmers research (the interaction between language and memory) participants were asked to estimate speeds of colliding vehicals, the students' lack of driving experience acted as an extraneous variable because their judgement of speed would have been less accurate than those with driving experience.
Extra (A*) Other methods such as case studies are perhaps more advantageous than lab experiments because there aren't any extraneous variables involved, this is because there is no manipulation of variables The consequence of having extranous varales leads to invalid results.
Paragraph 5. Reductionism (simplifying)
Definition The belief that complex systems can be explained in terms of their components. In lab experiemtns we simplify human behaviour to varialed that are measures.
Explain This is a disadvantage because some behaviours cannot be simplified to certain components. E.g depression cannot be simplified to one specific component.
Example Loftus and Palmer simplified eye witness testimony by manipulating the verbs in the questionnaire in order to measure the participant's estimate of speed in mph therefore simplifying a very complex component.
Extra (A*) Lab experiments are not holistic, meaning they don't take into account peoples individual differences. Where as case studies look in depth at peoples uniquness and collect qualittative data- gaining a deeper insights.
Paragraph 6. Ecological validity
Definition Ecological validity is defined by how much the situation reflects real life. For example, a lab experiment uses an artificial enviroment so it isn't always ecologically valid.
Point This is a disadvantage because lab experiments are in artificial enviroments, so behaviour does not reflect how you would behave in real life (not natural) therefore it's difficult to generealise the results beyond the situation.
Example Asche's lab study measuring conformity lacked ecological validity . The reasons for this are because there was a high control the variables and the study took place in an artificial enviroment. In normal everyday life, conforming is ambiguous but in Asche's study, they measured using an unambiguous task.
Extra (A*) Unlike lab studies, case studies have high ecological validity. Which is an advantage over lab studies: as this means that the behaviour is realisticic and reflects real life.
Paragraph 7. Sampling Bias
Definition A sample which doesn't reflect the population and have been chosen by the researcher in a subjective way in a lab experiment.
Point This is a disadvantage because the participants from the sample are all similar meaning you aren't getting a variety of participants.
Example For example, in Milgram's study, he collected his sample by using the 'volunteering method' where he placed an advert in a news paper. This is a disadvantage as only 20-50 year old American males volunteered, this gave an unrepresentative sample of the target population.
Extra (A*) However there is a sampling technuique named stratified sampling that can provide a representative sample and therefore enables generalisation to the target population.