experiments Flashcards
what is a laboratory experiment?
a laboratory experiment is a controlled experiment. the laboratory is an artificial environment in which the scientist can control different variables. the researcher first takes a set of subject (things or people on whom the experiment will be conducted). these must be identical in all respects. they are then divided into two random groups:
- an experimental group
- an a control group.
the conditions of both groups are measured before and after the experiment. if we detect a change we can conclude that it was caused by the different treatment of the two groups
whats the experimental group?
with this group, we might vary the quantity of nutrients that they received, carefully measuring and recording any changes in the plants size that we observe
whats the control group?
with this group, we would keep the quantity of nutrients constant, also measuring and recording any changes in the size of the plants
the lab experiment in scientific terms
the logic of the experimental method is that the scientist manipulates the variables in which they are intrested in, in order to discover what effects they will have. by following this method scientists can establish a cause and effect relationship. once an experiment has been completed others can replicate it. the laboratory experiment is therefore seen highly reliable.
reliability of lab experiments
- other scientists can replicate it and can repeat it in exactly every detail. therefore highly reliable, producing the same results each time. there are two reasons for this:
- the original experimenter can specify precisely what steps were followed in the original experiment.
- it is a very detached method: the researcher merely manipulates the variables and records the results.
advantages of lab experiments
has major advantages as the method used to identify cause and effect relationships in the natural sciences. for this reason, we might expect positivist sociologists to use laboratory experiments, since they favour a scientific approach. however, there are reasons why this method is rarely used.
practical issues of lab experiments
- open systems - people such as keat say that society is an open system and therefore not suitable like physics and chemistry to lab experiements. society is an open system which as countless factors that interact with each other in complex ways.
- individuals are complex - it is not really possible to match the members of the control and experimental groups exactly. while we can find identical samples of chemicals, not two human beings are the exactly the same
- studying the past - lab experiments cannot be used to study an event in the past since we cannot control variables that were acting in the past. not can we keep people in lab conditions for long periods so we can study them.
- small samples - lab experiments can only study small samples are not sutiable for large scale phenomena
- hawthorne effect - a lab experiment is an artificial environment and any behaviour that occurs in it may also be artifical. if participants know that they are being experimented on they may act differently.
ethical issues of lab experiments
- lack of informed consent - as a general principle, the researcher needs the informed consent of the research participants. however, this may be difficult to obtain from groups such as children or people with learning difficulties who may be unable to understand the nature and purpose of the experiment
- deception - it is also generally considered wrong to mislead people as to the nature of the experiment, as milgram did in his famous studies of obedience to the purpose of the research.
- harm - the experiment may also harm the participants.
the hawthrone effect
a lab is not a normal or natural environment. it is likely that any behaviour in these conditions is also unnatural or artificial. if people do not behave in true to life ways, the experiment will not produce valid results
-if people know that they are being studied, they may behave differently, for example by trying to second guess what the researcher wants them to do and acting accordingly. this will ruin the experiment.
free will - lab
interprevists argue that human beings are fundamentally different from plants, rocks and other natural phenomena studied by natural scientists.unlike these objects they have free will and choice. our actions can only be understood in terms of the choices we freely male on the basis of the meanings we give to events
- for intervetivists therefore the lab method with its search for causes is a fundamentally inaporopriate method for studying human beings
theoretical issues of lab experiments
- positivists favour experiments in principle because of their reliability
reliability - a reliable method is one that can be replicated. postivists see this as important because it enables you to check the work of other researchers by repeating it.
postitivits favour lab experiments for three reasons:
1. the original expreimenter can control the conditions and specify the precise steps needs to repeat it
2. it produces quantitive data that can be compared to the original
3. it is detached and objective metho
field experiments
a field experiment has two features that distinguish it from a lab experiment:
- it takes place in the subjects natural surroundings rather than in an artificial laboratory environment
- those involved are generally not aware that they are the subjects of an experiment, in which case there is mo hawthorne effect.
the researcher mainpulates one or more variables to see what effect this has on people (rosenthal and jacobsons work on labelling)
critics of field experiments
some critics argue that field experiments are unethical, since they involve carrying out an experiment on their subjects without their knowledge or consent
example of an field experiment - noons research
- sent out application forms for jobs using the same details apart from changing the ethnicty and last names of the supposed applicants and found that the white applicant was more likely to be offered the job in most cases.
the comparative method
unlike other experiments, the comparative method is carried out only in the mind of the sociologist. it is a ‘thought experiment’ and it does not involve the researcher actually experimenting on real people at all. however, like lab and field experiments, it is too designed to discover cause and effect relationships. it works as:
step 1: identity two groups of people that are alike in all major respects except for the one variable we are intrested in
step 2: then compare the two groups to see if this one differnece between them has any effect
