experiments Flashcards
(41 cards)
- Laboratory experiments
- most scientific method researcher can use - tightly controlled - artificial environment - to see if one variable has an impact on another variable (in/dependant)- experimental group vs control group
Lab exp - example
An example will help us illustrate the basic principle of the experimental methods. If we want to discover what causes plants to grow, one way would be to take a set of identical plants and randomly divide them into two groups - an experimental and control group - we then treat them differently
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
Control group
We would keep the quantity of nutrients constant, also measuring and recording any changes in the size of the plants
Evaluation - lab exp example
On comparing results, we notice the plants in the experimental group have grown more rapidly than the plants in the control group after receiving extra nutrients - may have discovered a cause and effect relationship
Logic of experimental method
The scientist manipulates (alters) the variables in which they are interested in order to discover what affect they have - by following this method, the scientist can establish a cause and effect relationship which will allow them to predict accurately what will happen in the future under specific conditions
Reliability - lab exp
- experiments can be replicated exactly again - should produce the same results every time - scientists personal feelings / opinions have no impact on the results or outcomes - followed by positivist sociologists
Practical issues - lab exp
- Open systems - lab exp are only suitable for studying closed systems. Society is an open system (lots of variables at work) so it’s impossible for researchers to identify, or control, all of them. Lab exp are not useful in studying social phenomena 2. Studying the past - lab exp can’t be used to study the past 3. Small samples - lab exp are small samples so hard to investigate large scale phenomena 4. Hawthorne effect 5. Expectancy effect - form of experimenter bias, what a researcher expects to happen can influence the outcome
Ethical issues - lab exp
- Informed consent - gaining the subjects consent means informing them of all the details of the experiment. This can be self deflecting and therefore subjects must be deceived so they do not act differently 2. Harm to subjects - some argue that minor or temporary harm may be justified ethically if the results yield significant social benefit and if the experimental group are gaining from the treatment they’re receiving, treatment should be made available to the control group 3. The Milgram experiment is a good example of this
Theoretical issues - lab exp
Positivists favour lab experiments due to reliability. However they have important limitations. Interpretivists would go as far as to argue that lab experiments lack validity
Reliability and hypothesis testing
Positivists say lab experiments are highly reliable as results can be tested over and over again - experimenter can control conditions - produces quantitive data - detached and objective method
Representativeness - lab exp
Positivists see representativeness as important - aim to make generalisations about wider social structure shaping individuals behaviour
External validity - lab exp
Cannot be sure they are reflective of wider population 1. Small samples - greater risk of not being representative of cross section / findings cannot be generalised2. Lack of external validity due to high level of control / high level of control = less like the world outside of lab
Internal validity - lab exp
Findings may not be the truth for the subjects of experiment. Artificiality of the lab may encourage Hawthorne Effect. Subjects react to being studied and change their behaviour thus invalid results are produced
Interpretivism and free will
Humans are fundamentally different to subjects studied by natural scientists. Humans have free will and choice. Behaviour is not caused by external factors, so cannot be explored in terms of cause and effect statements. Actions can only be understood by the choices we make based on the meanings we give to events
Lab exp
Fundamentally inappropriate method to study humans
Methods in context links - lab exp
How experiments can be used to study issues in education - teacher expectations - class room interaction - labelling - pupils self fulfilling prophecy - self concept
Lab experiments and teacher expectations
- Harvey and Slatin - Charkin et Al - Mason
Harvey and Slatin
Used a sample of 96 teachers. Each teacher was shown 18 photos of children from different social class backgrounds - to control other variables, the photographs were equally divided in terms of gender and ethnicity - teachers were asked to rate the children on their performance, parental attitudes to education and aspirations - found that lower class children were less rated favourably - teachers based their ratings on the similarity of the photos and students they have taught - study indicates that teachers label pupils from different social classes and use these to pre judge pupils potential
Charkin
Used a sample of 48 uni students who taught a lesson to a 10 year old boy - high expectancy group were told the boy was highly motivated and intelligent / the low expectancy group were told he was poorly motivated with low IQ / rest were given no information - videoed the lessons and found those in high exp group made more eye contact and gave more encouragement than low exp group
Mason
Looked at whether negative or positive expectations had the greater effect - teachers were given positive, negative or neutral reports on a pupil. The teachers then observed video recordings of the pupil taking a test, watching to see if any arrows were made - they were asked to predict the pupils end of year attainment - he found that the negative reports had much greater impact than positive ones on the teachers expectations
Practical issues - lab exp
- schools are large institutions that have many variables that may affect teachers expectations - expectations may be influenced by other things such as class size, streaming or type of school - impossible to identify and control all the variables that might influence teachers expectations - large scale social factors cannot be studied in small scale lab settings
Artificiality - lab exp
Lab exp are artificial - Charkin ; used uni students not real teachers - Harvey and Slatin - used photos rather than real students
Ethical issues - lab exp
Those that do not involve real pupils have fewer ethical issues - Mason / H + S ; no use of real pupils - Charkin ; used real pupils