Experimental methods
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This document discusses experimental methods in psychology. It describes experiments as a quantitative method used to establish cause-and-effect relationships between variables under controlled conditions. An example experiment aims to determine if noise (the independent variable) affects one's ability to recall information (the dependent variable). The variables must be clearly operationalized by describing how they will be measured. The researcher would form a null hypothesis that noise has no effect and an experimental hypothesis that noise decreases recall. Various types of experiments and biases are also discussed.
Experimental methods
- 2. Experiments in Psychology One of the most widely used methods in the study of behavior Goal is to establish a cause and effect relationship between two variables Performed under highly controlled conditions Experiment is an example of quantitative research – it generates numerical data Can be statistically tested to rule out the role of chance in results
- 3. Does noise affect one’s ability to recall information? • Aim of study – will one variable (noise) has an effect on another variable (recall or information) • Independent Variable (IV) – causes a change in another variable, it is manipulated by researcher • Dependent Variable (DV) – variable that is measured after the manipulation of the IV
- 4. Operationalizing Variables • The experiment must be written in a way that it is clear WHAT is being measured. Here, noise is the independent variable – It could be operationalized as high music at volume 35 • The number of words remembered would be the DV – It could be operationalized as words remembered from a list of 20 words
- 5. Apply your Knowledge Operationalize your variables by considering each of the following descriptions and deciding whether it is an example of aggression or not. Write a well-worded definition of aggression. 1. Two men fight over a parking place 2. A football player kicks the ball into the goal 3. Two girls give a boy the “silent treatment” on the playground 4. A man kicks the back of his car when it will not start 5. Three students have a heated debate about whether global warming is happening
- 6. Formalize the aim – Researcher forms an experimental hypothesis • Researcher predicts the relationship between the IV and the DV – what we expect will come out of the manipulation of IV • In this case there will be 2 conditions: – Participants recall words in the quiet – Participants recall words with loud noise the quiet condition is called the CONTROL CONDITION so that we can see if there is a difference
- 7. Make up an experimental hypothesis for this study
- 8. How About Noise will decrease the number of words that an individual is able to recall from a list of words. The IV (noise) is predicted to have an effect on the DV (recall)
- 9. More Kinds of Hypothesis • In Experimental Research you need a NULL HYPOTHESIS and an EXPERIMENTAL HYPOTHESIS • A null hypothesis: Noise has no effect on an individual’s ability to recall a list of words • Remember, you can never prove anything! You can only disprove.
- 10. A researchers goal: • Refute the null hypothesis (that sound makes no difference in recall) • Or accept the null hypothesis • We can accept the experimental hypothesis only if we demonstrate the effect was due to the manipulation of the IV
- 11. Identify the IV and DV in each of the experimental hypothesis: 1. People are more likely to make a risky decision when they are in a group than when they are alone. 2. An increase in carbohydrates decreases one’s ability to concentrate. 3. People will react more quickly to an auditory stimulus than a visual stimulus. 4. Lack of sleep will affect learning new words negatively.
- 12. Kinds of Experiments • Laboratory – Strict control of variables, easy to replicate – Artificial environment, participants may react differently than real life (ecological validity?) • Field – Natural environment (ecological validity) but can’t control all variables • Natural – Researchers have no control over variables. – Naturally occurring, researchers are there to study
- 13. Biases on experiments Demand characteristics is a subtle cue that makes participants aware of what the experimenter expects to find or how participants are expected to behave. Demand characteristics can change the outcome of an experiment because participants will often alter their behavior to conform to the experimenters expectations. use single blind control) • The Hawthorne effect is a term referring to the tendency of some people to work harder and perform better when they are participants in an experiment. Individuals may change their behavior due to the attention they are receiving from researchers rather than because of any manipulation of independent variables.
- 14. Biases in experiments • Researcher bias – researcher sees what he is looking for • Experimenter expectancy – tendency for experimeter`s knowledge of what is being tested to influence the outcome of reserach use double blind control • Confounding/ extranous Variables – anything other than the independent variable thatcould affect the dependent variable • Participant variability use random samples • Ecological validity – the extent to which reserach can be generalised to other places or conditions
- 15. Correlational studies are used to look for relationships between variables. There are three possible results of a correlational study: 1. a positive correlation, 2. a negative correlation, and 3. no correlation. • The correlation coefficient is a measure of correlation strength and can range from –1.00 to +1.00. • There is no CAUSE-and-EFFECT relationship. • http://tylervigen.com/