1 / 15

Research in psychology

Research in psychology. 1.3 Experimental methods. Variables. A variable is any characteristics or factor that can vary, e.g : gender, age, grade points, stress, motivation, etc.

maia
Download Presentation

Research in psychology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Research in psychology 1.3 Experimental methods

  2. Variables • A variable is any characteristics or factor that can vary, e.g:gender, age, grade points, stress, motivation, etc. • Independent variable- the IV produce a change in another variable- deliberately manipulated by the researcher - all other variables are kept constant- Example: new antidepressant medication • Dependent variable- measured after alteration of the IV- is it influenced by the IV?- Example: Did the medication affect the depression?

  3. Operationalized • Operational definition translates an abstract term (variable) into something observable and measureable. • The operational definition gives the variable meaning within a particular study.’ • In precise terms, what is being measured?- Example: aggression vs. how many times the participant will kick the doll during one hour

  4. Hypothesis • Experimental hypothesis is a prediction of how the IV will affect the DV Example: the new therapy will decrease the participants anxiety more than the old one • A null hypothesis is prediction that there will be no change Example: The new therapy will have no effect on the participants anxiety compared to the old one Most often two conditions: • Experimental (treatment) condition- Situation where a variable is being manipulated • Control condition - Situation where a variable is not being manipulated • Is there a significant difference between the two?

  5. Be a thinker p. 27 • Identify the Independent variable and dependent variable in each of the following experimental hypothesis.

  6. Placebo • People who receiving a treatment show a change in behaviour because of their expectations, not because the treatment itself had any specific benefit

  7. Case • Study on the effect of the new antidepressant drug • One group receives the new antidepressant drug and told they receive it – experimental condition (treatment group) • One group receives a placebo pill but told they receive the new antidepressant drug – control condition (group) • Does the antidepressant work better than the placebo?

  8. Experiments • Laboratory experiments+ easy to replicate+ easy to hold variables constant- artificial environment- low ecological validity • Field experiments+ Ecological validity- hard to hold variables constant • Natural experiment+ Unique situations- No control over variables

  9. Experiments • Laboratory experimentsExample:Study on the effect of the new antidepressant drug • Field experimentsExample: Piliavin and Rodin (1969) in the New York subway – investigated helping behaviour regarding sober or drunk person • Natural experimentExample: aggression before and after TV came, stroke victims

  10. Confounding variables (undesirable variables that influence the IV and DV) • Demand Characteristics (aka Hawthorne effect, taken from the Hawthorne Works plant of Western Electric in the US)- Participants act differently because they are in a study and trying to guess what the researcher is after- To counteract: Use single blind control: participants are not told the aim

  11. Confounding variables • Researcher bias (observer bias)- When expectations of the researcher affects the findings, often in subtle and unintentional ways- To counteract: Use double blind control in which both participant and experimenter are unaware if the participant is in the control group or the experimental group

  12. Confounding variables • Participantvariability • Whencharacteristics of the sampleaffect the dependentvarible • To counteract: userandom sampling

  13. Correlation studies – an experiment cannot be carried out but data are collected which show a relationship • Data is gathered that relates to the IV and the DV • If one variable change the other change as well • Positive correlation:- Same change in both variables- both in increase or both decrease- Example: Life expectancy and hours of exercise+ 1 = perfect positive correlation • Negative correlation:- When one variable increase the other decrease- Education and time in jail- minus 1 = perfect negative correlation

  14. Correlation studies • Example: 1. Researcher measures one variable (wealth)2. Researcher measures a second variable (happiness)3. The researcher statistically determines whether wealth and happiness are related. +

  15. Bidirectional ambiguity • Cause-and-effect? • Example: Better social relationships and greater happiness are correlated • But, which causes which? Better social relationships = greater happiness or Greater happiness = better social relationships or is there that another variable responsible for the behaviour? • Correlation between eating ice cream and drowning? = ?

More Related