RESEARCH METHODS - COGNITIVE Flashcards
(22 cards)
What is an experiment?
A research method which demonstrates causal relationships, and always have an IV and a DV
An independent variable: a factor that is directly manipulated by the experimenter in order to observe the effect of his variation on the dependent variable
The dependent variable: measured by the experimenter to assess the effects of the IV
Operationalisation: variables must be defined in a way that they can be easily tested
What is a laboratory experiment, and what are the strengths and weaknesses?
experiment controlled in a very controlled environment
Strengths:
High levels of control possible and therefore confounding and extraneous variables can be minimised
Can be easily replicated because it is controlled, making it reliable
Weaknesses:
A contrived situation where participants may not behave naturally so has low ecological validity
Demand characteristics and researcher bias/effects may reduce validity
What is a field experiment, and what are the strengths and weaknesses?
experiment conducted in more everyday surroundings than la laboratory
Strengths:
Less contrived, the whole experience feels more like everyday life so has high ecological validity
Avoids demand characteristics and researcher bias/effects if participants are not aware of being studied
Weaknesses:
Less control of extraneous variables which reduced validity
May be more time-consuming as the researcher has to set up the whole experiment at a distant location - may be more expensive
May be ethical issues if informed consent and debriefing aren’t possible
What is an experimental hypothesis?
a hypothesis is not a question, it is a statement about the effect of the IV on the DV (a prediction)
What is a null hypothesis?
a statement of no difference (except for chance)
What is a directional and non-directional hypothesis?
Directional (one tailed) hypothesis: states the direction of the hypothesis
Non-directional (two tailed) hypothesis: just states there is a difference
What is a repeated measures design, and what are the strengths and weaknesses?
each participant takes part in every condition being tested, and each condition represents one level of the IV (may be a control condition)
Strengths:
Good control of participant variables because the same person is tested twice
Fewer participants are needed for more results, making the conclusion more dependable
Weaknesses:
Order effects are produced, for example a participant may be better on the second test because of experience, or may perform less well because of being bored or tired
Participants may guess the purpose of the experiment because they do both conditions and this makes the aim obvious (leading to demand characteristics)
What is an independent groups design, and what are the strengths and weaknesses?
different participants are allocated to two experimental groups representing two different levels of the independent variable (may be a control group)
Strengths:
Avoids order effects because each participant is only tested once
Avoids participants guessing the aims of the experiment
Weaknesses:
There is no control of participant variables, making it less valid and reliable
Needs more participants which could be time consuming
What is a matched pairs design, and what are the strengths and weaknesses?
participants who are similar on key variables are paired (independent groups design)
Strengths:
Controls for participant variables because of the matching
Avoids order effects because it is an independent groups design
Weaknesses:
Very time consuming to match participants on key variables
May not control all participant variables because you can only match on variables that are known to be relevant, but other variables could be important
What is internal validity, and what is needed?
the researcher is testing what they intended to test
Extraneous variable: any variable other than the IV that might potentially affect the DV
Eg participant and situational variables
Confounding variable: a type of extraneous variable that changes systematically with the IV (will definitely have an affect)
What is predictive validity?
the researcher is testing what they intended to test
Extraneous variable: any variable other than the IV that might potentially affect the DV
Eg participant and situational variables
Confounding variable: a type of extraneous variable that changes systematically with the IV (will definitely have an affect)
What are demand characteristics?
cues in a research situation that communicate to participants what is expected of them and they unconsciously affect their behaviour
What is ecological validity?
concerns the ability to generalise a research finding beyond the particular setting in which is is demonstrated to other settings
What is an inferential test?
procedures for drawing logical conclusions about the target population from sample
What is an observed and critical value?
Observed value: the number produced after applying an inferential test formula (calculated value)
Critical value: the number which must be achieved in order for a result to be significant
What is significance?
a statistical term indicating that the research findings are sufficiently strong to enable a researcher to reject the null hypothesis and accept the alternative hypothesis
Levels of significance: the level of probability at which it has been agreed to reject the null hypothesis (must decide before the study)
What is a Wilcoxon Signed Ranks Test and how is it carried out?
Used when an experiment has a repeated measures design and we are comparing performance in two conditions - level of measurement must be at least ordinal
The process involves:
State the alternative hypothesis
Place raw data in table
Find differences between the two conditions and rank (ignore if difference is 0) ignoring the signs
Calculate the observed value by adding up the ranks with a positive difference, and then again for the ranks with a negative difference, then use the smallest value
Compare to the critical value and report the conclusion
What is a Mann Whitney U Test, and how is it carried out?
Used when an experiment has an independent groups design and the level of measurement must be at least original
The process involves:
State the alternative hypothesis
Place raw data in a table
Rank each data set separately (each condition)
Add the ranks separately for each condition
Calculate the observed value for each condition using the equation (in booklet)
Compare to the critical value and report the conclusion
What is a type I and type II error?
Type I error: occurs when a researcher rejects the null hypothesis which is true
Type II error: when a researcher accept the null hypothesis that was not true
What is a normal distribution?
occurs when certain variables are measured, and most of the scores are clustered around the mean, median and mode (all measures of central tendency are at the mid-point)
The curve has a characteristic symmetrical bell-shape
What is a skewed distribution?
the mean, median and mode do not all share the same value
In a positive skew most of the scores are bunched to the left
In a negative skew most of the scores are bunched to the right
What is a case study, and what are the strengths and weaknesses?
the detailed study of one case, which could be one person or a group
Strengths:
Can be used to investigate instances of human behaviour and experience that are rare or cases which cannot be created in research labs
The method produces rich, in-depth data because of the complex interaction of many factors being studied - holistic approach
Weaknesses:
It is difficult to generalise from each individual case as each one has unique characteristics
It is often necessary to use recollection of past events which could be unreliable
Researchers may lack objectivity as they get to know the case, which leaves room for bias
There are important ethical issues, such as confidentiality and anonymity
