Why do formal research in psychology?
Because it enables use to test and justify our claims and to discard propositions that are false. Research is what distinguishes psychology from other bases for claims about the causes of behaviour, and the effectiveness of treatment.
Why is it important that the details of a study's methods, analysis and results are published?
Our conclusions can be scrutinised by others. We can determine the justifiability of other's conclusions. It allows us to judge the strength of effects It makes us and other psychologists accountable.
Why is it important to learn about research methods even if we don't intend to do research?
It allows us to be discerning consumers of the products of others research.
The truthfullness of the results and conclusions that derive from a piece of research depends on... ?
The quality of the design The quality of the measures The appropriateness of the statistical analyses The nature (e.g., size) of effects The match between the results and the conclusion
What are the three essential conditions for establishing causation?
1. Covariation: two events must occur/change together (including non-occurrence) 2. Temporal order: the cause must precede the effect 3. Elimination of plausible alternative explanations for covariation
If the only substantial difference between 2 conditions is A (an independent variable) does that allow us to determine that A is the cause of B (the dependent variable)
What is Internal Validity?
The extent to which we can say that (any) effects on the DV were caused by the IV (as opposed to something else)
What is selection threat? How can it be controlled?
Anything that can result in non-equivalent groups in different conditions (it reflects the method of condition assignment) (A threat to internal validity) It can be controlled with Random Assignment.
What is History Threat? How can it be controlled?
Another event could coincide with a study and affect its results. (A threat to internal validity) It can be controlled with random assignment
What is Maturation? How can it be controlled?
Refers to changes in participants as a result of the passage of time. (A threat to internal validity) It can be controlled with randomisation and a control group.
What is regression towards the mean? How can it be controlled?
Refers to the fact that scores that are very different from the mean on a first measurement occasion can be nearer on the mean when the measure is taken again.
What is selection threat? How can it be controlled?
Selection is anything that can result in non-equivilant groups in different conditions. Any non-random method of allocating participants to conditions leads to selection threat. E.g., testing YOGA program on workers in a large company whereby volunteers go to the yoga-condition and non-volunteers go to the control group. IT can be controlled by random allocation (of sufficient numbers), because this should produce equivalent groups. Note: DON'T CONFUSE this with ways of 'selecting' people from a population from a study
What is a confound?
Another variable that is RELATED to the IV (e.g., differs between conditions).
Not just any extraneous/uncontrolled variable that could apply randomly to different individuals regardless of condition. (e.g., NOT, 1 person breaks a leg, 1 person gets promotion)
e.g., rats have tail removed die and rats who don't have their tail remove survive......do rats need their tail to survive? NO, surgery and human handling are confounds.
What is instrumentation threat?
Changes in the way a measure is applied or intepreted.
e.g., an experimenter gets better at encoding a behaviour, or a patient gets less diligent over time recording in a diary
What are testing effects?
Changes that occur in a measure/score over 2+ testing occassions, BECAUSE of the earlier measure.
What are demand effects?
Responding in a way that is consistent with the researcher's expectations as a result of participants knowing/guessing what the researcher expects.
What are non-specific treatment effects?
Benefits of warmth, attention, support, reassurance and the mechanics of homework exercises (rather than from the specific treatment itself)
What are placebo effects?
Changes owing to the receipt of a treatment (not owing to the actual treatment). People can feel better just because they know they're receiving a treatment. Placebo effects result from participants' own expectations about what will happen.
What is attrition?
(aka 'mortality') drop outs (people who leave the study before all of the intended data are collected from them). Some attrition is common in studies that use repeated measures over time. It's not necessarily a problem: it depends on the pattern and possible causes.
What is experimenter bias?
Researchers might inadvertently administer experimental instructions differently in different conditions, or administer or interpret measures differently in different conditions (this only applie when discretion/judgment is used in determining scores)
How do we (in general) control for threats to internal validity?
Ensure that threats apply similarly in all conditions.
The only difference should be on the IV.
A control condition should be used if appropriate - placebo should be similar to actual treatment
Counterbalencing (when experimental conditions are varied within subjects, the order should be varied when feasible.
Blind assessment prevents administration or intepretation bias
Rigorous training for measures requiring skilled delivery or intepretation.
What are the features of an appropriate placebo?
Is similar to the real treatment in:
Attention, warmth etc from the researcher
Ideally, method of administration (drug/individual)
Do all treatment studies need a placebo?
Depends on research question
- relative effects of A and B (comparison study)
- is A better than placebo
- Correlation study - control condition mostly irrelevant
How do we control for researcher/bias (Where applicable)?
Standardisation instructions to participant
Very good training in the use of measures requiring skill (to avoid bias, instrumentation effects)
what does it mean to say a threat is controlled?
That the threat applies similarly to differet conditions, or more or less randomly across different people in a study, it has been controlled.
What is a quasi-experimental design? What is it's major flaw?
Ps not randomly allocated to levels of the IVs
- Sometimes because the IV can't be manipulated E.g emplyed vs. unemployed, asthma vs. not
Ps might differ in ways other than the IV
What is a Factorial Design?
2 or more CATEGORICAL (factors) IVs are manipulated (or measured) AND all combnations of the IVs are tested.
"an experiment whose design consists of two or more factors, each with discrete possible values or "levels", and whose experimental units take on all possible combinations of these levels across all such factors."
How are factorial designs written?
By specifying the no. of levels of each IV
e.g., a 2x2 design has 2 IVs and each has 2 LVLs
How do you determine the number of cells in a factorial design?
Multiply the number of levels of each IV together
- 2x2 has 4 cells
- 2x3 has 6 cells
- 2x2x2 has 8 cells i.e., (2x2)x2
- 3x3 has 9 cells
What is the differece between 'between-subjects', 'within-subjects' and 'mixed' manipulation of an IV?
Between-subjects = Each Participant is only in one level of the IV
Within-subjects = Each participant participates in each level of the IV
Mixed = At least one IV is varied between subjects and at least one is varied within subjects (e.g., pre-post time)