First Quant textbook released in 1938
Experimental Psych - Robert Session
Purpose of experiment?
To demonstrate causality
3 requirements for causality?
Early psych research was linked to what kind of science?
hardline sciences, more quantitative, focused on proving
Best friend in research
Control
Three key features of an experiment
E.C.M
Establish IVs - create conditions that are under control of researcher
Controlling Ext Vrs - avoid confounding
Measuring dep vars - must be precisely defined
Minimum no. of levels for IVs?
2
List 4 categories of IVs
What do we need to control?
EVERYTHING that is not of interest to us
How could one control for observer expectancy?
A double blind study
What is a vital element in establishing credibility in an experiment
The operational definitions
Should op defs be based on context, culture, times etc?
Yes
List 4 types of validity in experimental research
(ICES)
Components of Stat conc val? (4 points)
Two questions surrounded construct validity?
Central issue around external validity
GENERALIZABILITY
- across pops
- across environments
- across time
Definition of Internal validity
The degree to which a study is methodologically sounds and confound free
General process of exp studies?
OXO
Threats to Internal Validity
HMTSIAR
HOW MANY TEA SPOONS IN A REACTOR
(History, Maturation, Testing, Selection Bias, Instrumentation, Attrition, Regression to the mean)
History
what happens between the pre- and post-test that is outside of the study (war, protest, life change, retrenchment)
Maturation
Improvement or decline in abilities due to age/maturation (mostly bio/physiological, and mostly relevant to young/old pops)
Testing (threats to Int Val)
And possible solution
process of pre-test (rather than intervention) that affects change seen in post-test. (learning skills, gaining insight into own lives, asking big questions of their own life etc)
Distinction between testing and history/maturation is that is was the process of the pre-test which stimulated the change.
Possible sol: use a distractor
Instrumentation (threats to int val)
Lack of reliability and poor op defs introduce confounds (decrease int val)
Sol: Have good Rel and Op Defs
Selection bias (threats to IV)
And possible solution?
Sub-con selection of people who may respond better.
Sol: RA (needs LS)