Measuring Behaviour Etc Flashcards
Operational definition
- the phenomena to be measured should be defined in terms of the operations used to measure them
- a good operational definition is reliable and reproducible
- loss of contract validity can occur (conventional meaning may be lost)
- eg: alcoholism, PMS, ADHD etc
- essential in experimental research
Ostensively definitions
-phenomena to be observed should be carefully described (textually, graphically, photographically) and examples can be given
-common in observational research
(Basis of ethograms and systematic behaviour)
Nominal scales
- categories, taxonomies, typologies
- eg: male/female; liberal/conservative/democrat; ADD+H/ADD-H; extroverted/introverted
- types of statements: x is different from y; assignment of labels
- purely qualitative information
Ordinal scales
- continuum or spectrum of observations.
- ranking within a category is possible; often different names and certainly different quantities
- absolute values not known
- eg: low, moderate, high self-esteem; ranking of a race
- types of statements: x is greater than y; assignment of values
- qualitative with some crude degree of quantity (ranked)
Interval scales
- has no absolute zero point, i.e. arbitrary
- eg: Celsius scale (0 is a relative point on the scale, when ice melts; it is a convenient convention). Likert scales
- common in psychology and neuro: rating scales, from 0-10 (where 0 does not mean no liking at all), IQ scale (0 does not mean no intelligence)
- quantitative; we know by how much the values differ
- spacing between values is known, but a score 120 is not necessarily double a score of 60
Ratio scales
- has an absolute zero point (absence of the quantity can be indicated)
- zero means zero
- eg: Kelvin (0K is the absence of heat
- common in psych and neuro: from no response to n degree of response
- eg: score on memory test
- quantitative; we know how much of the quantity exists
Scales of measurement: the implications
- nominal and ordinal can be analyzed with a number of non-parametric statistical analyses
- interval and ration analyzed with parametric stats
Environmental/situational variables
- variables referring to the manipulation of the environment
- eg: treatment, tasks
Instructional variable
- variables referring to what is told to a participant, instructed, or simply suggested
- applies mostly to human research and animal research
Subject, participant, or individual variables
- quasi independent variables
- differences in individuals
- eg: ethnicity, habits, diseases etc
- important in idiographic vs nomothetic research
- not true independent variable because it is not manipulated
Controlled variables
-any variable that is controlled or held constant across all treatment conditions of experiment
Extraneous variables
- “threatening variable”
- “obscuring factors”
- impact on dependent variable that is not ind variable
- variables that are not being studied
Confounding variables
- an extraneous variable (usually unmonitored) that can inadvertently affect another experimental variable
- potential source of variability (experimenter-expectancy effects
Solutions for confounding/extraneous variables
- random assignment of participants to treatment conditions
- keeping extraneous variable constant
- matching participants on extraneous variable
- building the extraneous variable into study or blocking so that the extraneous variable becomes an independent variable
- statistical control of variable: ANCOVA so that extraneous variable become a covariate
Experimental research designs and variables
goal: causal relationships
Variables: IV=manipulated by experimenter; DV=measured by experimenter
Issues: internal validity (confounding variables); external validity: generalizability, ecological validity.