PS295 Chapter Two Summary
Behaviour Variability and Research
Schemas provide us with frameworks for organizing, remembering and acting on the
information we receive.
Variability and the Research Process
Proposition 1: psychology and other behavioural sciences involve the study of behavioural
- researchers want to know how and why behaviour varies across situations, among people and
- people and other animals behave differently in different situations.
- behaviour varies among individuals, everyone is different act differently
- behaviour also varies over time. E.g. a baby who could barely walk a few months ago can run
Proposition 2: research questions in all behavioural sciences are questions about behavioural
- e.g. imagine we are interested in whether a particular form of counselling causes changes or
variation in a family’s interactions
- any specific research question we might develop can be phrased in terms of behavioural
Proposition 3: research should be designed in a manner that best allows the researcher to
answer questions about behavioural variability
- research studies must be designed in a way that allows us to identify, as unambiguously as
possible, factors related to the behavioural variability we observe.
- researchers must be sure that their research will permit them to answer their questions about
Proposition 4: the measurement of behaviour involves the assessment of behavioural variability
- all behavioural research involves the measurement of some behaviour, thought, emotion or
- no matter what is being measured, we want the number we assign to a participant’s behaviour
to correspond in a meaningful way to the behaviour being measured
Proposition 5: statistical analyses are used to describe and account for the observed variability
in the behavioural data.
- the purpose of statistics is to summarize and answer questions about behavioural variability
we observe in our research
- descriptive statistics – used to summarize and describe the behaviour of participants in a study
- inferential statistics – are used to draw conclusions about the reliability and generalizability of
Our research questions concern the causes and correlates of behaviour variability Understanding variability will provide you with a schema for understanding, remembering and
applying what you learn about behavioural research.
Variance: An index of variability
Researchers use variance to indicate the amount of observed variability in a participants’
To explain variance there are several possible ways
One way is taking the difference between the largest and smallest scores. That is the range.
E.g. (4 (largest # subtract smallest #)
The problem is the range only tells us how much the largest and smallest scores vary but does
not account for the other scores
The mean is another effective way, it calculates the average accounting for all scores.
Deviation score – subtracting the mean from each score. By looking at these scores we can see
how much the score varies or deviates from the mean
If we sum the deviation scores for all of the participants it will always add to zero. So therefore