P2 - Research methods

Experimental methods

• laboratory

• field

• quasi

• natural

Laboratory experiments - strengths

• can establish cause-effect relationship

• IV=cause, DV=effect

• replicability - repeat and achieve same finding

• more objective than other methods

• highly controlled

Laboratory experiments - limitations

• lacks mundane realism

• lacks ecological validity

• lacks experimental realism

• know they’re being observed = demand characteristics (e.g. ‘screw you effect’)

• evaluation apprehension (nervous of judgement

• limited sample size - population validity

laboratory experiments - important

random allocation to conditions so there are no major differences that affect results

laboratory experiments - ethical considerations

need informed consent, consider long term effects (physical/psychological harm), need right to withdraw

Field experiments

• carried out in natural setting, e.g. school, work, etc.

• IV deliberately manipulated

• participants unaware

Field experiments - research

Shotland and Straw 1976

• Male and female confederates staged an argument

• 1 condition F: ‘I don’t know you!’, 2 condition: ‘I don’t know why I ever married you!’

• found less likely to help when ‘married’

• IV: shouted phrase, DV: number of people who attempted to help

• ethical: possible psychological harm

Field experiments - strengths

• no demand characteristics

• mundane realism = higher ecological validity

• experimental realism

• no evaluation apprehension

• scenario can be replicated

• can establish cause and effect

Field experiments - limitations

• many extraneous validity (lacks internal validity)

• lack of informed consent

• C-E relationship less clear

• random allocation is difficult

• ethics: almost impossible to offer right to withdraw or give debriefing

Quasi experiment

• when its not possible/unethical to randomly allocate participants/manipulate the IV

• resembles true experiments but weak on some characteristics, key differences in point 1

• use pre-existing group e.g. effects of divorce on young children or relation between heart disease and personality

Quasi experiment - strengths

• investigate effects of IV that would be unethical to manipulate

• participants behave naturally

Quasi experiment - limitations

• less control as IV not manipulated

• no random allocation

• difficult to establish C-E

• requires ethical sensitivity

Natural experiments

• type of quasi experiment

• use of naturally occurring event for research purposes, e.g. social/geographic

• experimenter has no control over changes in IV

• e.g. affects of stress after natural disaster/bereavement

• natural disasters, elections, wars, riots, terrorism, pandemic

Natural experiments - research

Kario et al. 2003 studied effects of Kobe earthquake, 6400 people died, measured stress of those closest to epicentre, increased rate of heart attacks and sudden death 24 hours after

Natural experiments - strengths

• participants often not aware they’re taking part in an experiment

• allows us to study effects on behaviour of IV that would be unethical (mostly impossible) to manipulate

Natural experiments - limitations

• participants have not been assigned at random

• IV not controlled

• cannot make causal inferences

• participants unaware of participation

• sensitivity - experimenter attitude

Observational techniques

involves observing behaviour covertly (natural) or openly (overt/controlled) or as a participant in the activity

• natural observation

• controlled observation

• participant observation

Natural observation

unobtrusive observational study conducted in a natural setting

natural observation - strengths

• participants unbiased

• mundane realism = higher generalisability

• flexible

• external validity

• don’t have to obtain consent

• works well with children/non-humans

Natural observation - limitations

• too many uncontrolled and unknown factors

  • extraneous variables, hard to establish C-E

• observer has to be natural (or response changes)

• ethical - participant doesn’t realise they’re participating

• training observer is time consuming and expensive

• impossible to replicate

controlled observation

observations whereby the researcher exercises control over environment in which the observation is conducted

controlled observation - strengths

• easily replicated

• good control of variables, establish cause and effect

• less risk of extraneous variables

• comparison of extraneous - rich in detail and more complete

controlled observations

• lacks mundane realism - hard to generalise

• investigator effects - experimenter expectations

• social desirability bias

• demand characteristics

  • awareness = change in behaviour

participant observation

• observers in natural setting where observer interacts directly with participants

covert observation

undercover

overt observation

obvious