Nonexperimental designs

• Description is one level of scientific inquiry– Remember

• Description• Prediction• Explanation

– useful for describing human behavior• but does not allow for prediction• does not allow for causal inference

– valuable techniques for certain situations• When you cannot run an experimental design

• Before we get into specific descriptive methods we need to discuss a couple of concepts that are important for evaluating any research methodology

• Those concepts are– internal validity– external validity

– quantitative approaches– qualitative approaches

Internal validity

• Internal validity– The degree to which a research design allows

us to form causal relationships– experimental methods tend to be high– nonexperimental methods tend to be low

external validity

• external validity (generalizability)– Do the findings from a research project

generalize to people in real world settings?• nonexperimental descriptive approaches tend to

be higher – often done with humans– often done in real world settings.

• Experimental/laboratory methods tend to be low– Contrived laboratory settings– Animal research

• Thus,– nonexperimental methods tend to be high in

external validity, but low in internal validity.• Studying children born to mothers that used

cocaine during pregnancy

– Experimental methods tend to be high in internal validity, but low in external validity

• Studying neonatal rat pups exposed to cocaine.

• research designs can also be described as primarily qualitative or primarily quantitative.– qualitative

• Written descriptions. • Expressed in nonnumerical terms.

– quantitative• Data is expressed numerically

• The designs we will discuss in this section are nonexperimental and their goal is to describe.

• Tend to be low in internal validity, but higher in external validity.

• Also tend to rely on qualitative data • We will discuss four approaches

– phenomenology– case studies– field studies– survey research

• Phenomenology– Similar to Wundt and Titchener’s introspection. – A description of one’s own immediate experience

• Not a scientific method– not publicly observable

• Nevertheless has been used as a first step in developing research questions– Purkinje

• Purkinje shift (1825)– noticed that the brightness of colors changed at the

end of the day as the sun was going down– day

• reds and yellows appeared brighter than blues and greens

– twilight• blues and greens appeared brighter than reds and yellows

• duplex theory of vision– cones– rods

• benefits of phenomenology– can lead us to new hypotheses and discoveries– can be useful technique to ask participants about the

study after they get done.• how the felt about the study

– bored?– difficult?

• problem with phenomenology– not public (private experience)

• difficult to know if others would have the same experience– therefore any observations would have to be verified

with a scientific method.

• Case studies or case history

• A descriptive record of an individuals experiences and/or behaviors kept by an outside observer

• Clinical psychologists often use case studies

• Kazdin (1992) has argued that case studies serve five major purposes– 1) They are a source of inferences,

hypotheses, and theories• The dopamine hypothesis of schizophrenia was

developed from medical case studies– drugs that worked for psychosis caused Parkinson’s

symptoms

• 2) Source for developing therapy techniques– try a new therapy and document its

performance• doesn’t constitute hard evidence that it is effective• that would require control groups

• 3) They allow the study of rare phenomena– Luria (1968)

• the mind of a mnemonist

– H. M. (surgery in 1953)

• 4) They provide exceptions, or counter instances, to accepted ideas theories or practices– Gazziniga (1972) Split brain patients

• we tend to believe that we have one unified consciousness• there is evidence that the two hemispheres represent

separate consciousness that cooperate– corpus callosum

• reach in bag• touch object with right hand – can tell you what it is

– right hand goes to left brain• touch with left hand – can’t reply verbally, but can point to

correct

• 5) they have persuasive and motivational value– Endel Tulving (forms of memory)

• Episodic, Semantic,Procedural– H. M.

• Drawbacks of case studies– When it is a rare disorder it is difficult to know if others

will show similar effects• small N

– When we rely on self report people may leave things out that they don’t think are important or are embarrassed about.

– when they rely on retrospective data (memory) information can be inaccurate

• people may not remember well• memories can be altered or reconstructed

– by the way questions are asked.

• Field studies– naturalistic observation– systematic observation– participant observer studies

– naturalistic observation• Jane Goodall – Chimps• Gans (1962)

– studied people living in slums– watched people– listened to conversations– attended meetings

• found people were opposed to having the old buildings replaced

• Naturalistic observation requires the researcher to be as unobtrusive as possible.

• It is also primarily a qualitative method• Of course watching people in natural

settings leads to high rates of external validity.

• But with no manipulation of variables the internal validity is low.

• Systematic observation is a more quantitative approach to naturalistic observation

• the researcher creates a prearranged strategy for recording observations.

• The observations are recorded using specific rules

• Bakeman and Brownlee (1980)• social behavior in children• Videotaped three year olds playing together• taped for 100 minutes

– observers viewed the tape and recorded behavior every 15 seconds according to the following criteria

• 1) unoccupied: child is not doing anything in particular or is simply watching other children

• 2) solitary play: Child plays alone with toys, but is uninterested in or affected by the activities of other children

• 3) together: child is with other children bus in not occupied with any particular activity

• 4) parallel play: child plays beside other children with similar toys but does not play with others

• 5) group play: child plays with other children, including sharing toys, or participating in organized play activities as part of a group of children.

• Type a number into the computer 1-5 every 15 seconds. – now you have quantitative data– which activity occurred the most?– what order do activities occur in? Bakeman and

Brownlee noted the sequence of play activities

• children rarely went from being unoccupied to group play

• often went from parallel to group play• perhaps parallel play is a transitional state.

• participant observer studies– This is a form of naturalistic observation in which the

researched pretends to be a member of the group they are studying

• Jane Goodall...and chimps might be an example.

– Humphreys (1970)• befriended gay men that were meeting and having sexual

encounters in public restrooms– served as a lookout– but was really collecting data

• even wrote down license plate numbers, obtained addresses, disguised himself, and visited their homes to interview them.

– unethical

• Methodological issues for all forms of field studies

• Reactivity– The presence of an observer may effect

behavior• unobtrusive measures

– one way mirror– hidden camera– 90 degree lens --- eyebrow arch

• Reliability– the degree to which a measure is stable or consistent

• inter-rater reliability• two people must score the data

– if the scores are very similar you have a reliable measure

• requires clear operational definitions• don’t make things too complicated

– my Master’s project

» 6 chambers

» turning, twitching, locomotion, rearing, yawning, locomotion against wall.

• Survey Research– rather than simply observing you directly

question your participants about their behavior, attitudes, beliefs, and intentions

• past, present, or future

– two major considerations• sampling technique• construction of questionnaire

• population vs. sample• Surveys are concerned with external validity.

– does the data reflect how the population actually feels– to ensure that it does the sample has to be

representative• convenience• simple random sampling• stratified sampling

– form subgroups and sample randomly from each

» Freshman, sophomores, juniors, seniors

• proportionate sampling– form subgroups and sample randomly, but only as

many in each group as is in actual population• freshman (31), sophomore (25), junior (14), senior (19), other

(11)

• cluster sampling– usually used with bigger populations

• randomly select courses to be sampled• everyone in course would get the survey

– better example might be school districts in Indiana.

– every individual in district gets surveyed if selected.

• open ended vs. closed ended questions• open ended

– what do you think of parking on IPFWs campus• closed ended

– How difficult is it to find a parking spot on IPFWs campus• a) easy – parking is readily available• b) somewhat easy – some days I have to look for a while• c) difficult – most days I have to look for a while• d) very difficult – Every day I spend a significant amount of time

looking for a spot– likert scale

• On a scale of 1-7 with 1 being very easy and 7 being nearly impossible how would you rate the ease at which you can find a parking space on IPFWs campus

– 1...2...3....4...5....6....7