@ 2012 wadsworth, cengage learning chapter 11 the ecology of the experiment: the scientist and...

@ 2012 Wadsworth, Cengage Learning

Chapter 11Chapter 11

The Ecology of the The Ecology of the Experiment: Experiment:

The Scientist and The Scientist and Research Participant Research Participant in Relation to Their in Relation to Their

EnvironmentEnvironment



Topics

1. Ecology2. Experimenter Factors3. Subject Factors4. Cultural and Social Bias


Ecology


Ecology

• Scientific study of the relationship of living organisms with each other and their environment (Miller, 1988)

• Ecology of the psychological experiment– Examine the relationships among: • The scientist• The research participant• The experimental situation


Ecology (cont’d.)

• Ecological validity– Seeks to determine whether the impacts of the

important relationships among the scientist, the participant, and the context have been considered fully in evaluating a given piece of research

• Our goal in science:– Use science to ask questions and to increase our

understanding of a given phenomenon• Not to perform a perfect experiment


Experimental Factors


Experimenter Factors

• Experimenter effects: portion of the results of an experiment affected by the attitudes or behavior of the experimenter

• Two types of experimenter effects:– Those due to biased data collection by the

experimenter– Those stemming from the experimenter’s biasing

the participant’s performance


Biased Data Collection

• Potential source of bias: individuality• Two experimenters may see the world

differently• Astronomer named Bessel– One of the first researchers to point out the effect

that inherent differences in experimenters can have on the data they record


Biased Data Collection (cont’d.)

• Personal equation: the constant error in the observations of different scientists

• Common procedure in an observational or rating experiment– Use two or more independent observers

• Correlation between two raters: interrater reliability



• The higher the correlation between the ratings of two independent observers– The less the ratings represent inconsistent

subjective factors of the raters

• Source of experimenter bias: personality• If an experimenter makes an error recording a

single piece of data– That error is most likely to be in support of the

research hypothesis (Rosenthal, 1979)



• A scientist can influence the outcome– Barber (1976) suggests that some of our more

famous scientists may have presented their data as being more precise than was possible during the time in which they lived

• Commission on Research Integrity – Established by the National Institutes of Health



• Experimenter bias can:– Affect the data the experimenter records – Exert a strong influence on the theoretical

interpretation of the finding

• Scientists may choose to view their own and other scientists’ results from a biased position


Biased Interactions With Research Participants

• Consider yourself a participant– Hypothesis: more college men than women dream

about violating social taboos

• Imagine what type of person you would be:– Most willing to tell your uncommon dreams – Least likely to tell your dreams

• Research participants might react differently to different experimenters


Biased Interactions With Research Participants (cont’d.)

• Classic study: Rosenthal and Jacobson (1966)– Teachers were told that certain students (chosen

at random) had shown great promise on an IQ test– Students did show increased achievement gains 8

months later– Teachers treated the randomly selected group in a

different manner than those who were not named by the researchers as having great promise


Biased Interactions With Research Participants (cont’d.)

• Task of the scientist and the witness – To ask whether experimenter bias might influence

either the treatment of participants or the collection of the data

• Examine human behavior and experience in its complexity– Including the manner in which scientists and

participants interact


Some Ways to Avoid Experimenter Bias

• Use several different experimenters• Keep the person who is interacting with the

participants blind to: – The hypothesis and– The particular groups with which he or she is

working

• Try consciously to see the experiment from varying perspectives


Subject Factors


Subject Factors

• Potential source of misinterpretation • Present when the research participants are

not behaving in the way we expect them to behave– Highly motivated– Behave in a way that will support or sabotage the

experiment


Subject Factors (cont’d.)

• Experiment conducted in the 1930s– Hawthorne plant of Western Electric

• Determine how factors such as lighting and working hours affect productivity– Participants were a group of women– In many cases, the productivity increased– Even increased under a condition in which the

lighting in the experimental condition was not as good as that in the actual plant


Subject Factors (cont’d.)

• Women had been given special attention just by being in an experiment

• Hawthorne effect– Warning to experimenters that humans may

respond differently to the knowledge that they are part of a research study


Placebo Factors

• Potential problem in an experiment • Placebo: from the Latin verb placere, “to

please”• Phenomenon that some people show

physiological changes just from the suggestion that a change will take place


Placebo Factors (cont’d.)

• Double-blind experiment– One group is given the actual treatment– The other is given a treatment exactly like the

experimental treatment, but without the active ingredient

• The term double-blind – Indicates that the physicians or nurses giving the

medication also do not know which medication is experimental and which is placebo


Demand Characteristics

• Occur when a participant’s response is influenced more by the research setting than by the independent variable

• Pose a significant threat to internal validity• Offer an alternative explanation for

understanding the influence of the independent variable


Cultural and Social Bias


Cultural and Social Bias

• Science is not immune to a shared cultural view

• People who go to an outpatient psychiatric facility for intervention – Often receive treatment based on factors such as

their ethnic backgrounds– African Americans: psychopharmacological

interventions– Caucasians: verbal psychotherapy


Cultural and Social Bias (cont’d.)

• In 1994, the U.S. National Institutes of Health implemented a policy – Required all federally funded research involving

human participants to include women and members of minority groups

• Paradigm– An accepted worldview– Ideas about the value of what one is doing– Specific assumptions about how the world operates



• At one time, it was considered impossible to have a scientific study of consciousness– Consciousness has now become an important

focus for the neurosciences

• Previous paradigm emphasized the negative and pathological– Today’s view includes a positive psychology



• We introduce a bias into our scientific research by– Letting the believed limitations of our time restrict

the scope of our vision

• Every scientist holds limited views of the world– This is not the issue– The point is to realize that this is the case


Summary

• Experimenter effects: changes in the dependent variable produced by the attitude or behavior of the experimenter

• Research participants may bias an experiment• Placebo effect: a suggestion of change actually

produces a change• Demand characteristics: research participants’

being more influenced by the experimental setting than by the independent variable

@ 2012 wadsworth, cengage learning chapter 11 the ecology of the experiment: the scientist and...

Documents

cengage learning slide

cengage learning ecology

cengage learning chapter

biased position slide

perfect experiment slide

social bias slide

experimenter records

experimental situation