Chapter 7: Experimental Research Strategy Flashcards
The goal of experimental research strategies are to rule out ______ relationships
coincidental
4 requirements to be a true experiment
1) manipulation: changing the independent variable
2) measurement: a dependent variable is analyzed
3) comparison: scores of one condition will be compared with the scores of another condition
4) control: all extraneous variables are controlled
experimenters are involved in the direct manipulation of the ___ variable
independent
What is a third variable problem?
when a 3rd unidentified variable is CONTROLLING the relationship between 2 experimental variables.
What is an example of a third variable problem?
for example, researchers are determining if there is a relationship between math ability and weight gain in children between the ages of 6-12. They notice that as the children gain more weight, they have increased mathematical ability. However, there is a problem with this relationship: is mathematical ability related to weight gain or is related to maturity as the kids age to 12 and gain more education? Kids will naturally gain weight from age 6-12 so although that is occurring at the same time as their education, their weight gain most likely is not contributing to their mathematical ability.
describe an example where a true relationship is hidden by nature
example: the law of gravity, which states that all objects will fall at the same rate. This relationship is hidden due to air resistance. experimental conditions may test gravity in a no- air environment: will show the relationship
goal of an experiment
to demonstrate the existence of a cause-effect relationship between 2 variables.
What’re the 2 unique elements that completely distinguish an experiment from other research strategies?
1) manipulation of the IV
2) control of extraneous variables.
What is a confounding variable and how does it differ from other extraneous variables?
a confounding variable that is (often unknowingly) allowed to change systematically along with 2 variables being studied, and may provide an alternative explanation for the results seen.
Different than other extraneous variables because:
1) they influence the dependent variable
2) the systematically vary with the independent value
Name 2 problems that manipulation solves in an experimental design and give examples
1) manipulation solves directionality
ex/ it is noted that there is a relationship between ice cream and temperature, but does temperature affect ice cream consumption or does ice cream consumption affect temperature?
you can determine directionality by manipulating the variables: ex/ does increasing the temperature in the stadium lead to more ice cream being eaten during the baseball game? or does handing out free ice cream increase the temperature of the stadium? Most likely the first answer. Therefore, you can determine the directionality of the relationship: temperature affects ice cream.
2) Manipulation solves the third variable problems: you do not need to wait for the variables to change on their own, or else other things may be happening at the same time.
Ex/ increasing temp increases ice cream consumption, but it also increases crime rate. If you allow the temperature to fluctuate naturally/ (ie/ wait for summer), you may notice that crime rate increases and thus may make a conclusion that ice cream consumption is related to crime rate. This is most likely false, and you can prove this by handing out free ice cream and monitoring the crime rates (probably no correlation). You could also create a lot of crime scenarios and see if there is an increase in ice cream consuption (probably unlikely). Therefore, because the variables were manipulated, you can determine that the changes in the independent variable are NOT BEING CAUSED BY SOME OUTSIDE VARIABLE.
3 general categories of extraneous variables
1) environmental (room temp, type of room)
2) Individual differences (age, sex, IQ)
3) time related: treatment conditions are conducted over a period of time–> may cause fatigue
T/F a variable that is changing randomly with the independent variable is a confounding variable
false. A variable is only confounding if it changes SYSTEMATICALLY with the independent variable.
3 Methods of controlling extraneous variables:
1) control by holding a variable constant
2) control by matching values across treatment conditions
3) control by randomization
explain controlling extraneous variables by holding a variable constant and its drawbacks
extraneous variables by holding a variable constant entails making the variable the same for very observation, and standardizing the environment and procedures (ex/ choosing only 6 yo male participants who have completed grade 1, and testing them all in the same environment and same time of day.
A drawback of doing this is that it limits EXTERNAL VALIDITY OF THE EXPERIMENT because there are so many controls, there is also A LOT OF EFFORT INVOLVED
explain controlling extraneous variables by matching values across treatment conditions and its drawbacks.
controlling extraneous variables by matching values across treatment conditions entails allowing the variable to STILL BE PRESENT, but making the variable THE SAME in all treatment conditions. For example; you realize that the group of participants are not uniform in age- 5 are 10 years old and 5 are 15 years old. Instead of scrapping the group and creating uniform group, each separate treatment condition could also have 5 10 year olds and 5 15 year olds- the variability is still there, but the variability is matched.
you could also match time-related factors by varying the ORDER OF TREATMENTS (COUNTER BALANCING) so that you can say that time being tested (earlier rather than later) does not affect results
a drawback of matching variables is that it is time consuming an intensive, usually requiring more measurements to even group participants in the first place.
explain control of extraneous variables by randomization and its drawbacks
control of extraneous variables by randomization entails using a RANDOM PROCESS to avoid a SYSTEMATIC RELATIONSHIP between a 3rd variable and the DV. Allows the DISTRIBUTION of extraneous variables ACROSS ALL TREATMENT CONDITIONS.
Advantages: can control many variables simultaneously and does not require attention to each variable.
Disadvantages: does not guarantee that extraneous variables are controlled because IT USES CHANCE, needs LARGE SAMPLES
What is a placebo control group?
a control group that is given an inert medicine/fake treatment
What is a manipulation check?
a manipulation check sees if the IV has an intended effect by assessing how the participants perceived and interpreted the manipulation, and to assess the direct effect of manipulation
2 ways to check for manipulation?
1) explicit measuring of the independent variable (stress test)
2) embed specific questions about the manipulation in a questionaire to be completed after the experiment (ex/ did you notice and change in the behaviour of the research)?
4 Situations where you can apply a manipulation checK?
1) participant manipulations: did the experiment induce the right effect in a participant?
2) subtle manipulations: the variable being manipulated may not be noticed by participants
3) simulations: effectiveness relies on participants’ perception and acceptance
4) Placebo controls: placebo must be believed to be real, manipulation check can be used to assess the realism of the placebo
What happens if you do not conduct a manipulation check?
you do not know whether participants:
1) did not notice the manipulation
2) noticed but did not have expected impact
3) manipulation had impact but not expected impact
What is a confound check?
measures to determine whether manipulation had unwittingly caused differences on confound variables/
What is a simulation
create conditions within an experiment that simulates or duplicates the natural environment.
Mundane Realism
superficial characteristics of simulation, which probably has little positive effect on external validity (ex/ lab room changes to make it look like a bar)
What is experimental realism
psychological aspects of the simulation, the extent to which the participants become immersed in the simulation and behave normally.
ex/ Standford prison experiment has high experimental realism
Advantages and Disadvantages of simulation
Pros: investigate behaviors in life like situations, opportunity to control assignment of participants into conditions
cons: lose control over the situation and risk compromising internal validity. Dependent on willingness to accept simulation
Advantages and Disadvantages of a Field Study
Pros; investigate behavior in life like situations, high external validity, people act normally
cons: lose control over the situation, low internal validity. Ethnical approval for watching people needed. Difficult to apply random assignment because they are usually pre existing groups (ex/ a high school class)
