The Experimental method

Question 1

Define ecological validity

Answer 1

the degree to which an investigation represents real life

Question 2

what is the investigator effect?

Answer 2

the ways that the experimenter can accidentally influence the participant through their appearance or behaviour. This can include anything from the design of the study to the selection of, and interaction with, participants during the research process.

Question 3

How do you limit/avoid the investigator effect?

Answer 3

DOUBLE BLIND RESEARCH METHOD

Question 4

What is the double blind research method?

Answer 4

where neither the participants or the experimenters know who’s being given the treatment or control treatment-useful for preventing bias due to demand characteristics or the placebo effect.

Question 5

What are demand characteristics?

Answer 5

clues in the experiment that lead the participants to think they know what the researcher is thinking (e.g.experimenter’s body language). May lead to a participant changing their behaviour within the research situation (SCREW U or PLEASE U effect).

Question 6

How to limit/avoid demand characteristics?

Answer 6

SINGLE BLIND RESEARCH METHOD (DECEPTION)

Question 7

What is the single blind research method?

Answer 7

where the researchers don’t tell the participants if they’re being given a test treatment or a control treatment-ensures that the participants don’t bias the results by acting in ways they think they should act.

Question 8

What is randomisation?

Answer 8

The use of chance in order to control the effects of bias when designing materials and deciding the order of conditions.

Question 9

What is standardisation?

Answer 9

Using exactly the same formalised procedures and instructions for all participants in a research study.

Question 10

What is an independent variable?

Answer 10

variable the experimenter manipulates-assumed to have a direct effect on the DV.

Question 11

What is a dependent variable?

Answer 11

variable the experimenter measures.

Question 12

What is an extraneous variable?

Answer 12

are all variables, which aren’t the IV, but could impact the results (the DV) of the experiment. They should be controlled when possible.

Question 13

What are confounding variables?

Answer 13

variables that have impacted the results (DV), apart from the IV. Could be an EV that hasn’t been controlled. They vary systematically with the IV.

Question 14

What is operationalisation?

Answer 14

process of strictly defining variables into measurable factors. The process defines fuzzy concepts and allows them to be measured, empirically and quantitatively.

Question 15

What is a lab experiment?

Answer 15

• an experiment conducted in a well controlled environment-not necessarily a lab- and ergo accurate measurements are possible.
• Researcher decided where the experiment will take place, at what time, with which participants, in what circumstances and using a standardised procedure. Participants are randomly allocated to each IV group.

Question 16

Examples of lab experiments…

Answer 16

• Milgram’s study on obedience

* Lotus and Palmer’s car crash study

Question 17

What are the strengths and limitations of lab experiments?

Answer 17

STRENGTHS=
+easier to replicate a lab experiment.
+allows for precise control of EVs and IVs-allows a cause and effect relationship to be established.

LIMITATIONS=

• artificiality of setting may produce unnatural behaviour that doesn’t reflect real life…means that it would’t be possible to generalise the findings to a real life setting (LOW ECOLOGICAL VALIDITY).
• demand characteristics or investigator effects may bias the results and become CVs.

Question 18

What is a field experiment?

Answer 18

Done in the everyday environment of the participants. The experimenter still manipulates the IV, but in a real life setting so can’t control EVs.

Question 19

Example of a field experiment…

Answer 19

*Holfing’s hospital study on obedience.

Question 20

What are natural experiments?

Answer 20

are conducted in the everyday environment of the participants, but here the experimenter has no control over the IV as it occurs naturally in real life.

Question 21

Example of a natural experiment…

Answer 21

*Hodges and Tizard’s attachment research (1989)-compared the long term development of children who have been adopted, fostered or returned to their mothers with a control group of children who had spent all of their lives with their biological parents.

Question 22

What are the strengths and limitations of natural experiments?

Answer 22

STRENGTHS=
+behaviour is more likely to reflect real life because of its natural setting (VERY HIGH ECOLOGICAL VALIDITY)
+There’s a less likelihood of DCs affecting the results as participants may not know they’re being studied.
+can be used in situations where it’d be ethically unacceptable to manipulate the IV (e.g.researching stress)

LIMITATIONS=

• may be more expensive and time consuming than lab experiments.
• there’s no control over EVs that might bias the results…makes it more difficult for another researcher to replicate the study in exactly the same way.

Question 23

What are the strengths and limitations of field experiments?

Answer 23

STRENGTHS=
+behaviour is more likely to reflect real life as it’s in a natural setting (HIGH ECOLOGICAL VALIDITY)
+less likelihood of DCs impacting the results as participants may not know they’re being studied. This occurs when the study is covert.

LIMITATIONS=
-less controls over EVs that might bias the results…makes it difficult for another researcher to replicate the study in exactly the same way.

Question 24

Define covert

Answer 24

not openly acknowledged or displayed.

Question 25

What is a quasi experiment?

Answer 25

Isn't a true experiment as the researcher isn't able to randomly allocate participants to different conditions of the experiments- usually because the IV is a quality of the participant. Sometimes known as a difference study.

Question 26

Examples of quasi experiments...

Answer 26

* an experiment with an IV of gender is described as a quasi-experiment as the researcher can't randomly allocate participants to either the male or female condition. * testing people with Autism and Down's syndrome for their ability to understand other people's emotions. * Comparing older and younger participants' ability to solve a word search.

Question 27

What are the strengths and limitations of quasi experiments?

Answer 27

STRENGTHS= +are often carried out under controlled conditions and thus share almost the same strengths and weaknesses of lab experiments (e.g. highly controlled with low ecological validity) LIMITATIONS= -because the allocation to the IV isn't random we can't be certain that the IV has caused any change to the DV. Ergo they're said to be lower in internal validity than a well controlled lab experiment. However it's possible to improve it by increasing the size of the sample thus reducing participant differences or using a comparison group who are very similar.

Question 28

What is the difference between a natural and quasi experiment?

Answer 28

Quasi experiments involve a planned IV.