Experimental Methods

Question 1

What is an extraneous variable?

Answer 1

Any variable other than the IV that affects the DV

Question 2

\What are the 2 types of extraneous variable?

Answer 2

1. Noise (unwanted variables that cause variability of scores within groups to increase) ie. time of day, mood of participants. Want to minimise as much as you can but there are certain things you cannot minimise.
2. Confounders – do need to worry about – something that is not of research interest that varies with the IV (think Harlow monkeys studies)

Question 3

What is the Hawthorne Effect and how does this relate to demand characteristics?

How could we potentially control this?

Answer 3

• Hawthorne effect (Expectancy effect) – testing people alone changes their behaviour. It is a type of demand characteristic.
• Demand characteristics – more general, Hawthorn effect more specific is a type of demand characteristic. Funnel debrief for this to help with it and assess it. ‘Features of the experiment that make the participant behave in a particular way’. So example of this is people aware being tested so change their behaviour.

Question 4

What is researcher bias?
How might we control this?

Answer 4

Researcher bias – Expectancy effects – if a child expects a teacher to do well then they do do well. Self-fulfilling prophecy. Similar effects can be found with researchers and participants through subtle cues.

** You can avoid research expectancy effects using double blind procedures**

Question 5

What experimenter affects might happen when we have the results?

Answer 5

Researchers can affect analysis as well ‘p hacking’
- They want to get a significant result
- Picking the analysis that gets p equal or same as 0.05
- Continuing data collection until p is same or equal to 0.05 (lets keep trying with more sets of participants until we get the results we want)

Question 6

What are some overall ways in which confounding variables might be introduced into an experiment?

Are these all threats to internal validity?

Answer 6

• Maturation (the change that occurs in participant as they do the experiment ie. boredom, fatigue) – counterbalancing to control this.
• History –
• Hawthorne effect (Expectancy effect) / demand characteristics
• Researcher bias (and can happen at analysis)
• Attrition or morality

Question 7

What are types of generalisation? What people are usually used in psychological studies?

Answer 7

• Population generalisation
• Stimulus generalisation
• Environmental generalisation
  – Ecological validity (the way people behave in the lab study they’ll behave in a similar way outside the lab setting)
• Temporal generalisation

WEIRD people studied (western, educated, industrialised, rich, democracies)

Question 8

What is external validity? Is it essential?

Answer 8

• An evaluation of an experiment that asks
  whether the observed results generalise to
  populations or situations different from
  those in the experiment.
• Things that prevent the observations being
  generalisable are threats to external
  validity.

External validity you can take or leave but internal validity Is vital for an experiment.

Question 9

What do we mean by a control?

Question 10

Experimenter effects at analysis: what is harking?

Answer 10

Hypothesizing After the Results are Known

• Hypotheses should be clear before the experiment is carried out
• An experiment might throw up many results, one happens to be significant, a hypothesis is then generated for that significant finding post hoc but is claimed to be a priori

Question 11

How to turn potential confounding variables into noise when:

1. Within participants
2. Between participants

Answer 11

• Within participant
  – (Everyone does all conditions)
  – Counterbalancing
• Between participant
  – (Each person does one condition)
  – Matching
  – Randomisation