Experimental Methods Flashcards

1
Q

What is a Laboratory experiment?

A

Carried out in a controlled environment, where the researcher manipulates the IV and measures the effect on the DV

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2
Q

What are strengths of using a lab experiment?

A
  • Possible to determine cause and effect relationship between IV and DV
  • Controlled environment allows great control over extraneous variables - ensure high internal validity
  • Replication is easy - check for reliability
  • Participants agree to take part, consent less of an issue (deception may prevent informed consent)
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3
Q

What are limitations of using a lab experiment?

A
  • Artificial setting of lab means research may lack ecological validity, making it difficult to generalise results to other settings
  • Being in a lab means participants are aware they’re being observed, making demand characteristics more likely which may lower the internal validity
  • Fact people are being tested on how they perform on a task increases the likelihood of evaluation apprehension - again, effect behaviour and have an effect on the internal validity
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4
Q

What is a field experiment?

A

An experiment that takes place in a natural setting where the experimenter manipulates the IV and measures the DV

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5
Q

What are the strengths of using a field experiment?

A
  • Ecological validity is easier to achieve as the setting is not artificial, more likely to generalise to other settings
  • Participants are often unaware they’re involved in an experiment and will not respond to demand characteristics
  • IV still manipulated by the researcher, so cause and effect can still be established
  • Replication is SOMET|MES possible, as long as the environmental circumstances do not change too much, reliability can sometimes be checked (not as easily as in lab)
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6
Q

What are limitations of using a field experiment?

A
  • The researcher does not have control of the setting, so there is a greater chance of confounding variables, making it less likely the experiment has internal validity
  • Difficult to replicate (precise circumstances may not occur twice) so may be difficult to check the reliability of the findings
  • Difficult to carry out using complicated apparatus
  • May be more time consuming if researcher has to wait for the right time of day, right number of people, type of people etc
  • Participants usually unaware they are taking part in an experiment, consent is difficult to obtain, debrief may be hard to carry out etc, ethical issues.
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7
Q

What is a quasi experiment?

A

An experiment often conducted in controlled conditions where the IV simply exists so there can be no random allocation to the conditions (may be referred to as not a true experiment) - No control condition, simply a comparison condition

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8
Q

What are the strengths of using a quasi experiment?

A
  • Enables the investigation of variables that, for either practical or ethical reasons, cannot be manipulated by the researcher
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9
Q

What are the disadvantages of using a quasi experiment?

A
  • There is less control over extraneous variables (e.g. participant variables) so there is a greater chance that these will confound the results - validity harder to achieve
  • Because the IV is not manipulated by the researcher, cause and effect relationships cannot be concluded
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10
Q

What is a natural experiment?

A

An experiment where the change in the IV already exists naturally, rather than being manipulated by the researcher

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11
Q

What are the strengths of using a natural experiment?

A
  • Enables the investigation of variables that for either practical or ethical reasons, cannot be manipulated by the researcher
  • Often the ecological validity is high, as the setting is the real world, and it is real events that are being studied
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12
Q

What are limitations of use a natural experiment?

A
  • Less control over extraneous variables (e.g. participant variables), so there is a greater chance that they will confound the results, internal validity harder to achieve
  • Because the IV is manipulated by the researcher, cause and effect relationships cannot be concluded
  • As they rely on naturally occurring events, they are difficult to replicate, so it is hard to check for reliability
  • May be ethical issues which need to be controlled
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13
Q

What is repeated measures design?

A

An experimental design where each participant takes part in both/all conditions of the IV

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14
Q

What are the strengths of using RM design?

A
  • Participant variables are controlled - helps to increase the internal validity
  • Fewer participants are needed - reduces time and expense
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15
Q

What are the limitations of using RM design?

A
  • Possibility of order effects - participant may get better through practice OR performance get worse due to fatigue or boredom
  • Participants may be able to guess the purpose of the experiment as they’re exposed to both conditions of the IV - performance may change due to demand characteristics
  • Inappropriate design if participation in one condition would affect the response in the other condition (deception involved)
  • Some experiments its impossible for participants to be in both conditions e.g. sex differences
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16
Q

How are order effects controlled?

A

Counterbalancing - half participants do condition A then B, other half do B, then A, any order effects should cancel each other out

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17
Q

What is independent groups design?

A

An experimental design where each participant only takes part in one condition of the IV

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18
Q

What are strengths of using independent groups?

A
  • No problem with order effects
  • Only see one value of IV - less problem with demand characteristics
  • Enables experiments where completion of the task would make it impossible for participants to complete the task a second time
  • Often, both conditions can be tested at the same time, which saves time
19
Q

What are the limitations of using independent groups?

A
  • Participant variables can be a problem as if the participants in each condition differ in some systematic way, this can be a confounding variable
  • More participants are required, which can be time consuming
20
Q

How can participant variables be addressed?

A

By randomly allocating participants to conditions

21
Q

What is matched pairs design?

A

An experimental design where pairs of participants are matched on important characteristics and one member is allocated to each condition of the IV

22
Q

What are strengths of using matched pairs design?

A
  • Reduced chance of participant variables confounding the results compared to IG design
  • Since participants only do task once, less of problem with them guessing the purpose - less chance of demand characteristics
  • Enables experiments to take place where completion of the task would make it impossible for participants to complete the task a second time (knowing about deception for example)
  • Enables experiments where participants cannot be in both conditions
  • Often, both conditions tested at the same time which saves time
23
Q

What are limitations of using matched pairs design?

A
  • Still possibility of confounding participant variables - impossible to have perfect match on many variables
  • Matching participants is extremely time consuming, makes the experiment more expensive and difficult to carry out practically
24
Q

What is the independent variable?

A

The variable that the experimenter manipulates

25
Q

What is the dependent variable?

A

The variable that is measured to tell you the outcome

26
Q

What is an extraneous variable?

A

Variables that if not controlled may affect the DV and produce a false impression that an IV has produced changes it hasn’t - NOT SYSTEMATIC

27
Q

What is a confounding variable?

A

An extraneous variable that varies SYSTEMATICALLY with the IV so we cannot be sure that the true source of the change of the DV

28
Q

What are common examples of extraneous variables?

A

Age of participants, lighting or noise conditions in a lab

29
Q

What are participant variables?

A

any aspects of the participants that could affect the research e.g. age, sex, intelligence

30
Q

How do we control for participant variables?

A
  • Use RM design where possible
  • Where not possible, use matched pairs
  • If independent groups is necessary, use random allocation to conditions
31
Q

What are situational variables?

A

any aspects of the environment in which the research is taking place that could have an effect e.g. temperature, noise level, visual cues, time of day, light level etc

32
Q

How do we control for situational variables?

A

ensure all conditions are carried out in the same situation - STANDARDISATION

33
Q

What is participant reactivity?

A

when individuals alter their performance or behaviour due to the awareness that they are being observed - may be positive or negative, but threatens the internal validity of the experiment

34
Q

What are demand characteristics?

A

when participants try to work out the purpose of the research, and behave difference as a result - behave according to interpretation of the situation

35
Q

How do we reduce the effect of demand characteristics?

A
  • use independent groups OR matched pairs design
  • double-blind procedure
  • deception
36
Q

What is a double-blind procedure?

A

participants and researchers who interact with them are unaware of which condition they have been placed in, reduce knowledge of how they’re expected to behave)

37
Q

What is evaluation apprehension?

A

participants’ concern about being evaluated/judged in an experiment - suspect that arousal level will increase as they’re concerned others are evaluating their behaviour which may effect the validity of the research

38
Q

What are investigator/experimenter effects?

A

any aspects of the person conducting the research that can effect the results e.g. personality, looks, sex, educational/racial background, age etc.
Examples:
- experimenter expectancy (can have systematic effect on how experimenter unconsciously communicates - use double-blind)
- loose procedure effect (if procedures not specifically specified leaves room for investigator to influence how it’s conducted, influencing results - control with double-blind and standardisation)
- design effect (not allow time for effect to appear)
- investigator fudging (fudge/fake results)

39
Q

What is standardisation?

A

ensures all participants have the exact same experience so that differences between experience of individuals does not case the participants to engage with the study differently

40
Q

What is operationalisation?

A

clearly describing the variables (IV and DV) in terms of how they will be manipulated (IV) or measured (DV)

41
Q

What is an aim?

A

a precise statement of why a research study is taking place - state what is being studied and what the study is trying to achieve

42
Q

What is a hypothesis?

A

a precise, testable statement of expected outcome of a research study - variables must be operationalised

43
Q

What are the two types of experimental (or alternative) hypothesis?

A

Directional or Non-directional

44
Q

What is a null hypothesis?

A

States what will happen if the theory is wrong - No significant difference/correlation - realise we cannot prove a theory true and only fail to falsify it