PSYCH RM

One way to control for demand characteristics

One way to control for demand characteristics is to use a single-blind procedure. This means that the participants do not know which condition they have been assigned to
Therefore they are not able to respond according to what they think is being tested in that condition

what are investagator effects and how can they effect the experiment

Investigator effects occur when the researcher's presence/behaviour interferes with the research process and becomes a source of bias
The researcher's characteristics, such as age, gender and ethnicity, could influence how participants interact with them. The researcher could be biased in the way that they instruct participants or lead a task e.g.
if the researcher has hypothesised that X condition will result in higher scores then they may unconsciously communicate this to the participants

how to contol investagator effects

One way to control for investigator effects is to use a double-blind procedure
This means that the participants and the researcher do not know which condition each participant has been assigned to. this reduces unconscious bias

Randomisation meaning

Randomisation refers to the deliberate avoidance of bias on the part of the researcher to keep the research as objective as possible.Keeping participant allocation to condition random is one form of control that researchers have as it excludes the possibility of bias invalidating the research

what is Standardisation

Standardisation is the term used to describe the identical procedure set up in an experiment (or the questions used in self-report measures) across all conditions/participants.Standardisation means that no participant receives an unfair advantage or is treated any differently than any of the other participants. Standardised instructions are given to all participants
Standardised briefing before the procedure

There are three main types of experimental design

Independent Groups design
Repeated Measures design
Matched Pairs design

independant group design

In an independent groups design participants only experience one condition of the independent variable (IV) e.g.
participant A learns a poem with music playing (condition 1)
participant B learns the same poem in silence (condition 2). generates unrelated data

Evaluation of independent groups design & random allocation

Strengths:
The use of independent groups design means that demand characteristics are unlikely to act as a confounding variable.
As participants only take part in one condition of the IV they are less likely to guess the aim of the study and act accordingly, increasing internal validity.
As participants experience only one condition it means that order effects are eliminated
Participants will not become tired, bored or overly practised at the task
This is a strength as it increases the validity of the findings.
Limitations:
Participant variables may affect the validity of the findings
If more participants with a particular characteristic are all randomly allocated to one condition then this presents an unfair playing field
The results are thus not a true measure of the IV's effect on the DV.
More participants are needed for an independent groups design
This may cause logistical issues if there are enough people available to take part in the research

Repeated measures design & counterbalancing

n a repeated measures design participants experience all conditions of the IV e.g.
participant A learns a poem with music playing (condition 1)
participant A learns a different poem in silence (condition 2).
Each participant completes each of the experimental conditions
Repeated measures design generates related data
'Related' refers to the fact that each participant's score on condition 1 is compared to their score on condition 2.
Participants act as their own control group as their performance in condition 1 can be compared to their performance in condition.
A repeated measures design may give rise to order effects which consist of
fatigue, boredom and practice.

To avoid order effects researchers use

To avoid order effects researchers use counterbalancing. he researcher splits the participants in half e.g. 20 in one group, 20 in the other group
Half of the participants experience condition A followed by condition B
The other half of the participants experience condition B followed by condition A

Evaluation of repeated measures design & counterbalancing

:Strengths:
Participant variables are not an issue with a repeated measures design. This is because each participant's performance in one condition is measured against their performance in another condition so they act as their own control group
This increases the internal validity of the study
Fewer participants are needed for a repeated measures design as each participant generates 2 scores.
Limitations:
Demand characteristics may become a confounding variable. As participants take part in both conditions of the IV they may guess the aim of the study and act accordingly. If not controlled for, order effects may lower the validity of the study

Matched pairs design

A matched pairs design is one in which participants are matched based on a specific characteristic or variable that is important for the research they are taking part in e.g.
age
gender
ethnicity
IQ
aggression. Participants may be matched on more than one variable or characteristic
The matched participants are then randomly allocated to one condition each.
This matching helps to factor out the similar thing as a possible confounding variable in the experiment - any difference in scores should be due to the effect of the IV and not due to similar characteristic levels

Evaluation of matched pairs design

Strengths:
The matched pairs design almost factors out individual differences as a confounding variable
This means that each participant's performance is compared to someone very similar to themselves so participant variables are controlled to some extent, increasing reliability
As participants take part in the only condition of the IV this means that demand characteristics are reduced
Limitations:
Matching is a difficult and time-consuming process.
If one participant drops out of the research, then the researcher has to find someone very similar to replace them. less funding as timeline is involved

what is an aim

A general statement of what the researcher intends to investigate; the purpose of the study.

what is investigator effects

any effect of the investigator's behaviour, conscious or unconscious

validity

when a test claims to be measuring what it says its going to measure

uncontrolled extraneous variables means that the study lacks…

extraneous variables

When assessing the concurrent validity of a test, we…

compare the results obtained to a previous test of the same behaviour, that is known to be valid.

when we conduct face validity, we see if the experiment

is measuring what it says its measuring

We say that studies are reliable when…

the results of the study are consistent every time it is repeated.

A study can lack reliability if…

The test or questionnaire used to measure the DV is itself unreliable.
There are extraneous variables affecting the measurements.

external reliability

external reliability is when the results of a test are consistent every time it is used.

internal reliability

internal reliability is when the individual items within a test are consistent with each other.

The split-half method tests…

internal reliability, by splitting the test items in two and comparing the results.

how do we check if something is externally reliable

using test-retest method

The test-retest method is…

a method in which the researcher gets the same participants take the same questionnaire or test on two separate occasions and compares the results obtained both times.

Two ways we can assess validity

Two ways we can assess validity include testing the face validity of a study or measure, and testing the concurrent validity of a measure.

3 types of extraneous variables

participant, situational, experimenter

What are participant variables?

Personal characteristics of the participant which may affect the DV.

There are investigator effects in a study when…

The researcher influences the behaviour of the participants, and therefore the results of the study.

Situational variables are…

Extraneous variables that are features of the external environment.

Why can the researcher's expectations cause investigator effects?

Researcher expectations can affect their behaviour, which can lead to participants behaviour changing and, therefore, can affect the results of the study.

Matching means…

making sure a particular characteristic of the participants is divided equally across groups.

To control situational variables and investigator effects we can use…

standardisation

To summarise, we've seen that an experiment is..

A study that investigates cause and effect

what is A laboratory experiment

A laboratory experiment is an experiment where the independent variable is manipulated in an artificial environment.

Having a high control over extraneous variables means that the experiment will have

High internal validity

What is one strength of conducting a laboratory experiment?

The researcher can carefully control extraneous variables increasing the internal validity of the study.

But a con of laboratory experiment is…

The artificial environment may mean participants behaviour is not generalisable to everyday life, meaning the study may have low ecological validity.

a feild experiment is

an experiment where the independent variable is manipulated in a natural, everyday life setting.

:Field experiments have low/high internal validity?

:Field experiments have low internal validity as its hard toi control EVS

To sum it up, we've now seen the pros and cons of field experiments…

a pro is that they have higher ecological validity than laboratory experiments.
a con is that it is harder to establish clear cause and effect relationships between the variables.
a con is that researchers have less control over extraneous variables meaning the study has lower internal validity.

quasi experiment

IVs are already personal characteristics e.g age, personality and gender

quasi experiment pros

A pro is that they enable researchers to study independent variables that can't be studied in laboratory or field experiments.

quasi experiment cons

low internal validity as it doesnt establish cause and effect relationship

participants can't be randomly allocated to groups, meaning that uncontrolled participant variables might act as confounding variables.

a natural experiment is…

Used when it wouldn't be practical or ethical to manipulate the independent variable e.g car crash
An experiment where the independent variable is an event that has already happened.
An experiment where the independent variable isn't manipulated and can't be randomly allocated.

pros of natural experiment

It enables researchers to study independent variables that it would be unethical or impractical to investigate in a laboratory or field experiment.

con of natural experiment

confounding variables can br extraneous variables causing low internal validity
A con of natural experiments is that the researchers have little control over extraneous variables so the study has low internal validity.
A con is that it is difficult to establish a cause and effect relationship between the independent variable and the dependent variable.

ypes of experimental design, which means….

The choice of how to allocate participants to experimental groups.

strength of matched pairs

A strength of the design is that the researchers can establish a clearer cause and effect relationship between the independent variable and the dependent variable.
A strength of the design is that the researcher can control for some participant variables which increases the internal validity of the study.

two limitations of using matched pairs are…

We can't control for every possible participant variable so some may not be controlled.
Matching is time-consuming because the researcher must measure the personal characteristics of the participants.

independant groups design

when the researcher allocates different participants to each group but doesn't match the participants for any variables. can use random allocation
adv:dont get order effects,demand characteristics less likely 2 occur

Repeated measures design is….

when the same participants take part in all of the experimental conditions.
adv: particicpant variables can no longer act as confounding variables, fewer participants needed

wo limitations of the repeated measures design

the results can be influenced by order effects: which is when the order of the experimental conditions influences the results of a study.
participants are more likely to respond to demand characteristics when they repeat the same task multiple times.

matched pairs and i groups limitation

participant variables influence. i groups can control this using random allocation

in quasi and natural experiments the researcher cant use…

random allocation

How are participant variables controlled in an independent groups design?

random allocation

paradigm

A paradigm is a set of shared assumptions and methods.

thomas khun said that in order for something to be a science

it must have a paradigm

A paradigm shift is

a change in the set of assumptions
that a science follows. and advance science forward

falsifiability

It must be possible to prove a hypothesis false.
a feature of a scientific theory, in which it is possible to collect data that will prove the theory wrong

In science, objectivity means…

not letting personal bias affect the way you carry out an experiment.

emerpical evidence

Empirical evidence refers to when information is collected using direct observations.

theory construction

A theory is a comprehensive explanation that has already been backed up by the scientific method. And we construct theories to make predictions about the world. Theory construction is the final feature of science.

The seven features of science

they are hypothesis testing, empirical evidence, falsifiability, replicability, control, objectivity, and theory construction.

informed consent

Participants have given written agreement to take part in the study.
Participants fully understand what the study involves.

The third ethical guideline is protection from harm, which means that..

researchers must make sure the participants are in no more physical and emotional harm than they would be in normal life.

ourth ethical guideline is the right to withdraw, which means…

The five main ethical guidelines all psychology researchers should follow

informed consent, deception, confidentiality, the right to withdraw, and protection from harm.

population

large group of people that a particular researcher is interested in studying

random sample

people all have an equal chance of being selected. e.g all peoples names in a bag and first name goes into bag 1 second into bag 2 third in bag 1 forth in bag 2.
unbiased so extraneous variables are removed.

• difficult and time consuming to conduct and unrepresentitive

systematic sample

where every nth person is selected, e.g every 3rd prson on a school register.
objective- no influence over who is chosen
time consuming and people may refuse to take part

stratified sample

representitive over a large group of people.
representitive
-doesnt represent subgroups

opportunity sample

researcher just chooses whoever was around during the time
economical as everyone is already there and no need to divide

• unrepresentitive, people can just be from one demographic
  -researcher bias

volunteer sample

participants selecting themseleves tk be part of a sample
economical. minimal input required from researcher and less time consuming
volunteer bias

naturalistic observation

where the target behaviour would usually occur. however its useful to control certain aspects of the situation, e.g a one way mirror to not disturb the experiment and control extraneous variables

covert observation

participants are unaware but need to be ethical.

overt observation

participants give consent before study is taken

• demand characteristics
  +minimal ethical issues

participant obseervations

reaearcher acts as a participant with the group.
better insight but loses objectivity

non participant observations

reasercher isnt in the group. higher internal validity but lose valuable insight