AICE Psychology - Chapter 1 Research Methods

Dependent variable (DV)

The factor in an experiment that is measured and is expected to change under the influence of the independent variable

Experiment

An investigation that allows researchers to look for a causal relationship; an independent variable is manipulated and is expected to be responsible for changes in the dependent variable

Independent variable (IV)

The factor under investigation in an experiment that is manipulated to create two or more conditions (levels) and is expected to be responsible for changes in the dependent variable

Uncontrolled variable

A variable that either acts randomly, affecting the DV in all levels of the IV, or systematically, i.e. on one level of the IV (called a confounding variable) so can obscure the effect of the IV, making the results difficult to interpret, the effects of which have not or cannot be limited or eliminated

Experimental condition

One or more of the situations in an experiment that represent different levels of the IV and are compared (or compared to a control condition)

Control condition

A level of the IV in an experiment from which the IV itself is absent. It is compared to one or more experimental conditions

Experimental design

The way in which participants are allocated to levels of the IV

Independent measures design

An experimental design in which a different group of participants is used for each level of the IV (condition)

Demand characteristics

features of the experimental situation which give away the aims. They can cause participants to try to change their behavior, for example to match their beliefs about what is supposed to happen, which reduces the validity of the study

Random allocation

A way to reduce the effect of confounding variables such as individual differences. Participants are put in each level of the IV such that each person has an equal chance of being in any condition

Repeated measures design

An experimental design in which each participant performs in every level of the IV

Participant variables

Individual differences between participants (such as age, personality and intelligence) that could affect their behavior in a study that would hide or exaggerate differences between levels of the IV 

Confounding variable

An uncontrolled variable that acts systematically on one level of the IV so could hide or exaggerate differences between levels and therefore 'confound' or confuse the results making it difficult to understand the effect of the IV on the DV

Order effects

Practice and fatigue effects are the consequences of participating in a study more than once, for example in a repeated measures design. They cause changes in performance between conditions that are not due to the IV, so can obscure the effect on the DV

Practice effect

A situation where participants' performance improves because they experience the experimental task more than once, for example due to familiarity or learning the task

Fatigue effect

A situation where participants' performance declines because they experience the experimental task more than once, e.g. due to physical tiredness or boredom with the task

Randomization

A way to overcome order effects in a repeated measures design. Each participant is allocated to perform in the different levels of the IV in a way that ensures they have an equal chance of participating in the different levels in any order

Counterbalancing

A way to overcome order effects in a repeated measures design. Each possible order of levels of the IV is performed by a different sub-group of participants. This can be described as an ABBA design, as half the participants do condition A then B, and half do B then A

Matched pairs design

An experimental design in which participants are arranged into pairs. Each pair is similar in ways that are important to the study and one member of each pair performs in a different level of the IV

Laboratory experiment

A research method in which there is an IV, a DV and strict controls. It looks for a causal relationship and is conducted in a setting that is not in the usual environment for the participants with regard to the behaviour they are performing

Controls

Ways to keep potential confounding variables constant, for example between levels of the IV, to ensure measured differences in the DV are likely to be due to the IVI raising validity

Standardization

Keeping the procedure for each participant in a study (e.g. an experiment or interview) exactly the same to ensure that any differences between participants or conditions are due to the variables under investigation rather than differences in the way they treated

Reliability

The extent to which a procedure, task or measure is consistent, for example, that it would produce the same results with the same people on each occasion

Validity

The extent to which the researcher is testing what they claim to be testing

Pilot study

A small-scale test of the procedure of a study before the main study is conducted. It aims to ensure that the procedure and materials are valid and reliable, so that they can be adapted if not

Replication

Keeping the procedure and materials exactly the same between studies when attempting, for example, to verify results or to enable other studies to use exactly the same techniques to answer related questions

Operational definition

The clear description of a variable such that it can be accurately manipulated, measured or quantified, and the study can be replicated. This includes the way that the IV and DV in experiments, and the co-variables in correlations, are described

Placebo

A pill or procedure given to a patient who believes it to be a real treatment which in fact has no active 'ingredient', i.e. no active drug in the case of a pill or no therapeutic value in the case of an intervention

Field experiment

An investigation looking for a causal relationship in which an independent variable is manipulated and is expected to be responsible for changes in the dependent variable. It is conducted in the normal environment for the participants for the behaviour being investigated and some control of variables is possible

Generalize

To apply the findings of a study more widely, e.g. to other settings and populations

Ecological validity

The extent to which the findings of research conducted in one situation would generalize to other situations. This is influenced by whether the situation (e.g. a laboratory) represents the real world effectively and whether the task is relevant to real life (has mundane realism)

Hypothesis (plural hypotheses)

A testable statement based on the aims of an investigation

Alternative hypothesis

The testable statement predicting a difference in the DV between levels of the independent variable in an experiment (or a relationship between variables in a correlation)

Non-directional (two-tailed) hypothesis

A statement predicting only that one variable will be related to another, for example that there will be a difference in the DV between levels of the IV in an experiment (or that there will be a relationship between the measured variables in a correlation)

Directional (one-tailed) hypothesis

A statement predicting the direction of a relationship between variables, for example in an experiment whether the levels of the IV will produce an increase or a decrease in the DV (or in a correlation whether an increase in one variable will be linked to an increase or a decrease in another variable)

Null hypothesis

A testable statement saying that any difference or correlation in the results is due to chance, that is, that no pattern in the results has arisen because of the variables being studied

Informed consent

Knowing enough about a study to decide whether you want to agree to participate

Right to withdraw

A participant should know they can remove themselves, and their data, from a study at any time

Protection from harm

Participants should not be exposed to any greater physical or psychological risk than they would expect in their day-to-day life

Deception

Participants should not be deliberately misinformed (lied to) about the aim or procedure of the study. If this is unavoidable, the study should be planned to minimise the risk of distress, and participants should be thoroughly debriefed. It may be done to reduce the effects of demand characteristics but should be avoided

Privacy

Participants' emotions and physical space should not be invaded, for example they should not be observed in situations or places where they would not expect to be seen

Confidentiality

Participants' results and personal information should be kept safely and not released to anyone outside the study

Self-report

A research method, such as a questionnaire or interview, which obtains data by asking participants to provide information about themselves

Questionnaire

A self-report research method that uses written questions through a 'paper and pencil' or online technique

Closed questions

A question format in questionnaires, interviews or test items that produces quantitative data. They have only a few, stated alternative responses and no opportunity to expand on answers

Open questions

A question format in questionnaires, interviews or test items that produces qualitative data. Participants give full and detailed answers in their own words, that is, no categories or choices are given

Inter-rater reliability

The extent to which two researchers interpreting qualitative responses in a questionnaire (or interview) will produce the same records from the same raw data

Generalizability

How widely findings apply, e.g. to other settings and populations

Social desirability bias

Trying to present oneself in the best light by determining how to respond to the in a way that would be most acceptable to other people, rather than to the researcher

Filler questions

Items put into a questionnaire, interview or test to disguise the aim of the study by hiding the important questions among irrelevant ones so that participants are less likely to work out the aims and then alter their behavior

Interview

A research method using verbal questions asked directly, using techniques such as face to face or telephone

Structured interview

An interview format using questions in a fixed order that may be scripted. Consistency might also be required for the interviewer's posture, voice, etc. so they are standardized

Unstructured interview

An interview format in which most questions (after the first one) depend on the respondent's answers. A list of topics may be given to the interviewer

Semi-structured interview

An interview format using a fixed list of open and closed questions. The interviewer can add more questions if necessary

Subjectivity

The effect of an individual's personal viewpoint on, for example, how they interpret data. Interpretation can differ between individual researchers as a viewpoint may be biased by one's feelings, beliefs or experiences, so is not independent of the situation

Objectivity

The impact of an unbiased external viewpoint on, for example, how data is interpreted. Interpretation is not affected by an individual's feelings, beliefs or experiences, so should be consistent between different researchers

Case study

A research method in which a single instance, e.g. one person, family or institution, is studied in detail

Triangulation

Is when different techniques, e.g. observations, interviews and tests, are used to study the same phenomenon. If they produce similar results, this suggests the findings are valid

Naturalistic observation

A study conducted by watching the participants' behavior in their normal environment without interference from the researchers in either the social or physical environment

Controlled observation

A study conducted by watching the participants' behavior in a situation in which the social or physical environment has been manipulated by the researchers. It can be conducted in either the participants' normal environment or in an artificial situation

Unstructured observation

A study in which the observer records the whole range of possible behaviors, which is usually confined to a pilot stage at the beginning of a study to refine the behavioral categories to be observed

Structured observation

A study in which the observer records only a limited range of behaviors

Behavioral categories

The activities recorded in an observation. They should be operationalized (clearly defined) and should break a continuous stream of activity into discrete recordable events. They must be observable actions rather than inferred states

Inter-observer reliability

The consistency between two researchers watching the same event, i.e. whether they will produce the same records

Participant observer

A researcher who watches from the perspective of being part of the social setting

Non-participant observer

A researcher who does not become involved in the situation being studied

Overt observer

The role of the observer is obvious to the participants

Covert observer

The role of the observer is not obvious, e.g. because they are hidden or disguised

Co-variables

The two measured variables in a correlation

Correlation

A research method that looks for a relationship between two measured variables. A change in one variable is related to a change in the other (although these changes cannot be assumed to be causal)

Causal relationship

A link between two variables such that a change in one variable is responsible for (i.e. causes) the change in the other variable, such as in an experiment

Positive correlation

A relationship between two variables in which an increase in one accompanies an increase in the other, i.e. the two variables increase together

Negative correlation

A relationship between two variables in which an increase in one accompanies a decrease in the other, i.e. higher scores on one variable correspond with lower scores on the other

Longitudinal study

A research method that follows a group of participants over time, weeks to decades, looking at changes in variables to explore development or changes due to experiences, such as interventions, drugs or therapies

Cross-sectional study

Compares people at different ages or stages by comparing different groups of participants at one point in time

Cohort

A group of participants selected at the same age or stage

Longitudinal design

An experimental design where the same participants are tested on two or more occasions over a long time, e.g. before and after a six-month intervention

Situational variable

A confounding variable caused by an aspect of the environment, for example the amount of light or noise

Intelligence quotient (IQ)

A measure of general reasoning and problem solving ability

Sample attrition

The loss of participants from a sample over time. This may be due to many reasons, such as losing contact, the desire to discontinue, for example though boredom, being unavailable or death

Aim

The intention of the study, the idea being tested or the purpose of the research, such as to investigate a question or solve a problem

Standardized instructions

The written or verbal information given to participants at the beginning and sometimes during a study that ensure the experience of all participants, regardless of level of the IV, is as similar as possible

Population

The group, sharing one or more characteristics, from which a sample is drawn

Sample

The group of people selected to represent the population in a study

Sampling technique

The method used to obtain the participants for a study from the population

Opportunity sample

Participants are chosen because they are available, for example university students are selected because they are present at the university where the research is taking place

Volunteer (self-selected) sample

Participants are invited to participate, for example through advertisements via email or notices. Those who reply become the sample

Random sample

Sampling all members of the population (i.e. possible participants) are allocated numbers and a fixed amount of these are selected in an unbiased way, for example by taking numbers from a hat

Quantitative data

Numerical results about the amount or quantity of a psychological measure, such as pulse rate or a score on an intelligence test

Qualitative data

Descriptive, in-depth results indicating the quality of a psychological characteristic, such as responses to open questions in self-reports or case studies and detailed observations

Measure of central tendency

A mathematical way to find the typical or average score from a data set, using the mode, median or mean

Mode

The measure of central tendency that identifies the most frequent score(s) in a data set

Median

The measure of central tendency that identifies the middle score of a data set, which is in rank order (smallest to largest). If there are two numbers in the middle, they are added together and divided by two

Mean

The measure of central tendency calculated by adding up the values of all the scores and dividing by the number of scores in the data set

Measure of spread

A mathematical way to describe the variation or dispersion within a data set

Range

The difference between the biggest and smallest values in the data set plus one (a measure of spread)

Standard deviation

A calculation of the average difference between each score in the data set and the mean. Bigger values indicate greater variation (a measure of spread)

Bar chart

A graph used for data in discrete categories and total or average scores. There are gaps between each bar that is plotted on the graph because the columns are not related in a linear way

Histogram

A graph used to illustrate continuous data, e.g. to show the distribution of a set of scores. It has a bar for each score value, or group of scores, along the x-axis. The y-axis represents frequency of each category

Scatter graph

A way to display data from a correlational study. Each point on the graph represents the point where one participant's score on each scale for the co-variables cross