psych chapter 1 - key science skills

independent variable

the variable for which quantities are manipulated by the researcher, and the variable that is assumed to have a direct effect on the dependent variable

dependent variable

the variable the researcher measures in an experiment for changes it may experience due to the independent variable

types of psychological studies

• controlled experiment

• case studies

• correlational studies

types of controlled experiment designs

• within-subjects design

• between-subjects design

• mixed design

within-subjects design

an experimental design in which participants complete every experimental condition.

between-subjects design

an experimental design in which individuals are divided into different groups and complete only one experimental condition.

mixed design

an experimental design which combines elements of within-subjects and between-subjects designs. Allows experimenters to note differences that occur within each experimental group over time, and compare differences across experimental groups.

population

the group of people who are the focus of the research and from which the sample is drawn.

sample

a subset of the research population who participate in a study

generalisability

the ability for a sample’s results to be used to make conclusions about the wider research population

acheiving a representative sample is dependent on

• its size; the bigger the sample, the more likely it is to be representative of the population

• the sampling techniques used; how a sample is selected can determine whether it is biased or representative (how accurately it reflects the population’s makeup)

sampling techniques

-convenience sampling

-random sampling

-stratified sampling

convenience sampling

any sampling technique that involves selecting readily available members of the population

random sampling

any sampling technique that uses a procedure to ensure every member of the population has the same chance of being selected

stratified sampling

any sampling technique that involves selecting people from the population in a way that ensures its strata are proportionally represented in the sample

allocation

the process of assigning participants to experimental conditions or groups

extraneous variables

any variable that is not the independent variable but may cause an unwanted effect on the dependent variable

confounding variable

a variable that has directly and systematically affected the dependent variable, apart from the independent variable

examples of extraneous and confounding variables

• participant related variables

• order effects

• placebo effects

• experimenter effects

• situational variables

• non-standardised instructions and procedures

• demand characteristics

participant-related variables

characteristics of a study’s participants that may affect the results (e.g. age, intelligence, and socioeconomic status)

order effects

the tendency for the order in which participants complete experimental conditions to have an effect on their behaviour. occurs primarily in within-subjects experimental designs

placebo effect

when participants respond to an inactive substance or treatment as a result of their expectations or beliefs.

experimenter effects

when the expectations of the researcher affect the results of an experiment

situational variables

any environmental factor that may affect the dependent variable (e.g. temperature, lighting, weather, time of day)

non-standardised instructions and procedures

occur when directions and procedures differ across participants or experimental conditions, introducing unwanted situational variables.

demand characteristics

cues in an experiment that may signal to a participant the intention of the study and influence their behaviour.

preventing extraneous and confounding variables

• having a larger sample size - increases sample’s representativeness of the population

• experimental design choice - prevents order effects when using within-subjects design

• counterbalancing - reduces order effects that involves ordering experimental conditions in a certain way

• placebo - compare results with participants who are given an active treatment

• single-blind procedures - participants are unaware of the experimental group/condition they have been allocated to

• double-blind procedures - neither researcher nor participant are aware

primary data

data collected first-hand by a researcher

secondary data

data sourced from other’s prior research, not collected directly by the current researcher

quantitative data

data that is expressed numerically, such as test scores or measurements of weight, and may be collected through methods such as close-ended surveys, rating scales, or mcqs

qualitative data

data that is expressed non-numerically, such as a participant’s verbal description of how they are feeling, and may be collected through methods such as open-ended questionnaires and interviews

objective data

data that is observed and measured independently of a personal opinion, such as a person’s weight in kg or their numerical scores on an intelligence test

subjective data

data that is informed by personal opinion, perception, or interpretation, and comes from participant’s own qualitative descriptions and self-reports

accuracy

how close a measurement is to the true value of the quantity being measured

precision

how closely a set of measurement values agree with each other

measurement errors

• systematic erros

• random errors

systematic errors

errors in data that differ from the true value by a consistent amount, and may occur due to environmental factors, observational/researcher error, or incorrect measurement instrument calibration

random errors

errors in data that are unsystematic and occur due to chance, and may occur due to poorly controlled or varying measurement procedures, imperfect or faulty measurement tools, variations in measurement contexts.

random errors can be reduced by

• repeating and conducting more measurements

• calibrating measurement tools correctly

• refining measurement procedures

• controlling any other extraneous variables

• increasing the sample size of participants

repeatability

the extent to which successive measurements or studies produce the same results when carried out under identical conditions within a short period of time.

reproducibility

the extent to which successive measurements or studies produce the same results when repeated under different conditions

validity

the extent to which psychological tools and investigations truly support their findings or conclusions

internal validity

the extent to which an investigation truly measures or investigates what it claims to.

external validity

the extent to which the results of an investigation can be applied to similar individuals in different settings

ethical concepts

• beneficence

• integrity

• respect

• justice

• non-maleficence

beneficence

the commitment to maximising benefits and minimising risks and harms involved in taking a particular position or course of action

integrity

the commitment to searching for knowledge and understanding, and the honest reporting of all sources of information and results, whether favourable or unfavourable, in ways that permit scrutiny and contribute to public knowledge and understanding

justice

the moral obligation to ensure that there is fair consideration of competing claims; that there is no unfair burden on a particular group from an action'; and that there is fair distribution and access to the benefits of an action.

non-maleficence

the principle of avoiding causing harm, implies that the harm resulting from any position or course of action should not be disproportionate to the benefits from an position or course of action.

respect

the consideration of the extent to which living things have an intrinsic value, giving due regard to the welfare, liberty and autonomy, beliefs, perceptions, customs, and cultural heritage of both the individual and the collective.

ethical guidelines

• confidentiality

• voluntary participation

• debriefing

• informed consent procedures

• withdrawal rights

• use of deception

confidentiality

the privacy, protection, and security of a participant’s personal information in terms of personal details and the anonymity of individual results, including the removal of identifying elements.

informed consent procedures

processes that ensure participants understand the nature and purpose of the experiment, including potential risks, before agreeing to participate in the study.

deception

the act of intentionally misleading participants about the true nature of a study or procedure

debriefing

a procedure that ensures that, at the end of the experiment, the participant leaves understanding the experimental aim, results, and conclusions

voluntary participation

a principle that ensures there is no coercion or pressure put on the participant to partake in an experiment, and they freely chose to be involved.

withdrawal rights

the right of participants to be able to discontinue their involvement in an experiment at any time during, or after the conclusion of an experiment without penalty.