Studied by 11 peopleVariable
something in which individuals, animals or objects differ among themselves, can vary in amount or kind, and is measurable.
Controlled variable
Has an effect on the dependent variable so it is held constant to remove its potential effect.
Extraneous variable
Any variable other than the IV that may influence the DV and affect the results.
Confounding variable
An uncontrolled and unwanted variable that changes with the IV. A systematic variable that is not controlled for.
Random errors
Errors due to some chance factor or variation in a measurement.
Systematic errors
Produced by some factor that consistently favours one condition rather than another, such as a faulty measuring instrument
Accuracy
Relates to how close it is to the true value of the quantity being measured.
Precision
Refers to how closely a set of measurement values agree with each other.
Personal errors
Refers to how closely a set of measurement values agree with each other.
Outliers
Readings that lie a long way from other results; occurring by chance or larger sample sizes.
Uncertainty
All measurements are subject to uncertainty and may have many potential sources of variation and this uncertainty extends to all inferences and conclusions that depend on uncertain measurements.
Placebo effect
A change in the participants' response or behaviour due to expectation.
Experimenter effect
Unintentional personal characteristics of the experimenter can affect participant responses (experimenter bias).
Participant variables
The personal characteristics that individuals bring to an experiment that could influence their responses.
Situational variables
External factors associated with the experimental setting that may influence participant responses.
Order effects
Occurs when the performance on the DV is influenced by the specific order in which the experimented tasks are presented rather than the IV.
Practice effects
Influence on performance (the DV) that arises from repeating and/or prior experience with a task, including the test materials, procedures and settings.
Carryover effects
Influences that a task has on performance in a task that follows it; arises simply from completing a task.
Demand characteristics
Cues in an experiment that may influence or bias a participant’s response, thereby distorting the results.
Population
The larger group of research interest from which the sample is drawn and to which the researcher will seek to generalise the results of their investigation.
Sample
Smaller representative subset of participants drawn from the population of research interest.
Representative sample
A sample that closely resembles the population from which it is drawn in key characteristics.
Biased sample
A research sample that does not adequately represent the key characteristics of its population.
The law of large numbers
Suggests that as sample size increases, the attributes of the sample more closely reflect the attributes of the population from which the sample was drawn.
Random sampling
Used to obtain a representative sample from a population; ensuring every member of the population has an equal chance.
EXAMPLE:
An enrolment record of a student population in a school is used to randomly select 30 students using a lottery system.
ADVANTAGES:
– Useful for comparing specific subgroups within populations
– When randomly selected, it increases representativeness.
LIMITATIONS:
– Requires access to a relatively complete and up-to-date list of the target population
Stratified sampling
Targets specific subgroups within a population and seeks to achieve proportional representation of those subgroups within the final sample.
EXAMPLE:
A record of student enrolment at a school is referenced to proportionally select students from each year level in the same ratio as enrolments.
ADVANTAGES:
Helps ensure selection of a representative sample, thereby minimising sample bias in relation to participant variables..
LIMITATIONS:
– Time consuming
– Resource intensive to select a large sample
– Not using random sampling for subgroup selection results in non-representativeness.
Convenience sampling
Involves a choice of participants who are readily or most easily available.
EXAMPLE:
The first 30 students who walk through the school gates are asked to participate in a student wellbeing survey.
ADVANTAGES:
Usually time and cost effective as participants can be accessed relatively easily due to their availability.
LIMITATIONS:
– Tends to produce sample bias
– Thereby limiting generalisations to the population of research interest.
Sampling bias
Increases the likelihood of a biased sample being obtained and `doesn’t represent the key characteristics of the population.
Why need experimental and control groups?
– experimental group participants are exposed to the IV.
– control group participants are not exposed to the IV.
– both groups’ participants are measured on the DV.
– the purpose of the control group is to provide baseline data.
Between subjects
Each participant is allocated to 1, 2 or more groups or conditions.
ADVANTAGES:
– Short time period between conditions.
– Prevents participant attrition.
– No order effects to control.
LIMITATIONS:
– Larger number of participants is required to help ensure a larger variety of participant variables.
– Less control over participant variables, especially with a smaller sample size.
Within subjects
Has each participant in both the experimental and control groups. The groups/conditions are therefore identical in composition so individual participant differences may be controlled.
ADVANTAGES:
– Can control the unwanted influence of variables.
– Requires a relatively smaller number of participants.
LIMITATIONS:
– Does not necessarily control all participant variables that can influence the results.
– Fatigue is also more likely to occur with this design.
Mixed designs
Combines features of both a between and within subjects design. The researcher can assess the potential differences between two or more separate groups of participants, as well as change in the individual members of each group over time (i.e. within subjects).
ADVANTAGES:
– The researcher can capitalise on the strengths of the between subjects and within subjects designs.
– Fewer participants are needed for the experiment
– Greater sensitivity in the results; more precise.
LIMITATIONS:
– Internal validity threats reduce the likelihood of establishing a direct relationship between variables.
– Time-related effects, such as growth, can influence the outcomes.
– Carryover effects mean that the specific order of different treatments affect the outcomes.
Correlational studies
Investigates the relationship that exists between variables.
Quantitative correlation
By a correlation coefficient. Which, when calculated, ranges from -1 to +1.
Advantages:
– can be used to test hypotheses when it isn’t desirable / possible to experimentally manipulate the IV.
– can be conducted outside an artificial laboratory situation where the results may also be more realistic.
– useful for discovering relationships between variables.
– correlations can indicate patterns or trends, thereby contributing to the development / testing of theories.
Limitations:
– do not permit the researcher to draw firm conclusions about cause-and-effect relationships.
– not a legitimate research method for studying causality.
Self-reports
A participant’s answers to questions presented by the researcher.
Common methods are questionnaires and interviews and the researcher may choose to use free-response or fixed response questions.
Structured interview
Where the participant is asked specific, predetermined questions in a controlled manner.
e.g. the interviewer follows a script with fixed questions that are read in a neutral manner.
Semi-structured interview
The interviewer may use free response questions, but follows a script to ensure all are treated equally.
Unstructured interview
The researcher has an overall aim of what data should be collected but spontaneously generates questions.
Focus groups
Small set of similar people and are selected to discuss a topic that they have personal experience.
Advantages:
– able to collect data from a large number of people in a short period of time
– cost effective
– easy to administer
– anonymity
Limitations:
– assumption that people are self aware of their behaviours and personal experiences
– honesty
– bias
– social desirability
Observational studies
Involves a collection of data by carefully watching and recording behaviour as it occurs without any intervention or manipulation of the behaviour being observed.
Naturalistic observation
The researcher watches and records behaviour in the natural, ‘real life’ environment where it would ordinarily occur without manipulation of variables or other controls that occur in a laboratory setting.
Contrived environment
One that the researcher creates or sets up for the specific purpose of conducting an observational study. It is an artificial ‘non-naturalistic’, ‘controlled’ environment for the behaviour of interest.
Participant observation
A trained investigator studies a pre-existing group by joining it as a member, while avoiding a conspicuous role that would change what occurs in the group and biases the data.
Non-participant observation
Researcher tries to conceal their presence so that observations are made in an entirely inconspicuous manner.
Advantages:
– naturalistic observation, they can watch and record spontaneous, everyday behaviour without the need for any manipulation or intervention.
Limitations:
– cannot be used to determine the cause of behavioural interest that is observed, because many factors may influence that behaviour and there is a lack of control of such variables.
– naturalistic observation studies often lack a representative sample.
Observer bias
Researchers often use two or more observers for data collection and check for inter-rater consistency to avoid.
Case studies
An intensive, in-depth investigation of some behaviour, activity, event or problem of interest in a single individual, group, organisation or situation.
Advantages:
– the depth of analysis and richness of data.
– can avoid artificiality and provide a ‘snapshot’ of the actual or real life experience of one or more individuals.
– provides insights into how others may think, feel or behave under similar circumstances.
– a valuable source of hypotheses for further research / data to support theory building.
Limitations:
– cannot test or establish a cause-effect relationship as does a controlled experiment.
– small sample size; therefore, lack of generalisability.
– time consuming.
– often susceptible to biased information from the participants or researchers.
Simulation studies
Reproducing situations of research interest in a realistic way to investigate the behaviour and/or mental processes of individuals in that environment, such as the Stanford Prison experiment.
Advantages:
– can be a suitable alternative when the real environment is not available or possible.
– the diversity of research questions that can be investigated means that they can be a valuable source of hypotheses for further research or for data to support or challenge a theory or model.
– when a simulator and/or computer assisted technology is used, this may also be time and cost effective.
– greater experimental control.
– the capability of reproducing an identical environment whenever needed also supports replication.
Limitations:
– artificial and therefore studies may lack realism.
– artificiality makes it difficult to generalise the results of many simulated studies to the population or other situations of research interest.
Beneficence
The commitment to maximising benefits and minimising the 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.
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.
Non-maleficence
Involved avoiding the causations of harm; however, as a position or course of action may involve some degree of harm, the concept of non-maleficence implies that the harm resulting from any position or course of action should not be disproportionate to the benefits from any position or course of action.
Respect
Involves consideration of the extent to which living things have an intrinsic value and/or instrumental value; giving due regard to the welfare, liberty and autonomy, beliefs, perceptions, customs and cultural heritage of both the individual and the collective.
Ethical concepts
Supplemented by the following ethical guidelines, which should be considered when conducting and evaluating psychological investigations.
Confidentiality
The privacy, protection and security of a participant’s personal information. Anonymity of individual results, including the removal of identifying elements.
Debriefing
Ensures that at the end of the experiment, the participant leaves understanding the experimental aim, results and conclusions. Any participant questions are addressed, and support is also provided.
Debriefing is essential for all studies that involve deception.
Informed consent procedures
Ensures participants understand the nature and purpose of the experiment, including potential risks before agreeing to participate in the study.
Voluntary written consent should be obtained by the experimenter and if participants are unable to give this consent, then a parent or legal guardian should provide this.
Deception
Only permissible when participants knowing the true purpose of the experiment may affect their behaviour while participating in the study, and the subsequent validity of the experiment.
Voluntary participation
Ensures that there is no coercion or pressure put on the participant to partake in an experiment.
Withdrawal rights
Involves a participant being able to discontinue their involvement in an experiment at any time during or after the conclusion of an experiment, without penalty. This may include the removal of the participant’s results from the study after it has been completed.
Variability
The degree to which measures or values differ from one another.
Inferential statistics
A formal data analysis that measures the likelihood of results obtained for a study occurring by chance.
Allows us to deduce whether the effect observed within the results is probably typical of the target population from which the sample was derived.
Validity
The extent to which an assessment tool measures what it is designed to measure.
Reliability
The extent to which an assessment tool consistently measures what it is supposed to measure every time it is used, indicated by:
– repeatability = same conditions
– reproducibility = changed conditions
Internal validity
The extent to which an investigation actually investigated what it is set out to investigate / claims to have.
Lacking internal validity = gaps / flaws in experimental procedures and measures.
How to address it…
Through design and controlling EVs and CVs such as counterbalancing and blind procedures.
External validity
The extent to which the results obtained for a study can be applied beyond the sample that generated them, specifically to individuals in a different setting and over time.
Lack of external validity = the results of the research may not apply to individuals who are different from the population.
How to address it…
Conducting an experiment in a real world setting that is appropriate to the research question of interest and therefore more like an event in ‘real life’.
– internal validity is a precondition for external validity.
What do generalisations require?
– results are statistically significant.
– sample is representative of the population.
– the method of sampling is appropriate.
– all EVs and CVs have been controlled for.
Central nervous system
A major division of the nervous system consisting of all the nerves in the brain and spinal cord.
Function of the central nervous system:
– receives sensory information from the peripheral nervous system (body).
– sends motor information to the peripheral nervous system.
Brain
Regulates and guides all parts of the nervous system, responsible for…
– vital body functions.
– receiving information from the outside world via senses and coordinating appropriate responses.
– higher order functions.
– emotions, personality, sense of humour, etc…
Spinal cord
A cable-like column of nerve fibres that is encased by a series of bones called vertebrae, its function is to:
– send sensory / afferent information towards the brain through afferent tracks.
– send motor / efferent information away from the brain through efferent tracks.
When the spinal cord is injured, the brain can lose both sensory input from and control over the body. The severity of feeling loss and paralysis depends on where the spinal cord is injured & the severity of injury.
Peripheral nervous system
Everything outside of the central nervous system, which consists of muscles, organs and glands.
– sends sensory information to the central nervous system
– receives motor information from the central nervous system
Broken into somatic and autonomic nervous systems.
Somatic nervous system
A network of neurons within the body that transmit information from receptor sites to the central nervous system, and then carry information to the muscles to initiate voluntary movements.
Autonomic nervous system
A network of neurons that carry information between the central nervous system, and the other organs and glands, to ensure they are regulated without conscious awareness.
Broken into the sympathetic, parasympathetic and the enteric nervous systems.
Sympathetic nervous system
Prepares the body for action; to deal with a potential threat and activates the fight-flight-freeze response.
Activates the adrenal glands to release hormones such as adrenaline and cortisol into the bloodstream.
Fight-flight-freeze response
Initiated by the sympathetic nervous system and prepares the body to confront a stressful situation to optimise chances of survival.
This response is most prominent during acute stress.
Can include any adaptive responses that gives the body all necessary resources to maximise survival.
Parasympathetic nervous system
Maintains the body in a state of homeostasis and returns the body to a state of calm following stress / heightened arousal.
Responsible for maintaining automatic daily bodily functions such as digestion, heart rate, and breathing.
Physiological reactions due to activation of the parasympathetic or sympathetic nervous systems
Sympathetic NS (arousing) | Parasympathetic NS (calming) |
– contracts pupil – accelerates heartbeat – inhibits digestion – stimulates glucose release by liver and secretion of epinephrine and norepinephrine – relaxes bladder | – dilates pupil – slows heartbeat – stimulates digestion – stimulates gallbladder – contracts bladder |
Awareness
The state or ability to perceive, to feel, or to be conscious of events, objects, or sensory patterns.
Conscious response
The stimulus has been noticed and processed by the brain and leads to a voluntary and intentional response.
Unconscious response
The stimulus has not been noticed by the conscious mind and leads to an involuntary, uncontrolled and unintentional response.
e.g. pumping blood from your heart and digesting your food which are named autonomic reflexes.
Neurons
Building blocks of the nervous system. There are over 200 types and look different depending on their function.
e.g. pain or soft touch.
Sensory neurons
Neurons that are afferent, register pain and carry sensations and feelings.
Interneurons
Neurons that communicate between other neurons and they work heavily in coordinating the brain.
Motor neurons
Neurons that are efferent and have a large range of responses.
Spinal reflex
Also called a reflex arc, its an automatic, unconscious response that is initiated by interneurons in the spinal cord, independent of the brain.
When does it occur?
– pain, aid, survival.
How does it occur?
– intercepted by interneurons in the spinal cord.
Why does it occur?
– faster reaction time for larger chance of survival.
Five steps of the spinal reflex
stimulus is detected in a receptor.
sensory (afferent) neurons send the message to the spinal cord.
the interneurons within the spinal cord send the message to the motor neuron.
the motor (efferent) neuron sends the message to the muscles.
the muscles contract and move the hand away from the danger.
Structure of a neuron
Neurons | Key Components |
Dendrite | Receives incoming neural messages. |
Soma | The body of the neuron, containing the nucleus with the genetic material for the neuron. |
Axon | The pathway down which the neural message travels. |
Myelin Sheath | Fatty tissue that encases the axon to aid in speed of transmission. |
Axon Terminal | Exit pathways for neural messages to make their way to the next neuron. |
Terminal Buttons | Releases a chemical substance known as a neurotransmitter to a receiving neuron for communication purposes; also referred to as synaptic knobs. |
Lock and key process
neurotransmitters are contained in small sacs known as synaptic vessels within the terminal button of each neuron’s terminal axon.
when a presynaptic neuron fires, the synaptic vessels move towards the presynaptic membrane. Some synaptic vesicles stick to the membrane and break open to release the neurotransmitter into the synaptic cleft.
once in the synaptic cleft, some of the neurotransmitters will bind with protein molecules known as ‘receptors’ that are located in the dendrites of the postsynaptic neuron.
the receptor acts like locks that can only be opened with the particular ‘key’/neurotransmitter.
when a receptor binds with the neurotransmitter that ‘fits’ it (that has the appropriate molecular structure and electrical charge), the postsynaptic neuron is either activated or inhibited.
Synaptic gap
A minuscule space between the terminal buttons of the presynaptic neuron and the dendrites of a postsynaptic neuron.
Neural synapse
The site where communication occurs between adjacent neurons.
Neurotransmitters
Chemicals that transmit information from one neuron to the next, that usually either have an excitatory or inhibitory effect.
Its effects are due to the neurotransmitter binding itself to receptor sites of the postsynaptic neuron which are specialised to receive that type of neuron.
Re-uptake of neurotransmitters
After the postsynaptic neuron has received the neurotransmitter, any additional neurotransmitters in the synapses that have not been absorbed will be reabsorbed into the presynaptic neuron to be used again later.
Some medications are made to encourage the process of reuptake, which increases or decreases the availability and abundance of different neurotransmitters in the brain.
Glutamate
A type of excitatory neurotransmitter that sends signals to other cells to create large brain networks.
Helps with the formation and retrieval of memory, and hence enables learning as a result.
Too much glutamate can cause the over-excitation of neurons which can lead to neuronal damage and death.
Gamma-amino butyric acid (GABA)
Gamma-amino butyric acid is a type of inhibitory neurotransmitter that blocks or inhibits brain signals.
Largely associated with calming feelings of anxiety, stress and fear.
A reduced amount of GABA in the brain can cause seizures similar to epilepsy and other health issues.
Neuromodulators
Works together with neurotransmitters to enhance the inhibitory and excitatory effects and to create more widespread impacts in the brain.
– enhances signal transmission.
– effective on a group of neurons and their impacts can last longer.
– still chemicals and are released similarly to neurotransmitters.
Neuromodulation
Synaptic transmission between the pre and postsynaptic neurons are either decreased or enhanced through the action of a neuromodulator.
Any chemical communication that involves:
– not resulting in excitation or inhibition.
– not point-to-point.
– not necessarily fast.
Dopamine
Involved in drive, motivation and motor movement and associated with…
– addictive behaviours such as gambling due to the ‘dopamine hit’
– why “to-do lists” are so powerful for motivation
– low levels can cause Parkinson’s disease
The brain has several distinct dopamine producing areas and neural pathways along which dopamine travels to convey information to different areas and exert its influence; forming the dopaminergic system.
Two of the pathways are the nigrostriatal pathway which originates from the substantia nigra and the mesolimbic pathway.
Nigrostriatal pathway
Coordinates movement and originates in the substantia nigra.
If the substantia nigra is diseased = reduction in available dopamine & other brain structures linked to the pathway, receives fewer / irregular messages about motor activity.
Mesolimbic and mesocortical pathways
These pathways overlap and are heavily involved in the dopamine reward system and pleasure.
When achieving something, dopamine is released in the mesolimbic pathway.
Parkinson’s disease
A progressive degeneration of the nervous system, characterised by tremors and muscle rigidity.
Caused by low levels of dopamine and high levels of GABA (influences dopamine and blocks more messages).
Serotonin
Strictly inhibits and is our mood stabiliser; plays an important role in wellbeing, happiness, digestion, metabolism and stress and associated with…
– low levels linking to mental health issues such as sleep issues, depression and anxiety
Plays a large role in our daily sleep-wake cycle and has a relationship with melatonin.
Our brain uses serotonin in the pineal gland to produce melatonin.
Too much serotonin can lead to serotonin syndrome, which is characterised by fever, elevated heart rate, restlessness, agitation, confusion, hallucinations, delirium and seizures and can be fatal if not treated; often results from too high a dosage of medications used to increase low serotonin levels.
– illegal drugs such as ecstacy, cocaine and amphetamines (‘speed’/‘meth’/‘ice’) that act as stimulants in the CNS can also increase serotonin to a toxic level.
Serotonergic system
A collection of neurons and nuclei distributed along the brainstem in two groups sending projections in many directions.
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