Physiological measures of stress | AQA A-Level Psychology Revision
- Revision Notes
- Aug 6
- 22 min read
Updated: Aug 14
For 7182 specification, first teach in September 2025
AQA A-Level Psychology | Free Revision Notes
Estimated study time: 60 minutes
These physiological measures of stress A-Level Psychology revision notes explain how changes in bodily arousal can be used to investigate stress. You will study skin conductance response, focusing on how increased moisture at the skin raises electrical conductivity. Physiological measurements will then be compared with questionnaire and rating-scale methods [Measuring stress through self-report]. Although physiological data are objective and can be recorded in real time, they may measure general arousal rather than stress specifically.
Learning Objectives 🎯
By the end of this revision page, you should be able to:
Define a physiological measure of stress.
Explain the relationship between arousal, skin moisture and conductivity.
Interpret changes in skin conductance during a stressful task.
Compare physiological measures with self-report measures.
Apply skin conductance response to unfamiliar research scenarios.
Evaluate the objectivity, reliability and validity of physiological measurement.
Revision Notes 📚
What does the AQA specification require?
Within the Stress option, AQA requires students to study:
Self-report measures of stress, including the Social Readjustment Ratings Scale and Hassles and Uplifts Scale.
Physiological measures of stress, including skin conductance response.
This lesson therefore focuses on skin conductance response as the named physiological measure.
You should be prepared to:
Explain how skin conductivity changes during stress-related arousal.
Interpret higher and lower skin conductance readings.
Compare physiological and self-report measurements directly.
Explain why physiological measures are considered objective.
Evaluate whether skin conductance is a valid measure of stress.
What is a physiological measure?
A physiological measure records bodily activity associated with a psychological state or response.
Rather than asking a participant whether they feel stressed, a researcher records a change in physical functioning.
Physiological indicators of arousal may include:
Skin conductance.
Heart rate.
Blood pressure.
Muscle tension.
Hormonal activity.
For this part of the specification, the named measure you must understand is skin conductance response.
Physiological arousal and stress
Stress can activate the autonomic nervous system.
This may produce bodily changes such as:
Increased heart rate.
Faster breathing.
Increased blood pressure.
Greater sweating or moisture at the skin.
Increased muscular tension.
These changes form part of the body’s preparation to respond to a demand or threat.
Knowledge of rapid sympathetic arousal [The sympathomedullary pathway] helps explain why a stressful situation may produce observable physiological changes.
Physiological arousal is not the same as stress
A crucial distinction is:
Stress may produce physiological arousal, but physiological arousal does not necessarily prove that the person is stressed.
Arousal can also occur during:
Excitement.
Surprise.
Fear.
Physical activity.
Anticipation.
Anger.
A physiological measure may therefore detect that the body is activated without revealing the exact psychological reason.
This is the central validity problem with physiological measurement.
Skin Conductance Response
What is skin conductance response?
Skin conductance response, often abbreviated to SCR, is a physiological measure based on changes in how well the skin conducts electricity.
When a person becomes physiologically aroused:
Moisture at the surface of the skin increases.
The skin conducts electricity more easily.
Skin conductivity increases.
The increased conductivity is used as an indication of greater physiological arousal.
AQA has directly assessed this relationship. The correct sequence is:
Skin moisture increases → skin conductivity increases
Skin conductance and sweating
Stress-related sympathetic arousal may increase activity associated with sweating.
The increase may be very small and may not be visible to an observer. However, even a small rise in moisture can alter how readily the skin conducts electricity.
The relationship is:
Skin moisture | Skin conductivity |
Lower moisture | Lower conductivity |
Higher moisture | Higher conductivity |
The key rule is:
More moisture means greater conductivity.
How skin conductance indicates arousal
A researcher can compare the participant’s skin conductivity:
Before a possible stressor.
While the stressor is present.
After the stressor has ended.
If conductivity rises when the participant encounters the stressor, this indicates increased physiological arousal.
For example:
Stage | Relative skin conductance |
Resting baseline | Low |
Waiting to give a speech | Higher |
Giving the speech | Highest |
Resting afterwards | Falling |
The researcher may infer that the speech task produced physiological arousal.
However, the measure alone cannot establish whether the participant felt:
Stressed.
Excited.
Embarrassed.
Frightened.
Highly motivated.
The importance of a baseline
A baseline is an initial measurement taken before the relevant condition or stimulus begins.
The baseline provides a comparison point.
Without it, a researcher may know that a participant’s conductance reading is a particular value but may not know whether this represents an increase for that person.
A basic procedure might involve:
Allowing the participant to sit quietly.
Recording baseline skin conductance.
Introducing the possible stressor.
Recording conductance during the task.
Comparing the task reading with the baseline.
A rise from baseline indicates increased arousal relative to the participant’s own resting level.
Why compare each person with their own baseline?
People may differ naturally in their resting physiological responses.
One participant may have higher skin conductivity than another because of individual or situational factors unrelated to stress.
Comparing each participant’s task response with their own baseline can reduce problems caused by these differences.
For example:
Participant | Baseline | Stressful task | Change |
A | 3 | 7 | +4 |
B | 6 | 8 | +2 |
Participant B has the higher reading during the task, but Participant A shows the larger increase from baseline.
The change score may therefore provide more useful information than the task reading alone.
Tonic and changing levels of arousal
A researcher may be interested in:
The general level of skin conductance over a period.
Rapid changes following a particular stimulus.
For AQA examination purposes, the essential point is that an increase in moisture and conductivity indicates increased physiological arousal.
You do not need to treat every small fluctuation as evidence of a separate stressful event.
A complete explanation of skin conductance response
A developed examination explanation might state:
A stressor activates physiological arousal. Moisture on the surface of the skin increases, which allows the skin to conduct electricity more effectively. An increase in skin conductivity compared with the person’s baseline can therefore be used as an indication of increased arousal.
This answer includes:
The stressor.
Physiological arousal.
Increased moisture.
Increased conductivity.
Comparison with baseline.
Skin conductance and the autonomic nervous system
Skin conductance reflects activity associated with the autonomic nervous system.
The autonomic nervous system controls involuntary physiological functions.
The participant does not normally decide consciously to alter their skin conductivity. This is one reason skin conductance may be considered less vulnerable than self-report to deliberate dishonesty.
However, the participant can still be affected by:
Awareness of being measured.
Anxiety about the equipment.
Expectations about the task.
Other sources of arousal.
Skin conductance and fight or flight
A possible stressor may activate the sympathetic branch of the autonomic nervous system.
The sympathetic response prepares the person for action and may be accompanied by:
Increased heart rate.
Increased breathing.
Greater moisture at the skin.
Increased skin conductivity.
Skin conductance is therefore one observable part of a broader physiological response.
It should not be confused with the full fight-or-flight pathway [The sympathomedullary pathway]. SCR measures one consequence of arousal rather than describing the complete biological sequence.
Using Skin Conductance in Research
Experimental measurement
Physiological measures can be used in an experiment.
A researcher might:
Record the participant’s baseline conductivity.
Present a potentially stressful task.
Record conductivity while the task is completed.
Remove the task.
Record the recovery response.
Compare the readings across conditions.
For example, participants might complete:
A difficult timed task.
A public-speaking task.
A task involving unexpected noise.
A control task designed to be less demanding.
If skin conductivity rises more in the stressful condition, this supports the conclusion that the condition produced greater physiological arousal.
Independent and dependent variables
In an experiment investigating stress:
The independent variable could be the type or difficulty of the task.
The dependent variable could be the change in skin conductivity.
For example:
IV: difficult timed task or simple untimed taskDV: increase in skin conductance from baseline
A controlled experiment may allow stronger conclusions than a purely correlational self-report study, provided other variables are controlled effectively.
Repeated-measures design
A researcher might expose the same participants to both:
A potentially stressful condition.
A control condition.
This is a repeated-measures design.
A strength is that each participant acts as their own control. Individual differences in resting conductivity are therefore less likely to explain differences between conditions.
A limitation is that the first condition may affect the second through:
Practice.
Fatigue.
Familiarity.
Anticipation.
Counterbalancing could be used to reduce order effects.
Independent-groups design
Alternatively, separate groups might complete the stressful and non-stressful tasks.
This avoids order effects because each participant completes only one condition.
However, differences in skin conductivity could result partly from differences between the groups rather than the task.
Random allocation may reduce this risk.
Standardisation
The researcher should standardise relevant parts of the procedure, including:
Instructions.
Task duration.
Room conditions.
Time allowed for the baseline.
Timing of measurements.
Researcher behaviour.
Standardisation improves reliability because each participant experiences a similar procedure.
Interpreting a rise in conductivity
Suppose the mean results are:
Condition | Mean increase from baseline |
Untimed task | 2 units |
Timed task | 7 units |
The timed task produced the larger mean increase.
A suitable conclusion is:
Participants showed greater physiological arousal during the timed task than during the untimed task.
A less defensible conclusion is:
The timed task definitely made every participant feel stressed.
The second statement is too strong because:
A mean does not describe every participant.
Conductance records arousal, not the participant’s interpretation.
Other factors could have affected the measurement.
Recovery after a stressor
A researcher may continue recording after the task ends.
A fall towards baseline may indicate that physiological arousal is reducing.
For example:
Time | Relative conductivity |
Baseline | 3 |
During task | 9 |
One minute after task | 7 |
Five minutes after task | 4 |
The pattern suggests:
Arousal increased during the task.
Arousal remained temporarily elevated.
Conductivity moved back towards baseline during recovery.
This does not prove that all psychological stress has ended. The person may still report feeling worried after their physiological response has begun to fall.
Applying skin conductance response
Consider this example:
A researcher records Meera’s skin conductance while she prepares to give a speech. Her reading is low while she rests, rises sharply when she is told she must speak next and falls after the speech has finished.
A developed application would explain:
The resting measurement provides Meera’s baseline.
Being told she must speak next acts as the possible stressor.
Sympathetic arousal increases moisture at the surface of her skin.
Increased moisture raises skin conductivity.
The sharp rise indicates increased physiological arousal.
The fall after the speech suggests that arousal is reducing during recovery.
Application structure
Use the following structure:
Scenario detail → physiological process → measurement → interpretation
For example:
Meera’s conductance rises when she is told she must speak. This suggests that increased physiological arousal produced greater moisture at the skin, increasing conductivity compared with her baseline.
Avoid writing:
Meera’s stress score went up because she was nervous.
This does not explain what was physically measured.
Comparing Physiological and Self-Report Measures
What are self-report measures?
Self-report measures ask participants to provide information about their own experiences.
The named AQA measures are:
The Social Readjustment Ratings Scale.
The Hassles and Uplifts Scale.
These are explained fully in questionnaires and rating scales for stress [Measuring stress through self-report].
The key difference is:
Physiological measures record bodily activity.
Self-report measures record what participants say about their experiences.
Direct comparison table
Feature | Physiological measures | Self-report measures |
What is recorded? | Bodily activity or arousal | Reported experiences, events or judgements |
Example | Skin conductance response | SRRS or Hassles and Uplifts Scale |
Timing | Can record responses in real time | Often retrospective |
Objectivity | More objectively observable | More subjective |
Participant awareness | Does not depend on recognising or describing arousal accurately | Depends on understanding, recall and honesty |
Research design | Can be used experimentally | Often used in correlational research |
Duration measured | Particularly useful for immediate responses | Useful for ongoing or long-term stressors |
Data | Quantitative readings | Quantitative scores or ratings |
Main validity issue | May measure general arousal rather than stress | May be affected by interpretation or inaccurate recall |
Context | Does not explain why the person is aroused | Can identify events and personal experiences |
These comparisons reflect the distinctions identified in AQA’s November 2020 mark scheme.
Comparison 1: objectivity
Physiological measures are more objective because bodily responses are recorded using equipment.
The participant does not decide what conductivity value to produce or report.
Self-report measures are more subjective because participants must:
Remember events.
Interpret questions.
Judge severity.
Choose an answer.
However, more objective does not automatically mean more valid.
Skin conductance may provide an accurate measurement of arousal while failing to show whether that arousal was caused by stress.
Comparison 2: real-time and retrospective measurement
Skin conductance can be recorded while a possible stressor is occurring.
This means it can show:
When arousal begins.
How rapidly it changes.
When it reaches its highest level.
How quickly it returns towards baseline.
Self-report scales are often retrospective.
For example:
The SRRS asks about life events during an earlier period.
The Hassles and Uplifts Scale records experiences over a monthly period.
Retrospective reporting may be affected by forgetting, but it can cover a much longer period than a brief physiological recording.
Comparison 3: experimental and correlational research
A physiological measure can be used in an experiment.
The researcher may manipulate a task and record skin conductance as the dependent variable.
Self-report stress scores are often correlated with:
Illness.
Anxiety.
Depression.
Other reported outcomes.
Experiments may provide greater control and stronger evidence of cause and effect.
However, an experimental stressor may be artificial and less representative of serious real-life stress.
Comparison 4: immediate and ongoing stress
Skin conductance is well suited to measuring immediate changes in arousal.
It may be less practical for measuring the cumulative effect of:
A year of major life changes.
A month of recurring hassles.
A long period of workplace stress.
Self-report measures can ask about events across longer periods.
AQA’s mark scheme identifies self-report measures as particularly useful for ongoing stress and long-term research.
Comparison 5: source and response
The SRRS and Hassles and Uplifts Scale primarily provide information about potential sources of stress.
Skin conductance records part of the body’s response.
For example:
“Changing job” identifies a potential stressor.
“Skin conductivity increased” identifies physiological arousal.
A full understanding of stress may therefore require both:
What happened to the person, and how their body responded.
Comparison 6: individual meaning
Self-report allows the participant to communicate:
Which event occurred.
How severe it felt.
Whether they viewed it positively or negatively.
What they believed caused their stress.
Skin conductance cannot reveal this meaning.
Two participants may show similar conductivity while interpreting the same task differently.
One might report fear, while another reports excitement.
Comparison 7: deliberate response bias
Self-report may be affected by:
Social desirability.
Demand characteristics.
Self-presentation.
Inaccurate recall.
A participant may minimise or exaggerate stress.
Skin conductance is less vulnerable to deliberate distortion because the physiological response is not normally under straightforward conscious control.
However, participants may still react to the research setting or equipment itself.
Comparison 8: quantitative data
Both approaches can produce quantitative data.
Examples include:
Skin conductance readings.
Change scores from baseline.
Total life change units.
Hassle severity scores.
The data can be:
Averaged.
Compared across conditions.
Presented graphically.
Analysed statistically.
This is a similarity rather than a difference.
Comparison 9: validity problems
Both methods have validity limitations.
For self-report:
People interpret events differently.
Participants may forget.
Ratings are subjective.
For skin conductance:
Increased conductivity indicates arousal.
It does not prove the arousal was caused by stress.
AQA’s mark scheme makes this distinction directly: self-report validity is affected by differences in interpretation, while skin conductance may reflect general autonomic arousal rather than stress.
Writing effective comparisons
A strong comparison states both sides in the same point:
Physiological measures can record bodily arousal as it occurs, whereas self-report scales frequently require participants to remember events from an earlier period.
A weak answer states:
Physiological measures are objective. The SRRS has 43 items.
The weak answer gives two facts but does not compare the methods on the same feature.
Useful comparative words include:
Whereas
Both
In contrast
Compared with
Similarly
Unlike
Evaluating Physiological Measurement
Strength: objective measurement
A major strength is that physiological responses are objectively observable.
Skin conductivity is recorded as a numerical value rather than being estimated from the participant’s opinion.
This can reduce the influence of:
Social desirability.
Participant dishonesty.
Inaccurate descriptions of bodily arousal.
Different understandings of questionnaire items.
Objective recording may therefore increase scientific credibility.
Strength: real-time recording
Skin conductance can be recorded while the participant encounters the possible stressor.
This allows the researcher to identify:
The onset of arousal.
Changes during the task.
Peak arousal.
Recovery after the task.
A retrospective questionnaire cannot provide the same continuous record.
Real-time recording also avoids asking the participant to remember exactly how aroused they were several weeks earlier.
Strength: quantitative data
Physiological recording produces numerical data.
Researchers can calculate:
Means.
Ranges.
Changes from baseline.
Differences between conditions.
Associations with other measures.
Quantitative data can be analysed using statistical tests and the procedure can be replicated.
Strength: reduced social desirability
A participant might claim not to feel stressed because they want to appear confident.
Their physiological response may still show increased arousal.
Skin conductance is therefore less dependent on the participant openly admitting stress.
This can be useful in contexts where participants:
Feel embarrassed.
Want to appear resilient.
Fear judgement.
Cannot describe their internal state accurately.
However, the reading still cannot prove that the hidden state was stress rather than another form of arousal.
Strength: can be used experimentally
A researcher can manipulate a task and record skin conductance.
This allows:
Greater control over the possible stressor.
Standardised exposure.
Comparison with a control condition.
Measurement before and during the task.
Stronger investigation of cause and effect.
For example, if a timed task consistently produces a larger increase than an untimed task, the time pressure may have caused greater physiological arousal.
Limitation: general arousal rather than stress
The most important limitation is low specificity.
Skin conductance measures autonomic arousal, which can occur during many emotional or physical states.
An increased reading may reflect:
Stress.
Excitement.
Fear.
Surprise.
Anger.
Anticipation.
The researcher may correctly conclude that arousal increased but incorrectly label the response as stress.
This reduces construct validity, meaning the measure may not assess the exact psychological concept intended.
Limitation: it does not identify the source of stress
A skin conductance reading cannot explain what the participant found stressful.
For example, a reading may rise during a public-speaking task, but the participant might be responding to:
Fear of judgement.
Unfamiliar equipment.
The researcher watching them.
Concern about making a mistake.
Excitement about performing well.
Self-report may be needed to identify the participant’s interpretation.
Limitation: individual differences
Participants may differ in:
Resting skin conductivity.
Size of physiological response.
Speed of recovery.
Responsiveness to the same task.
A single universal cut-off for “stressed” may therefore be misleading.
Using a personal baseline and measuring change can reduce this problem but may not remove it completely.
Limitation: environmental and situational influences
A conductivity reading may be affected by factors other than the experimental stressor.
If conditions vary between participants, the resulting differences may not reflect stress accurately.
Standardising the environment and recording a baseline can improve control.
The essential evaluation point is:
A numerical measurement may be objective, but its interpretation still depends on an appropriately controlled procedure.
Limitation: the equipment may itself increase arousal
Participants know that they are being measured.
They may become aroused because:
The equipment is unfamiliar.
They are concerned about the procedure.
They believe their stress is being judged.
They try to predict what the researcher expects.
This measurement reactivity may raise skin conductance independently of the intended task.
Allowing an adaptation period before taking the baseline may help, but the effect may remain.
Limitation: artificial research situations
Physiological measures are often used in controlled settings.
This improves internal validity but may reduce ecological validity.
A short laboratory task may not represent:
Long-term caring responsibilities.
A year of life changes.
Persistent workplace pressure.
Repeated daily hassles.
Participants may respond differently to an artificial task than to stressors in ordinary life.
Limitation: a brief measure may miss chronic stress
Skin conductance is particularly useful for immediate arousal.
It may not capture the full effects of long-term stress if the participant is measured only briefly.
A person experiencing chronic stress might:
Show no major rise during the short recording period.
Still report substantial life changes or daily hassles.
Experience stress at times when the equipment is not attached.
Self-report may therefore be more practical for long-term or recurring stress.
Limitation: reductionism
Physiological measurement can be described as biologically reductionist because it reduces a complex experience to a bodily reading.
Stress may also involve:
Thoughts.
Appraisal.
Emotion.
Perceived control.
Social context.
Coping resources.
A skin conductance value provides information about bodily arousal but not the complete psychological experience.
Reductionism can still be useful because it creates a precise, measurable variable.
The limitation is that the reading should not be treated as a complete definition of stress.
Reliability and validity
Physiological measures may have high reliability when:
Equipment is calibrated consistently.
The procedure is standardised.
Measurements are taken in the same way.
Clear operational definitions are used.
However, reliability does not guarantee validity.
A machine may reliably record skin conductivity while the researcher incorrectly assumes every increase represents stress.
Combining physiological and self-report measures
One solution is to use both types of measure.
For example, a researcher could record:
Skin conductance during a task.
The participant’s rating of how stressful the task felt.
This provides:
An objective measure of physiological arousal.
A subjective account of the participant’s experience.
Possible outcomes include:
Skin conductance | Self-reported stress | Possible interpretation |
High | High | Physiological and subjective measures agree |
High | Low | Arousal occurred, but the participant did not label it as stress |
Low | High | The participant reports stress without a large skin response |
Low | Low | Both measures suggest a limited response |
Disagreement does not automatically mean that one measure is wrong. They may be measuring different parts of the stress response.
Practical application to biofeedback
Physiological measurement can be used to provide information about normally involuntary responses.
In Biofeedback, a person receives feedback about changes in bodily arousal and learns to reduce the response.
Skin conductance, heart rate or muscle tension may therefore be used not only to investigate stress but also to help manage it.
Overall evaluation
Physiological measures such as skin conductance response provide objective, quantitative and real-time information about bodily arousal. They avoid many recall and self-presentation problems associated with questionnaires and can be used in controlled experiments.
However, skin conductivity is not specific to stress. It may reflect general autonomic arousal, and measurements can be affected by individual differences, the setting and awareness of the equipment. Physiological data are most informative when interpreted alongside context and self-report rather than being treated as a complete measurement of stress.
Planning an extended response
For an extended question on physiological measurement, organise your answer around explanation, comparison and evaluation.
Knowledge and understanding
Explain:
Skin conductance response.
Increased physiological arousal.
Increased moisture at the skin.
Increased skin conductivity.
The role of a baseline.
Measurement before, during and after a stressor.
Interpretation of changes from baseline.
Comparison
Directly compare physiological measures with self-report on:
Objectivity.
Timing.
Experimental use.
Long-term usefulness.
Quantitative data.
Validity.
Context and meaning.
Recall and social desirability.
Evaluation
Develop points such as:
Objective recording.
Real-time measurement.
Quantitative data.
Reduced social desirability.
Experimental control.
General arousal rather than stress.
Individual differences.
Research-setting effects.
Measurement reactivity.
Ecological validity.
Reductionism.
Combining methods.
Key Words 🔑
Key word | Student-friendly definition | How it may be used in an exam |
Physiological measure | A method that records bodily activity associated with a psychological response | Identify the general type of stress measurement |
Skin conductance response | A measure of changes in how readily the skin conducts electricity | Explain the named AQA physiological measure |
SCR | An abbreviation for skin conductance response | Use after writing the full term once |
Galvanic skin response | Another term sometimes used for changes in skin conductivity | Recognise the term if it appears in an assessment |
Physiological arousal | Increased bodily activity associated with alertness or activation | Explain what a raised conductivity reading indicates |
Skin moisture | Moisture at the skin surface which increases during arousal | Link arousal with increased conductivity |
Conductivity | The ease with which electricity passes through a material | Explain why increased moisture changes the skin reading |
Baseline | A measurement taken before a condition or stimulus begins | Compare resting and task responses |
Autonomic nervous system | The system controlling involuntary bodily functions | Explain why skin conductance changes are not usually deliberate |
Sympathetic nervous system | The branch of the autonomic system associated with increased arousal | Link stress-related activation with greater skin moisture |
Objective measurement | Measurement based on observable recording rather than personal judgement | Explain a strength of physiological measures |
Self-report measure | A method in which participants describe their own experiences | Compare questionnaires with physiological recording |
Real-time measurement | Recording a response while it is occurring | Contrast physiological recording with retrospective self-report |
Retrospective measure | A measure requiring participants to remember earlier events | Evaluate the SRRS and Hassles and Uplifts Scale |
Quantitative data | Numerical information | Explain a similarity between physiological and self-report scores |
Validity | The extent to which a measure assesses what it claims to assess | Evaluate whether conductivity specifically measures stress |
Reliability | The consistency of a measure or procedure | Evaluate standardisation and replication |
Construct validity | Whether a method accurately measures the intended psychological concept | Explain the problem of measuring arousal rather than stress |
Measurement reactivity | A change in behaviour or arousal caused by awareness of being measured | Evaluate the possible effect of equipment |
Ecological validity | The extent to which findings reflect real-life experiences | Evaluate artificial laboratory stressors |
Biological reductionism | Explaining a complex experience through bodily processes | Evaluate the narrow focus on physiological arousal |
Hints from the Examiner Reports 💡
Examiner hint: Learn the direction of the relationship precisely. AQA’s 2022 question required students to recognise that when moisture at the skin increases, conductivity also increases.
Examiner hint: Do not reverse conductivity and resistance. For this specification, remember the simple rule: more moisture produces greater conductivity.
Examiner hint: A physiological reading indicates arousal, not automatically stress. This is the main validity issue identified in AQA’s mark scheme.
Examiner hint: Make comparisons explicit. Examiner commentary on extended comparison questions has noted that students may show sound knowledge but fail to establish clear, direct comparisons.
Examiner hint: Use paired statements. Write that physiological measures can record arousal in real time, whereas self-report measures are often retrospective.
Examiner hint: Do not assume that “objective” means “perfectly valid”. A conductivity reading can be recorded accurately while still being caused by excitement or another form of autonomic arousal.
Examiner hint: In an application question, identify the baseline, describe the change and then interpret what the difference suggests.
Examiner hint: When interpreting data, refer to increases or decreases rather than simply copying numerical values from a table.
Common Mistakes ⚠️
Mistake: Saying that stress reduces skin moisture.
Why this is incorrect:Stress-related physiological arousal is associated with increased moisture at the skin.
How to improve:Remember: arousal increases moisture.
Mistake: Saying that more moisture reduces conductivity.
Why this is incorrect:Greater moisture allows the skin to conduct electricity more readily.
How to improve:Learn the chain: more moisture, more conductivity.
Mistake: Defining skin conductance as a self-report measure.
Why this is incorrect:It records a physiological response rather than asking the participant to describe their experience.
How to improve:Classify it as an objective physiological measurement.
Mistake: Saying a high reading proves that the participant is stressed.
Why this is incorrect:The reading indicates increased arousal, which may have several causes.
How to improve:Write that the reading is consistent with stress but does not prove it.
Mistake: Ignoring the baseline.
Why this is incorrect:Participants may naturally differ in resting conductivity.
How to improve:Compare each person’s task response with their own resting measurement.
Mistake: Comparing raw readings from different people without considering individual differences.
Why this is incorrect:One participant may naturally have a higher resting response.
How to improve:Use change-from-baseline scores where appropriate.
Mistake: Saying physiological measures explain why a person is stressed.
Why this is incorrect:They record bodily activity but do not reveal the meaning or source of the response.
How to improve:Use self-report or contextual information alongside the physiological reading.
Mistake: Assuming physiological measures cannot be affected by the research situation.
Why this is incorrect:Unfamiliar equipment or being observed may itself increase arousal.
How to improve:Discuss measurement reactivity and the need for a suitable baseline.
Mistake: Calling self-report data entirely non-numerical.
Why this is incorrect:The SRRS and Hassles and Uplifts Scale produce quantitative scores.
How to improve:Recognise that both physiological and self-report methods can generate numerical data.
Mistake: Writing two separate descriptions in a comparison question.
Why this is incorrect:The examiner needs an explicit relationship between the methods.
How to improve:Use one feature at a time and compare both methods directly.
Mistake: Saying physiological measures are always better.
Why this is incorrect:They are objective but may lack context and measure general arousal rather than stress.
How to improve:Give a balanced conclusion and consider combining methods.
Mistake: Treating one brief laboratory response as a complete measure of chronic stress.
Why this is incorrect:A short recording may miss recurring stress across days or months.
How to improve:Explain that self-report may be more useful for ongoing stress.
Exam-Style Questions ✍️
Question 1
Which of the following describes what happens when skin conductance is used to indicate increased stress-related arousal?
A. Skin moisture decreases and conductivity decreases.B. Skin moisture decreases and conductivity increases.C. Skin moisture increases and conductivity decreases.D. Skin moisture increases and conductivity increases.
[1 mark]
Question 2
Define skin conductance response.
[2 marks]
Question 3
Explain how skin conductance response can be used to measure physiological arousal.
[4 marks]
Question 4
A participant has a skin conductance reading of 4 units while resting and 11 units during a timed task.
Explain what the result suggests and identify one conclusion that cannot be drawn.
[4 marks]
Question 5
A researcher records the following mean skin conductance scores:
Stage | Mean conductance score |
Resting baseline | 3.1 |
Waiting to give a speech | 6.8 |
Giving the speech | 9.4 |
Five minutes after the speech | 4.0 |
Explain the pattern shown in the table.
[4 marks]
Question 6
Explain three differences between physiological and self-report measures of stress.
[6 marks]
Question 7
Explain one strength and one limitation of skin conductance response as a measure of stress.
[6 marks]
Question 8
Evaluate physiological measures of stress.
[8 marks]
Question 9
Ravi completes two tasks while his skin conductance is recorded. Before each task, the researcher records a resting baseline.
During Task A, Ravi completes a simple untimed puzzle. During Task B, he must complete a difficult puzzle while being watched and told that his performance will be compared with other participants. Ravi’s skin conductance rises much more during Task B. Afterwards, he reports that he found both tasks enjoyable.
Discuss physiological measures of stress. Refer to Ravi in your answer.
[16 marks]
Answers and Mark Scheme
Question 1
Answer: D
The level of moisture at the surface of the skin increases and conductivity increases.
[1 mark]
Question 2
Award up to two marks:
Skin conductance response is a physiological measure of how readily the skin conducts electricity.
Increased moisture during physiological arousal increases skin conductivity.
[2 marks]
Question 3
Award up to four marks:
A baseline skin conductance measurement is recorded.
A possible stressor or demanding task is introduced.
Physiological arousal increases moisture at the surface of the skin.
Increased moisture raises conductivity, so an increase from baseline indicates greater physiological arousal.
[4 marks]
Question 4
Award up to four marks:
The reading increased by seven units from baseline.
This indicates greater physiological arousal during the timed task.
The pattern is consistent with the task producing a stress response.
The researcher cannot conclude that the participant definitely felt stressed because conductivity may reflect another form of autonomic arousal.
[4 marks]
Question 5
Award up to four marks:
Conductivity is lowest during the resting baseline.
It rises while participants wait, suggesting anticipatory physiological arousal.
It is highest during the speech, suggesting that arousal is greatest while performing the task.
The score falls towards baseline after the speech, indicating physiological recovery.
Credit conclusions stated cautiously in terms of arousal.
[4 marks]
Question 6
Award up to two marks for each developed comparison:
Physiological measures record bodily activity, whereas self-report measures record participants’ descriptions of their experiences.
Physiological measures can record arousal in real time, whereas self-report measures are often retrospective.
Physiological measures are more objectively observable, whereas self-report measures depend more on interpretation and judgement.
Physiological measures can be used experimentally, whereas stress scales are often used in correlational research.
Physiological measures are useful for immediate arousal, whereas self-report measures may be more useful for ongoing stress.
Physiological measures may detect general arousal without identifying its cause, whereas self-report can provide context and meaning.
Both methods can produce quantitative data.
Maximum [6 marks].
Question 7
Award up to three marks for the strength and three marks for the limitation.
Possible strength:
Skin conductance provides an objective numerical measure. It does not rely on the participant remembering events or honestly reporting how stressed they feel. This may reduce social-desirability and recall problems.
Possible limitation:
Skin conductance measures general autonomic arousal rather than stress specifically. A reading may rise because the participant is excited, surprised or anxious about the equipment. This reduces construct validity.
Credit other developed strengths and limitations.
[6 marks]
Question 8
Indicative content may include:
Knowledge
Physiological measures record bodily activity.
Skin conductance response measures changes in skin conductivity.
Arousal increases moisture at the skin.
Greater moisture increases conductivity.
Baseline and task readings can be compared.
Recordings can be taken before, during and after a stressor.
Evaluation
Objective measurement.
Real-time recording.
Quantitative data.
Reduced social-desirability and recall problems.
Ability to use controlled experiments.
General arousal is not specific to stress.
The source and meaning of arousal cannot be identified.
Individual differences in resting response.
Research equipment may increase arousal.
Laboratory tasks may lack ecological validity.
Brief readings may not represent chronic stress.
Physiological measurement may be reductionist.
Combining physiological and self-report measures may improve understanding.
For the highest marks, evaluation should be developed and linked to the usefulness and validity of the measurement.
[8 marks]
Question 9
Indicative content may include:
Knowledge and understanding
Skin conductance response measures physiological arousal.
A baseline allows task readings to be compared with resting activity.
Increased arousal produces greater moisture at the skin.
Increased moisture raises skin conductivity.
Physiological measures are objective and can operate in real time.
Conductivity may indicate general autonomic arousal rather than stress specifically.
Application to Ravi
Recording a baseline before each task provides a resting comparison.
The simple untimed puzzle is likely to produce less physiological arousal.
Being watched, timed or compared with others may increase arousal during Task B.
Ravi’s larger increase during Task B suggests greater physiological activation.
His report that both tasks were enjoyable shows that increased arousal was not necessarily experienced as negative stress.
Ravi may have felt excitement, motivation or anticipation rather than stress.
The disagreement between the two measures shows that they assess different aspects of the response.
Evaluation
The numerical reading is objective and is not dependent on Ravi admitting stress.
Measuring both tasks allows direct comparison.
Using Ravi’s baseline helps control individual differences in resting conductivity.
A controlled task may allow the researcher to investigate cause and effect.
Awareness of being watched or attached to equipment may itself increase arousal.
Task B contains several possible causes of arousal, including difficulty, observation and comparison.
Skin conductance cannot reveal which feature affected Ravi.
Laboratory puzzles may not represent chronic real-life stress.
Ravi’s self-report supplies useful information about his interpretation.
Self-report may itself be influenced by self-presentation or limited awareness.
Combining physiological and self-report evidence provides a more complete account than either alone.
A high-level response will explain the physiological mechanism accurately, apply several details from Ravi’s situation and make direct, developed comparisons with self-report measurement.
[16 marks]
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