Pearson Edexcel International A Level Psychology XPS11

🧠 Pearson Edexcel International A Level Psychology Reference Sheet 2026

Every approach, named study, treatment, and statistical test from Units 1–4 of the Pearson Edexcel International A Level Psychology specification (XPS11/YPS11, papers WPS01–WPS04).

Unit 1 Foundations Unit 2 Applications Unit 3 Health Unit 4 Clinical

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Aligned with the latest 2026 syllabus and board specifications. This sheet is prepared to match your exam board’s official specifications for the 2026 exam series.

All the Core Edexcel International A Level Psychology Frameworks in One Place

Pearson Edexcel International A Level Psychology (XPS11/YPS11) demands precise knowledge of named studies, classic theories, and the right statistical test for each design. This 2026 reference sheet pulls together every approach (social, cognitive, biological, learning), every clinical disorder framework, BPS ethical guidelines, and every research-methods tool needed across the four units (papers WPS01, WPS02, WPS03, WPS04).

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Unit 1 — social, cognitive, biological, and learning approaches with named studies

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Unit 2 — applications (Clinical compulsory + 1 of Criminological/Health/Sport/Child)

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Unit 3 Health Psychology and Unit 4 Clinical Psychology in depth

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Statistical test selection chart and BPS Code of Ethics

Unit 1 (WPS01) — Social & Cognitive Foundations

Two of the four foundational approaches — name 2 explanations and key studies for each.

Social Psychology — Obedience, Conformity, Prejudice

Classic studies and theories you must reference precisely.

Milgram (1963)

Obedience study — 65% of participants delivered max 450V shock; situational explanation, agentic state, legitimate authority

Sherif — Robbers Cave (1954)

Realistic conflict theory — competition for scarce resources → in-group/out-group hostility; superordinate goals reduced it

Tajfel — Social Identity Theory

Categorisation → identification → comparison → in-group favouritism (even with minimal groups)

Agentic state

Acting as the agent of an authority figure → diffusion of personal responsibility

Always distinguish situational (context) from dispositional (personality) explanations.

Cognitive Psychology — Memory

Models and a key applied study (eyewitness testimony).

Multi-Store Model (Atkinson & Shiffrin 1968)

Sensory register → STM (≈7 items, ≈18s, acoustic) → LTM (unlimited, lifelong, semantic) — encoded by rehearsal

Working Memory Model (Baddeley & Hitch 1974)

Central executive | Phonological loop (verbal) | Visuospatial sketchpad | Episodic buffer (Baddeley 2000)

Loftus & Palmer (1974)

Eyewitness testimony — leading questions ('smashed' vs 'hit') → reconstructive memory and post-event information effect

Schema theory

Organised knowledge structures shape encoding and retrieval; can introduce systematic distortion

Unit 1 (WPS01) — Biological & Learning Approaches

Biological bases of behaviour and the learning theories.

Biological Psychology

Brain, neurochemistry, hormones, and aggression.

Genetic explanation

Twin studies (MZ vs DZ concordance), heritability estimates, genetic predispositions for aggression/personality

Brain structure

Limbic system (amygdala — emotion; hippocampus — memory) | Prefrontal cortex (impulse control) | Hypothalamus (drives, hormones)

Neurotransmission

Action potential → vesicles release neurotransmitter → receptors on post-synaptic neuron → reuptake/breakdown

Fight-or-flight

Hypothalamus → sympathetic NS → adrenal medulla → adrenaline; HPA axis → cortisol (longer term)

Raine et al. (1997)

PET scans of NGRI murderers vs controls — reduced prefrontal activity, asymmetric amygdala → biological basis for aggression

Learning Theories

Three key theories with classic studies.

Classical conditioning (Pavlov)

UCS → UCR; pair NS with UCS repeatedly → NS becomes CS → CR (e.g., dogs salivating to a bell)

Operant conditioning (Skinner)

Positive reinforcement | Negative reinforcement | Positive punishment | Negative punishment — Skinner box experiments

Social learning theory (Bandura 1961)

Bobo doll study — children imitate observed aggressive models; 4 stages: attention → retention → reproduction → motivation

Unit 2 (WPS02) — Applications of Psychology

Clinical (compulsory) plus one of Criminological / Health / Sport / Child.

Clinical (Compulsory) — Diagnostic Manuals

Two systems used for classification.

DSM-5

Diagnostic and Statistical Manual (American Psychiatric Association, 5th edition, 2013) — categorical, multi-axial removed

ICD-11

International Classification of Diseases (WHO, 2018/2022) — used widely outside the US

Issues: reliability (consistency between clinicians), validity (does diagnosis match the disorder?), cultural bias.

Schizophrenia

Symptoms, 2 explanations, 2 treatments.

Symptoms

Positive (hallucinations, delusions) | Negative (avolition, alogia, flat affect)

Biological explanation

Dopamine hypothesis — excess dopamine in mesolimbic pathway; genetic predisposition (MZ concordance ≈48%)

Cognitive explanation

Faulty information processing — Frith's metarepresentation deficit; abnormal source-monitoring

Treatments

Antipsychotic drugs (typical: chlorpromazine; atypical: clozapine) | CBT for psychosis (CBTp)

Criminological Option

Theories of crime: biological (XYY, brain abnormality), social learning (Bandura), Eysenck's personality theory (E, N, P)
Treatments: anger management, token economy in prisons, restorative justice

Child Option

Attachment: Bowlby's monotropic theory; Ainsworth's Strange Situation (secure, insecure-avoidant, insecure-resistant)
Deprivation/privation; daycare effects; cross-cultural variation (Van IJzendoorn & Kroonenberg)

Sport Option

Personality & sport (trait vs interactionist); arousal (Yerkes-Dodson inverted U), Catastrophe theory
Goal setting (SMART); imagery; self-efficacy (Bandura)

Unit 3 (WPS03) — Health Psychology

Substance misuse, stress, and health behaviour change.

Theories of Addiction

Biological

Dopamine reward pathway (mesolimbic); genetic vulnerability (DRD2 polymorphism)

Learning theory

Operant conditioning — positive reinforcement (pleasure) and negative reinforcement (withdrawal relief)

Cognitive

Faulty beliefs / expectancy theory; self-medication hypothesis

Treatments for Addiction

Drug therapies

Methadone (heroin substitution), nicotine replacement therapy (NRT), naltrexone, varenicline

Aversion therapy

Pair the substance with an unpleasant stimulus (e.g. disulfiram for alcohol — Antabuse)

CBT

Identify and challenge faulty cognitions; relapse-prevention planning

Stress & Coping

Stress response

Selye's General Adaptation Syndrome (GAS) — alarm → resistance → exhaustion

Coping styles

Problem-focused (active) vs emotion-focused (avoidant/regulating)

Stress measurement

Holmes & Rahe Social Readjustment Rating Scale (SRRS); physiological measures (cortisol, blood pressure)

Unit 4 (WPS04) — Clinical Psychology in Depth

Diagnosis, anomalies and the major therapy approaches.

Depression / OCD

Two explanations and two treatments per disorder.

Depression — biological

Low serotonin (monoamine hypothesis); genetic vulnerability

Depression — cognitive

Beck's negative triad (self/world/future) | Ellis's ABC model (Activating event → Beliefs → Consequences)

Depression — treatments

SSRIs (e.g., fluoxetine) | CBT (challenges negative automatic thoughts)

OCD — biological

Genetic (COMT/SERT genes); abnormal worry circuit (basal ganglia, OFC)

OCD — treatments

SSRIs | ERP (exposure and response prevention) within CBT

Therapy Approaches

The major therapeutic frameworks.

CBT

Identifies & restructures dysfunctional thoughts; behavioural experiments; homework tasks

Drug therapies

Antipsychotics, antidepressants (SSRIs, SNRIs, tricyclics), anxiolytics — fast-acting but side-effect heavy

Psychoanalysis

Freud — making unconscious conflicts conscious through free association, dream analysis, transference

Anomalies of Diagnosis

Reliability

Inter-rater reliability between clinicians; test-retest of diagnostic instruments

Validity

Concurrent (matches another measure), predictive (predicts course/outcome), construct (matches theoretical model)

Cultural bias

Disorders defined by Western norms may pathologise normal behaviour in other cultures (e.g. hearing voices in some belief systems)

Research Methods (across all units)

How psychology is researched and evaluated — heavily tested across WPS01–WPS04.

Designs & Data Collection

Designs and data collection.

Experimental: lab, field, natural, quasi — IV, DV, control of EVs/CVs; experimental designs (independent, repeated, matched)
Non-experimental: observation (covert/overt, naturalistic, structured), self-report (questionnaire, interview), correlational, case study, content analysis

Reliability, Validity & BPS Ethics

Quality criteria and professional standards.

Reliability

Internal (split-half) | External (test-retest, inter-rater)

Validity

Internal (no confounds) | External (population, ecological, temporal) | Construct | Face

BPS Code of Ethics

Respect | Competence | Responsibility | Integrity — covers consent, deception, withdrawal, debriefing, confidentiality, protection from harm

Descriptive Statistics

Summarising data.

Central tendency

Mean (interval) | Median (ordinal) | Mode (nominal)

Dispersion

Range | Standard deviation (interval); IQR (ordinal)

Distribution

Normal (mean = median = mode) | Positive skew (tail right) | Negative skew (tail left)

Inferential Statistics — Test Selection

Choose the right test from level of data + design.

Mann-Whitney U

Difference | Independent groups | Ordinal data

Wilcoxon signed-rank

Difference | Repeated measures/matched pairs | Ordinal data

Spearman's rho

Correlation | Ordinal data

Chi-squared

Difference/association | Independent | Nominal (frequency) data

Sign test

Difference | Repeated measures | Nominal data

Reject H0 if observed value is in the critical region (depends on N, p, one/two-tailed). Critical level p ≤ 0.05 standard.

Exam Technique & Issues/Debates

How to convert content into top-band marks across WPS01–WPS04.

Issues & Debates (run through every approach)

Nature vs nurture | Free will vs determinism | Reductionism vs holism | Idiographic vs nomothetic | Ethics | Cultural bias | Gender bias

Use these as evaluation hooks in extended-response essay questions.

Essay Structure (extended-response)

AO1 (knowledge) → AO2 (application to scenario) → AO3 (evaluation: strengths, weaknesses, alternative explanations) → conclusion that answers the specific question

How to Use This Reference Sheet

Boost your Cambridge exam confidence with these proven study strategies from our tutoring experts.

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Build Named-Study Cards

For each named study (Milgram, Sherif, Loftus & Palmer, Raine, Bandura, Pavlov, Skinner, Atkinson & Shiffrin, Baddeley & Hitch...) write Aim → Procedure → Findings → Conclusion → 2 evaluations on a single card.

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Master the Stats Test Chart

Draw the test selection flowchart (difference vs correlation × design × data level) until you can choose the correct test in 30 seconds — heavily tested in WPS04.

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Drill the Clinical Triad

For schizophrenia, depression and OCD, lock down 2 explanations + 2 treatments each — this is the highest-yield content across WPS02 and WPS04.

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Evaluate With Issues & Debates

Practise inserting nature/nurture, reductionism, ethics (BPS code), and cultural bias as evaluation points across every approach to lift AO3 marks.

Reference Sheet FAQ

Quick answers about this free PDF and how to use it for exam revision and active recall.

Is the Pearson Edexcel International A Level Psychology Reference Sheet 2026 free to download as a PDF?

Yes. This Tutopiya formula sheet is free to use and you can download it as a PDF from this page for offline revision. There is no payment or account required for the PDF download.

What Psychology topics and equations does this formula sheet cover?

This page groups key Psychology formulas in one place for revision. Master Pearson Edexcel International A Level Psychology (XPS11/YPS11) with this 2026 reference sheet. Covers Unit 1 Foundations (social, cognitive, biological, learning), Unit 2 Applications, Unit 3 Health Psychology,… Always cross-check with your official syllabus and past papers for your exam session.

Can I use this instead of the official exam formula booklet in the exam?

No. In the exam you must follow only what your exam board allows in the hall—usually the official formula booklet or data sheet where provided. This page is a revision and teaching aid, not a replacement for board-issued materials.

Who is this formula sheet for (Post-Secondary)?

It is written for students preparing for assessments at Post-Secondary in Psychology, including classroom revision, homework support, and independent study. Teachers and tutors can also share it as a quick reference.

How should I revise with this formula sheet?

Work through past paper questions, quote the correct formula before substituting values, and check units and notation every time. Pair this sheet with timed practice and mark schemes so you see how examiners expect working to be set out.

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This reference sheet aligns with Pearson Edexcel International A Level Psychology (XPS11/YPS11, papers WPS01, WPS02, WPS03, WPS04) specification content for assessment in 2026.

Always reference named studies precisely (researcher + year), apply theories to the specific scenario in the question, and cite BPS ethical guidelines where relevant.