What is memory?

Memory is the process of storing and retrieving information. Psychologists model it as a system with different stores, each holding information for a different length of time and in a different form.

The Multi-Store Model (Atkinson and Shiffrin)

• Information flows through three stores: Sensory Register, Short-Term Memory (STM), and Long-Term Memory (LTM).
• Sensory Register: holds information for less than half a second, huge capacity, coded in the form it was received (e.g. visual, sound).
• STM: very limited capacity, around 5 to 9 items (Miller's magic number 7 plus or minus 2), lasts about 18 to 30 seconds without rehearsal, coded mainly acoustically (by sound).
• LTM: potentially unlimited capacity, can last a lifetime, coded mainly semantically (by meaning).
• Attention is needed to move information from the sensory register to STM. Rehearsal (repeating information) moves it from STM into LTM.
• Common mistake: students say STM 'becomes' LTM automatically. It only transfers with enough rehearsal.

Capacity, duration and coding

• These are the three key features examiners test: how much can be stored (capacity), how long it lasts (duration), and what format it's stored in (coding).
• Know the classic studies: Miller for STM capacity (7 plus or minus 2 chunks), Peterson and Peterson for STM duration (around 18-30 seconds without rehearsal, tested using a distractor task like counting backwards), Bahrick for LTM duration (people recognised old school classmates decades later).

Forgetting

• Interference theory: forgetting happens because memories confuse or disrupt each other. Proactive interference is old learning disrupting new learning. Retroactive interference is new learning disrupting old memories.
• Retrieval failure: forgetting happens because the right cues aren't present at recall, even though the memory is still stored. Context and state cues help retrieval.
• Common mistake: confusing proactive and retroactive interference. Remember pro = forward (old blocks new), retro = backward (new blocks old).

Improving memory

• Strategies include chunking (grouping information into meaningful units), rehearsal, using cues, and organisation of material.
• Eyewitness testimony links to memory: leading questions and misleading information can distort recall (Loftus-style research), showing memory is reconstructive, not a perfect recording.

Exam tips

• Always link capacity, duration and coding to the correct store.
• Use exact figures (7 plus or minus 2; 18-30 seconds) in answers for AO1 marks.
• For evaluation, discuss real-world application (e.g. revision techniques, police interviews) and research support or limitations.

What perception and cognition means

Perception is how the brain organises and interprets information from the senses (mainly vision). Cognition is the broader mental process of thinking, remembering and problem-solving. Edexcel GCSE Psychology looks at how we perceive the visual world and how factors distort or improve accuracy.

Visual cues and depth perception

We use monocular cues (need only one eye) to judge depth and distance:

• Height in plane: objects higher up in a scene are seen as further away.
• Relative size: smaller objects are perceived as further away.
• Occlusion (overlap): an object that blocks another is seen as nearer.
• Linear perspective: parallel lines appear to converge with distance.

These cues let us build a 3D understanding from a 2D retinal image.

Visual illusions

Illusions show that perception is not a direct copy of reality but a constructed interpretation. Key named illusions to know:

• Ponzo illusion: converging lines make equal-length objects look different sizes because the brain applies linear perspective wrongly.
• Muller-Lyer illusion: arrow fins on line ends make equal lines look unequal in length.
• Ames room: a distorted room tricks the brain into misjudging the size of people inside it because it exploits assumed rectangularity.

Common mistake: students confuse the Ponzo and Muller-Lyer illusions or forget which cue each one exploits — always link the illusion to the specific cue being misapplied.

Factors affecting perception

• Past experience: we interpret new information based on what we already know (schemas).
• Culture: research (e.g. cross-cultural studies using illusions) shows people from different environments are more or less susceptible to certain illusions, e.g. those from 'carpentered' environments with lots of straight edges are more fooled by the Muller-Lyer illusion.
• Expectation: what we expect to see shapes what we actually perceive.
• Emotion: mood can affect how we interpret ambiguous stimuli.

Face and object recognition

Cognition includes how we recognise faces and objects — this draws on stored memory templates being matched against new sensory input. Perceptual set theory says we have a readiness to perceive things a certain way based on expectation, context, and motivation.

Common mistakes to avoid

• Don't muddle sensation (raw data hitting the eye) with perception (the brain's interpretation of it) — always define both if asked.
• Always name the specific cue or illusion, not just 'the way we see things'.
• When explaining culture and perception, use the correct term 'carpentered world hypothesis', not a vague description.
• Learn the difference between monocular and binocular cues even though this topic focuses mainly on monocular ones.

Brain development basics

The brain is not fully wired at birth. It develops through infancy, childhood and adolescence, shaped by genes AND experience (nature and nurture working together).

• Synaptogenesis: babies overproduce synapses (connections between neurons) rapidly in the first 2 years.
• Synaptic pruning: unused connections are cut back through childhood and the teenage years, making the brain more efficient. 'Use it or lose it.'
• Myelination: nerve fibres get coated in myelin (a fatty sheath), which speeds up neural signals. This continues into the twenties, especially in the frontal lobe.

The developing brain and behaviour

Different brain areas mature at different rates:

• The frontal lobe (planning, impulse control, decision-making) is one of the LAST areas to fully mature, often not until the mid-20s.
• The limbic system (emotion, reward) develops earlier and is very active in adolescence.
• This mismatch (fast emotional system, slow control system) helps explain risk-taking, mood swings and impulsivity in teenagers — it is biological, not just 'bad behaviour'.

Nature vs nurture in brain development

• Genes set the basic blueprint (nature).
• Environment and experience shape how the brain actually wires up (nurture) — this is called plasticity.
• Plasticity: the brain's ability to change and reorganise itself in response to experience, learning or damage. It is highest in early childhood but continues throughout life.
• Enrichment/deprivation studies (e.g. Hubel and Wiesel-type findings on early visual experience) show that a lack of normal stimulation in critical early periods can permanently affect development.

Common mistakes

• Don't say the brain 'stops developing' at 18 — full maturation (especially frontal lobe) runs into the mid-20s.
• Don't muddle synaptogenesis (making connections) with pruning (cutting them) — one builds, one refines.
• Remember plasticity is a strength (recovery from damage, learning) not just a fact to state — always link it to behaviour or evidence in exam answers.
• Always explain WHY a brain feature links to behaviour (e.g. immature frontal lobe = weaker impulse control = teenage risk-taking) rather than just naming it.

What is social influence?

Social influence is the way other people affect our thoughts, feelings and behaviour. Edexcel GCSE Psychology focuses on two big processes: conformity and obedience.

Conformity

Conformity means changing your behaviour or opinions to match a group, even without direct pressure.

• Compliance: going along with the group publicly but not privately agreeing (surface change, easily reversed).
• Internalisation: genuinely changing your private beliefs to match the group (deep, lasting change).
• Identification: changing behaviour because you value belonging to a group, without full private agreement.

Asch's line study is the key evidence: participants were asked to match a line to one of three comparison lines. When surrounded by confederates giving an obviously wrong answer, many genuine participants conformed at least once, showing the power of group pressure even when the correct answer was obvious.

Why people conform

• Normative social influence: wanting to be liked or accepted, so we go along with the group (linked to compliance).
• Informational social influence: believing the group knows better than us, especially in unclear or ambiguous situations (linked to internalisation).

Obedience

Obedience means following a direct order from an authority figure. Milgram's study is the classic example: participants were told by an experimenter to give what they believed were increasingly severe electric shocks to another person. A high proportion of participants obeyed to the maximum level, showing how strongly people obey legitimate authority figures even against their own conscience.

Factors affecting obedience

• Proximity: obedience drops when the authority figure or the victim is physically closer.
• Location: obedience is higher in settings seen as legitimate (for example a university) than informal settings.
• Uniform: obedience increases when the authority figure wears a uniform or symbol of status.

Common mistakes to avoid

• Do not muddle conformity (group pressure, no direct order) with obedience (direct order from authority).
• Do not say Asch and Milgram are the same study; keep the aim, procedure and findings of each separate.
• Always link a term (compliance, internalisation, identification) to a real example when explaining it in an exam answer.
• Remember normative influence is about fitting in; informational influence is about being right.

What counts as a psychological problem

Psychology defines abnormality using four main models: deviation from social norms, failure to function adequately, deviation from ideal mental health, and statistical infrequency. No single definition works alone, so exam answers should always weigh strengths and limitations of each.

Deviation from social norms

Behaviour is judged 'abnormal' if it breaks the unwritten rules of a society. The problem: norms change over time and between cultures, so this definition risks being used to label anyone who is simply different, not disordered.

Failure to function adequately

Rosenhan and Seligman set out signs that someone is failing to cope: personal distress, observer discomfort, irrationality, unpredictability, and being unable to carry out normal day-to-day activities (work, relationships, self-care). Common mistake: students forget this is about coping, not just unusual behaviour - eccentric but functioning people are not 'abnormal' by this definition.

Deviation from ideal mental health

Jahoda listed the qualities of good mental health, including a positive view of the self, resistance to stress, personal growth, and an accurate view of reality. Anyone falling short of these ideals could be labelled abnormal. Weakness: almost nobody meets every criterion, so the definition is extremely demanding and culturally biased towards Western individualist values.

Statistical infrequency

Behaviour is abnormal if it is rare - statistically far from the average, usually measured against a normal distribution curve. Common mistake: students assume 'rare' always means 'bad', but exceptionally high intelligence is also statistically rare and clearly not a disorder.

Phobias, depression and OCD

Edexcel expects you to know the characteristics (behavioural, emotional, cognitive) of specific disorders:

• Phobias: marked, persistent fear, avoidance, panic, recognition the fear is excessive.
• Depression: low mood, low energy, negative self-view, disturbed sleep/appetite, lasting at least two weeks.
• OCD: recurring intrusive thoughts (obsessions) paired with repetitive actions (compulsions) done to reduce anxiety.

Explanations and treatments

Behavioural explanations (classical/operant conditioning) link well to behavioural treatments like systematic desensitisation and flooding for phobias. Cognitive explanations (irrational thinking, faulty schemas) link to Cognitive Behavioural Therapy (CBT), which challenges and restructures negative thought patterns. Always match explanation to treatment in exam answers - this is where marks are lost.

Common exam mistakes

• Confusing the four definitions of abnormality with each other.
• Forgetting that each definition needs both a strength AND a limitation for AO3 marks.
• Mixing up systematic desensitisation (gradual exposure with relaxation) and flooding (immediate, intense exposure).

Why research methods matter

Edexcel GCSE Psychology treats research methods as a skill running through every topic. You need to know how psychologists design studies, collect data, and avoid bias, and you must be able to evaluate a given study using the right vocabulary.

Types of study

• Experiments (lab, field, natural) test a hypothesis by manipulating an independent variable (IV) and measuring a dependent variable (DV).
• Lab experiments happen in controlled settings, giving high control but lower ecological validity.
• Field experiments happen in real-life settings, giving more natural behaviour but less control.
• Natural experiments use a naturally occurring IV (like an existing difference between people) that the researcher cannot manipulate, so cause and effect is harder to claim.
• Correlations measure the relationship between two co-variables without manipulating anything, so they cannot show cause and effect, only association.

Sampling methods

• Random sampling: every member of the target population has an equal chance of selection, often using a random number generator.
• Opportunity sampling: using whoever is available and willing at the time; quick but biased.
• Volunteer (self-selected) sampling: participants respond to an advert; may attract a certain personality type.
• Systematic sampling: selecting every nth person from a list.

Key terms and rules

• Hypothesis: a testable, precise prediction. A directional hypothesis states which way the results will go; a non-directional hypothesis just predicts a difference or relationship.
• Extraneous variables must be controlled so they do not become confounding variables that mess up the DV.
• Reliability means consistency of results if repeated; validity means the study measures what it claims to measure.
• Ethics (BPS guidelines): informed consent, right to withdraw, confidentiality, protection from harm, and debriefing after the study.
• Data types: quantitative data is numerical (easy to compare, less detail); qualitative data is descriptive (rich detail, harder to analyse).

Common mistakes

• Confusing correlation with causation: a correlation never proves one variable causes the other.
• Mixing up reliability (consistency) with validity (accuracy of measurement).
• Forgetting that natural experiments have a naturally occurring, not researcher-manipulated, IV.
• Not naming both strengths AND weaknesses when asked to evaluate a method.
• Writing a hypothesis that is too vague to test, rather than clearly linking IV and DV.