Issues and debates: how psychology has developed over time

Changing methods and approaches

• Late 1800s: introspection (people reporting their own thoughts), criticised as subjective.
• Early twentieth century (the component guide dates the shift to around 1930): behaviourism studied measurable behaviour (Watson and Rayner, 1920; Skinner, 1948).
• Cognitive psychology: models of memory such as the multi-store model (1968) and working memory model (1974), building on Bartlett (1932).
• Neuroscience: CAT, PET and fMRI have changed explanations, for example Raine et al. (1997) and Johnstone et al. (1976) on brain differences.
• Statistics and RCTs became the standard for treatment evidence.

Changing ethics

• Watson and Rayner (1920) and Milgram (1963) would not pass ethics committees today.
• The BPS Code (2009), UNCRC (1989), ASPA (1986) and HCPC standards formalised protection.
• Burger (2009) replicated Milgram ethically by stopping at 150 V and screening participants.

Changing ideas about mental health

• From asylums and lobotomy to antipsychotics (1950s) and community care.
• Homosexuality removed from DSM-II in 1973.
• DSM-IV-TR (2000) to DSM-5 (2013): schizophrenia subtypes removed, bereavement exclusion removed, amenorrhoea removed for anorexia; ICD-11 in effect from 2022.
• Rosenhan (1973) challenged diagnosis; later manuals aimed for clearer criteria and better reliability.
• Family therapy (from the 1980s) and CBT (from Beck's work) broadened treatment beyond drugs.

Worked example

Use the example of schizophrenia to show how psychology has developed over time.

1. Diagnosis: Schneider's first-rank symptoms, then DSM criteria; DSM-5 dropped subtypes because they were unreliable.
2. Explanation: from the dopamine hypothesis (based on drug effects) to glutamate and imaging research.
3. Treatment: from asylums to antipsychotics in the 1950s, then atypicals and family intervention.
4. This shows knowledge, techniques and values all drive change.

Answer: Diagnosis, explanation and treatment have all changed with new evidence and values.

Check yourself

1. Why was introspection criticised?
   • It used brain scans
   • It relied on subjective reports of one's own thoughts
   • It was too objective
   • It only used animals
   Show answer

   It relied on subjective reports of one's own thoughts. Self-reports cannot be checked objectively.

2. How many years passed between Milgram's (1963) study and Burger's (2009) replication?
   Show answer

   46. 2009 - 1963 = 46 years.

3. Which change was made in DSM-5 (2013)?
   • Homosexuality was added
   • Schizophrenia subtypes were removed
   • Depression was removed
   • Anorexia was removed
   Show answer

   Schizophrenia subtypes were removed. Subtypes were unreliable.

4. Which development most changed biological explanations of mental disorders?
   • Introspection
   • Questionnaires
   • Neuroimaging such as CAT, PET and fMRI
   • Content analysis
   Show answer

   Neuroimaging such as CAT, PET and fMRI. Scans allow the brain to be studied directly.

5. Explain how ethical standards in psychology have changed over time, using an example.
   Show answer

   Milgram's 1963 study used deception and caused distress, but today guidelines such as the BPS Code require protection from harm, so Burger's 2009 replication stopped at 150 volts and screened participants.. Compare an old study with a modern guideline or replication.

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Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Psychology specification (issue January 2026)
• Pearson IAL Psychology component guide: WPS04 (Issue 2, November 2024)
• Drescher (2015), Out of DSM: depathologizing homosexuality, Behavioral Sciences 5(4)
• American Psychiatric Association: highlights of changes from DSM-IV-TR to DSM-5
• WHO: 72nd World Health Assembly resolution adopting ICD-11

Last updated 8 November 2026. Spotted a mistake? Tell us.