IB Diploma Programme Psychology: Subject Overview

Course note (legacy syllabus): This resource describes IB DP Psychology for first assessment 2019 – the course version currently completing its final teaching cycle. This course’s last examination session is November 2026. From May 2027, first assessment moves to a newly rebuilt course (launched February 2025): the four options described below are replaced by four contexts studied at both SL and HL (one of which absorbs what was the abnormal psychology option – the IB itself describes abnormal psychology as “renamed” to health and well-being); six named concepts are introduced; the internal assessment becomes a research proposal marked out of 24; and every paper’s duration, mark total and weighting changes. A companion resource set describing the first-assessment-2027 course does not yet exist on this site.

At the core of IB Diploma Programme Psychology (first assessment 2019) is an introduction to three different approaches to understanding behaviour: the biological, cognitive and sociocultural approaches. Students study and critically evaluate the knowledge, concepts, theories and research that have developed understanding in these fields. The IB’s 2019 subject brief describes the interaction of these approaches as the basis of a holistic and integrated approach to understanding mental processes and behaviour, understood through four options in applied psychology (abnormal psychology, developmental psychology, health psychology and the psychology of relationships). The course also promotes an understanding of qualitative and quantitative research methods, used both to reflect critically on evidence and to design, implement, analyse and evaluate students’ own investigations.

Aims

The course aims for students to:

• develop an understanding of the biological, cognitive and sociocultural factors affecting mental processes and behaviour
• apply an understanding of the biological, cognitive and sociocultural factors affecting mental processes and behaviour to at least one applied area of study
• understand diverse methods of inquiry
• understand the importance of ethical practice in psychological research in general and observe ethical practice in their own inquiries
• ensure that ethical practices are upheld in all psychological inquiry and discussion
• develop an awareness of how psychological research can be applied to address real-world problems and promote positive change.

How it’s assessed

DP Psychology is assessed differently at SL and HL. At SL, students sit two external papers – Paper 1 (2 hours: three short-answer questions on the core approaches to understanding behaviour, plus one essay from a choice of three) worth 50% of the final grade, and Paper 2 (1 hour: one essay-style question on a single option, chosen from abnormal, developmental, health or relationships psychology) worth 25%. External assessment totals 75% of the SL grade. At HL, students sit the same Paper 1 (2 hours, reweighted to 40%), but a substantially longer Paper 2: because HL students study two options rather than one, HL Paper 2 runs 2 hours and requires two essay-style questions – one from each of the two studied options – rather than SL’s single essay on a single option, and is worth 20%. HL students also sit a third paper (1 hour: three short-answer questions on research methodology) worth 20%, bringing external assessment to 80% of the HL grade across three papers totalling 5 hours, compared with SL’s two papers totalling 3 hours.

The remaining 25% (SL) or 20% (HL) is internal assessment: an experimental study, in which students design, carry out (usually in a small group), analyse and individually write up a simple experiment, then evaluate it and suggest modifications. This component is externally moderated by IB examiners rather than marked solely by the student’s own teacher.

The four options – abnormal psychology, developmental psychology, health psychology, and psychology of human relationships – give students a chance to apply what they have learned about the biological, cognitive and sociocultural approaches to a specific area of applied psychology. Across all assessment components, students are expected to progress through four assessment objectives: knowledge and comprehension of specified content; application and analysis of psychological theories and research; synthesis and evaluation of that research; and selection and use of skills appropriate to psychology, including the design, conduct and ethical practice of their own investigations.

At HL, students are additionally expected to analyse qualitative and quantitative research methods and to evaluate research scenarios from a methodological and ethical perspective – reflecting the extra breadth that comes with the HL-only Paper 3 on approaches to research.

The three core approaches

Every DP Psychology student studies three core approaches to understanding behaviour, and they are not alternatives to choose between: the biological approach, examining the relationship between the brain and behaviour, hormones and pheromones and their effects on behaviour, the relationship between genetics and behaviour and, at HL only, the role of animal research in understanding human behaviour; the cognitive approach, examining how mental processes such as memory, perception and thinking shape behaviour; and the sociocultural approach, examining how social and cultural context shapes both behaviour and mental processes. Many topics within the core are deliberately revisited from more than one approach – memory, for example, can be examined biologically through brain structures, cognitively through information-processing models, and socioculturally through the influence of schema and culture on recall – and the course expects students to recognise a given topic from multiple angles rather than filing it under a single approach only. Approaches to researching behaviour is taught alongside these three content approaches rather than as a separate block, covering the qualitative and quantitative methods psychologists use to test their ideas, and is examined specifically in Paper 3 at HL, separately from the content approaches tested in Paper 1.

The four options

Unlike the compulsory core, students study only one option at SL and two options at HL, chosen from abnormal psychology (the definition, explanation and treatment of psychological disorders), developmental psychology (how cognition, behaviour and identity change across the lifespan), health psychology (the psychological factors influencing health, illness and healthcare behaviour), and psychology of human relationships (how relationships form, function and sometimes end). Because HL Paper 2 requires one essay question from each of the two studied options, HL students should confirm with their teacher exactly which two options their own course has covered, since this genuinely differs between schools and the exam paper’s structure follows that difference directly rather than allowing a choice on the day.

Preparing studies for evaluation, not just recall

Across all three core approaches, Paper 1’s essay question specifically rewards evaluation rather than accurate description alone, so preparation for any given study should include not just what it found but its methodology and at least one genuine evaluative point – a strength or limitation of how it was conducted. This applies just as much to the chosen option as to the compulsory core: because only one option is studied at SL, the studies and theories within it require the same depth of evaluative preparation as the core, rather than a lighter treatment on the assumption that a single option needs less rigour than three compulsory approaches.

The internal assessment and research methodology

The experimental study that makes up the internal assessment is most often let down not by weak content knowledge but by insufficient ethical planning and an under-justified choice of experimental design, so the research-methodology content covered within “approaches to researching behaviour” applies directly to a student’s own investigation rather than functioning only as separate exam content. Students who can explain why they chose their specific experimental design, and what its ethical considerations were, with the same rigour they would apply to evaluating a published study, tend to score more highly than those who describe their procedure without justifying the choices behind it.

Source

International Baccalaureate Organization, Diploma Programme Subject Brief – Individuals and Societies: Psychology, first assessment 2019, © 2018. (The IB also publishes a current subject brief for the replacement course, first assessment 2027, © 2025 – see the course note above. This resource is sourced from the 2019 brief throughout, not a mixture of the two.)