Sources of Bias (OCR GCSE Psychology): Revision Note

Sources of bias in psychological research

• Researchers aim to make their studies as objective as possible, but bias can occur at any stage — from selecting participants to analysing results

  • In psychology, bias refers to any factor that distorts findings, preventing them from accurately representing reality

• A biased study reflects the researcher’s expectations or social assumptions rather than objective evidence

Impact of bias

• Bias reduces the scientific value of research by:

  • Lowering validity – findings may not reflect real behaviour or experiences

  • Reducing reliability – results may not be consistent or replicable

  • Limiting generalisability – conclusions may not apply beyond the specific sample studied

• By recognising and minimising bias, psychologists can produce research that is more credible, objective, accurate, and ethical

Gender bias

• Gender bias occurs when research favours one gender over another or generalises findings from one gender to everyone

• This can lead to distorted or incomplete conclusions about behaviour

  • E.g. a study that includes only male participants but assumes the results apply equally to females

• Reducing gender bias:

  • Use balanced samples, including all genders

  • If the study includes only one gender (e.g. male participants), ensure findings are only generalised to that group, not to everyone

  • Avoid gender-stereotyped assumptions when interpreting findings

Cultural bias

• Cultural bias happens when researchers judge other cultures by the standards of their own or assume findings from one cultural group apply universally

• This limits how well results can be generalised across different societies or cultural contexts.

  • E.g. studying only British participants and assuming the findings apply to people in all cultures

• Reducing cultural bias:

  • Use cross-cultural samples

  • If the study includes participants from one culture (e.g. British people), ensure findings are only generalised to that group, not to everyone

  • Avoid ethnocentrism — the belief that one’s own culture is the norm or superior

Age bias

• Age bias occurs when research favours certain age groups over others, or when results from one age group are wrongly generalised to everyone

  • E.g. designing a study where the content appeals mainly to teenagers, meaning the findings may not apply to older adults

• Reducing age bias:

  • Include participants from multiple age ranges

  • Use age-appropriate materials and methods

  • Analyse differences between age groups rather than combining all results

Experimenter bias

• Experimenter bias arises when the researcher’s own beliefs or expectations influence how data is collected or interpreted

• This can lead to results that support the researcher’s hypothesis rather than the true outcome

  • E.g. a researcher subtly giving positive feedback to participants in one condition but not the other

• Reducing experimenter bias:

  • Use double-blind procedures, where neither participants nor researchers know who is in which condition

  • Standardise instructions and procedures

  • Train researchers to maintain objectivity

Observer bias

• Observer bias occurs when researchers’ expectations influence how they record or interpret participants’ behaviour

• This often affects observational studies, where interpretation is subjective.

  • E.g. rating an offender’s body language as “defensive” because the observer assumes guilt

• Reducing observer bias:

  • Use operationalised behaviour categories (clearly defined actions)

  • Employ inter-rater reliability checks to compare observers’ data

  • Keep observers blind to the study’s aims

Bias in questioning

• This type of bias occurs when questions are phrased in a way that leads or influences participants’ responses, often unintentionally

• It reduces the validity of the data by encouraging one-sided answers

  • E.g. asking, “Don’t you think you need more sleep?” instead of “How many hours do you sleep each night?”

• Reduce bias in questioning:

  • Use neutral wording

  • Pilot questions to check for unintended influence or ambiguity

  • Include a range of possible responses, not just one implied direction