Researcher & Participant Biases (DP IB Psychology): Revision Note

Researcher biases

• Researcher biases occur when the researcher’s presence, behaviour, or expectations interfere with the research process, reducing validity

Investigator effects

• One source of researcher bias is known as the investigator effect

  • This occurs when the researcher's characteristics, such as age, gender and ethnicity, influence how participants interact with them

    • E.g., a participant may react differently if the researcher reminds them of someone from their past

• The researcher's tone of voice, non-verbal communication and what they are wearing can impact how participants respond to the research process

  • A harsh or overly excited tone of voice adds emotion to a neutral task

  • Using overly dramatic body language is at odds with scientific research and is likely to put participants in the wrong frame of mind

  • Wearing clothing that is overly vibrant, patterned or includes slogans is too personal and unprofessional

Confirmation bias

• Another source of researcher bias is confirmation bias (opens in a new tab)

  • This is the tendency for researchers to focus on evidence that supports their hypothesis while overlooking contradictory findings

    • E.g., Ainsworth (1970) may have overlooked secure behaviours in a child already judged as insecure

Question order bias

• Another source of researcher bias is question order bias

  • The researcher could be biased in the way that they order the questions on a questionnaire or interview

  • Early questions influence how later ones are answered

    • E.g., asking, “Are you against animal testing?” early on may bias subsequent answers

  • A solution is to begin with neutral questions and move on to specific/loaded ones later

Leading question bias

• Another source of researcher bias is leading questions bias

  • This occurs when researchers ask questions which suggest what the answer should be

    • E.g., 'Don't you agree that animal testing is wrong?'

• Bias can also emerge through instructions or task framing, subtly signalling researcher expectations

  • E.g., if the researcher has hypothesised that X condition will result in higher scores, then they may unconsciously communicate this to the participants

Sampling bias

• Another source of researcher bias is sampling bias

  • This occurs when the researcher obtains a sample that does accurately represent the target population

    • This is more likely to occur with sampling methods such as opportunity sampling and self-selecting sampling

  • Sampling bias means that the findings cannot be generalised to a wider population, reducing the study's external validity

Participant biases

• Participant biases occur when participants alter their behaviour (consciously or unconsciously) because being studied is not a natural experience

Demand characteristics

• Because taking part in research is not an everyday experience, participants may behave in a way which does not reflect their usual, everyday behaviour

• Participants pick up cues about what is expected

• They may try to confirm (or resist) the researcher’s aim

• Influences include:

  • The research setting (e.g., artificiality of a lab)

  • Any verbal or non-verbal communication from the researcher

  • Participants’ motives (e.g., to please, rebel, or because of nerves)

• If participants behave according to what they think the aim of the research is, it leads to artificial behaviour that lacks ecological validity

Social desirability bias

• Another source of participant bias is social desirability bias

  • This is the tendency for people to under-report negative and over-report positive aspects of themselves when completing a questionnaire or interview

• Social desirability bias is common in self-report methods such as questionniares and interviews

Dominant respondent bias

• Another source of participant bias is dominant respondent bias

  • This occurs when a lone individual (particularly in qualitative research such as focus groups) dominates the proceedings, possibly influencing the opinions and responses of the other participants

• Unless the dominant participant is handled (carefully and sensitively) by the researcher, they can invalidate research due to the impact of their presence

Acquiescence bias

• Another source of participant bias is acquiescence bias

  • This occurs when participants overwhelmingly say 'yes' or give agreement to questions asked by the researcher

• It may reflect a desire to please the researcher, personality tendencies, or lack of investment in the task

• Acquiescence bias an be reduced by:

  • Using open-ended questions

  • Encouraging participants to provide their own views