Cognitive biases are systematic errors in thinking that affect the judgements and decisions all people make. They are not signs of stupidity — they are features of how human brains process information efficiently. However, in research they can seriously undermine the validity and objectivity of an investigation if left unexamined.
A cognitive bias is a predictable, systematic pattern of deviation from rational judgement. Biases arise because the brain uses mental shortcuts (heuristics) to process information quickly. These shortcuts are often useful, but they can lead to distorted conclusions when applied to complex research questions.
KEY TAKEAWAY: Cognitive biases affect every stage of research — from formulating the question, to selecting sources, to interpreting data, to writing conclusions. Recognising them is the first step to reducing their impact.
Definition: The tendency to search for, favour and remember information that confirms your existing beliefs, while ignoring or underweighting contradictory evidence.
In research: A student who believes social media is harmful to teenagers may unconsciously select only sources that support this view and dismiss studies with contrary findings.
How to counter it: Actively seek out literature that contradicts your hypothesis. Acknowledge opposing evidence in your report.
Definition: Over-relying on the first piece of information encountered (the “anchor”) when making decisions.
In research: If a student’s first source estimates an effect size as large, they may unconsciously evaluate all subsequent sources against that anchor, inflating their own conclusions.
Definition: Judging the likelihood or importance of something based on how easily examples come to mind.
In research: Overestimating the prevalence of dramatic events (e.g., rare diseases) because they receive more media coverage.
Definition: Drawing conclusions from a sample that is not representative of the broader population.
In research: Surveying only classmates to draw conclusions about all VCE students introduces selection bias.
Definition: After an outcome is known, believing you “knew it all along” — distorting memory of prior uncertainty.
In research: Affects how researchers narrate their findings, making the outcome seem more predictable than it was. This can make a report appear more authoritative than the evidence warrants.
Definition: Allowing a positive impression in one area to influence judgement in unrelated areas.
In research: Trusting a source uncritically because it comes from a prestigious university, even when the methodology has significant flaws.
EXAM TIP: When asked to “identify a cognitive bias” in a scenario, name the bias, quote the specific behaviour that demonstrates it, and explain why it is that bias (not a different one). Vague answers do not score well.
| Stage | Potential Bias | Example |
|---|---|---|
| Choosing a topic | Confirmation bias | Choosing a question you already believe you know the answer to |
| Selecting sources | Confirmation bias, availability heuristic | Only reading articles that appear on the first page of Google |
| Designing data collection | Selection bias | Only surveying friends |
| Interpreting results | Confirmation bias, hindsight bias | Emphasising results that fit your hypothesis |
| Writing conclusions | Overclaiming, hindsight bias | Stating findings as definitive when they only “suggest” |
COMMON MISTAKE: Thinking that acknowledging bias means your research is flawed. All research has potential for bias — the mark of good research is being transparent about it and taking steps to minimise it.
When evaluating published research, check:
- Funding source: Industry-funded studies are more likely to find results favourable to the funder
- Publication bias: Journals are less likely to publish negative or null results, skewing the overall literature
- Researcher background: Prior commitments or theoretical allegiances can bias interpretation
REMEMBER: Your Extended Investigation Journal should include reflections on how cognitive bias may have influenced your own choices during the research process. This metacognitive commentary is evidence of intellectual maturity and is rewarded in assessment.
