Signal Detection Theory
Explore signal detection theory - learn how we distinguish signals from noise in perception.
Frequently Asked Questions
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What is signal detection theory doing here?
It separates your sensitivity to the signal from your response bias using four outcomes: hits, misses, false alarms, and correct rejections.
What is d-prime?
A bias-free index of discriminability — the separation between the signal and noise distributions. Higher d-prime means better detection. Note: we compute d′ as the probit z-difference between your hit and false-alarm rates, with a log-linear correction for extreme rates (Hautus, 1995).
What does the response criterion mean?
How willing you are to say "yes." A liberal criterion yields more hits and more false alarms; a conservative one yields fewer of both. Two people with equal sensitivity can differ enormously in bias.
Why does this framework matter?
It underlies modern analysis of perception, medical diagnosis, memory, and alarm systems — accuracy alone is misleading without separating sensitivity from bias.
References
- Green, D. M., & Swets, J. A. (1966). Signal detection theory and psychophysics. Wiley.
- Tanner, W. P., Jr., & Swets, J. A. (1954). A decision-making theory of visual detection. Psychological Review, 61(6), 401-409.
- Stanislaw, H., & Todorov, N. (1999). Calculation of signal detection theory measures. Behavior Research Methods, Instruments, & Computers, 31(1), 137-149.
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About This Experiment
This experiment is an educational adaptation for demonstration purposes. It is not a clinical diagnostic tool. Results reflect your performance in this specific session and should not be interpreted as an assessment of your cognitive abilities.
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