Questions and Answers
What is signal detection theory?
A theory predicting how and when we detect the presence of a faint stimulus amid background stimulation. It assumes that detection depends on a person's experience, expectations, motivation, and alertness.
Which of the following is an example of signal detection theory today?
What does the term 'signal' refer to in signal detection theory?
What the observer is trying to detect.
What is the meaning of 'noise' in signal detection theory?
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What does 'criterion' refer to in signal detection theory?
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What does a 'HIT' mean in terms of signal detection?
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What is a 'FALSE ALARM' in signal detection?
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What is a 'MISS' in signal detection terms?
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What does 'CORRECT REJECTION' mean in signal detection theory?
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What does 'sensitivity' refer to in signal detection theory?
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What does a larger gap between the d' prime indicate?
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What is the ROC curve used for?
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List some factors of sensitivity.
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What are the factors that influence criterion?
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Study Notes
Signal Detection Theory
- Predicts detection of faint stimuli (signal) amidst background noise.
- Detection influenced by experience, expectations, motivation, and alertness.
- No absolute threshold exists; detection varies with context and observer.
Practical Applications
- Used in TSA procedures at airports to identify potential threats.
- Employed by doctors to interpret EKGs for heart conditions.
- Relevant in aviation, with pilots detecting signals during flight.
Key Terminology
- Signal: The desired stimulus that the observer attempts to identify.
- Noise: Both internal (e.g., biases, distractions) and external (e.g., environmental sounds) interference affecting detection.
- Criterion: An observer's personal internal threshold for determining signal presence; can adjust based on context and individual differences.
Decision Outcomes
- HIT: Signal correctly detected; observer answers "yes" when signal is present.
- FALSE ALARM: Observer mistakenly identifies a signal when none is present.
- MISS: Signal present but not detected; observer answers "no."
- CORRECT REJECTION: No signal detected and accurately reported; observer answers "no" when signal is absent.
Sensitivity and Measurement
- Sensitivity (d' prime): Reflects the observer's ability to detect signals; higher sensitivity indicates clearer discrimination between signal and noise.
- Greater gap between d' prime thresholds indicates a higher sensitivity due to larger differences in noise.
ROC Curve
- Graphically represents an observer's responses in a signal detection experiment.
- Visual tool for analyzing trade-offs between HIT rates and FALSE ALARM rates.
Influencing Factors
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Sensitivity Factors:
- Level of background noise affects detection capacity.
- Strength of the stimulus plays a role in recognizability.
- Redundancy within a stimulus can enhance detection rates.
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Criterion Factors:
- Observer's expertise impacts judgment frequency and accuracy.
- A high propensity to say "yes" increases likelihood of identifying signals.
- Attention levels and motivation directly influence detection effectiveness.
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Description
Explore the fundamental concepts of Signal Detection Theory through flashcards. This quiz provides definitions and real-life examples, helping you understand how we detect faint signals against background noise. Perfect for students and professionals in psychology and related fields.
