IV. Cognitive Level · Cognition
The cognitive level explores the computational mechanisms of decision-making, perception, and coding. The drift-diffusion model describes decisions as evidence accumulation; signal detection theory quantifies perceptual sensitivity; population coding theory reveals how the nervous system represents external stimuli precisely through population activity.
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Drift-Diffusion Model
— DDM — Evidence Accumulation in Decision-Makingdx = μ·dt + σ·dW with absorbing boundaries ±a. Higher drift → higher accuracy and faster RT; wider boundary → higher accuracy but slower RT.
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Signal Detection Theory
— SDT — d', Criterion, and ROCd' = z(H) - z(FA) separates sensitivity from response bias. The area under the ROC curve is AUC = Φ(d'/√2).
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Population Coding
— Tuning Curves, Fisher Information, and the Cramér–Rao BoundTuning curves (Gaussian/von Mises) describe each neuron's preference for a stimulus. Fisher information quantifies coding precision.