Finding

palmer-huk-shadlen-2005.chronometric.subject.phs-eh

Palmer J, Huk AC, Shadlen MN. The effect of stimulus strength on the speed and accuracy of a perceptual decision. Journal of Vision, 2005, 5(5):376-404. · Human random-dot motion button reaction-time task · chronometric

Observed curve and fits

Joint-fit companions

Other findings jointly fit by the same model fits.

Fit diagnostics

Caveats on these fits (2 terms)

Each tag below is attached to one or more candidate fits for this finding. The chip column in the table flags which row carries which tag.

chronometric-summary fit
Descriptive median-RT-by-strength fit over summary chronometric points, not a full reaction-time likelihood or process model.
aggregate DDM RT approximation
DDM likelihood uses aggregate chronometric constraints rather than a full trial-level response-time likelihood.
Variant AIC Δ AIC RMSE Caveats
chronometric-hyperbolic-rt winner 6.3 0.0 0.0367
  • chronometric-summary fit
chronometric-constant-rt 8.1 1.8 0.1658
  • chronometric-summary fit
ddm-vanilla 468.0 461.7 -
  • aggregate DDM RT approximation
Full diagnostics (logL · n · params · max abs error)
Variant logL n Free params Max |error| Predicted points
chronometric-hyperbolic-rt -0.1 560 3 0.0595 6
chronometric-constant-rt -3.0 560 1 0.2844 6
ddm-vanilla -231.0 560 3 - 0

Residuals

Fit parameters and provenance

chronometric-hyperbolic-rt.palmer-huk-shadlen-2005.chronometric.subject.phs-eh

dirty fit

half_saturation_strength=49.079 · rt_floor=0.000 · rt_span=0.907

Method
scipy.optimize.minimize
Commit
3ec74b4
Predicted points
6
BIC
5.7

Fitted with scipy.optimize.minimize via behavtaskatlas.model_fits.chronometric-hyperbolic-rt; success=True; CONVERGENCE: NORM OF PROJECTED GRADIENT <= PGTOL

chronometric-constant-rt.palmer-huk-shadlen-2005.chronometric.subject.phs-eh

dirty fit

rt_level=0.718

Method
manual
Commit
3ec74b4
Predicted points
6
BIC
7.9

Fitted with manual via behavtaskatlas.model_fits.chronometric-constant-rt; success=True; closed-form weighted constant RT estimate

ddm-vanilla.palmer-huk-shadlen-2005.psychometric.subject.phs-eh

dirty fit

boundary=1.044 · drift_per_unit_evidence=0.138 · non_decision_time=0.434

Method
scipy.optimize.minimize
Commit
67b9019
Predicted points
0
BIC
481.0

Fitted with scipy.optimize.minimize via behavtaskatlas.model_fits.ddm-vanilla; success=True; CONVERGENCE: RELATIVE REDUCTION OF F <= FACTR*EPSMCH

Observed points

Absolute motion coherence median_rt_s n
0.000 0.8480 92
3.200 0.8800 96
6.400 0.8560 92
12.800 0.7300 90
25.600 0.5700 95
51.200 0.4340 95

Take it with you

Cover sheet

Self-contained Markdown for citation, slides, or notebooks

The cover sheet pins the finding to the atlas commit and includes the observed points, fit ranking, caveats, and provenance — everything needed to drop into a paper or notebook without losing the trail back to the deploy.