Finding

palmer-huk-shadlen-2005.psychometric

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 · psychometric

Observed curve and fits

Joint-fit companions

Other findings jointly fit by the same model fits.

Fit diagnostics

Caveats on these fits (1 term)

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.

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
ddm-vanilla winner 2238.2 0.0 0.0102
  • aggregate DDM RT approximation
logistic-4param 2238.6 0.4 0.0099 —
ddm-drift-bias 2239.2 0.9 0.0100
  • aggregate DDM RT approximation
ddm-starting-point-bias 2240.2 2.0 0.0100
  • aggregate DDM RT approximation
sdt-2afc 2247.0 8.7 0.0162 —
Full diagnostics (logL · n · params · max abs error)
Variant logL n Free params Max |error| Predicted points
ddm-vanilla -1116.1 3,373 3 0.0196 11
logistic-4param -1115.3 3,373 4 0.0197 11
ddm-drift-bias -1115.6 3,373 4 0.0212 11
ddm-starting-point-bias -1116.1 3,373 4 0.0213 11
sdt-2afc -1121.5 3,373 2 0.0412 11

Residuals

Fit parameters and provenance

ddm-vanilla.palmer-huk-shadlen-2005.psychometric

dirty fit

boundary=0.998 · drift_per_unit_evidence=0.239 · non_decision_time=0.409

Method
scipy.optimize.minimize
Commit
10e1c18
Predicted points
11
BIC
2256.6

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

logistic-4param.palmer-huk-shadlen-2005.psychometric

dirty fit

bias=-0.008 · lower_lapse=0.001 · slope=4.142 · upper_lapse=0.000

Method
scipy.optimize.minimize
Commit
24fd416
Predicted points
11
BIC
2263.1

Fitted with scipy.optimize.minimize via behavtaskatlas.model_fits.logistic-4param; success=True; CONVERGENCE: RELATIVE REDUCTION OF F <= FACTR*EPSMCH

ddm-drift-bias.palmer-huk-shadlen-2005.psychometric

dirty fit

boundary=0.917 · drift_bias=0.008 · drift_per_unit_evidence=0.260 · non_decision_time=0.407

Method
scipy.optimize.minimize
Commit
10e1c18
Predicted points
11
BIC
2263.7

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

ddm-starting-point-bias.palmer-huk-shadlen-2005.psychometric

dirty fit

boundary=0.998 · drift_per_unit_evidence=0.239 · non_decision_time=0.409 · starting_point=0.502

Method
scipy.optimize.minimize
Commit
10e1c18
Predicted points
11
BIC
2264.7

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

sdt-2afc.palmer-huk-shadlen-2005.psychometric

dirty fit

criterion=-0.006 · d_prime=0.133

Method
scipy.optimize.minimize
Commit
24fd416
Predicted points
11
BIC
2259.2

Fitted with scipy.optimize.minimize via behavtaskatlas.model_fits.sdt-2afc; success=True; CONVERGENCE: RELATIVE REDUCTION OF F <= FACTR*EPSMCH

Observed points

Signed motion coherence p_right n
-51.200 0.0000 283
-25.600 0.0070 285
-12.800 0.0432 278
-6.400 0.1585 284
-3.200 0.3369 279
0.000 0.4982 560
3.200 0.6982 285
6.400 0.8136 279
12.800 0.9601 276
25.600 0.9965 282
51.200 1.0000 282

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.