Psychophysics

Toolkit for estimation of psychometric functions

Provides builders for configuring psychophysical estimation methods (Psi, Up-Down, Discrete Up-Down) and access to predefined psychometric functions.

Availability:

context.Psychophysics

Properties

Name Type Description
Functions FunctionsToolkit Factory for creating psychometric functions (e.g., Logistic, Weibull).

Methods

Name Signature Description
PsiMethod PsiMethod() -> PsiMethodCreator Creates a builder for configuring a Psi method.
UpDownMethod UpDownMethod() -> UpDownMethodCreator Creates a builder for configuring an up-down method.
DiscreteUpDownMethod DiscreteUpDownMethod() -> DiscreteUpDownMethodCreator Creates a builder for configuring a discrete up-down method.

Typical usage example

# Create a Psi method
psi = context.Psychophysics.PsiMethod() \
    .NumberOfTrials(40) \
    .Alpha(0.1, 1.0, 10) \
    .Beta(0.5, 5.0, 10) \
    .Intensity(0.1, 1.0, 20) \
    .Function(context.Psychophysics.Functions.Logistic()) \
    .Create()

# Create an up-down method
ud = context.Psychophysics.UpDownMethod() \
    .Up(1) \
    .Down(2) \
    .StepSize(0.1) \
    .StartIntensity(0.5) \
    .Function(context.Psychophysics.Functions.Weibull()) \
    .Create()

Psi Method Creator (PsiMethodCreator)

Description

Builder for configuring a Psi adaptive psychophysical method.

Availability

context.Psychophysics.PsiMethod()

Properties

No public readable properties are defined.

Methods

Name Signature Description
NumberOfTrials NumberOfTrials(trials: int) -> PsiMethodCreator Sets total number of trials.
Function Function(function: PsychometricFunction) -> PsiMethodCreator Sets psychometric function.
Alpha Alpha(x0: float, x1: float, n: int) -> PsiMethodCreator Defines alpha parameter range using linear spacing.
Beta Beta(x0: float, x1: float, n: int) -> PsiMethodCreator Defines beta parameter range using linear spacing.
Intensity Intensity(x0: float, x1: float, n: int) -> PsiMethodCreator Defines stimulus intensity range using linear spacing.
Create Create() -> object Finalizes and returns the configured method.

Up-Down Method Creator (UpDownMethodCreator)

Description

Builder for configuring a standard up-down staircase method.

Availability

context.Psychophysics.UpDownMethod()

Properties

No public readable properties are defined.

Methods

Name Signature Description
Up Up(value: int) -> UpDownMethodCreator Number of consecutive correct responses required to increase intensity.
Down Down(value: int) -> UpDownMethodCreator Number of consecutive incorrect responses required to decrease intensity.
IncreasingInitialDirection IncreasingInitialDirection() -> UpDownMethodCreator Sets initial direction to increasing intensity.
DecreasingInitialDirection DecreasingInitialDirection() -> UpDownMethodCreator Sets initial direction to decreasing intensity.
StepSize StepSize(value: float) -> UpDownMethodCreator Sets step size for both up and down directions.
StepSizeRection StepSizeRection(reduction: float, maxReduction: float) -> UpDownMethodCreator Configures step size reduction behavior.
StepSizeRelative StepSizeRelative() -> UpDownMethodCreator Uses relative step size.
StepSizeAbsolute StepSizeAbsolute() -> UpDownMethodCreator Uses absolute step size.
StopRule StopRule(value: int) -> UpDownMethodCreator Defines stopping rule.
SkipRule SkipRule(value: int) -> UpDownMethodCreator Defines skip rule.
StartIntensity StartIntensity(value: float) -> UpDownMethodCreator Sets starting intensity.
MaximalIntensity MaximalIntensity(value: float) -> UpDownMethodCreator Sets maximum allowed intensity.
MinimalIntensity MinimalIntensity(value: float) -> UpDownMethodCreator Sets minimum allowed intensity.
TerminateOnLimitReached TerminateOnLimitReached(value: bool) -> UpDownMethodCreator Enables termination when limits are reached.
Function Function(function: PsychometricFunction) -> UpDownMethodCreator Sets psychometric function.
Create Create() -> object Finalizes and returns the configured method.

Discrete Up-Down Method Creator (DiscreteUpDownMethodCreator)

Description

Builder for configuring a discrete up-down method using predefined intensity levels.

Availability

context.Psychophysics.DiscreteUpDownMethod()

Properties

No public readable properties are defined.

Methods

Name Signature Description
StopCriterion StopCriterion(value: int) -> DiscreteUpDownMethodCreator Defines stopping criterion.
SkipRule SkipRule(value: int) -> DiscreteUpDownMethodCreator Defines skip rule.
InitialStepSize InitialStepSize(value: int) -> DiscreteUpDownMethodCreator Sets initial step size.
IncreasingInitialDirection IncreasingInitialDirection() -> DiscreteUpDownMethodCreator Sets initial direction to increasing.
DecreasingInitialDirection DecreasingInitialDirection() -> DiscreteUpDownMethodCreator Sets initial direction to decreasing.
IntensityRange IntensityRange(values: Iterable[float]) -> DiscreteUpDownMethodCreator Defines discrete intensity levels.
Function Function(function: PsychometricFunction) -> DiscreteUpDownMethodCreator Sets psychometric function.
Create Create() -> object Finalizes and returns the configured method.

Functions Toolkit (FunctionsToolkit)

Description

Factory for creating psychometric functions used by estimation methods.

Availability

context.Psychophysics.Functions

Properties

No public readable properties are defined.

Methods

Name Signature Description
Gumbel Gumbel(alpha=0.5, beta=1, lambda=0.02, gamma=0.0) Creates a Gumbel psychometric function.
HyperbolicSecant HyperbolicSecant(alpha=0.5, beta=1, lambda=0.02, gamma=0.0) Creates a hyperbolic secant function.
Logistic Logistic(alpha=0.5, beta=1, lambda=0.02, gamma=0.0) Creates a logistic function.
LogQuick LogQuick(alpha=0.5, beta=1, lambda=0.02, gamma=0.0) Creates a log-Quick function.
Normal Normal(alpha=0.5, beta=1, lambda=0.02, gamma=0.0) Creates a normal (Gaussian) function.
Quick Quick(alpha=0.5, beta=1, lambda=0.02, gamma=0.0) Creates a Quick function.
Weibull Weibull(alpha=0.5, beta=1, lambda=0.02, gamma=0.0) Creates a Weibull function.

Parameters (common to all functions)

Name Type Description
alpha float Threshold/location parameter.
beta float Slope parameter.
lambda float Lapse rate.
gamma float Guess rate.

Notes / gotchas

  • All creators follow a builder pattern and must end with .Create() to produce a usable method.
  • Parameter ranges (e.g., Alpha, Beta, Intensity) are generated using linear spacing.
  • No validation is performed at this level; invalid configurations may fail later during execution.
  • Functions must be compatible with the selected estimation method.
Last modified May 21, 2026: Device server implementation (#1375) (5dd5648d)