QuestHandler

data QuestHandler

A Trial Handler that implements the Quest algorithm for quick measurement of psychophysical thresholds. QuestHandler relies on the jsQuest library, a port of Prof Dennis Pelli's QUEST algorithm by Daiichiro Kuroki.

Constructor

new QuestHandler(options)

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Parameters:
Name Type Description
options Object

the handler options

Properties
Name Type Attributes Default Description
psychoJS module:core.PsychoJS

the PsychoJS instance
varName string

the name of the variable / intensity / contrast / threshold manipulated by QUEST
startVal number

initial guess for the threshold
startValSd number

standard deviation of the initial guess
minVal number

minimum value for the threshold
maxVal number

maximum value for the threshold
pThreshold number <optional>
 0.82

threshold criterion expressed as probability of getting a correct response
nTrials number

maximum number of trials
stopInterval number

minimum [5%, 95%] confidence interval required for the loop to stop
method QuestHandler.Method

the QUEST method
beta number <optional>
 3.5

steepness of the QUEST psychometric function
delta number <optional>
 0.01

fraction of trials with blind responses
gamma number <optional>
 0.5

fraction of trails that would generate a correct response when the threshold is infinitely small
grain number <optional>
 0.01

quantization of the internal table
name string

name of the handler
autoLog boolean <optional>
 false

whether or not to log

Extends

  • TrialHandler

Members

(static, readonly) Method :Symbol

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Properties:
Name Type Description
QUANTILE Symbol

Quantile threshold estimate.
MEAN Symbol

Mean threshold estimate.
MODE Symbol

Mode threshold estimate.

QuestHandler method

Type:
  • Symbol

intensity

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Get the current value of the variable / contrast / threshold.

This is the getter associated to getQuestValue.

Methods

(protected) _estimateQuestValue()

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Estimate the next value of the QUEST variable, based on the current value and on the selected QUEST method.

(protected) _setupJsQuest()

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Setup the JS Quest object.

addResponse()

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Add a response and update the PDF.

confInterval()

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Get an estimate of the 5%-95% confidence interval (CI).

getQuestValue() → {number}

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Get the current value of the variable / contrast / threshold.

Returns:

the current QUEST value for the variable / contrast / threshold

Type
number

mean() → {number}

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Get the mean of the Quest posterior PDF.

Returns:

the mean

Type
number

mode() → {number}

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Get the mode of the Quest posterior PDF.

Returns:

the mode

Type
number

quantile() → {number}

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Get the standard deviation of the Quest posterior PDF.

Returns:

the quantile

Type
number

sd() → {number}

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Get the standard deviation of the Quest posterior PDF.

Returns:

the standard deviation

Type
number

setMethod(method, log)

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Setter for the method attribute.

Parameters:
Name Type Description
method mixed

the method value, PsychoPy-style values ("mean", "median", "quantile") are converted to their respective QuestHandler.Method values
log boolean

whether or not to log the change of seed

simulate()

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Simulate a response.