Contributions:ForagingTask

Demo video of the task. The participant has learned that the brown are the most valuable, then secondly the green ones.

Synopsis

This task presents the participant with a matrix of dots to forage. The colors of the dots have different value, and the only way the participant knows the difference is by listening to the feedback given after harvesting the dot. Over time, the participant will learn which type will give them the highest reward, and will optimize each trial. After each trial, the participant is also shown their previous trial's score to help with their learning as well.

This task can easily be used in BCI2000, and has many adjustable settings to allow for the perfectly designed experiment.

Versioning

Authors

Max Marcus

Will Engelhardt (engelhardt@neurotechcenter.org)

Limitations

Audio Stimuli

The audio currently must have a specific format. It must be a .wav file. It must be in the format of <mean>-<number (0-9)>.wav. There must be 10 types of each mean, which is the 0-9 number. The mean corresponds to the amount of sound/reward in the audio file, and the files will be chosen based on the parameter ForagingStimuliDistribution, where you give the mean and standard deviation.

Parameters

Foraging

ForagingColumns	Number of columns of dots
ForagingRows	Number of rows of dots
Trials	Number of trials in a run

CursorControl

EyetrackerCursor	Enable to use the eyetracker. Otherwise, the expression filter will be used, where any Expression or State can control the cursor.
ShowCursor	Enable to show the participant the cursor on their screen
CursorColor	Color of the cursor (if shown)
CursorSize	CursorSize (if shown)
UseVelocity	Enable to control the cursor by adding a velocity to it. Otherwise, the cursor is set with position.

Foraging Dot Size

MinDotRadius	Normal pixel size of the radius of each dot
MaxDotRadius	Maximum pixel size of the dot when increasing upon dwelling
DwellVisualAngle	Degrees of visual angle that triggers dwell. Uses Eye-tracker's state of distance to screen to create pixel size
FixationDotRadius	Radius of fixation dot
FixationVisualAngle	Degrees of visual angle for fixation dot to be held
ViewingDistanceInCm	Distance of participant from screen (cm). To be used for calculating pixel size of dots. If eyetracker is enabled, this will not be used, and the distance will instead be measured with the eyetracker.
WindowDiagonalInCm	Length of the application window's diagonal. This helps calculate the conversion from centimeters to pixel size.

Foraging Stimuli

ForagingStimuliDirectory	Folder that contains the audio stimuli. Must be in format specified in Audio Stimuli
ForagingStimuliDistribution	Mean and standard deviation of audio files for each type of stimulus
ForagingStimuliColors	List of colors to be used. The first column must be the names of the colors, then the second column is the hex values of the colors.
ColorsInATrial	Number of colors to show per trial. Cannot be greater than the size of the given color list

Foraging Timing

ForagingTrialTime	Length of time that subject gets to forage
DwellTime	Duration that subject has to dwell on a dot to receive reward
InterTrialTime	Length of time between trials
ScoreFeedbackTime	Length of time to show user previous round's score
FixationTime	Time to fixate
FixationHoldTime	Time to hold fixation before starting trial (once dots have appeared)

ProgressBar

The progress bar lets the experimenter know how much time has passed and how much is left. These parameters allow for customization of the bar.

PhotoDiodePatch

A photodiode patch is for use with a photodiode, which measures if the light input is below or above a threshold. Used for measuring the exact time ofthe screen presentation. These parameters allow for customization of the location of the patch, the shape, and the (in)active colors.

States

All states are integers.

CursorPosX	The X position of the cursor, between 0 (left) and 1000 (right)
CursorPosY	The Y position of the cursor, between 0 (top) and 1000 (bottom)
TargetX	Column of the target that the cursor is in
TargetY	Row of the target that the cursor is in
TargetType	Each color is a type. Type of the target that the cursor is closest to
Score	Each round's score
TrialPhase	Phase of trial we are currently in Fixation = 0 FixationHold = 1 Feedback = 2 InterTrial = 3 ScoreFeedback = 4
Trial	Trial number (1 - number of trials)
Dwelling	Number of blocks that have occurred when the participant has been dwelling on the dot. Once it gets above the time set by #DwellTime, the reward is given and it goes back to 0
DotExists	Describes which dots exist in a trial. Each target is stored in a bit. The order starts top left, goes through the row, then goes to the next row. For example, in a trial with 3 rows and 4 columns, the starting value will be 2^12 = 4096. If the top left target gets acquired, it no longer exists so the first bit will be flipped: 4096 - 2^0 = 4095. If the bottom right one gets chosen next, the 12th bit will be flipped: 4095 - 2^11 = 2047. This way, when decoded, you can be certain about the dot matrix after the experiment.

See also

Contributions:Applications