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In this experiment you can see how well attention can be divided between two tasks, in this case a tracking task and a target detection task. This expeirment is modeled generically on dual task methodologies used in the human-factors field. The tracking task is called the primary task and the target detection is called the secondary task. IN this experiment, the IV is the difficulty of the secondary task as manipulated by the duration that the secondary task is on. You can also manipulate other variables but that would require multiple runs of the experiment.

Setup Instructions

You can adjust several parameters to design your own version of the experments. The settings are discussed below.

Settings for the Stimuli

You can adjust several parameters to design your own version of the experments. The settings are discuss below.

Primary Task Variables

Angle Uncertainty: The dot that moves will randomly change direction, the angle uncertainty indicates the largest angle that the dot will change.

Speed of dot (relative to width): how fast the dot moves.

Size of Tracking Box (relative to width): how big is the box that you need to keep the dot inside.

Give tracking feedback: change the color of the box to indicate how far you are from the dot (cyan for inside, yellow for near, and red for far).

Use Sound in Tracking Feedback: if giving feedback, play a beep when the box if far from the dot (that is the box will be drawn red).

Secondary Task Variables

Percentage of Targets: of the secondary stimuli, what percentage are targets.

Average time between Stimuli (ms): on average, how much time elapses between secondary targets.

Variation in ISI: what proportion of that average wcan the time between targets (ISI) vary.

Font Size: choose the font size of the letters. The bigger the letters the farther the outside letters will be from the fovea.

General Stimulus Variables

Require Button Press: if, yes, a pop up window will appear that you have press the button on to start the trial. Otherwise the end of one trial will go to the fixation mark for the next trial.(Yes is recommended.)

Background Gray Level : the brightness of the background, in basic display units. This variable alters the contrast between the letters and the background.

Duration of Fixation (ms): how long the fixation mark is on (ms).

Stimulus Delay (ms from end of fixation): how long after the fixation mark is removed till the beginning of the stimulus. This number needs to be big enough for any arrows that occur before the stimulus (the negative numbrer includes the duration of the stimulus). Reset Stimulus At the top of the settings is a Reset Stimulus button. Pressing this button restores the method settings to their default values.

Experimental Method Settings

Secondary Stimulus Duration (ms): choose the different duration that the secondary target will be on. This is the primary indendent variable. These trials are presented in blocks.

Trial Duration: how long the tracking period should be.

Number of Trials/Duration: how many trials at each level of secondary target duration.

Reset Method At the top of the settings page is a Reset Method button. Pressing this button restores the stimulus settings to their default values.


Settings for the Stimuli

Change the settings below to alter the stimulus parameters in this experiment.

Experimental Method Settings

Change the settings below to alter the parameters of the experimental method.

Instructions for Experiment

Below, press the spacebar or the Open Experiment Window button on the screen to open the window where the experiment will run. When this screen opens, press the spacebar or click the "Start" button to begin the experiment. There are instructions above the "Start" button. Read them to know how to perform the experiment. Keep your eyes fixated on the red plus sign in the middle of the screen.

Results Tab

Your data will be presented on the results tab. The x-axis will have the secondary stimulus durations. The y-axis will show the different dependent variables (tracking error and secondary target measures). To download your trial-by-trial, press the Show Data link. To download the summary data press the Show Summary link. This data will be stored in a csv format readable by most spreadsheet and statistical programs.

Your Results