Introduction
This demo is an adaptation of the Posner Cueing Task (Posner, M. I. (1980). Orienting of attention. Quarterly Journal of Experimental Psychology, 32, 3–25). It aims to reorient visual attention with an exogenous inducer (a white dot) to more easily detect a target (a red dot). The inducer gives the right cue in 80% of trials. As such, researchers could measure the number of incorrect responses by the participant and compare reaction times across congruent/incongruent trials. The TRACKPixx3 can also be integrated to record eye fixations during the task.
Prerequisites
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LabMaestro is installed and activated
Project Files
Experiment Overview
The experiment uses a Simple Method to define trials with two variables: Inducer, which specifies the inducer's position in degrees of visual angle, and Stim, which specifies the target's position in degrees of visual angle. 10 trials are defined; 8 in which the target appears in the same position (4 to the left and 4 to the right), and 2 in which the target appears in different positions (one in which the target is to the left, one in which it is to the right). By default, two fully randomized replications are done, for a total of 20 trials, 16 congruent and 4 incongruent.
The experimental timeline is very simple, consisting of only two epochs. The first epoch shows a fixation cross with task instructions and waits for the participant to press SPACE to begin the experiment.
The second epoch contains the task itself. The fixation cross remains on the screen, and after a certain amount of time defined in the Wait command (default = .4 second), the inducer in the position Inducer appears for a time defined by the command Inducer_Time (default=.05 second). Then, after a delay defined by the ISI variable (Inter-Stimulus Interval, default = .2 second), the target appears at position Stim for a duration defined by Target_Time (default = .05 second). The task then waits for up to 5 seconds for the participant to answer, and the input is saved to the data file.
Related Links
Understanding Timeline Behavior