Signal Detection Experiment

In the following you will have the opportunity to run a version of the Signal Detection experiment and collect data yourself.  The experiment will consist of 6 blocks of 20 trials each.  In each trial, you begin by pressing the Start Trial button.  You should fix your gaze on the cross-hatch in the middle of the screen.  A brief randomly determined period of time will pass.  After this brief period, a small black dot will either appear or not appear on the screen.  The appearance/non-appearance of the signal will be followed by another brief span of time.  Once the trial has run its course, the two buttons marked Signal Detected and No Signal Detected will be enabled, thus marking the end of the trial.  At this point you should press the button corresponding to whether you saw a signal: if a signal did seem to appear to you, press the Signal Detected button; otherwise, press the No Signal Detected button.  You should make what you determine to be the correct response as quickly as possible.  Each of the buttons are large enough so you should be able to click the correct one without having to
avert your gaze from the display area.

Once you have responded, the Start Signal will be re-enabled.  Press that button when you are ready for the next trial.  The next trial will not start until you have pressed this button.  At the end of each block, you will be prompted to start the next block.

Two different signals will be presented, differentiated in terms of size.  These different sizes will be mixed at different rates of probability for each block of trials.

If you have a small monitor, it is a good idea to maximize your browser window.  Even if you don't maximize your browser window, it is still a good idea to close or minimize all other windows on your desktop so that the only window showing is the browser window.  Also, this might be a good time to read the general instructions for setting up your monitor and for setting your distance from the monitor for optimal performance of this experiment.

In order to get some sense of how the experiment will go, you can take a practice experiment.  The practice experiment consists of two blocks of 10 trials each.  It is advised that if you wish to collect data for your performance of this experiment (or for that of a another subject), that you take the practice run, so you can get a sense of the flow of the experiment.

At the end of the experiment, data will be displayed which you can save to a file or print out.