Cognition Laboratory Experiments

John H. Krantz, Hanover College, krantzj@hanover.edu

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Hanover College
Psychology Department

Instructions for the
Attentional Blink Experiment

 

When you click on the link below, you will be presented with the experiment setup screen.  On this screen will be the variables you can set to define your condition.  Here is a list of the variables and their settings.  Not all variables will be visible all the time.  Only those variables appropriate to the stimulus and other settings will be shown.  So changing some values may alter what is shown on the setup screen.

Variable Settings
Condition The type of stimulus: Letters, Faces with faces with facial hair as targets, Faces with older faces as targets, or Pictures of dogs.
Number of Repetitions Number of times each trial type will be shown.
Number of Items The number of items that will be shown in the sequence.  Limits depend upon stimulus type.  This affects the total number of trials as the separations between the two targets will be from 0 to 1/2 the length of the string.
Font Size If using a letter stimulus (from 10 to 64 point)
Fixation Duration The length of the fixation prior to the first item in the sequence being shown.
Item Duration How long each item in the sequence is shown.

After you have finished making your settings, press the Done button at the bottom of the screen.  The Attentional Blink experiment screen will then be presented. 

Press the space bar to begin the experiment.  A fixation mark will appear for the indicated time.  Then, one at at time, each letter or picture in the sequence will be presented.  One or two of the targets will be presented.  The letter targets are "J" and "K".  If the stimuli are faces, the targets will be either faces with facial hair or older faces.  One or two of these faces will be shown. The dog targets are the two dogs shown below (a Saint Bernard or a Scottish Terrier):

or

For the young old faces, the targets are below:

Old TargetYoung Target

Either target can be presented and the targets can be presented in either order.  At the end of the sequence you are to indicate which targets you saw, order does not matter.  For the letters, you indicate you saw the "J" by pressing the j key and that you saw the "K by pressing the k key.  The letters you type will be shown at the bottom of the screen.  If you miss type a letter, use the backspace to remove it.  For the faces or dogs, there will be pictures of both target images shown at the bottom of the screen.  Click on which you have seen.  When you do, the text next to the dog's picture will change from "Not Seen" to "Saw".  If you miss click, click the picture again and the text will change back to "Not Seen". When you are done, press the space bar to go to the next trial. 

At the end of the experiment, your results will be presented.  The results will be the accuracy for responding to the first and second item for each of the different distances between the first and second letter.  A sinlge target means that onlye the first item was shown so you can use this to check the results for guessing as no second item was presented.  You can also get your trial by trial results.  In the response part of the trial results, a null indicates that no selection was made.  Closing your results window(s) will take you back to the setup window so you can run another experiment.

Click here to start the experiment.