TrainType2 version 2-8

 

 

 

On every trial, you present a single letter randomly and independently drawn from a set of eight letters.  There are four possible response keys <ZXCVM,./>.  The mapping is the same for every subject:

 

 LETTER                                RESPONSE KEY

K                                             Z

Q                                             X

D                                             C

S                                             V

T                                              M

L                                              ,

J                                              .

Z                                              /

 

 

The letter are large and in the center of the screen.  It remains present until the subject responds, and then it disappears. 

 

To receive a reminder about the finger stimulus mapping subjects are asked to press the spacebar (labeled “HELP”).  Then the letters appear in smaller print at the bottom of the display.

 

Response-stimulus interval (from keypress to next response) should be a random number between 1 second and 2 seconds.  (Save what it was!)

 

There should be sixteen blocks of 40 trials.  Again, on every trial letter is randomly selected; that automatically determines the correct response. 

 

You should ask the experimenter for initials, subject number, and whether the subject is in condition 1, 2, 3 or 4.  Subject_Condition determines how the letters are selected in the first 8 blocks

 

Subject_Condition 1:            Randomly select the letter independently on each trial in all of the 16 blocks, so there is a 1 in 8 chance of each letter being presented independent of whatever happened before.

 

Subject_Condition 2:  In Blocks 1-8:  On the first trial in blocks 1-8, select the letter randomly.  For all the remaining trials in that block, the letter should repeat what was presented on the previous trial with prob=0.85; with probability 0.15 it should be different (0.05 chance of each of the other 3 lettters). In Blocks 9-16: choose letters randomly and independently just as in Condition 1.

 

Subject_Condition 3:  In each of blocks 1-8, you always present just one of the letters.  Tell the subject at the beginning of the trial “please keep all eight response fingers rested on the keys throughout this block; we will only be training on one letter”.  The letter should rotate, so that each of the four letters is used in two separate blocks out of the first 8 blocks.  In Blocks 9-16: choose letters randomly and independently just as in Condition 1.

 

Subject_Condition 4:  In each of blocks 1-8, each letter is preceeded by a hint, visually showing which key to press for the response.  Subjects are asked to keep their focus in the center of the screen.  In Blocks 9-16: choose letters randomly and independently just as in Condition 1.

 

 

Instructions are presented within the program.

(e.g. Condition 1)

 

  Welcome to our experiment. We are looking at how fast you can respond to letters by pressing a button. On every trial, you will see one of six possible letters.  There are six response keys marked on the lower row of the keyboard. You should rest your index, middle, and ring fingers of your left and right hands comfortably on these response keys when the experiment begins. Please keep them there while the experiment is running.

 

There are eight possible letters. The assignment is like this

 

K         Q         D         S            T          L          J          Z

 

So if you see a K, you would press the leftmost key. If you see a L, you would press the third key from the right.

 

 

We will do sixteen blocks of trials. Each block will last just a few minutes. At the end of each block, there will be a rest period. Take a minute to relax, and then when you’re ready to resume, just press one of the response keys and the experiment will begin. If you need a reminder of which keys go with which letter, press the SPACEBAR.  The eight letters will then sit at the bottom of the screen until you complete that trial. Please only check the letters if you need to.

 

            Please try to respond as rapidly and accurately as possible. If you have any questions, ask the experimenter now. We appreciate your participation and hope you find this task at least somewhat entertaining. Just concentrate on trying to do your best and we will be finished before you know it.

 

 

 

 

 

 

 Each display should look something like this, with the eight letters appearing when the spacebar is pressed.

 

 

 

 

 

 

 

 

 

S

 

 

 

 

 K         Q          D          S                                  T          L          J           Z

 
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Timing

 

When the subject presses a key to start a block, wait 1.5 seconds, then put up a plus sign in the middle for 1 second, then take that away for 500 msec, then put up the first letter.  Each letter should always remain present until the subject responds.  As soon as the subject responds, the letter should disappear.  The next letter should appear after the randomly chosen intertribal interval (1000 msec – 2000 msec).  During this intertrial interval, there should be nothing on the screen. 

 

End of Block

 

At the end of the block, put up a sign that says REST PERIOD – PLEASE REST AT LEAST 10 SECONDS.  Also display the subject’s mean response time and number of errors from each of the previous blocks.  That way the subject can track their improvement (and they will improve a lot).  This makes it more motivating to the subject.  Make them rest 10 seconds before you put up PRESS ANY KEY WHEN YOU ARE READY TO RESUME.

 

Data Analysis

 

The raw data file should contain

 

<block  trial   letter     subject_condition  RT  correct-response  actual-response intertrial-interval-after-response  AskedForHelp>

 

When you make the Sfile, blocks should be a factor.  So the S-file should have these factors:

 

<subject   subject_condition   block   mean_RT   number-of-errors>