Subjects made their selection by pressing one of two labeled keys on a response box.
After a stimulus screen, a central question mark appeared for 3000 ms and the participants were required to provide their response by pressing with their thumb one of the three keys on a response pad (corresponding to 0, 1, and 2 strings containing two identical consecutive characters, respectively).
During the present EAST participants were asked to sort target and attribute pictures as fast as possible using a left and a right response key on an unmarked response box.
Participants were required to decide whether the stimulus was a word or pseudoword and to press the appropriate key on the response box, one marked "word" and the other marked "pseudoword".
They could make their rating at any time during the response-period, by pressing one of three buttons on a response key-pad corresponding to the rating options with their right hand.
In it delay frustration is indexed as the number and duration of responses made on a response key during a series of unpredictable and unsignalled delay periods, which interrupt the completion of a simple computer-based tests.
All participants signaled the presence of each non-target number via a manual finger press on a response key.
The participants were instructed to decide whether the letter string appearing on the computer screen was a Finnish word or not by pressing the appropriate "yes" or "no" key on the response box.
Immediately following each display, the target stimulus and its matched pair-mate were displayed one above the other, in random order, and participants indicated which had been shown by pressing the appropriate key on the response box.
Participants could stop the bar at any point in the trial by pressing a button with their right hand (space key in behavioral study, index button on a response pad in the fMRI experiment) and were instructed to stop the bar as close to the target line as possible.
