In this experiment, you will first be asked to solve the following puzzle:

There are three vertical pegs on a board, which are named Tower A, Tower B, and Tower C from the left to the right.  Initially, there are several disks of different size on one of the pegs (the 'Source Tower') with the configuration that each disk lies above the disk(s) bigger than it is.

YOUR TASK is to transfer those disks to another peg (the 'Target Tower', which is coloured BLUE) by MOVING ONE DISK AT A TIME to one of the towers other than the tower on which the disk lies, and by following the RULES:

(a) You CANNOT PUT A DISK ONTO A DISK that is SMALLER than itself, and 
(b) you CANNOT MOVE A DISK ON WHICH ANOTHER DISK LIES (i.e., you can only move the topmost disk of a tower).

As the problem is presented on a computer, you will have to use the mouse to move disks between towers.  

The program can be used in two separate modes:

(1) In SOLUTION MODE you can move disks between towers by using the mouse cursor to indicate from and to which tower you want to transfer a disk.  Each moves counts towards your move total and you can only solve the problem whilst in this mode.

(2) By pressing and holding the <SHIFT> key, the program switches into EXPLORATION MODE.  In this mode, you can also move the disks between towers, but the moves are not counted as part of your solution. This allows you to explore the consequences of moves without them contributing towards your total move score.

As soon as the <SHIFT> key is released, the program switches back into
SOLUTION MODE and restores the problem to the state at which you switched into EXPLORATION MODE. (You can use the EXPLORATION MODE as often as you want, or not at all.)

To familiarize yourself with the software interface, you will now receive a simple PRACTICE TRIAL.

