Appendix A

Initial Description of a Software Environment
for Demanding Tasks: Missile Command

Download & Installation

The initial version of the game can be played on any computer of your choice provided you have the Adobe Flash Player 10 internet plugin installed. Download and unpack missilecommand.zip and doubleclick on the .html file. This will open a browser window with Missile Command. To view the game in full screen mode (Windows): press F11 in your browser.

Performing the task: playing

In Missile Command, the player faces objects falling from the top towards the bottom of the screen. The player's task consists in classifying each object as ally or enemy, and shooting down the enemies before they reach the ground while letting allies land safely.

Identification of an object is a cognitive task in simplified form represented by an arithmetical calculation. In order to determine whether an object is an ally or an enemy, the player mouse-clicks on the object whereafter an arithmetical formula appears next to that object. A correct formula means that we are dealing with an ally while enemies show false formulas. To categorize an object as ally, press ←; press → for enemies. A spoken voice will confirm your choice. If you made a mistake classifying an object you can select it again and enter the correct identification. Objects designated as allies turn (eventually) greenish yellow while those identified as enemies go reddish orange. The picture shows an identified ally to the left and an identified enemy to the right.

 

 

The player uses the cannon at the bottom of the screen to shoot down (hostile) objects. Position the mouse cursor where you expect the object to be in a few seconds, and press spacebar to launch a missile. First few attempts may result in misses but you'll get the hang of it in no time. Once an object is shot, you cannot resurrect it.

Scoring and costs

 

—Allied objetcs:

            • landed, regardless of identification: +1 point;

            • shot down, regardless of identification: –1 point;

 

—Enemy objects:

            • landed, regardless of identification: –1 point;

            • shot down, regardless of identification: +1 point;

 

 

The costs are +1 per fired missile; costs are calculated and shown independently of the score. This way you can investigate if support measures affect the efficiency of the task execution.