A hypothesis testing video game

The Blob Fam­ily is a sim­ple game made by Leon Arnott. At heart, it’s a game about test­ing hy­pothe­ses and get­ting the right an­swer with the least amount of ev­i­dence you can.

The me­chan­ics work like so: Balls bounce around the screen ran­domly and you con­trol a char­ac­ter who needs to avoid them. You can aim the mouse any­where and ac­ti­vate a sonar. On the right side are rules for how var­i­ous balls will re­act to this, and your goal is to figure out which ball is which. As you use the sonar more, the balls speed up, so it be­comes more difficult to stay al­ive, thus giv­ing an in­cen­tive to test your hy­poth­e­sis in as few clicks as pos­si­ble.

It very nicely illus­trates the prin­ci­ple that, to test a hy­poth­e­sis, you must de­sign tests to fal­isfy your in­tu­itions rather than to con­firm them. For ex­am­ple, in one level, when you use the sonar:

  • 1 ball heads to­ward the center

  • 1 ball heads away from the center

  • 1 ball heads away from the mouse

  • 1 ball heads away from you

I found my­self mis­tak­enly click­ing in the cen­ter of the screen to test hy­poth­e­sis 1, but this is in­suffi­cient. To de­sign the proper tests, you need to keep the mouse out of the cen­ter, keep it away from you, and de­pend­ing on the po­si­tion of the balls keep it off a straight line from you.

It could also demon­strate the abil­ity of a fast brain to test hy­pothe­ses quickly. For many lev­els, if you could slow time down and set up a very good test, you could solve the prob­lem with a sin­gle click. But we hu­mans aren’t usu­ally so at­ten­tive.

Just thought the LW crowd might en­joy it.