1
00:00:00,366 --> 00:00:07,614
Intense focusing on a task can make people effectively blind, even to stimuli that normally attract attention.

2
00:00:07,614 --> 00:00:15,310
The most dramatic demonstration was offered by Christopher Chabris and Daniel Simons in their book The Invisible Gorilla.

3
00:00:15,310 --> 00:00:22,900
They constructed a short film of two teams passing basketballs, one team wearing white shirts, the other teams wearing black.

4
00:00:22,901 --> 00:00:29,498
The viewers of the film are instructed to count the number of passes made by the white team, ignoring the black players.

5
00:00:29,501 --> 00:00:32,514
This task is difficult and completely absorbing.

6
00:00:32,539 --> 00:00:39,400
Halfway through the video, a woman wearing a gorilla suit appears, crosses the court, thumps her chest, and moves on.

7
00:00:39,401 --> 00:00:41,829
The gorilla is in view for 9 seconds.

8
00:00:41,857 --> 00:00:47,885
Many thousands of people have seen the video, and about half of them do not notice anything unusual.

9
00:00:47,885 --> 00:00:54,640
It is the counting task ― and especially the instruction to ignore one of the teams ― that causes the blindness.

10
00:00:54,685 --> 00:00:58,835
No one who watches the video without that task would miss the gorilla.

11
00:00:58,912 --> 00:01:07,451
Seeing and orienting are automatic functions of System 1, but they depend on the allocation of some attention to the relevant stimulus.

12
00:01:07,451 --> 00:01:14,378
The authors note that the most remarkable observation of their study is that people find its results very surprising.

13
00:01:14,401 --> 00:01:22,553
Indeed, the viewers who fail to see the gorilla are initially sure that it was not there ― they cannot imagine missing such a striking event.

14
00:01:22,557 --> 00:01:31,080
The gorilla study illustrates two important facts about our minds: we can be blind to the obvious, and we are also blind to our blindness.