In the 1950s, university professor Curt Richter conducted a gruesome experiment with rats to test how long they could tread water.
Richter first took a dozen rats, put them into jars half-filled with water, & watched them drown. The glass jar was very large therefore the rats couldn't cling to its sides or jump out of it.
On average they'd give up and sink after 15 minutes.
Then Richter re-ran the experiment but with a twist. Right before they gave up due to exhaustion, the researchers would pluck them out, dry them off, let them rest for a few minutes, then put them back in for a second round of treading water.
In this second try, after they had just swam until failure only a few short minutes earlier, they lasted on average 60 HOURS!
Richter's results showed that removing or "saving? the rats just before drowning allowed those same rats to swim approximately 240x longer the next time they were put in the bucket. One rat even lasted an astonishing 81 hours.
The conclusion drawn was that since the rats BELIEVED that they would eventual- ly be rescued, they could push their bodies way past what they previously thought impossible.