False

The study was over clipping rats wiskers and triming their hair in between wild and domesticated rats. The study is On the Phenomenon of Sudden Death in Animals and Man.

Study

Domesticated rats

Using electric clippers, the whiskers and hair o£ the facial area were trimmed before the animals were placed in water at 95 ° F., a temperature at which most intact, control rats swim 60 to 80 hours.

Hybrid rats

Five of 6 hybrid rats, crosses between wild and domesticated rats, similarly treated, died in a very brief time.

Wild Rats

We then tested 34 clipped wild rats, all recently trapped. These animals are characteristically fierce, aggressive, and suspicious; they are constantly on the alert for any avenue of escape and react very strongly to any form of restraint in captivity. All 34 died in 1-15 minutes after immersion in the jars.

That is to say, wilds rats die in 1-15 minutes because they panic.

Conclusion and potential confusion

The conclusion from the paper, is this

From the results we concluded that trimming the rats' whiskers, destroying possibly their most important means of contact with the outside world, seemed disturbing enough, especially to wild rats, to cause their deaths.

The confusion probably comes from this,

At present it appears that of all these factors, two are the most important: [the restraint involved in holding the wild rats, thus suddenly and finally abolishing all hope of escape; and the confinement in the glass jar, further eliminating all chance of escape and at the same time threatening them with immediate drowning.

But the group that swam longer did NOT do so because they were taught they'd be rescued and swam longer with hope (expectation). They swam longer because they were domesticated rats and NOT wild rats.