How do scientists know that gold fish only have memory for 3 seconds?

Question

How can you measure a gold fish's memory?

Answer 1

scientists proved that their memory is longer than 3 seconds as they taught them to associate a certain coloured area with feeding

for example some associated the red area with feeding, some a blue area.

Answer 2

it's a myth

Answer 3

I believe they reached that conclusion from measuring the size of the part of the brain relating to memory. However, as the above poster pointed out, the 3-second memory thing is not actually true. Goldfish can be trained, and anyone who's kept them as pets will know that, when you approach the tank to feed them, they swim up to the surface in anticipation of the food being dropped in. Obviously they would not remember that a person approaching the tank means food from one day to the next if they really had a 3-second memory.

Answer 4

Mythbusters proved this myth to be BUSTED.  They have much longer memories.  The length they stopped at was a full week.