It’s long been a common belief that fish have the memory capacity of only a few seconds. People often make fun of people with bad short-term memory by saying they have the “memory of a goldfish.”
This belief about fish spread even further after being highlighted in Disney’s “Finding Nemo” films where Dory, played by Ellen DeGeneres, has a memory that lasts only about 10 seconds. However, a new study from Oxford University may have just proved that we got Dory all wrong.
To find out if goldfish have memories, the team at the University of Oxford trained nine goldfish to swim 2.3 feet and back to get a reward. Yes, goldfish are even smart enough to be trained. All these years they’ve been swimming in circles in small bowls when we could have been teaching them to do some fun behaviors.
The researchers marked off the tank in vertical stripes every ¾ inch.
Once the fish swam the 2.3 feet, they were given a physical cue from a researcher to turn around and swim back to where they started. If they did so, they’d receive a tasty bloodworm.
After the fish got that pattern down, the researchers changed the starting point and didn’t give any cues to turn back. Eight out of the nine fish swam the same exact distance before turning around. It seems that the fish used external cues to mark the distance and then turned around at the appropriate point. This type of measurement is known by scientists as “optic flow.”
This proves that fish actually do have decent memories.
The one thing that tripped the fish up was when the vertical stripes were moved closer together, they didn’t swim as far before turning back.
The fish also didn’t appear to use time as a way of marking distance.
“We did not find a significant effect of time on the distance travelled and the coefficient of variation in time travelled was two to three times higher than the coefficient of variation in distance estimate for most fish,” the researchers wrote. “Video analysis revealed high variation in time spent to perform the experiment within a day or a session without any apparent pattern, further supporting this hypothesis.”
This study definitely changes the way people will look at the film “Finding Dory” and how they relate to their goldfish. Remember that time you forgot to feed him? He remembers.
“Forgetful people say they have a mind like a goldfish, but that’s not fair,” Dr. Adelaide Sibeaux, who led the study at the University of Oxford, told Daily Mail. “Goldfish are clearly not stupid at all, as they have a good memory for distance based on the flow of objects passing by as they swim, like stripes on their tanks.”
“Even when I left for a week for Christmas, and came back to restart the study, they knew how to do it,” she continued.
So next time someone tells you they have the memory of a goldfish, let them know that it’s actually a compliment.