Whether it’s Pixar’s Dory with short-term memory loss or the saying “He has the brain of a goldfish” or constantly told that fish are simple and have poor memories, but are they more complex than we think?
This is the rotating snake illusion. As you move your eyes the snakes appear to be moving in circles, but the image is actually stationary.
It turns out that fish see this illusion in the similar way to you and I. Even though fish diverged from land vertebrates 450 million years ago, both have developed similar vision to hunt, escape predators, and avoid collisions.
Researchers have hypothesized that we see the same motion illusions as a result of convergent evolution, where organisms not closely related independently evolved similar traits as a result of having to adapt to similar environments.
Which one of these red circles is larger?
Your eyes are likely telling you the one on the right, and the fish would think so too. But it turns out that they’re the same size. In the study on red tail split fins the fish were trained to discriminate between discs of different sizes and to prefer larger discs and then when presented with a similar illusion that they chose the deceptively larger one.
What about attention span? One particular report found that the human attention span is down from 12 seconds in the year 2000 to 8 seconds today. Our use of the internet and devices is theorized to play a role, but either way goldfish have a nine-second attention span, trumping that of a human. When it comes to forgetfulness, a study using African cichlids gave fish food reward in a particular zone of an aquarium for three days in a row. Then the fish were given a 12-day rest period before being reintroduced into the aquarium.
Using motion tracking software, the cichlids showed a distinct preference to the area of the aquarium where they had previously received a reward.
Studies have even shown goldfish can remember things for at least three months, distinguishing between shapes, colors, sounds, and even navigating mazes. On top of this, goldfish can recognize their owners.
Ultimately, fish have been shown to have quite good memories.
After all, they need to remember prey types, avoid predators and even avoid our hooks after being caught in the past. When it comes to pain, we’re actually quite different than fish. When you injure yourself receptors in your body called nociceptors send signals to the neocortex where the sensation of pain is processed. But many fish lack nociceptors and all fish lack a neocortex, so pain isn’t experienced in the same way.
When “Finding Nemo” was first released, hundreds of fish were flushed to set them free, when in reality these fish often die from trauma or exposure to fresh water.
Additionally, researchers worried that “Finding Dory”‘s release could increase the decline in ornamental fish populations, as more people will want the royal blue tang as a pet.
So we decided to make a video on eight other amazing aquatic animals on ASAPThought where we visited an aquarium to check them out in person.
Our lakes and oceans are full of some wild and beautiful creatures so be sure to check it out with the link below. And subscribe for more weekly science videos!