Fish can add and subtract

2022/03/31 Etxebeste Aduriz, Egoitz - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Zoologia

Fish have shown their ability to add and subtract in a study published in Scientific Reports. Thus, they have demonstrated that fish possess capacities comparable to other vertebrates and invertebrates.

They experiment with a cyclic (Pseudotropheus zebra) and a stripe (Potamotrygon motoro). Eight specimens of each species have been trained to be considered a symbol of the addition of a blue and yellow colour as a symbol of the elimination of one. The fish were taught letters with blue or yellow figures and placed two doors with different image numbers, one of them being the correct answer. For example, if they were taught a letter with three images or blue shapes, they had to add one and the right answer was to choose a door with four images. When they chose the straight door, they rewarded it.

Six cyclics and four stripes learned to do well these sums and remains, 28 cyclical sessions and 68 on average. Although cyclics learned faster, stripes got closer with the correct answer, for example in the sum, cyclics got closer in 78% and stripes in 94%. They all learned more easily to add up than to subtract. In the case of deductions cyclics were correct in 69% and stripes in 89%.