Fishing for truth: Investigating pre-verbal numerical systems

Today, we will enter the fascinating world of numerical abilities and the contribution of fish in the study of mathematical disabilities.

Numerical systems

Several studies have shown that humans have both verbal and pre-verbal numerical systems.

Verbal systems

Verbal systems are strictly related to language and are fundamental to our mathematical skills. Because of them, we can make mathematical operations and live in our society.

Pre-verbal numerical systems

On the other hand, we have pre-verbal numerical systems, such as the ability to quickly estimate which group is larger. These are very ancient systems that have permitted us to discriminate between quantities in nature during human evolution.

However, we still use pre-verbal numerical systems, even today​​—for instance, when we have to select which queue is shorter at the airport.

_{Group A or Group B?}

For example, if I ask you which is the larger group, I am sure you can tell me Group A. You did not count the elements like you learned at school, instead you used a pre-verbal numerical system; you basically saw the solution.

Investigating pre-verbal numerical systems

There are at least four different research fields in psychology that investigate pre-verbal numerical systems:

• Cultural Psychology
• Cognitive Psychology
• Developmental Psychology
• Animal Psychology

Let’s take a look at each one.

Cultural psychology

Cultural psychology studies the impact of culture/education in perceptual and cognitive processes. There is an Amazonian population, the Munduruku, that has a peculiar and limited number vocabulary: They have a term for 1, a term for 2, a term for 3, another for 4, and another one for 5. Then, only a single term to say “anything larger than 5”!

_{The Munduruku have their own number vocabulary}

Well, even though these individuals do not have verbal labels for large numbers, they still can discriminate between 10 and 20; so they have a rudimentary pre-verbal mechanism of numerical estimation.

Cognitive psychology

Cognitive psychology is the field that typically studies cognitive processes by testing individuals (mainly from Western societies)—for example, testing university students.

The challenge here is: how can we study pre-verbal abilities in individuals with a sophisticated language, like us?

Developmental psychology

_{These infants already have basic numerical abilities.}

Developmental psychology is also important to address a fundamental issue: what is the relationship between verbal and pre-verbal systems?

1. From pre-verbal abilities, we develop verbal numerical abilities.
2. From verbal abilities, we improve our pre-verbal abilities.
3. No relation at all, as the two abilities rely on independent cognitive systems.

Animal psychology

A similar result was then found in lionesses, hyenas, and even… ants!

1. Numerical abilities are useful in optimizing the possibility to have offspring. For example, it is known that male mosquitofish prefer to join a larger group of females in order to increase their possibility to copulate with one of them.
2. They are also useful in nature to optimize food intake, as they permit reaching the group containing the larger amount of food.
3. Finally, numerical abilities are useful as an anti-predator strategy. Indeed, several species tend to join the larger group of conspecifics in order to reduce the possibility of being spotted by predators. Safety in numbers, isn’t it?

But if we want to study the genetics behind mathematical abilities, you might benefit from a faster growing species, such as fish!

We’ll talk more about this in the second part of our step.