Do animals have a sense of numbers? Study involving rats suggests animals may be able to count

A recent study has confirmed the existence of a discrete number sense in rats, offering new insights into the specific neural circuits involved in number processing in animals. 

The research, conducted by a joint research team from the City University of Hong Kong and The Chinese University of Hong Kong, was published in Science Advances.  

According to the researchers, the study offers a significant animal model for analysing the neural basis of numerical ability and disability in humans. They deployed a numerical learning task, brain manipulation techniques and AI modelling to tackle an ongoing debate about whether rats can count.

The results shed light on the mechanisms that underlie numerical ability, a cognitive skill essential to mathematical proficiency, which is a defining characteristic of human intelligence. The researchers have titled the article "Disparate processing of numerosity and associated continuous magnitudes in rats."

Professor Yung Wing-ho, Chair Professor of Cognitive Neuroscience at CityUHK, said the research team aimed to minimise the impact of constant magnitudes in numerical tests and performed a detailed quantitative analysis to find the respective contributions of numbers and magnitudes.

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The animal-focused algorithm developed by the team generates stimuli that emphasise numbers while reducing the impact of other distractions. "This will help us better understand how animals perceive and quantify numbers," Professor Yung said. 

During the research, they found that the rats without previous knowledge of numbers developed a sense for them when trained with sounds representing two or three numbers. When given a choice of food rewards, rats consistently focused on the number of sounds rather than continuous magnitudes.

Furthermore, the findings help unveil the relationship between magnitude and numerosity processing. The researchers blocked a specific part of the rats' brain called the posterior parietal cortex. It impacted their ability to understand numbers but not their sense of magnitude. "This suggests that the brain has a specific area for dealing with numbers," Professor Yung continued. 

The study solved a long-standing mystery about how brains handle numbers and explained how genes are related to mathematical ability. The practical applications of neural network modelling extend to AI.

(With inputs from agencies)