Rats Can Count: Hong Kong Scientists Uncover Numerical Ability in Rodents

A joint research team from City University of Hong Kong (CityUHK) and The Chinese University of Hong Kong (CUHK) has made a remarkable discovery that appears to confirm the existence of discrete number sense in rats. This finding provides a crucial animal model for studying the neural basis of numerical ability and disability in humans.

The study, published in Science Advances, employed a numerical learning task, brain manipulation techniques, and AI modeling to address the ongoing debate about whether rats can count. Professor Yung Wing-ho, Chair Professor of Cognitive Neuroscience at CityUHK, collaborated with CUHK scientists at the Faculty of Medicine to shed light on the mechanisms underlying numerical ability, a cognitive skill fundamental to mathematical aptitude and human intelligence.

Innovative Approach Minimizes Distractions in Numerical Tests

To determine the respective contributions of numbers and magnitudes, the research team developed an algorithm that generates stimuli allowing animals to focus solely on numbers while minimizing other distracting factors. “This will help us better understand how animals perceive and quantify numbers,” Professor Yung explains.

The team discovered that rats with no prior knowledge of numbers could develop a sense of numbers when trained with sounds representing two or three numbers. Despite the influence of continuous magnitudes, the rats consistently focused on the number of sounds when making choices for food rewards.

Brain Area Specific to Number Processing Identified

The study also helps dissect the relationship between magnitude and numerosity processing. The researchers found that when they blocked a specific part of the rats’ brains, called the posterior parietal cortex, the rats’ ability to understand numbers was affected, but not their sense of magnitude. This suggests that the brain has a specific area dedicated to processing numbers, according to Professor Yung.

The findings not only solve a long-standing mystery about how brains handle numbers but also provide new insights into studying the specific neural circuits involved in number processing in animals and how genes are associated with mathematical ability. The results from neural network modeling could have practical applications in the field of artificial intelligence.

The study’s corresponding authors are Professor Yung and Professor Ke Ya from the School of Biomedical Sciences at the CUHK Faculty of Medicine. Other contributing authors include Dr. Liang Tuo, Dr. Peng Rongchao, Mr. Rong Kanglin, and Ms. Li Jiaxin from CUHK.

This groundbreaking discovery of numerical ability in rats opens up new avenues for research into the neural basis of numerical cognition and its potential applications in fields such as education, psychology, and artificial intelligence. By understanding how the brain processes numbers and the specific neural circuits involved, scientists can gain valuable insights into the development of mathematical skills and the causes of numerical disabilities in humans.

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