Grouping sets of elements into smaller, equal-sized, subsets constitutes a perceptual strategy employed by humans and other animals to enhance cognitive performance. We hypothesized that asymmetrical grouping, a characteristic of prime numbers, could provide visual cues enabling discrimination of prime from non-prime numerosities. Newborn chicks were habituated to even numerosities (as sets of elements presented on a screen), and then tested for their spontaneous choice among a prime and a non-prime odd numerosity. Chicks discriminated and preferred the prime over the composite set of elements. We discuss this result in terms of novelty preference. By employing different contrasts (i.e., 7vs.9, 11vs.9, and 13vs.15) we investigated the limits of such mechanism showing that induced grouping positively affects chicks' performance.

中文翻译：

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幼小雏鸡依靠感知分组来区分素数

将元素集分组为较小的，相等大小的子集构成了人类和其他动物用来增强认知能力的一种感知策略。我们假设不对称分组是素数的特征，可以提供视觉提示，从而能够区分素数和非素数。新生小鸡习惯于偶数（以屏幕上显示的元素集），然后测试它们在自然数和非自然数之间的自发选择。小鸡区分并优选素数，而不是复合元素集。我们根据新颖性偏好来讨论此结果。通过采用不同的对比（即7vs.9、11vs.9和13vs.15），我们研究了这种机制的局限性，表明诱导的分组对雏鸡的表现有积极影响。