In this review, we are pitting two theories against each other: the more accepted theory, the
number sense theory, suggesting that a sense of number is innate and non-symbolic …

Domestic chickens are members of an order, Aves, which has been the focus of a revolution
in our understanding of neuroanatomical, cognitive, and social complexity. At least some …

Land use and related pressures have reduced local terrestrial biodiversity, but it is unclear
how the magnitude of change relates to the recently proposed planetary boundary (“safe …

Studies of human adults, infants, and non-human animals demonstrate that non-symbolic
numerical cognition is supported by at least two distinct cognitive systems: a “parallel …

The ability to identify and retain logical relations between stimuli and apply them to novel
stimuli is known as relational concept learning. This has been demonstrated in a few animal …

The ability to estimate number is widespread throughout the animal kingdom. Based on the
relative close phylogenetic relationship (and thus equivalent brain structures), non-verbal …

Evidence has been reported for quantity discrimination in mammals and birds and, to a
lesser extent, fish and amphibians. For the latter species, however, whether quantity …

There has long been interest in how the mind represents numerical magnitude, particularly
in the absence of symbols. For humans and nonhuman animals, number represents a core …

Studies on the ontogenetic origins of human knowledge provide evidence for a small set of
separable systems of core knowledge dealing with the representation of inanimate and …

Non-symbolic numerical abilities are widespread among vertebrates due to their important
adaptive value. Moreover, these abilities were considered peculiar of vertebrate species as …