About this Research Topic
Despite once being reserved as perhaps a unique human ability, and one reliant on language, comparative and developmental research has shown that numerical abilities predate verbal language. Human infants and several non-human species have been shown to represent numerical information in varied contexts, and the capacity to discriminate both small and large numerosities has been reported in mammals, birds, amphibians, and fish. The similar performances often observed across such diverse species have led to the hypothesis that there may be shared core systems underlying number abilities of non-human species and human non-verbal numerical abilities. Thus, animal models could provide useful insight on our comprehension of numerical cognition, and in particular the evolution of non-verbal numerical abilities.
Several aspects need be clarified. For instance the ontogeny of numerical competence in animals has been rarely investigated. It is unclear whether all species can represent numerical information or, on the contrary, use non-numerical continuous quantities that co-vary with number (such as cumulative surface area, density and space). In addition, the existence of a specific mechanism to process small numbers (<4), traditionally called ‘subitizing’, is highly debated. Neuro-anatomical correlates of numerical competence need also to be clarified, as well as brain lateralization of non-verbal numerical abilities.
We solicit contributions in a variety of formats, from empirical research reports, to methodological, review and opinion papers that can advance our understanding on the topic. We particularly encourage papers exploring the following issues:
1. Do non-human numerical abilities improve in precision across development as observed in human infants?
2. Can animals discriminate between quantities by using numerical information only? Is number a ‘last resort’ strategy adopted when no other continuous quantity is available?
3. To what extent do animals show similar numerical abilities? Do they show evidence of a subitizing-like process?
4. What kinds of things can be represented numerically by animals? What evidence is there for cross-modal numerical judgments, or judgments of sub-sets of stimuli, or perhaps even counting-like behavior in non-human species?
5. Do comparative studies help us to shed light on the neuro-anatomical correlates of number?
By bringing together different studies on these issues we aim to contribute to a more complete picture of numerical competence in the absence of language.