One, two, three, four, or is there something more? Numerical discrimination in day-old domestic chicks

Abstract

Human adults master sophisticated, abstract numerical calculations that are mostly based on symbolic language and thus inimitably human. Humans may nonetheless share a subset of non-verbal numerical skills, available soon after birth and considered the evolutionary foundation of more complex numerical reasoning, with other animals. These skills are thought to be based on the two systems: the object file system which processes small values (<3) and the analogue magnitude system which processes large magnitudes (>4). Infants' ability to discriminate 1 vs. 2, 1 vs. 3, 2 vs. 3, but not 1 vs. 4, seems to indicate that the two systems are independent, implying that the conception of a continuous number processing system is based on precursors that appear to be interrupted at or about the number four. The findings from the study being presented here indicating that chicks are able to make a series of discriminations regarding that borderline number (1 vs. 4, 1 vs. 5, 2 vs. 4) support the hypothesis that there is continuity in the number system which processes both small and large numerousness.

Non-visual numerical discrimination in a blind cavefish (Phreatichthys andruzzii)

“…Our study was not expressly designed to test these hypotheses. However, the finding of Experiment 1 that cavefish proved able to make a direct comparison between small and large numbers (two versus six objects) is in line with recent studies in mammals (Cantlon and Brannon, 2007;Hanus and Call, 2007) and birds Rugani et al, 2013a;Rugani et al, 2013b) that showed no decrease in performance in small versus large number comparisons and thus is more in agreement with the single-system hypothesis.…”

Addition and subtraction in wild New Zealand robins

“…Avian numerical competence, like that of many species, is something that has become increasingly understood over the last two decades; from quantity discrimination (Emmerton and Renner, 2006;Stewart, 1989, 1993;Hunt et al, 2008;Garland et al, 2012;Rugani et al, 2008Rugani et al, , 2013aRugani et al, ,b, 2014, summation (Boysen and Berntson, 1989;Pepperberg, 1994;Rugani et al, 2011a,b), serial ordering and cardinality (Emmerton et al, 1997;Pepperberg, 1987Pepperberg, , 1988Pepperberg, , 2006aRugani et al, 2007) to simple arithmetic and proto-arithmetic (Emmerton, 1998;Pepperberg, 1983Pepperberg, , 2012Roberts et al, 2000), and even matching number with symbols (Rugani et al, 2013c;Xia et al, 2000Xia et al, , 2001. What is less entirely clear is the extent to which such a number sense may have evolved independently from the cognitive skills of primates and humans (Beran, 2006(Beran, , 2008Cantlon and Brannon, 2006;Feigenson et al, 2004;Hauser and Spelke, 2004;Wynn, 1992Wynn, , 1995Wynn, , 1998.…”

Numerical assessment in the wild: insights from social carnivores

“…Researchers in these fields have found that the ability to discriminate between different numbers of objects appears to be a foundational cognitive ability and have documented this ability in numerous species across the Animal Kingdom. For example, quantity discrimination has been demonstrated experimentally in several species of fish [5,11,[19][20][21], amphibians [8,22,23], birds [18,[24][25][26][27][28][29][30][31][32][33][34][35], mammals [9,[36][37][38][39][40][41], primates [42][43][44][45], human infants [46][47][48][49] and even some invertebrates [50][51][52]. The only study testing quantity discrimination in a reptile found that although ruin lizards (Podarcis sicula) do spontaneously select the larger quantity of food, they do not spontaneously select the option with a higher number of food items [53].…”