Marielle Grenade-Willis,
FOA Friends of
Animals
February 2018
Nonhuman animals’ counting capabilities allow them to navigate, protect themselves, forage, and find mates etc. Honoring this capability in whatever form it takes physiologically means honoring a myriad of other capabilities that support animal thriving.
Everyone remembers singing “The ants go marching one by one/Hurrah,
hurrah…” on bus rides home after school or to pass the time on a long road
trip during childhood. Numerosity, or “the ability to discriminate arrays of
objects on the basis of the quantity of items presented”, is an innate,
evolutionary ability that has served humans and nonhuman animals alike for
thousands of years. Interestingly, the physiological mechanisms that support
this survival capability are different for humans versus other animals but
may originate from the same source.
“Brains (both human and nonhuman) have evolved to deal with numerosity, with
different regions supporting different mechanisms of numerical
representation. These phylogenetically widespread capacities seem perfectly
suited to support survival. Any creature that can tell the difference
between a tree with 10 pieces of fruit from another with only six pieces, or
between two predators and three on the horizon, has a better chance of
surviving and reproducing. At the same time, telling the difference between
24 and 28 pieces of fruit (or nine predators versus 10) does not offer much
advantage.” – Dr. Michael J. Beran
According to neuroscience researcher Joonkoo Park, humans and many other
species possess a basic numerical ability that is rooted in the subcortex,
“an evolutionarily older brain structure” which connects the mid brain via
the brainstem to the spinal cord in humans. Although this ability is thought
to be mostly controlled by the parietal cortex in the primate brain, which
is responsible for integration of sensory information, selective attention,
and spatial awareness, other animals possess different, evolved neural
systems for counting.
Studies have shown crows to possess individual “number neurons” in their end
brain which correspond to certain numerical values. Robins are able to
differentiate the largest quantity of mealworms when compared with smaller
amounts. Free-ranging dogs are able to assess the group size of opponent
packs. And insects like bees and ants are able to measure distance. In
“Counting Insects“, Skorupski et al. have outlined different kinds of
numerosity (counting, estimation, and subitizing) and why most species can
only count up to about four items:
“Counting, in the strictest sense of the word, requires a symbolic number
system (numerals), developed in some human cultures [28]. In animals,
counting-like abilities are said to exist where a response to the number of
stimuli in a set can be abstracted to qualitatively different sets of
stimuli [29,30]. Subitizing is the ability to perceive the number of items
in a small set, which is accurate up to about four items (and in humans is
accomplished ‘at a glance’). Estimation is the ability to judge
approximately the numerosity of larger sets without counting.”
Nonhuman animals’ counting capabilities allow them to navigate, protect
themselves, forage, and find mates etc. Honoring this capability in whatever
form it takes physiologically means honoring a myriad of other capabilities
that support animal thriving.
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