Counting in rats: Its functional significance and the independent cognitive processes that constitute it.

Abstract

Four major conclusions were supported in seven runway experiments: Rats count; rats routinely and perhaps automatically count reinforcing events; counting reinforcing events is of importance for understanding instrumental learning and performance; and counting is the result of several independent coordinated cognitive processes. The results suggested counting rather than some simpler numerical ability because (a) they cannot be ascribed to other mechanisms (e.g., an identical-nonidentical discrimination (Experiments 4 and 5) or subitizing (Experiments 1-7); (b) qualitatively different reinforcers were categorized as both similar and different for counting purposes (Experiment 5); (c) the order-irrelevance principle was followed (Experiment 6-7); (d) abstract tags were assigned on the basis of number of events (Experiments 5-7); and (e) assignment occurred according to complex and situationally determined rules that were themselves abstract (Experiments 6-7). Number cues associated with reinforcing events are often valid in learning investigations but are invariably confounded with various, equally valid number and duration cues (related to trials, responses, etc.). Reinforcers were counted when confounded with these other cues (Experiments 1, 2, 3, and 5), which supported the sequential view that rats are highly disposed to using number cues associated with reinforcers and normally do so in instrumental situations. There was some evidence that one or more of the confounded events (unidentified) provided cues that were used by the rat, but this was of minor significance.

Symbolic number skills predict growth in nonsymbolic number skills in kindergarteners.

“…Recently, it has become apparent that humans and other species can do more than just compare nonverbal magnitudes, they can even perform simple, approximate arithmetic (such as sums and ratios; e.g., Capaldi & Miller, 1988;Brannon et al, 2001;McCrink & Spelke, 2010Matthews et al, 2016).…”

Acquisition and Limited Transfer of Numerical Discrimination of Object Stimuli in Rats

“…Apparently rats can discriminate the number of reinforced runs in a runway (Capaldi & Miller, 1988;Burns, Goettl, & Burt, 1995), the number of touches to their body (Davis, MacKenzie, & Morrison, 1989), the number of auditory tones (Davis & Albert, 1986;Breukelaar & Dalrymple-Alford, 1998), the number of electrical foot shocks (Davis & Memmott, 1983), and the number of lined tunnels in an open field (Davis & Bradford, 1986;Suzuki & Kobayashi, 2000). These studies controlled some physical aspects of the stimuli, such as total duration of a tone or spatial positions of tunnels, to prevent them from being used as effective discriminative cues.…”

Enumeration of briefly presented items by the chimpanzee (Pan troglodytes) and humans (Homo sapiens)

“…In animals, various types of tasks are used to assess their numerical ability, such as simple discrimination for relative or absolute numerical judgments (Davis, 1984;Dooley & Gill, 1977;Hicks, 1956;Honig & Stewart, 1989;Thomas, Fowlkes, & Vickery, 1980;Watanabe, 1998), discrimination of the number of rewards by using a runway apparatus (Capaldi & Miller, 1988), and identity matching of the number (Woodruff & Premack, 1981;cf. Hayes & Nissen, 1971).…”