Counting Behavior by Rats in a Simulated Natural Environment

Abstract

Three experiments were performed to explore the rat's ability to count objects in its environment. Previous research demonstrating counting behavior in animals has typically involved overtraining or extreme motivational conditions in which food or safety were at a premium. In the present experiments, a simulated natural environment was employed in which rats were required to enter a particular tunnel in an array of six to obtain food. Spatial, olfactory and visual cues were controlled so that selection of the correct tunnel was based solely upon the ordinal position of the tunnel. Experiments 1 and 2 demonstrated that this behavior could be learned relatively rapidly and maintained despite change in tht: spatial configuration of the test area. In Experiment 3, retention of the tunnel entry discrimination was demonstrated following an inactive period of one year as well as six months thereafter. Collectively, these data extend the range of situations in which rats have performed numerical discriminations, and suggest that the environmental support necessary to demonstrate such abilities may include relatively natural test situations, rather than the use of extreme motivational states induced under arbitrary environments.

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

“…The apparatus and task in the present study were modeled after Davis and Bradford (1986), in which rats were trained to respond to a specific tunnel ordinal position in a row of tunnels. Both variants of the apparatus allow rats to encounter object stimuli in multiple ways.…”

“…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.…”

Rudiments of mind: Insights through the chick model on number and space cognition in animals.

“…Rats are capable of learning to enter a target tunnel solely on the basis of its ordinal position in an array of 6 (Davis & Bradford, 1986) or 18 (Suzuki & Kobayashi, 2000) items. Honey bees are able to find a food source located between the third and the fourth position along a series of four identical, equally spaced landmarks (Chittka & Geiger, 1995).…”

Abstract numerical discrimination learning in rats

“…For example, it has been reported that rats can discriminate the number of reinforced runs in a Electronic supplementary material The online version of this article (doi:10.3758/s13420-016-0209-2) contains supplementary material, which is available to authorized users. straight runway (Capaldi & Miller, 1988), the number of touches to their body (Davis, MacKenzie, & Morrison, 1989), the number of auditory tones (Breukelaar & Dalrymple-Alford, 1998;Davis & Albert, 1986), and the number of lined tunnels in an open field (Davis & Bradford, 1986;Suzuki & Kobayashi, 2000). However, excluding an exceptional study, which tested the transfer of numerical discrimination of auditory stimuli to visual stimuli and showed no sign of transfer of learning (Davis & Albert, 1987), the abstractness of numerical concepts in rats has not been elucidated because the clear transfer of counting behavior to novel stimuli has not yet been documented in rats.…”