Use of Number by Crows: Investigation by Matching and Oddity Learning

Abstract

Hooded crows were trained in two-alternative simultaneous matching and oddity tasks with stimulus sets of three different categories: color (black and white), shape (Arabic Numerals 1 and 2, which were used as visual shapes only), and number of elements (arrays of one and two items). These three sets were used for training successively and repeatedly; the stimulus set was changed to the next one after the criterion (80% correct or better over 30 consecutive trials) was reached with the previous one. Training was continued until the criterion could be reached within the first 30 to 50 trials for each of the three training sets. During partial transfer tests, familiar stimuli (numerals and arrays in the range from 1 to 2) were paired with novel ones (numerals and arrays in the range from 3 to 4). At the final stage of testing only novel stimuli were presented (numerals and arrays in the range from 5 to 8). Four of 6 birds were able to transfer in these tests, and their performance was significantly above chance. Moreover, performance of the birds on the array stimuli did not differ from their performance on the color or shape stimuli. They were capable of recognizing the number of elements in arrays and comparing the stimuli by this attribute. It was concluded that crows were able to apply the matching (or oddity) concept to stimuli of numerical category.

The long and the short of it: Rule-based relative length discrimination in carrion crows, Corvus corone

“…Interestingly, Koehler worked almost exclusively with birds to show that pigeons, corvids and parrots discriminate set size. Since then, different forms of numerical competence have been reported in pigeons (Xia et al, 2001;Renner, 2006, 2009;Scarf et al, 2011), chicks (Rugani et al, 2008), parrots (Pepperberg, 1994;Al Ain et al, 2009) and corvids (Zorina and Smirnova, 1996;Smirnova et al, 2000;Bogale et al, 2011). Like many other animals, birds spontaneously respond to quantity and use this information adaptively.…”

Learning strategies in matching to sample: If-then and configural learning by pigeons

“…A large training set size appears to be sufficient but not necessary for pigeons to learn the abstract matching concept, as pigeons can fully learn the abstract concept with a small set size if a large sample observing response was required (Wright, 1997). The current study indicates that the observing-response requirement was not sufficient for abstract-concept learning, and either the FR needed to be increased or accompanied by horizontal stimulus presentation, a technique that has been adopted by several other studies (e.g., Lombardi, 2007;Smirnova, Lazareva, & Zorina, 2000;Wright & Delius, 2005).…”

Numbers and Number Sense

“…Indeed, this ability is common to many species, including dolphins, macaques, capuchins, baboons, wolves, canids, mice, parrots, crows, robins, bees, fish, and even beetles (Agrillo et al, 2009;Armstrong et al, 2012;Baker et al, 2012;Barnard et al, 2013;Beran et al, 2012;Carazo et al, 2012;Nieder, 2005;Pepperberg, 2013;Piffer et al, 2013;Smirnova et al, 2000;Utrata et al, 2012;Yaman et al, 2012 -for reviews, see Agrillo and Beran, 2013;Pahl et al, 2013). In sum, it is clear that the ability to process nonsymbolic magnitudes is not unique to humans, and it is surmised that our ability to do so is part of an innate capacity with deep evolutionary roots (Hubbard et al, 2008).…”