It's a red-letter day for intelligent horses everywhere. Dr. Claudia Uller and Jennifer Lewis of the University of Essex are presenting their research into numerical discrimination in horses at the British Psychological Society's Annual Conference in Dublin today.
Human adults, human infants and nonhuman primates are known to have a range of numerical abilities, but research into other species is relatively new.
In two tasks, modeled on those previously used with human infants and nonhuman primates to examine basic counting abilities, the researchers used apples placed in containers to measure whether horses would make a choice based on the number involved. Time, sound and smell cues were all controlled.
When given a choice, the animals chose the containers with the most apples significantly more often. This result suggests that horses too, and not only primates, are able to spontaneously discriminate between two small numbers.
In the first task 13 horses were tested in their stables, with a series of identical fake apples sequentially placed into two opaque containers in front of them - two into the first and three in the second. The containers were then held up to the horses at head level allowing them to make a choice. Eleven of the 13 horses selected the bucket containing three apples instead of two.
In a second experiment, 11 horses were shown two containers of apples that were matched in total amount of volume but differing in number: one contained two identical small apples and the second set consisted of one larger apple with double the surface area. Ten of the 12 horses selected the two apples instead of a single bigger one.
The results show that horses ?go for more' just like human infants and nonhuman primates have been shown to do in similar experiments.
Dr Uller said: "This result suggests that horses too, and not only primates, are able to spontaneously discriminate between two small numbers. This may be another piece in the jigsaw (puzzle) explaining the evolutionary origins of our ability to count."
Blogger's Note: This is a real turn of events! Throughout history, the ability of so-called "trick" or "wonder" horses to count has always been discounted by academics. Horses like Beautiful Jim Key and"Clever Hans" thrilled thousands and were summoned by royalty to perform, but were denounced from the ivory towers by doubting professors as being manipulated by trickster trainers. We'll never know just how smart those horses were.