Hundreds of studies have been performed in which horses have been tested for their ability to perform a task, but what happens when the task proves impossible?
Researchers in Italy have examined the question in a just-published study, focusing on whether horses might be seeking or hoping for assistance from people to access a food reward.
Alessandra Alterisio and his colleagues have described their controlled experiment, involving what is known as an impossible task paradigm, in the journal Animals.
The researchers noted that several studies have highlighted the cognitive abilities of horses in social interactions with humans. However, only a few studies have focused on referential communication between horses and humans.
An impossible task paradigm entails an unsolvable task preceded by a number of trials in which the subject learns how to obtain a reward independently without previous training.
To the best of the researchers’ knowledge, horses have never been subjected to an impossible task paradigm.
In their study, 30 horses of varying sex, breed and age, from three different riding schools, were used.
A table was placed outside the stall, close to the entrance, and the horse was prevented from exiting its stable by a rope.
A carrot or apple was initially placed on the table within reach of the horse, provided it stretched its neck. This helped determine the horse’s food motivation and allowed each animal to familiarize itself with the experimental setup.
The horses were subjected to a series of different scenarios, with and without people standing motionless nearby, in which the food reward could be reached on the table, or it was beyond reach.
The researchers, who videoed the behavior of the horses, measured the direction of each horse’s ears as an indicator of its visual attention – either both ears directed toward the target; or when the ears were directed differentially (split) between the motionless individuals and the table.
They also monitored touch interaction toward the table and people, smell exploration of the table, and recognised frustration behaviors.
When the food was placed out of reach, the most frequent behavior was rotating the ears differentially – that is, split between the people and table.
They speculate that the differential ear rotation could be a referential gesture aimed to link the solution of the task to the people, as a request for help.
“However, more studies should be done before considering definitively the visual differential attention as a referential gesture.
“In any case, our procedure proved to be a useful way to understand how horses try to attract human attention when they are in a restricted environment, a typical situation for horses living in domestic environments.”
Further, an increase in frustration behaviors, together with the behaviors involving the table, from when no food was present to when it was present but beyond reach, indicated an attempt of the horses to find the solution, supporting that the expectancy violation was effectively triggered in the horses, they said.
The full study team comprised Alessandra Alterisio, Biagio D’Aniello, Massimo Aria and Anna Scandurra, all from the University of Naples Federico II; and Paolo Baragli, from the University of Pisa.
Could the Visual Differential Attention Be a Referential Gesture? A Study on Horses (Equus caballus) on the Impossible Task Paradigm
Alessandra Alterisio, Paolo Baragli, Massimo Aria, Biagio D’Aniello, and Anna Scandurra.
Animals 2018, 8(7), 120; doi:10.3390/ani8070120