Horses not only have an understanding of pointing cues given by humans, but appear able to assess the credibility of the information being given, the findings of fresh research suggest.
Monamie Ringhofer and her fellow researchers, writing in the journal Scientific Reports, have described an experiment in which 38 horses were invited to choose which of two lidded buckets contained a carrot.
The horses had the benefit of two informants who pointed at the buckets — but only one knew which bucket contained the carrot. The other did not.
The researchers noted that studies have shown that several domesticated species can find hidden food by following human pointing in object-choice tasks — dogs, horses, cats, goats, and pigs. However, it is currently unknown, except for in dogs, if they can comprehend the communicative nature of such cues.
Recent studies have investigated whether dogs choose to evaluate the credibility of the information provided by humans and if they will follow the pointing of a human who has the correct information. These revealed that dogs could learn to follow the pointing of an honest human-informant who always pointed to a baited container, and not of a dishonest human-informant who always pointed to an un-baited container.
Ringhofer and her fellow researchers designed an experiment to investigate whether horses could follow the pointing of a human informant by evaluating the credibility of the information about the food-hiding place provided by the pointing of two individuals.
The researchers also investigated the horses’ visual attention levels towards human behaviour to evaluate the relationship between their motivation and their performance of the task.
The study apparatus comprised of two lidded buckets, both of which had a piece of carrot in them beforehand to eliminate the possibility of smell being used by the horses. The animals were familiarized with the apparatus before the experiment.
In the experimental phase, each horse could hear that a carrot was being placed in one of the buckets, both of which were hidden behind a small screen. They could see both informants during this time. One informant was looking as the carrot was being hidden and knew where it was; the other had their back turned and was only able to guess.
Once the carrot was placed, the screen was removed and the informants simultaneously moved in behind the buckets, each pointing to one of the buckets. The informant who saw the carrot being hidden always chose the correct bucket.
The study team found that the horses who had sustained high attention levels could evaluate the credibility of the information and followed the pointing of the informant who knew where the food was hidden.
“This suggests that horses are highly sensitive to the attentional state and pointing gestures of humans, and that they perceive pointing as a communicative cue,” the authors said.
Discussing their findings, the researchers said the study shows that horses with high sustained attention levels can evaluate the credibility of the pointing of human informants, as they tended to make correct decisions in the object-choice task based on whether the informants could see the hiding of the carrot or not.
“This suggests that horses may not follow human pointing automatically by the simple mechanism of stimulus enhancement but can recognise it as a communicative cue that contains information from humans as dogs do.
“Furthermore, this study provides evidence that horses have high socio-cognitive abilities to understand not only the pointing gesture but also the attentional state of humans.”
The horses, they noted, could discriminate the attentional state of two humans during the food-hiding event without directly observing where the food was hidden. They could then follow the pointing of a human who had witnessed the event when they made choices in the object-choice task later on.
The historical and daily interaction of horses with humans might be the reason for their high socio-cognitive abilities, they said.
“There are many studies on the socio-cognitive abilities of dogs compared with those for horses, and these studies suggest that the dogs’ sophisticated socio-cognitive abilities towards humans are influenced by the domestication process.”
Horses have different original ecological traits and domestication processes to dogs, but they also closely interact and cooperatively work with humans.
“However, there are still few studies on the socio-cognitive abilities of horses compared to those of dogs,” they noted.
The researchers said their work also shows that the difference in attention level in individual horses relates to their socio-cognitive abilities towards humans.
“Individuals with high attention levels towards human behaviour could follow the pointing of a reliable human who has the correct information of the hidden food and could make correct choices in the task, whereas those with low attention levels could not.”
They said their results, together with those of previous studies, show the importance of considering the motivation level of individuals/species in socio-cognitive studies in animals.
The study team comprised Monamie Ringhofer and Shinya Yamamoto, with Kyoto University in Japan; and Miléna Trösch and Léa Lansade, with the French science agency INRAE.
Ringhofer, M., Trösch, M., Lansade, L. et al. Horses with sustained attention follow the pointing of a human who knows where food is hidden. Sci Rep 11, 16184 (2021). https://doi.org/10.1038/s41598-021-95727-8