Volume 166, May 2015, Pages 80–88
Following human-given cues or not? Horses (Equus caballus) get smarter and change strategy in a delayed three choice task
Highlights
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- Horses remember the location of food hidden by the experimenter after a delay.
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- They understand the communicative meaning of a human positioned close to the target.
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- The same horses are capable of changing their decision-making strategy.
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- They are able to shift from accuracy inferred from human given cues to speed.
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- Horses can use human cues or not depending on time, cost, experience and reward.
Abstract
To
date, horses have seemed capable of using human local enhancement cues
only when the experimenter remains close to the reward, since they fail
to understand the communicative meaning of the human as momentary local
enhancement cue (when the human is not present at the moment of the
animal's choice). This study was designed to analyse the ability of
horses to understand, remember and use human-given cues in a delayed
(10 s) three-choice task. Twelve horses (experimental group) had to find
a piece of carrot hidden under one of three overturned buckets after
seeing the experimenter hide it. The results were then compared with
those of a control group (twelve horses) that had to find the carrot
using only the sense of smell or random attempts. At the beginning, the
experimental horses made more correct choices at the first attempt,
although they took more time to find the carrot. Later the same horses
were less accurate but found the carrot in less time. This suggests that
the value of the proximal momentary local enhancement cues became less
critical. It seemed, in fact, that the experimental and control group
had aligned their behaviour as the trials proceeded. Despite this
similarity, in the second half of the trials, the experimental group
tended to first approach the bucket where they had found the carrot in
the immediately preceding trial. Our findings indicate that horses are
capable of remembering the location of food hidden by the experimenter
after a delay, by using the human positioned close to the target as
valuable information. The same horses are also capable of changing their
decision-making strategy by shifting from the accuracy inferred from
human given cues to speed. Therefore, horses are able to decide whether
or not to use human given-cues, depending on a speed-accuracy trade-off.
Keywords
- Horse;
- Human-given cues;
- Momentary local enhancement cue;
- Speed-accuracy trade-off;
- Behavioural plasticity;
- Memory
- Corresponding author at: Department of Veterinary Sciences, University of Pisa, Viale delle Piagge, 2, 56124 Pisa, Italy. Tel.:
+39 0502216853/39 3395473780 (M); fax: +39 0502216851.
Copyright © 2015 Elsevier B.V. All rights reserved.
