Famous Pavlov experiment carried out on horses

Bill, 28, awaits the arrival of his dinner.
Bill, 28, awaits the arrival of his dinner.

Scientists have shown that the response shown in the famous “Pavlov’s dog” experiment can be replicated in horses, but have taken the research a step further, showing that individual temperaments play an important part in each animal’s response.

The findings, published in the open-access journal, PLoS ONE, add to a growing body of evidence revealing the importance of matching temperament to equine disciplines, be they sporting or otherwise, to achieve the best results.

Apparatus used for Pavlovian conditioning (left), instrumental conditioning, and PIT sessions (right).
Apparatus used for Pavlovian conditioning (left), instrumental conditioning, and PIT sessions (right).

Ivan Pavlov’s well-known experiment involved using a bell to call dogs to their food. After a few repetitions, the dogs started to salivate on hearing the bell. He referred to this as the conditioned response.

Researchers in France conducted a similar Pavlovian experiment, using the sight and sound of food pellets shaken in a container to signal food delivery in the first part of their horse study.

The work involved 19 Anglo-Arabian horses – 13 females and 6 males. All were used to being handled and had all been reared under the same conditions at the experimental station of the French National Stud.

In the first phase, the experimenter shook a one-litre plastic jug containing 500 grams of pellets, during which the experimenter distributed small handfuls of pellets at prescribed intervals into a fixed feed bucket. If a horse did not eat the pellets, they were removed after 20 seconds.

For each session, the proportion of horses eating the pellets in less than 20 sec was recorded. The numbers of behaviors directed towards the feed bucket were also measured.

Horses were then taught to touch with their noses a cone signaled by the experimenter in order to obtain a food reward.

Then, the cone phase was repeated but the rewards were sysematically withdrawn in the next phase of the experiment.

The horses were thus respectively subjected to Pavlovian conditioning, instrumental conditioning, and a Pavlovian to instrumental transfer (PIT) test, the researchers said.

In the next and final phase of the experiment, a series of behavioral tests was performed on all the horses to assess five aspects of temperament – fearfulness, gregariousness, level of activity, sensory sensitivity, and reactivity to humans – and their bearing on the results from each horse.

The results confirmed that the Pavlovian response could be observed in horses and that its effectiveness was greatly influenced by individual temperament.

Arena used for the temperament tests.
Arena used for the temperament tests.

Horses with the higher levels of gregariousness, fearfulness, and sensory sensitivity exhibited the strongest Pavlovian response.

The existence of the response in horses could play an important part in the optimization of training methods, the researchers said.

They said their experiment showed that external cues can trigger specific behaviors in horses, and that this was significantly influenced by individual temperament.

“We postulate that individuals with a fearful, gregarious, and sensitive temperament profile exhibited stronger PIT response because this profile confers specific constitutive cognitive abilities to horses independently of the emotion felt during the learning processes.

“… good PIT performance in fearful, gregarious, and sensitive horses could be mainly cognitively driven. Indeed, this temperament profile could be associated with enhanced or more-accurate processing of environmental cues.”


Lansade L, Coutureau E, Marchand A, Baranger G, Valenchon M, et al. (2013) Dimensions of Temperament Modulate Cue-Controlled Behavior: A Study on Pavlovian to Instrumental Transfer in Horses (Equus Caballus). PLoS ONE
8(6): e64853. doi:10.1371/journal.pone.0064853


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