What does the word “ball” mean to a dog? Does he understand it the same way we do? Dogs with an extensive vocabulary of object names, or as we call them, Genius Dogs, can help us answer this question.
In last week’s article we reviewed the very first experiments conducted with Genius Dogs. Those experiments mostly focused on the question how dogs learn a new word. Specifically, if they learn to associate a new word with a novel object in a similar way to humans. This week we will look into a few other aspects related to language perception and understanding.
Can dogs use icons?
The ability to understand that a symbol represents something is a fundamental principal in language comprehension. If you saw this $ on a gate, you would easily understand that it refers to the money in your pocket. If you want to pass that gate you must say goodbye to some of that money. This symbol appears on some of the bills in your pocket so the association is easy. Can dogs learn to associate pictures and objects?
Remember Rico from last week? Kaminski and colleagues1 conducted an additional study with him and 4 other dogs to test this. The dogs were shown an object and asked to select the object which was identical to it. They were also shown a picture of the object or a small replica of it.
All dogs were able to associate the full-size and miniature replicas with their appropriate matching object. Two of the five dogs were also able to do this with pictures. The results of this experiment suggest that dogs do possess some understanding of iconic meaning. However, there were only five dogs in the study and the results were never replicated.
What do dogs care about? Shape, texture or size?
When an infant learns a new word, like “car”, he would normally generalize this word to other objects with a similar shape. But what will a dog do? Gable, a Border Collie that knew the names of 54 objects, was confronted with this question. The researchers did this by teaching him the name of a new object. They then asked him to get the object, but presented him with 3 objects that were slightly different from the original. One had a different shape, one had a different texture, and one had a different size. Depending on his choice they could decide which of the three characters was the most important for him.
It turned out that, unlike humans, Gable generalized a new word to the objects size. After some training he also generalized the word to objects with similar texture, but he did not care about the shape of the objects2.
Could it be that the shape of an object is not so relevant for a dog while for us it is very important? Imagine entering a new house and looking for the remote control. You see many objects that have the same size as your remote control from home but you would probably pick up the object that has the most similar shape, even if it’s slightly bigger or smaller. On the other hand, dogs don’t really care if it’s a squirrel or a rat, they are both fun to chase. This principle is called biological relevance. Now let’s get back to discussing language.
So, dogs don’t care at all about shapes?
The last study on this topic was published in 2020 by the leaders of the Genius Dog Challenge, Claudia Fugazza and Adam Miklósi3. In a series of experiments, they tested if Whisky, one of the dogs participating in the Genius Dog Challenge, was able to categorize objects (rings, ropes and balls) according to their shape and color.
Unlike Chaser (a dog discussed in last week’s article4), which received specific training for this task, Whisky did not. Her owner, which is not a scientist, decided to name the toys with names that describe how they look. For example, green ring, yellow ball etc., a reasonable method to use when your dog has more than 100 toys, and you need to remember all their names.
This gave scientists a unique opportunity to see if in the process of learning the toy names, whisky also spontaneously categorized them according to their shape and color. She didn’t care about the color, but if you asked her to bring the rope out of a bunch of new toys, she indeed chose to bring you the rope. So, it turns out that sometimes the shape of an object is important to a dog.
What’s next?
There are still many questions to answer. Luckily for us, man’s best friend is happy to try and solve them. In the next article we will talk more about the use of dogs in the lab for behavioural research, we promise it’s not what you expect.
References
1 Kaminski, J., Tempelmann, S., Call, J., Tomasello, M., 2009. Domestic dogs comprehend human communication with iconic signs. Dev. Sci. 12, 831–837. https://doi.org/10.1111/j.1467-7687.2009.00815.x
2Zee, E. Van Der, Zulch, H., Mills, D., 2012. Word Generalization by a Dog ( Canis familiaris ): Is Shape Important ? PLoS One 7.
3Fugazza, C., Miklósi, Á., 2020. Depths and limits of spontaneous categorization in a family dog. Sci. Rep. 10, 1–9. https://doi.org/10.1038/s41598-020-59965-6
4Pilley, J.W., Reid, A.K., 2011. Border collie comprehends object names as verbal referents. Behav. Processes 86, 184–195
