Dogs are animals that have been raised all over the world as human companions since ancient times. They are not only pets, but also smart animals that help humans, such as guide dogs and drug detection dogs. However, a new study conducted by a team of Hungarian researchers revealed that dogs cannot understand the subtle differences in words spoken by humans.
Dogs have high social cognitive and communication skills and can listen to human instructions and collaborate to some extent. However, since there are not so many human words that can recognize dogs in general, humans and dogs cannot communicate as if they were talking.
The reason why dogs do not fully understand human speech despite their excellent hearing has been thought to have hints at brain activity in processing human language. A research team at the University of Eötvös Loránd Tudományegyetem in Hungary conducted an experiment that listened to human speech and measured dog brain waves with electrodes.
In this experiment, 17 dogs were guided to the laboratory with their owners, and the dog and owner were seated together on a mattress, and electrodes were attached to the dog’s head. The research team said that the EEG test is sensitive to muscle movement as well as brain activity. Therefore, muscle activity should be minimized during measurement.
In addition, it is said that some dogs who participated in the experiment were unable to perform the experiment quietly, calmly and well without special training. However, even untrained dogs did not have as many dropout rates as expected and only had the same level of dropout rates as those for human infants.
The research team then measured the potential for perception and thinking about words that say to sit on a dog, similar but subtly different words, and words that are completely dissimilar. Words are composed of certain sounds, and if the sound changes one by one, they become completely different meaning words, or words that have no meaning. Dogs will hear many words from their owners or others throughout their lives, but not many words can be learned.
To find out the reason for this, the research team invited the dog and its owner to the lab, gave them a break, and installed electrodes to conduct an experiment. Since the electrodes were installed with tape, no scars were left. A dog with electrodes attached to it listened to only the words they knew and the words they knew, but slightly different and three completely different words, and measured the brain waves that responded to them.
As a result of examining the brain waves for each word, they found that dogs can properly identify words that are completely different from the ones they know. Dogs recognized words only 200 to 300 milliseconds after they started listening and had a discernment speed equal to that of humans.
However, in the case of words that are similar to known words, that is, only one sound is different, dogs have found that they cannot clearly identify both. Although you can roughly identify a word, it suggests that we are not paying close attention to each sound as to how the whole word sounds.
The pattern is similar to human infants under 14 months of age, the researchers pointed out. Infants are said to be able to understand speech during the first few weeks of life, but at first they cannot discern detailed differences from word to word. It is about 14 to 20 months of age when infants can check each sound that makes up a word in detail, and this is an important change in infants’ acquisition of many vocabulary.
As in the case of human infants, the research team estimates that the similarity in dog brain activity to words similar to command words reflects prejudice on attention and processing, not perceptual limitations. Dogs may not pay close attention to audio when listening. Future research will be the cause of decline in dog vocabulary. Related information can be found here .