Language and the Brain

A very important aspect that must be considered in the study of Psycholinguistics is related to the brain. Since this field of Linguistics is concerned with the study of language acquisition, the characteristics and areas of this organ are involved in our scope of study. However, in this academic blog, the most essential and meaningful features will be highlighted in order to understand better the complex system called language. Moreover, Neurolinguistics is the study of the relationship between lanaguge and the brain, and we are not studying that discipline, but Psycholinguistics (which does not mean these two fields of Linguistics are separate areas, indeed, they are closely related to each other).

Parts of the brain

Since it was already said, some areas of the brain are essential for the use of language abilities and they are the following four: Broca’s area (also called anterior speech cortex), which was studied by a French surgeon (Paul Broca), who stated that damage to this specific part of the brain was related to extreme difficulty in producing speech, being concluded that Broca’s area is crucially involved in the production of speech. Wernicke’s area (also called posterior cortex), which was studied by a German doctor (Carl Wernicke), who stated that damage to this part of the brain was found among patients who had speech comprehension difficulties, being concluded that Wernicke’s area is crucially involved in the understanding of speech. The motor cortex, which was studied by the neurosurgeons Penfield and Roberts, generally controls movement of the muscles, being specified that close to the Broca’s area is the part of the motor cortex that controls the articulatory muscles of the face, jaw, tongue and larynx. The arcuate fasciculus, which is a bundle of nerve fibers, was also discovered by Carl Wernicke and it forms a crucial connection between Wernicke’s and Broca’s areas.

Brain Lateralisation

Since all the previously mentioned areas are located in the left hemisphere, it has been stated that this hemisphere has or develops a special responsability fro language; in fact, in most human beings, language appears to be particularly associated with the left hemisphere of the brain. The evidence comes from several sources, such as: brain damage, commisurotomy, wada injections and dichotic listening. And it is in the last source that this research will be focused, because of its connection with the field of Psycholinguistics.

First of all, we have to explain that a dichotic listening test is an experimental technique which has demonstrated that the language functions must be located in the left hemisphere, using the generally established fact that “anything experienced on the right-hand side of the body is processed in the left hemisphere of the brain and anything on the left side is processed in the right hemisphere”. Therefore, in simple words, the previous assumption leads us to think that:

The Experiment itself: a person sits with a set of earphones on and he/she is given two different sounds signals simultaneously, one through each earphone (for example, through one comes the sound dog, and through the other, comes the sound cat). When the man/woman is asked to say what was heard, he/she often identifies the sound which comes via the right ear. This process has been known as the right ear advantage for linguistic sounds.

But why? Because the language signal received through the left ear is FIRST sent to the right hemisphere AND THEN has to be sent to the left hemisphere for processing. While, a signal received through the right ear goes DIRECTLY to the left hemisphere and the first signal to get processed wins.

Perhaps, the explanation will be clearer if you have a look at the following representation of the language route:

It is also thought that the right hemisphere has the responsability for processing many incoming signals of a non-linguistics nature, because in the dichotic listening tests, the non-verbal sounds are recognized more often via the left ear, such as music, coughs, etc. Although, it can not be stated that the right hemisphere ONLY handles non-verbal sounds and that the left hemisphere handles language sounds, since we should avoid a reduccionist view of the human brain.

Up to now, you can conclude the brain lateralisation is closely related to the critical period (briefly explained in the key concepts), seeing it is generally thought that the lateralisation process begins in early childhood and it coincides with the period during the language acquisition takes place (this discussion will be explained below, in the section called first language acquisition).

If you want to watch an interesting video on what has been discused here, click on the following link: LEFT HEMISPHERE

In addition, if you want to watch another interesting video on what has been discused here, click on the following link: RIGHT HEMISPHERE

Finally, I challenge you to look at the following picture and say the COLOR, NOT THE WORD:

Why is it too difficult to do? Because your right hemisphere is trying to “say” the color, but your left hemisphere insists on reading the word. Interesting, isn’t it?