In the social world, we often encounter rules how things are said or done. For instance, each sentence has a structure that needs to be fulfilled in order to be understood (in technical language, this is called the «syntax»). However, similar rules are also inherent to actions. If we want to drink some juice, we have to open the lid of a bottle first and then pour juice into a glass. Former research has shown that syntax in language and in actions is processed similarly in the brain of adults. But why is this the case? Is it because adults verbalize actions, that is, they transform action steps into language units in their mind?
In one recent study of the research unit «Developmental Psychology: Infancy and Childhood», at the University of Zurich, published in the journal Developmental Science, Laura Maffongelli and her colleagues investigated whether six- to seven-month-old infants show similarities in their processing of action sequences as previously reported in language sequences. At this age, infants do not yet produce language and therefore they cannot verbalize action steps. The infants were presented with sequences of photographs depicting simple actions. Half of the sequences displayed the action steps in the correct order. In the other half, two relevant steps of the action were inverted, making the goal of the action no longer achievable. The infants’ brain activity during the presentation of the action sequences was measured by means of electroencephalography. Results showed that the infants were sensitive to the alternations of the action syntax, evident by different brain responses to the two conditions. Interestingly, these changes in brain activity were similar to activity known from studies in adults. The results of this study suggest that the processing of language and actions has a fundamental similarity: both depend on structural regularities. Therefore, language and actions seem to be linked much earlier and much more closely than previously assumed.
Maffongelli, L., Antognini, K., & Daum, M. M. (2018). Syntactical regularities of action sequences in the infant brain: When structure matters. Developmental Science. http://dx.doi.org/10.1111/desc.12682
Already at the age of 18 months, toddlers understand a lot of what is said. At this age, they not only understand the meaning of names for objects, animals, or people, but also they start to understand the meaning of verbs. They understand for instance what „to build“ or „to draw“ means. Somewhat later, at about 24 months, toddlers start to use these verbs in their daily life. In our study, we investigated what lies at the bottom of understanding and uttering verbs.
Verbs are words that describe actions. From former studies we know that adults process observed actions and verbs in the motor system of the brain, similar to actions they actually perform themselves: If we for instance observe a person drawing, our own motor system in the brain is active as if we were drawing a picture ourselves. If an adult hears or reads a verb, for instance “drawing”, the same thing happens. Although we know that motor activity during the observation of actions can already be found in infants, there were until recently no studies that investigated how language is interrelated with the motor system of the brain in young children.
In a study that we recently published in the international journal “Neuropsychologia”, we measured the brain activity of toddlers between 18 and 24 months of age while they listened to different verbs and observed the corresponding actions. The results show that the motor system of the toddlers’ brain was active when they were listening to verbs. However, this holds only true for verbs that the toddlers are familiar with. If they listen to an unfamiliar verb, for instance one that we made up, the brain does not react with motor activity.
The results show that the motor system plays an important role for the processing of verbs, already early in life. Different domains, such as language and motor development are not separate in early life, but instead they are closely related. The motor system of the human brain seems to be a junction, where actions of different kinds are processed. This processing seems to be irrespective of modality, that is if the actions are observed, heard or performs.
Antognini, K., & Daum, M. M. (2017). Toddlers show sensorimotor activity during auditory verb processing. Neuropsychologia. http://dx.doi.org/10.1016/j.neuropsychologia.2017.07.22