All of our experiments are reviewed and authorized by the Hungarian Egyesített Pszichológiai Kutatásetikai Bizottság (Unified Psychological Ethics Committee). Participation in all our studies in voluntary, and consent can be revoked at any stage of the experiment without justification.
Tools based on EEG are used to measure the natural electrical activity of the human brain. While these techniques have been used by researchers for decades, only developments in the past 20 years allowed scientists to use these type of tools on young infants as well. These types of recordings are very important as they allows researchers to make inferences about how the infant brain develops, as well as on the relationship between the development of brain regions and the development of infant behavior.
Neurons in the brain “communicate” by sending weak electrical signals to each other. By placing harmless electrodes on the head that can record these signals generated by the activity of neurons, we are able to “eavesdrop” on this electrical conversation. The tool we use for this purpose is named Geodesic Sensor Net, and it has been developed especially for infants: there are little pieces of soft sponges attached to all electrodes that are organized in a net and placed on the head of the babies. Wearing the net and measuring the electrophysiological response to stimuli is perfectly safe, and result in no alteration in the infant brain, either momentary or permanent.
Age range: 8-10 months
Question(s): What is the relationship between particular cognitive mechanisms and the activity of particular regions in the brain?
Assumption: The stimuli presented to the babies (pictures, sounds) will result in changes in the corresponding regions of the brain. These can be measured due to the electro-chemical activity of the neurons.
Procedure: You can read about the detailed procedure of an EEG study below.
- The baby is sitting on the lap of the caregiver, both during the preparations and experiment itself.
- First, we measure the head circumference of the baby with a soft tape measure, thus we are able to select the net with the appropriate size.
- Following this, we dip the net in mild salted water, so that the sponges become wet. This softens the sponges, and in this way, the sensors fit the scalp comfortably.
- The net can be placed on the head of the baby quickly and easily, just like a swimming cap. There are two persons handling this procedure, and as one of them is placing the net on the head of the baby, the other one is distracting the baby with playful interactions. The babies are usually calm during these preparations, as the process feels very similar to putting a swimming cap on. In case a baby starts to cry, we remove the net immediately.
- After this, we connect the net to a computer, which records the activity of the brain during the experiment. The experiments usually consist of images or events that are presented to the babies.
- After the experiment, the net is carefully removed from the head of the baby. Following the procedure, the net can leave mild red traces in the place of electrodes. After the removal, these traces will fade quickly.
Example: It is a well-documented phenomenon in adults that the brain reacts with a certain N400 brain wave to words which don’t fit into the given context. We have managed to show a similar phenomenon in babies: we have shown 9-month-olds a picture of a car (a word they know), and we labeled it with the word “apple”. As a result, the same N400 brain wave appeared, indicating that they indeed detected the mismatch between the meaning of word and the object.