Methods

Through the study, infants will go into a room and will be seated on the parents' lap. We will show them a short movie with simple images, and we will observe their natural reaction. In some studies, the adult accompanying the infant will be asked to wear headphones with music playing or dark glasses (provided by the center) to avoid a possible influence over the infant’s behavior. 

 

In our studies, we use different techniques and methods depending on the goal of the study, and all of it in an interdisciplinary framework that combines behavioral and electrophysiological techniques. The following is a summary of the main techniques and methods used in our center.  

- Guided looking

- Head-Turn preference Procedure (HTTP)

- Habituation

- Eye-tracker

Evoked potentials

 

Guided looking: 

The guided looking method is used to determine whether infants understand the meaning of words. The infant will go into a room and will be seated on the parents' lap. We will show them images on a computer screen. Through the guided looking method, we can follow the ocular movements of the infants throughout the study thanks to a camera placed one meter away from the infant; i.e., we are able to precisely know where the infant looks at a certain moment in response to the presented material.

An auditory word is presented while some images appear on the screen. The word might be known by the infant (e.g., house) or learned during the study (e.g., a word from an invented lexicon associated with an invented object). By presenting the word, if the infant has understood its meaning, we expect that he or she will turn his/her eyes towards the object representing this word.

   

 Head-Turn Preference Procedure (HPP):

The Head-Turn Procedure (HTP) method is used to investigate the infants’ capacity to discriminate between different auditory stimuli. The method consists of two phases: the familiarization and the test phase. Here you have an example toto make the explanation a bit easier: imagine we want to prove whether infants are able to discriminate between two sounds “ba” and “pa”. In the familiarization phase, we will only present the sound “ba”, and in the test phase we will randomly present both sounds “ba” and “pa”.

Familiarization phase: first of all, a green light will appear on the central screen to catch the infant’s attention. Once the baby is looking at the green light, a red light will appear on one of the side screens (either the one in the left or the right side). The infant will turn the head towards the screen where the red light has appeared, and at this moment, the sound “ba” will be presented from a loudspeaker behind that screen. 

Then, the test phase starts. In this phase, both sounds “ba” and “pa” are randomly presented on each of the screens. We expect that infants will look longer at the more familiar stimuli (in this case, the sound “ba”). 

 

 

Habituation

The habituation methods are used to see the discrimination infants make of two differentiated stimuli.

The infant will be seated on the parents' lap in front of a computer screen. Stimuli (sound, word or sentence), which are associated with an image on the screen, will continuously be presented. Once the infant gets bored of the stimuli, he or she will not pay more attention to it (they will not look at the screen anymore). At this moment, the test phase starts. A completely different stimulus is presented, and we expect that infants, surprised by this switch, will look back at the screen.  

 

 

Eye-tracker

An eye- tracker is a device for following the infant look when the study takes place. A camera placed two meters away from the infant measures eye positions, and draws a map which provides information about the infants’ exploration and interest on the stimuli presented on a computer screen.

Like all our studies, infants will be with their caretakers at all times. They will be seated on their parents’ lap, and watch a short movie. Afterwards, the researcher will analyze this data collected by the eye tracker to determine the infants’ points of interest. 

 

The blue spot follows baby's eye movement

 Evoked potentials

Evoked potentials method allows us to know the natural brain activity of babies in their firsts years of life. To do so, we use a special cloth cap for babies with small sensors that allow us to register the brain waves.

Like in all our studies, a parent will be with the baby all the time. The baby is seated on the parent’s lap, and they watch a children’s movie, or  listen to sentences.

Studies that use this method take approximately 10 minutes, but we can take a break or stop the study if the baby is not interested anymore.