#freshfromthelab. Dr Maria Laura Filippetti on how newborns begin to develop body perception and awareness, and a sense of self.
How do we begin to develop a sense of self? When do we begin to recognise ourselves in mirrors? How do we tell the difference between our own bodies and someone (or even something!) else’s?
Maria Laura is a researcher who has worked in a number of labs exploring how newborn babies and infants become aware of their own bodies. She has focused on senses such as touch and vision, using ingenious experiments to investigate how babies begin to integrate these senses in order to understand their body as belonging to themselves.
Previously, Chiara Bulgarelli wrote an article for BabyBrains on how babies begin self-recognition in the mirror. She explained how important social interactions and communication are to a baby’s ability to distinguish themselves from others. She also demonstrated the mirror ‘rouge test’. A task used to help determine whether infants can recognise themselves.
Have a look at the BBC 2 episode ‘Babies: Their Wonderful World, Episode 2 - Becoming Social’ at 39:00 minutes, where Chiara explains and demonstrates the mirror recognition task.
Maria Laura also emphasises that social interactions and the feedback our brains process from communicating with other people are important for reinforcing and identifying our sense of self. However, she has shown that before we can develop a sense of self (which is the idea that you are different and separate to another person), or even to simply begin recognising ourselves in a mirror or picture, we first have to perceive our physical body as our own. Her studies have shown that sensory inputs from the surrounding environment (such as touch, vision, and sound) are important to a baby’s ability to develop the perception of their body as their own.
Previously in adults, a number of unique studies have shown that the integration of information from different senses (known as multisensory integration) is key to body awareness. The ‘rubber hand illusion’ is an example of how we rely on multi-sensory information to identify our own bodies…
In the rubber hand illusion, the individual watches the ‘other’ rubber body part (in this case a hand) being brushed as his or her own body is brushed in the same way, but out of sight. It is important that the ‘visual sensory information’, so seeing the brushing of the rubber hand, and the ‘touch sensory information’ which is the brushing on the individual’s own hand, are happening synchronously. This creates what is known as ‘congruent sensory cues’ in the brain. It is because of this congruent sensory link between vision and touch, that the perception of self actually shifts to partially incorporate that ‘other’ rubber hand as belonging to them. Click here to watch BBC Horizon's take on this experiment.
In her new research, Maria Laura and her colleagues wanted to investigate this phenomenon by studying newborn babies, to see if they can begin to identify their own bodies through the same multisensory integration process.
In the study newborn babies were shown a video of another baby’s face being touched on the cheek with a paintbrush while the newborns’ own cheeks were stroked either simultaneously or with a time delay. To determine whether the babies associated the brush stroking they saw on-screen with their own bodies (like adults doing the rubber-hand illusion), the researchers measured how long the babies looked at the screen in each condition. Looking time is a standard measurement used in infant research because babies can't answer questions or be asked to indicate their interest.
What the researchers found was that the babies looked longer at the screen with the other baby’s face when it was stroked synchronously with their own. The researchers interpret their observations as evidence that babies have the essential mechanisms they need to begin building body perception. When what babies see in relation to their own bodies matches what they feel, they notice just as we adults do. This shows that, for babies, simultaneously experiencing different sensory cues, such as feeling and seeing matching inputs from their surrounding environment, means that they can begin to perceive their body as their own, and therefore begin the development of understanding their future self!
Author: Ceri Peck