Learning to listen

Dr Debi Vickers explains how the development of listening skills provides a young child with the foundations for speech, language and intellectual development.

Effective listening is reliant upon many functions working well together. It is a high level brain function dependent upon aspects such as hearing, attention and memory. It is very personal and an individual will listen to those sounds that are most interesting, important or meaningful.

We all listen in our own ways and enjoy listening to different things. Musical taste is a good example of how wide ranging listening interests can be. The listening choices that we make can be heavily influenced by the home environment, our family and peer interests as well as other cultural aspects.

Listening in the womb

The early building blocks for listening are put in place during foetal development. By 20 weeks of development of the foetus the cochlea (hearing organ) is formed, and by 3 months the nerves and the connections are in place to allow the developing foetus to start processing sounds. By 8 months the baby can already discriminate phonemes of their own language.

Sound measurements from within the womb show that certain sounds are passed to the baby better than others; in particular low frequency sounds, vowels, intonation and melody of the voice. Male voices travel better than female, however the mother's voice which travels through the body is higher in level than those voices outside. The cochlea works initially in the 1-3 kHz range, a critical frequency region for speech and a very important place to start listening.

Early development

The newborn baby can already recognise their mother's voice and discriminate it from the voices of other people, and they can be soothed by music that they heard when they were in the womb. This demonstrates that already the baby is learning to listen because they are calmed by familiar and meaningful sounds.

To build on these early listening skills there is a feedback loop between the baby and his/her family which is essential for developing good listening skills. When the baby responds to or makes sounds those around intuitively react or repeat the sound, making the baby aware that they had responded to or produced something important. At this stage the baby is already informing others of the sounds that they like to listen to and repetition of these sounds helps them to find patterns that assist with their own speech, musical and language development.

Early on, parents understand the need to speak in an interesting way emphasising intonation and phrasing, to get their baby's attention and then hold on to it. There is a tendency to use “child directed speech” or “motherese” when speaking to the baby. This is an exaggerated form of speech which is higher in pitch, with more exaggerated pitch changes, the speech sounds tend to be more clearly produced and generally it is slower than the normal rate of speech. Babies are more interested in this way of speaking and are more likely to listen and will try and produce some of the sounds themselves.

Within the first few months of life the development of listening skills pays off and the baby may produce sounds with their voice, cooing and playing with pitch and vowel sounds (such as “ooh” and “aah”). By listening to the sounds they make, comparing them to sounds they hear and watching the reaction of others they explore a wider repetoire of sounds.

By 7-11 months they may be able to say sounds with consonants in them like ma-ma, da-da and ta-ta. By repeating these sounds and exploring the responses of those around them further they develop to the one-word stage between 12-18 months. These early stages prepare the critical foundations for developing speech, language, communication and literacy skills.

The development of listening skills is paralleled by the dramatic maturation of the hearing system during the early months. By 7 months old the hearing system has become quite sophisticated and the baby has very good abilities for extracting pitch from the sounds they hear and they are sensitive to changes in timbre (the difference we hear when different musical instruments play the same notes, or the difference between speakers producing the same sounds). They are beginning to recognise the sounds of their own language and are less able to discriminate between the speech sounds of foreign languages. This shows that they are starting to listen to the speech and language aspects that are most familiar and thus relevant to them. They can even recognise some of the words of their own language. At this stage they will often turn to look at those sounds that interest them.

Babies and infants enjoy music and singing and often respond by rocking, waving hands or making their own sounds. Not only is the child having fun but this also has an impact on the child's understanding of how they respond to sound. There is evidence to show that in school age children musical perception is related to reading ability and speech sound awareness.

Listening at school

By the time the child is ready to start school, the expectation is that they have developed listening, language, attention and memory skills to underpin the challenging school environment that faces them, where the majority of the academic content is presented auditorily. There is evidence that suggests that good language skills help to organise thought processes which in turn reduce the effort required for listening.

The school setting is often not an ideal listening environment, with classrooms containing many hard surfaces for sounds to bounce off, lots of children and nearby classrooms to create noise and computers and equipment creating background buzzing and humming. To fully access the curriculum in such an environment requires well developed speech, language and listening skills. Recent evidence has shown that SATS scores are inversely correlated to noise levels in the classroom.

Listening difficulties

As active listening skills are laid down in early life, listening ability can be limited due to factors other than interest and importance of the sound. It can be difficult to know if problems with listening occur due to disinterest, developmental problems, home language, hearing difficulties or other higher level auditory or language processing problems. For example, children with dyslexia or attention deficit disorders may have difficulties labelled as “poorer listening”. These children may be trying to listen but can not extract the essential information from the sounds they hear.

Listening difficulties should not be overlooked because this could lead to poor concentration, behavioural issues, and ultimately a child that perhaps will not fulfil their academic and social potential.

My research interests

My personal research interests focus on children that may have difficulties with listening. I am keen to understand how hearing capabilities of children with cochlear implants and hearing aids relate to other abilities such as speech, language, music perception and ultimately listening capability. Another key consideration, particularly of importance to listening in hearing-impaired children, is that of English as an additional language. We should be aware of whether this creates an additional listening load. Ultimately we need to identify ways to optimise the listening capabilities of hearing-impaired children to ensure they have full access to the rich acoustic environment essential for speech, language and literacy development.

In summary, listening abilities start to develop very early on in the baby's life. They develop hand in hand with attention and memory and are influenced by hearing and other sound processing abilities. Listening is individual and depends on how interesting and salient the sounds around the developing baby are, how rich the sound environment is and the quality of the family feedback. Good listening abilities are crucial for development of speech, language and literacy skills and ultimately the intellectual and social development of the child.

Dr Debi Vickers started her research career in the Department of Phonetics and Linguistics at UCL and became interested in cochlear implants while working in the UCL Bioglass Extra - Cochlear Implant team. She then went on to spend eight years working in the Hearing Lab at the University of Cambridge, led by Brian Moore. After an exciting time as European Clinical Studies Manager for Advanced Bionics, Dr Vickers returned to research, and is now based at the UCL Ear Institute where she predominantly focuses on speech and psychophysics in hearing-impaired and cochlear implanted adults and children.