A. Listening: Top down and Bottom up
In 'real-life' listening, our students will have to use a combination of the two processes, with more emphasis on 'top-down' or 'bottom-up' listening depending on their reasons for listening.
Imagine the following situations:
Over lunch, your friend tells you a story about a recent holiday, which was a disaster. You listen with interest and interject at appropriate moments, maybe to express surprise or sympathy.
That evening, another friend calls to invite you to a party at her house the following Saturday. As you’ve never been to her house before, she gives you directions. You listen carefully and make notes.
How do you listen in each case? Are there any differences?
With the holiday anecdote, your main concern was probably understanding the general idea and knowing when some response was expected. In contrast, when listening to the directions to a party, understanding the exact words is likely to be more important – if you want to get there without incident, that is!
The way you listened to the holiday anecdote could be characterized as top-down listening. This refers to the use of background knowledge in understanding the meaning of the message. Background knowledge consists of context, that is, the situation and topic, and co-text, in other words, what came before and after. The context of chatting to a friend in a casual environment itself narrows down the range of possible topics. Once the topic of a holiday has been established, our knowledge of the kind of things that can happen on holiday comes into play and helps us to ‘match’ the incoming sound signal against our expectations of what we might hear and to fill out specific details.
In contrast, when listening to directions to a friend’s house, comprehension is achieved by dividing and decoding the sound signal bit by bit. The ability to separate the stream of speech into individual words becomes more important here, if we are to recognize, for example, the name of a street or an instruction to take a particular bus.
In reality, fluent listening normally depends on the use of both processes operating simultaneously. Think about talking to your friends (in your first language) in a noisy bar. It is likely that you ‘guess’ the content of large sections of the conversation, based on your knowledge of the topic and what has already been said. In this way, you rely more on top-down processing to make up for unreliability in the sound signal, which forms an obstacle to bottom-up processing.
Similarly, second-language listeners often revert to their knowledge of the topic and situation when faced with unfamiliar vocabulary or structures, so using top-down processing to compensate for difficulties in bottom-up processing. On the other hand, if a listener is unable to understand anything of what she hears, she will not even be able to establish the topic of conversation, so top-down processing will also be very limited.
In the classroom
In real-life listening, our students will have to use a combination of the two processes, with more emphasis on top-down or bottom-up listening depending on their reasons for listening. However, the two types of listening can also be practiced separately, as the skills involved are quite different.
Top-down listening activities
Do you ever get your students to predict the content of a listening beforehand, maybe using information about the topic or situation, pictures, or key words? If so, you are already helping them to develop their top-down processing skills, by encouraging them to use their knowledge of the topic to help them understand the content. This is an essential skill given that, in a real-life listening situation, even advanced learners are likely to come across some unknown vocabulary.
By using their knowledge of context and co-text, they should either be able to guess the meaning of the unknown word, or understand the general idea without getting distracted by it.
Other examples of common top-down listening activities include putting a series of pictures or sequence of events in order, listening to conversations and identifying where they take place, reading information about a topic then listening to find whether or not the same points are mentioned, or inferring the relationships between the people involved.
Bottom-up listening activities
The emphasis in EFL listening materials in recent years has been on developing top-down listening processes. There are good reasons for this given that learners need to be able to listen effectively even when faced with unfamiliar vocabulary or structures. However, if the learner understands very few words from the incoming signal, even knowledge about the context may not be sufficient for her to understand what is happening, and she can easily get lost. Of course, low level learners may simply not have enough vocabulary or knowledge of the language yet, but most teachers will be familiar with the situation in which higher-level students fail to recognize known words in the stream of fast connected speech.
Bottom-up listening activities can help learners to understand enough linguistic elements of what they hear to then be able use their top-down skills to fill in the gaps.
The following procedure for developing bottom-up listening skills draws on dictogloss, and is designed to help learners recognize the divisions between words, an important bottom-up listening skill. The teacher reads out a number of sentences, and asks learners to write down how many words there would be in the written form. While the task might sound easy, for learners the weak forms in normal connected speech can make it problematic, so it is very important for the teacher to say the sentences in a very natural way, rather than dictating them word-by-word.
Some suitable sentences are:
I’m going to the shop.
Do you want some chocolate?
Let’s have a party!
I’d better go soon.
You shouldn’t have told him.
What are you doing?
There isn’t any coffee.
What have you got?
He doesn’t like it.
It’s quite a long way.
Why did you think you’d be able to?
Can you tell him I called?
Learners can be asked to compare their answers in pairs, before listening again to check. While listening a third time, they could write what they hear, before reconstructing the complete sentences in pairs or groups. By comparing their version with the correct sentences, learners will become more aware of the sounds of normal spoken English, and how this is different from the written or carefully-spoken form. This will help them to develop the skill of recognizing known words and identifying word divisions in fast connected speech.
Successful listening depends on the ability to combine these two types of processing. Activities which work on each strategy separately should help students to combine top-down and bottom-up processes to become more effective listeners in real-life situations or longer classroom listening.