What is Top-down and Bottom-up processing?

In this post, we’ll talk about the two processes we use to comprehend written and spoken texts: top down and bottom up. We’ll talk about the difficulties students face when reading and listening to texts, provide definitions, real examples of the processes taking place in learning and share classroom ideas to help you plan effective receptive skills lessons to your learners.

Why do students find it difficult to read and listen in a second language?

Reading and Listening are both receptive skills, but the difficulties faced by students when reading or listening to a text vary.

In reading, we can receive information “at our own pace”: if a word / expression is unknown, the reader can stop, read again, and take their time to understand what is written. In listening, this does not happen - once the content is said, it is gone!

Written text is generally more standardised than spoken text - although there might be differences in spelling, vocabulary, and even use of grammar depending on where you are, spoken English is much more varied than written English. Accents and regionalisms are definitely more present in oral speech, and these may pose difficulties in comprehension

Because of the reasons mentioned above, students might get anxious and apprehensive when trying to understand spoken text. This hinders comprehension even more!

When people read or listen in their native language, they naturally employ strategies that help them decode the text. Also, their native knowledge of the language helps them comprehend the text with ease. In a second language, we need to consciously employ strategies (which we talk about in these posts). Apart from this, our brain finds a way to break down and process the information it receives. These processes are called top-down and bottom-up.

Top-down processing

Top-down processing has to do with how you use your background knowledge of the world (known as schema) to comprehend a text. Instead of relying on understanding individual letters, words, sentences or sounds, the reader / listener uses information and knowledge that might come from outside the text.

For example: I am currently visiting Ukraine for a CELTA course, and will stay here for two months. I don’t speak Ukrainian or Russian, and most of the written stimuli that I’ve been having is in one of these languages. To make matters worse, the alphabet used in this country is different from my own: everything is written in cyrillic script, with which I am familiar, but definitely not 100% comfortable with....

I was walking to work and saw this sign. I immediately knew what it was about because of my background knowledge on this topic:

Having been to gyms before, I know that this has some of the characteristics of a local gym ad: two muscular, hourglass figures, rejoicing, arms up in the air as a sign of victory.

This is an example of how top-down processing takes place: to comprehend a text, we may start from meaning, bringing our background knowledge and ideas to help us decode a message and overcome linguistic difficulties we may encounter.

Bottom-up processing

I wanted to be absolutely sure that, if I followed that arrow, I would end up in a gym. So I unconsciously started processing the information from the bottom up. I don’t know the Cyrillic alphabet, but I know Greek. Some letters are the same; and some letters are the same as in the Latin alphabet. So I started looking at the words to make sure I understood the message on that sign:

In this case, I’m using bottom-up processing: I’m looking at clues in the text to better comprehend it. These clues can be semantic, syntactic, phonological (in spoken texts). In this example, I needed to identify individual letters to reach word level. I recognised some of the words, and confirmed that the sign would actually take me to a gym!

During my trip, I collected more examples of moments when I caught myself understanding a text (mostly written) and reflecting on how top-down and bottom-up processing were taking place. More examples below:

It is important to bear in mind that, to reach comprehension, the two processes take place simultaneously, leading to the interactive processing of information. The amount of top-down and/or bottom-up processing done by the listener/reader will depend on how much they know about the topic and how much they know about the language. The purpose for reading and listening also affect how people process information - this is why it is so important to carefully design listening / reading tasks and think about activities that will be useful for students to develop their receptive skills.

Classroom ideas

Being aware of the mental processes that lead to better understanding of a text is vital to decide what to do in the classroom to help learners read and listen better. There’s no way to “choose” a process to develop - both take place at the same time. Here are some ideas that can ensure you give learners opportunities to develop their receptive skills:

Before students read or listen to a text, give them time to:

- Brainstorm information on what they already know about the topic

- Predict the content of the text

- Predict the characteristics of the text genre

- Think about possible questions related to the text / content (mainly if they don't have a lot of previous knowledge about it)

While students read a text, encourage them to:

- Identify words / phrases they already know (names, numbers, cognates)

- Use their knowledge of word formation (e.g. affixation) to understand words they don’t know

- Use their knowledge of discourse to understand how a text is structured (paragraphs, discourse markers)

While students listen to a text, encourage them to:

- Identify words / phrases they already know

- Pay attention to non-verbal clues (e.g. background noise)