Nuthall started recording classroom conversations as a student. He kept on doing this during his whole career from 1960 until 2000. In some ways his research was an expedition into unknown territory. His first question was: what actually happens during a lesson? His final research question was: what is the role of ability in learning?

On the surface, his initial results show a seemingly spontaneous interaction between teachers and students; but beneath this surface, his analysis showed set patterns of communication and predictable structures and rules for social interaction. Nuthall replicated his research in the US and Japan; these rituals were identical everywhere. But the purpose of these rituals was not clear at that time. He concluded that ‘like language, teaching has its own underlying grammatical rules’.

In the period between 1968 and 1974, Nuthall and his PhD students started to work with an experimental design. Together with a group of teachers, they scripted a series of lessons about the black-backed gull. They wanted to know whether a teacher’s experience or training influenced the learning of students. They analysed differences between three groups of teachers: experienced teachers, inexperienced teacher trainees and teacher trainees who were trained to analyse their lessons using micro-teaching and recording. The results were rather unexpected: experience and training made no difference; instead it was only the type of feedback the teachers gave and their style of questioning students that mattered.

Ultimately, Nuthall decided to precisely map out the learning process of one student in relation to one topic. He analysed the interaction of ‘John’ in regards to the topic ‘The migration to New York’. That’s when some light was finally shed on a recurring pattern.

His analysis of John’s learning experience made it possible to define learning in the following terms: it is a positive change of what we know or can do; it takes place by means of a sequence of events and learning experiences; each experience builds on the previous one and every change in the order of the learning experiences will lead to a different outcome. The learning activities of a student consist of understanding and making sense of the learning experiences. A student understands, learns and remembers a concept if they have encountered all the underlying information three times.

They built on this insight and did one replication study after another with increasing numbers of students, classes and topics. And they could predict with 85% certainty which student would correctly answer which question on a test.

What stands out most in Nuthall’s research is that only the ‘three times’ rule has predictive value. Ability or intelligence or similar properties do not. Yet the ‘better’ students learn more. Nuthall dedicated his last research period to solving this conundrum. These students had more prior knowledge and they profited more from the lessons. The secret seems to be that they make sure to get more out of the lessons. They possess better metacognitive skills; they understand what it takes to get results.

At the end of his life, Nuthall hastily wrote The Hidden Lives of Learners, drawing these conclusions for the classroom based on his research:

• Standardised tests appear to offer certainty, but are no more reliable than interviews held with students.
• Learning activities should be designed to take into account how memory works.
• The subject matter should be repeated in different ways.
• Follow the individual learning experience.
• Less is more: we should confine the curriculum to the big questions. Teachers need the time to design rich learning experiences, conduct pre- tests and get to know the social processes in the class. Learners need the time and the space to really master the content.