What is ‘executive function’?
There are two main types of human action. One includes habitual behaviours, like driving along a well-known route, that involve automatic responses and need little or no effortful, conscious processing. The second type includes flexible, adaptive responses to new or difficult situations, such as driving in an unfamiliar city. Executive function is an umbrella term used to describe the processes underlying this second type of action. More specifically, executive function is needed in situations that involve:

• the learning of new skills
• planning and decision making
• error correction or troubleshooting
• initiating novel sequences of actions
• danger or technical difficulty
• conscious moment-to-moment control of behaviour
• the need to overcome strong habitual responses

The development of executive function in children
For much of the twentieth century, research on executive function centred almost exclusively on adults. This was mainly because the prefrontal cortex was thought to become functionally mature only late in development, around adolescence (Luria, 1973). However, it has become increasingly clear that the onset of the development of executive function occurs much earlier than was previously thought. This has become apparent following the appearance of more appropriate tools for studying it at earlier ages. In this section we will look at the course of one aspect of early executive function development; inhibitory control.

Inhibitory control
We have seen in other chapters in this book that one aspect of child development concerns the progressive organization of children’s behaviour and experience. One factor that underpins this is a developing ability to inhibit responses to stimuli. Why is this so important?