Where decisions are made

Scientists have discovered that the process involved in decision making occurs in different areas of the brain's frontal lobe, depending on whether the decision is abstract or more concrete.

Damage to the frontal lobes of the brain can impair behavioural control, resulting in impulsivity and aggression. The frontal lobes are also important for cognitive control, or the ability to regulate the allocation of mental resources required for decision-making and planning. A study published online in Nature Neuroscience now finds that the tail end of the frontal lobes is more involved in cognitive control of more concrete actions, whereas the front end is more involved in cognitive control of more abstract actions.

David Badre and colleagues studied patients who had sustained damage to various parts of their frontal lobes. They had the patients do tasks which required either more abstract (for example, deciding whether to email a friend) or more concrete actions (such as actually hitting the keys required to type the email).? They found that patients with damage to the tail end of the frontal lobes were more likely to be impaired at performing concrete but not abstract actions. Conversely, patients with damage toward the front end of the lobes were more likely to be impaired at performing abstract but not concrete actions.

The frontal lobes are a large structure, and although earlier work had suggested that cognitive control in these lobes is organized hierarchically, with different parts of the frontal lobes regulating different types of decisions, this report represents the first direct evidence for this organization.