System 2: Effortful Control and Attention Allocation

Key Insight

System 2 is characterized by its allocation of attention to effortful mental activities, requiring conscious concentration and a sense of voluntary control. Its operations are disrupted if attention is diverted, exemplified by tasks like focusing on specific sounds in a noisy room, searching memory for details, maintaining an unnatural walking speed, or completing a tax form. These activities demand a deliberate focus of attention for successful execution, and performance diminishes or ceases without it.

A key function of System 2 is its ability to program System 1's automatic functions, influencing attention and memory. For instance, consciously setting oneself to look for a 'white-haired woman' in a crowd increases detection likelihood, or tasking memory to search for 'capital cities starting with N'. However, consistently maintaining such a 'set' requires continuous effort, as it goes against natural, automatic responses.

The phrase 'pay attention' accurately reflects that System 2 has a limited 'budget' of attention. Effortful activities interfere with each other, making multitasking difficult or impossible for complex tasks; one cannot compute 17 × 24 while navigating dense traffic. Simple, undemanding tasks can be done concurrently, like talking while driving on an empty highway. This limited capacity leads to social allowances, such as passengers ceasing conversation when a driver is performing a risky maneuver, acknowledging the driver's temporary 'deafness' due to focused attention.