How do System 1 and System 2 deal with effortful tasks? - Chapter 2

System 2 is defined by its effortful operations, although it is also lazy: it puts in no more effort than needed. Some crucial tasks can only be performed by System 2, because they require self-control and effort to overcome the impulses and intuitions of System 1.

The ‘Add-1’ task puts our System 2 to work and demonstrates the limits of our cognitive abilities within seconds. If you truly want to challenge yourself, try Add-3. Your body will also react to the mental work. Eckhard Hess, psychologist, described pupils as windows to the soul. He found that the pupils indicate the level of mental effort: they dilate more if people have to solve more difficult problems. Kahneman set up an experiment to study the reaction of pupils while the participant performed paced tasks. The pupils got wider as the tasks got more demanding. The Add-1 task demonstrated how longer strings of numbers caused bigger pupils. When performing the Add-3 task, the pupils got 50% bigger and the heart rate increased. This is the maximum of mental effort, people give up if the task gets more demanding than Add-3 (the dilating of the pupils stopped). The pupils had a constant normal size when the participant was chatting to someone else during a break. Engaging in small talks and easy tasks are deemed effortless, while tasks as Add-1 and Add-3 are extremely effortful. This can be compared to walking in a natural pace and sprinting. When we are (mentally) sprinting, we could become effectively blind, like the Invisible Gorilla experiment demonstrated. 

System 2 has limited capacity. It responds to threatened (mental) overload by protecting the most important activity. That activity gets the attention it needs. Remaining capacity will be divided to other tasks. An experiment regarding the detection of the letter K as a ‘side task’ showed that the observes failed when the main task was highly demanding.

The allocation of attention has always played an important role in our evolution. The ability to orient and respond rapidly to sudden threats or great opportunities was needed to survive, which we also recognize in the animal world. Even now, System 1 is activated when an emergency occurs and fully focuses on self-protection. We respond to a sudden threat before we are fully aware of it.

Brain studies have demonstrated that the degree of activity needed for an action changes as we become more skilled. An increase in skills resulted into the involvement of fewer brain regions. The same goes for talent: the brain activity and pupil size of highly intelligent people show they need less effort to successfully complete the same task. Law of least effort: if we have several options for achieving a goal, we choose the least demanding one. It is human nature to be lazy.  

Only System 2 is capable of following rules, comparing objects on different attributes and making conscious choices between multiple options. The automatic System 1 lacks these capabilities, it cannot deal with more than one task at once and is not able to use merely statistical information.

A key capability of System 2 is the adoption and termination of ‘task sets’: it can program our memory to follow instructions that overrule habitual responses. Psychologists call this ‘executive control’. If you get the task to count the occurrences of the letter ‘L’ in a text, the answer will not pop up in your head naturally and you have never done this specific task before, but your System 2 will be able to accomplish it. It takes some effort so set yourself up for the task and carry it out, which gets easier with practice. Imagine you get a second task after completing the first one: count all the capital letters in the following text. This will take more effort, as you have to fight the tendency to concentrate on the letter ‘L’. One of the most significant findings of cognitive psychologists in the last decades is that moving the focus to another task is effortful, particularly when there’s a time limit involved. This is why Add-3 is such a hard task. You have to remember several numbers and each number requires a specific action: one is in the middle of transforming, some are waiting to be transformed and others are already transformed and waiting to be reported. People who do well on tests that demand them to switch constantly between two effortful tasks are also likely to do well on tests of general intelligence.