How We Think: Systems 1 and 2

In his seminal book Thinking Fast and Slow¹, Nobel prize winning psychologist Daniel Kahneman talks about two very different kinds of thinking that we do. He refers to them as System 1 (fast, but often wrong) and System 2 (slower, more accurate).

While it’s not clear if these are an exact map for what we call the unconscious and conscious minds, the overlap is certainly very close. We can reasonably assume that System 2 describes the conscious mind and that System 1 describes the unconscious mind (everything that isn’t conscious).

Why would we need two different approaches to thinking?

Thinking is extremely expensive in terms of energy use. Our brains use 20% of all the energy expended while awake and in the quest for survival, our bodies optimize for energy usage². System 1 requires significantly less energy than System 2 does and so our brains want to use it as much as possible. Yet, System 1 has limitations that System 2 compensates for. It’s a balancing act between energy consumption and ability to operate effectively.

Let’s look at an example.

If you said that the ball was 10 cents then it was your System 1 that answered. The answer was fast and also wrong.

Now that I’ve said the answer was wrong, you’re likely looking at the problem with a more critical eye. Taking time to think your way through the problem. Now you’re using System 2.

System 1 is fast, automatic, impulsive and rule governed. System 1 is the realm of cognitive bias, where speed is more important than accuracy.

In their book Coaching the Brain³, O’Connor and Lages identify three main weaknesses to System 1.

1. It uses hardwired cognitive biases and applies them indiscriminately.
2. It is biased to believe - it understands by believing, not by analysis and reflection.
3. It is influenced by the situation and gives answers based on immediate context rather than general principles.

“System 1 can only do its job of delivering strong conclusions at lightning speed if it never pauses to wonder whether the evidence at hand is flawed or inadequate, or if there is better evidence elsewhere. It must treat the available evidence as reliable and sufficient”
Superforecasting⁴

System 2 is slow, deliberate, reflective and analytical. It requires constant attention and can easily be distracted. It requires considerable energy and time to reach an answer, although when it does, that answer will be more correct than what System 1 could have achieved.

“System 2, the rational and conscious system, is a highly controllable processing system, but it is also lazy and slow. System 2 is flexible and malleable through reasoning and is linked to language. It demands large amounts of cognitive resources and is limited by the capacity of working memory, which is short-term.”
The Illusionist Brain⁵

In the absence of psychological safety or in the presence of time pressure, we almost always get a System 1 response. Both of these are systemic problems that need to be addressed, if we’re to allow people to operate from System 2.

Multitasking makes it difficult to access System 2.

When coaching, there are certain language patterns that we should avoid, because they encourage System 1 thinking.

• Closed questions (that can be answered with yes/no) almost always get a System 1 response.
• “Why” questions usually get a System 1 response.
• Any statement that starts with “Obviously…” or “Clearly…” is almost certainly System 1 thinking.³

“When System 2 is otherwise engaged, we will believe almost anything. System 1 is gullible and biased to believe, System 2 is in charge of doubting and unbelieving, but System 2 is sometimes busy, and often lazy”
Thinking Fast and Slow¹

You may be tempted to think that System 1 is bad and that we always want to avoid it but that isn’t true. If it weren’t for System 1 taking most of the load of decision making, we’d get nothing done. Our brains just aren’t powerful enough to process all decisions through System 2.

What we do want do ensure is that we’re using System 2 to correct System 1 decisions when they’re wrong. Also, there are some times that we need to explicitly force System 2 thinking to get the best results. Being aware of the two systems and their behaviours is a first step towards making better decisions.