Daniel Kahneman, 'Thinking, Fast and Slow (Part 1): How Your Decisions Are Made' Introduction to Chapter 5
Can human intuition handle statistics well?
Hardly at all. This is because human judgment is subject to 'biases'. People try to find shortcuts to solutions by using the 'availability heuristic,' such as ease of recall or accessibility, or by using 'simplification heuristics' to replace difficult problems with similar, easier ones. As a result, they end up with answers that are completely different from statistics.
It was once believed that humans were rational and logical, but that assumption has been called into question.
For example, information covered by the media can be easily recalled from memory, and humans have a tendency to evaluate such easily recalled problems as relatively more significant. The information the media handles is usually 'matters that the media judges the general public to be interested in,' and matters lacking drama are not reported. And humans do not even think of matters with low availability in the first place.
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The concepts of 'heuristics' and 'biases' published by Amos Tversky and Daniel Kahneman in Science magazine in 1982 have come to be utilized in diverse fields such as medical diagnosis, judicial judgment, information analysis, philosophy, finance, statistics, and military strategy.
This book introduces how the workings of the brain are perceived, based on cognitive psychology and social psychology. In particular, it covers the astonishing aspects of intuitive thinking and its flaws, as well as knowledge regarding judgment and decision-making obtained through psychological experiments.
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Chapter 1: The Characters of the Story — System 1 (Fast Thinking) and System 2 (Slow Thinking)
Inside the brain, there are System 1 (fast thinking) and System 2 (slow thinking). These two systems interact. The impulsive and intuitive System 1 works automatically and uncontrollably, while the logical, attentive System 2 is often lazy and usually does very little work.
For example, when a judgment is considered unproblematic, the impressions and intuitions of System 1 are accepted by System 2 as they are, turning into unfounded convictions. On the other hand, when encountering a problem that System 1 cannot solve, System 2 is finally mobilized to exert attention.
By having the two systems divide the work in this way, the brain operates to minimize effort and optimize results. System 1's judgments about familiar situations are accurate, and short-term predictions are generally correct. However, System 1 is subject to bias and cannot be switched off, so it often makes errors in judgment. Therefore, it is difficult to avoid errors in intuitive thinking.
In emergencies, System 1 activates, prioritizing actions to protect oneself. It reacts automatically before one even recognizes what has happened. On the other hand, paying attention to serious threats or promising opportunities increases the chances of survival. Through a long history of evolution, System 2 has developed.
Humans believe that they have their own thoughts, make their own choices, and decide how and what to think and act. They think of that conscious, logical System 2 as their true self. However, in reality, it is known that System 2 often adopts the biased and error-prone intuitions of System 1 as its own judgments.
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Chapter 2: Attention and Effort — The Impulsive and Intuitive System 1
The 'law of least effort' applies not only to physical labor but also to the brain's cognitive abilities. In other words, when there are multiple ways to achieve a goal, humans choose the method that requires the least effort. If the automatic System 1 can operate without using the attention of System 2, it will do so. What System 1 is not good at is handling statistical information.
What System 2 can do includes following rules, comparing evaluation targets from multiple aspects, and choosing after deliberation from multiple options. Crucially, it can perform 'task setting'. It creates a process of setting attention to perform unfamiliar tasks well and making the effort to execute them. It is also a characteristic that the prefrontal cortex area of the brain has this function, and it is an area that is well-developed in humans compared to other primates.
As one becomes proficient in a task, the energy required decreases. Brain activity patterns associated with certain actions change with the improvement of skills, and the areas of the brain that are activated decrease. Talent is the same; smart people can solve the same problem with less effort than the average person. This has been proven through pupil measurement and brain activity. However, effort is a cost, and even when acquiring skills, the benefits and costs are weighed before doing so.
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Chapter 3: 'The Lazy Controller — System 2, Equipped with Logical Thinking Ability'
Humans can sometimes continue tremendous effort without difficulty for long periods without exerting willpower. This is called 'flow'. Concentration on a task continues without effort, and no self-control is required to maintain that focus of attention.
Such cognitive effort and self-control are known as a form of intellectual work. Many psychological studies suggest that when faced with difficult cognitive tasks and temptations simultaneously, one is more likely to give in to temptation. When System 2, which performs intellectual work, is overwhelmed, System 1 begins to have a significant influence on behavior.
For example, in a cognitively busy state, one is more likely to make selfish choices, use provocative language, and make superficial judgments about social situations. Also,
if you worry about whether what you are doing will go well, the extra worry puts a load on your short-term memory, which can actually lead to poor performance.
Continuing to exert strong willpower or self-control using System 2 is tiring. This is called 'ego depletion'. When subjects were instructed to suppress their emotional reactions while watching an emotional movie, their performance on a subsequent test of squeezing a hand dynamometer worsened. Because they had made the effort to suppress their emotions, their ability to endure the pain of maintaining muscle contraction was reduced.
By providing strong incentives, one can resist the effects of ego depletion to some extent. Also, the effects of ego depletion can be resolved by consuming glucose. Since the nervous system consumes the most glucose in the body, replenishing glucose levels restores brain function.
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One of the main functions of System 2 is to monitor and control the thoughts and actions proposed by System 1. It then permits some of those proposals, while rejecting or modifying others. The extent to which careful checking and exploration are performed depends on System 2, and this varies from person to person.
The ability to control attention is influenced by genes as well as upbringing. This ability is also closely related to performance on non-verbal intelligence tests and the ability to control one's own emotions.
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Chapter 4: 'The Associative Machine — Primes (Antecedent Stimuli) That Guide Us'
Words evoke memories, memories stir emotions, and emotions prompt facial expressions and other reactions (tension or avoidance behavior). These reactions then further intensify the emotions and strengthen thoughts consistent with those emotions. These things happen simultaneously in a very short time, creating a self-propagating pattern of cognitive, emotional, and physical reactions. This process is called associative activation.
According to Hume, there are three principles of association: resemblance, contiguity in time and place, and causality.
Psychologically, it is thought that ideas float within 'associative memory,' a vast network, acting as nodes linked to many other ideas. There are various types of links, such as cause and effect (virus and cold), object and attribute (lime and green), and object and category (fruit and category).
When one idea is activated, many other ideas are activated, which in turn activate other ideas, and so on. Only a tiny fraction of this reaches consciousness, and the majority of 'associative thinking' is hidden from the conscious self. You do not have access to all of your own thoughts.
'You know much less about yourself than you think you do'
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It has been observed that exposure to a certain word makes related words easier to recall. This is called the 'priming effect.' Associative activation spreads, and the ideas recalled by the prime are selected. It is not limited to concepts and words; events you were not even consciously aware of can act as primes, influencing your behavior and emotions. This phenomenon occurs within System 1, so it cannot be consciously accessed.
The associative network can lead to bidirectional relationships. If you are happy, you smile, and if you smile, you become happy. When subjects read comics with a pencil held horizontally to create an expression close to a smile, versus holding a pencil vertically to create an expression close to a frown, the degree of amusement was higher for those who read with the expression close to a smile. This is an example where common physical movements or changes were linked to emotions and judgments, independent of consciousness.
The 'priming effect' has overturned our self-image that we are independent, conscious selves making our own judgments and choices.
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Chapter 5: Cognitive Ease — Why We Like What Is Familiar
Whether we are conscious of it or not, our brains are constantly processing a vast amount of information simultaneously, and we are always updating answers to several important questions, such as what we should pay attention to or whether there are any signs of danger.
When cognitive ease is high among familiar things, we do not try to think too deeply. We trust our intuition and feel confident.
On the other hand, when we feel cognitive strain, we become cautious and skeptical, putting in more effort than usual and making fewer errors. We rely less on intuition and do not exhibit much creativity.
The sense of having seen or heard something before, or seeing a word again that we saw previously, leads to cognitive ease. This quality of 'pastness' is an illusion.
Cognitive ease and familiarity are easily confused with truth. System 1 forms such an impression, and System 2 makes a judgment without careful deliberation. Even if we cannot recall the source or relate it to the information at hand, the ease of processing is used as a cue.
To make it easier for a reader to believe something is true, as a general rule, you should reduce cognitive strain as much as possible. Words that are easy to pronounce and repetition also contribute to cognitive ease. Using difficult phrasing makes the reader skeptical and cautious. When something needs to be read seriously and analytically, imposing cognitive strain will bring System 2 into play.
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The mere exposure effect is felt as a stronger stimulus when we are looking at something without any conscious awareness. This effect does not depend on the experience of familiarity. For example, even if a word or photo is repeated and the recipient does not notice it, they will come to like the word or photo that was shown most frequently.
Living organisms react cautiously to newly appearing stimuli, but it is explained that the mere exposure effect occurs because nothing bad happened after repeated contact, leading to positive emotions. Living organisms distinguish safety based on whether something is familiar. The mere exposure effect forms the basis of social organizations and groups, serving as the foundation for psychological and social stability.
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Mood has a significant impact on the accuracy of intuition. It influences the workings of System 1. If you are in a bad mood or unhappy, your intuition becomes inaccurate. When you are in a good mood, your intuition is sharp and you exhibit creativity, but your vigilance decreases and you are more likely to make logical errors. Good humor, intuition, creativity, and gullibility all point to a reliance on the same System 1.
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Continued in Chapter 6 and beyond
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Daniel Kahneman, 'Thinking, Fast and Slow (Part 1): How Your Decisions Are Made', translated by Akiko Murai, Hayakawa Non-Fiction Bunko, 2014
Introduction to Chapter 5
