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Cognitive illusions are like optical illusions, they systematically mislead us and are predictable. They are predictable because they do not simply mislead us, but systematically distort our judgments. If we look at the two tables that appear in Sheppard’s famous illusion, the vertically oriented table invariably appears longer than the horizontally oriented table, although its dimensions are exactly the same as the other table.
However, the opposite never happens; that the vertical table appears shorter than the horizontal one. This type of systematic error is called “bias” by psychologists. Just as our visual perception can be fooled by an optical illusion, our judgments and decisions can also be influenced by corresponding cognitive illusions. Imagine, for example, that there is a water lily in a pond. The plant doubles in size every day.
If it takes 48 days for lily pads to cover the entire lake, how long does it take for the plant to cover half of it? At this point, the number 24 has popped up in the minds of most of us, even though the correct answer is 47. But 24 is the first number that comes to mind for most of us. Is a mistake? Not technical. Because if it was a real mistake, then some should have gotten to 26, others to 33, 40 or 22. Those would be their own mistakes.
The “bias” of weakness of will
In our case, however, it is a “distortion”, systematic and therefore predictable. There are a great many of these distortions and they relate to how our memory works, ignorance of probabilities, anchoring in the past, indolence, over-optimism and over-confidence, and so on. Economics Nobel laureate Richard Thaler and lawyer Cass Sunstein have suggested in their book Nudge that public policymakers can voluntarily use these biases to induce citizens to make better decisions based on the same citizens’ preferences. A realistic approach, based on the observation that real people are very different from the rational decision-makers of economists, and that this difference sometimes leads to the creation of voting environments that enable the very choices we wish to avoid.
One of the most widespread and strongest prejudices is associated with weakness of will, or “akrasia” as the Greeks called it. Economists speak of dynamic inconsistency in this context: Today I prefer to do one thing tomorrow, but when tomorrow comes I will rather do the opposite of what I preferred yesterday. Last night I decided to set my alarm clock early to start a good morning exercise today, but when the alarm went off this morning I preferred to turn it off and sleep a little later than to get up to do the exercises . This dynamic inconsistency can have very serious implications. Very often we set ourselves goals that can only be achieved with intermediate results: in order to graduate, I have to pass a certain number of exams; To lose weight I have to exercise every day and adjust my diet. In order to finance my children’s studies, I have to set aside something every month, etc.