In search of the secrets of human intelligence, researchers developed what is considered the shortest IQ test in the world. Although the “Cognitive Reflection Test” only contained three questions, it surprised participants: only 17% solved it successfully. 83% only answered one question correctly.
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First of all, intelligence quotient or IQ is a metric that assesses a person's intelligence by comparing their mental age with their chronological age. Traditionally, comprehensive tests cover a variety of areas, from language and math problems to logic and spatial questions.
The viral intelligence test
However, the recent online discovery of the “Cognitive Reflection Test” has piqued the curiosity of internet users around the world. Originally part of a 2005 study by MIT professor Shane Frederick, the test went viral, challenging even students from top universities in the United States such as Yale and Harvard.
The difficulty of the challenge
Of the more than 3,000 people who took part in the study, only 17% managed to answer all three questions correctly, highlighting the complexity of the proposed challenge. Professor Frederick explained that seemingly simple questions require the suppression of impulsive reactions in the mind, making the task more difficult than it seems.
The 3 questions of the intelligence test
- A racket and a ball cost a total of R$1.10. The bat costs R$1 more than the ball. How much does the ball cost?
- If it takes five machines five minutes to make five objects, how long would it take 100 machines to make 100 objects?
- There is a lotus bush in a lake. The massif doubles in size every day. If it takes the massif 48 days to cover the entire lake, how long will it take to cover half the lake?
The most common and incorrect answers are:
- 10 cents
- 100 minutes
- 24 days
However, the correct answers are:
- 5 cents
- 5 minutes
- 47 days
The traps of questions
Professor Frederick emphasizes that the apparent simplicity of the questions hides traps like the first, where the difference between R$1 and 10 cents is not R$1, as many mistakenly assume.
Answers and explanations
For those who want to try, game theory author Presh Talwalkar offers detailed explanations of the correct answers on his blog Mind Your Decisions. See below:
Answer 1: Suppose the ball has a total price of R$1.10. This implies that 2X + 1 = 1.10, so 2X = 0.10, so X = 0.05. This means that the ball is worth 5 cents and the bat is worth R$1.05.
Answer 2: If 5 machines produce 5 objects in 5 minutes, then 1 machine produces 1 object in 5 minutes (each machine produces one object in 5 minutes). If 100 machines work at the same time, each one will produce an object in 5 minutes. Therefore, in 5 minutes there will be 100 objects.
Answer 3: The massif is growing twice every day. Afterwards it decreases by half every day. On day 47 the lake is at half capacity.
The intelligence test lesson
Therefore, this revelation not only challenges the mind but also highlights the importance of a careful approach in solving seemingly simple problems.