Understanding and Belief

The Gilbert Experiment

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The Gilbert Experiment

Daniel Gilbert together with his colleagues put to test both Rene Descartes’ and Baruch Spinoza’s beliefs on whether belief is automatic or is a separate process that follows understanding. This argument has long been standing for at least 400 years before it was finally settled.

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Does understanding and belief happen at the same time almost instantaneously? How does a typical mind work when a new set of information is laid out for it to take in? Does it believe in the new information right away soon as it enters it or does your mind process these bits of information first before it accepts it?

People love to read because it furthers their knowledge and awareness regarding all matters of life. However, not everything that we can read especially now that a lot of information can be acquired through the Internet from non-credible sources, some information could be outright false. Hence it’s critical that we should not believe everything we read. However it still does happen for according to a classic psychology study, we can’t help but believe it at first.

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Research Question

Two philosophers have contrasting views when it comes to understanding and belief. The said argument has been going on for at least 400 years before a solution gave light to it. According to Rene Descartes, a well-known French philosopher, mathematician and physicist, understanding and belief are two separate processes. People take in some information first by paying attention to it, before they actually decide what to do with that information, which includes believing or rejecting it.

On the other hand, Baruch Spinoza, a Dutch philosopher and contemporary of Descartes, believed that the very act of understanding information was already believing it. According to him, after this we may be able to change our minds but until that time we do believe everything.

Daniel Gilbert along with his colleagues wanted to find out the answer to this in a couple of experiments to find out whether understanding and belief operate together or whether belief or disbelief comes afterwards.


The experiment studied 71 participants in totality. The subjects are to read statements about 2 robberies and will then be asked to give the robber a jail sentence. The statement varies in such a way that would seem to tweak the severity of the crime.

For example: “The robber had a gun.”

Thus making the crime seem worse. While there are other statements as well that make the crime look less serious.

For example: “The robber had starving children to feed.”

The twist was that not all statements that will be presented to them were true. Subjects were informed that all the statements that were true would be displayed in green, while the false ones would be in red.

To put both Spinoza’s and Descartes’ theory on the experiment, if we’ll be taking Spinoza’s theory, then subjects who get distracted by the colored statements will find a hard time to process the fact that statements written in red are therefore false, and would most likely be influenced by this when they give the robber his jail sentence in the end. While if we are to take Descartes’ theory, judgments made by those distracted by the color-coordinated statements will be no different at all since they wouldn’t have time to believe it or reject the false statements, so this would not make any difference to the jail term.


Results showed that when the false statements made the crime seem much worse rather than less serious, the subjects who were distracted by the color-coordination gave the robbers almost twice as severe jail terms, from about 6 years to around 11 years.

On the contrary, the group in which participants didn’t find the colored statements distracting at all, managed to effectively ignore the false statements. Consequently, there was hardly any difference between jail terms given that depended on whether false statements made the crime appear more severe or not.

Gilbert and his colleagues got the following results:

  • Not Interrupted
    • 6.03 years when false statements made crimes less serious.
    • 7.03 years when false statements made crimes more serious.
  • Interrupted
    • 5.83 years when false statements made crimes less serious.
    • 11.15 years when false statements made crimes more serious.


The results convey the idea that people, when given time to think, behave as though the false statements were actually false. Otherwise, people just open-handedly believe whatever they read.

To then answer the understanding/believing dispute between Descartes and Spinoza based on the experiment, Spinoza was right. Believing is not a two-stage process that’s independent of each other. Instead, understanding is already believing, although your mind might change after a split second the moment your mind decides otherwise as it further interprets and analyzes the new information.

Furthermore, Gilbert and his colleagues came about with these findings that explain other behaviors people regularly display:

  • Correspondence bias – people’s tendency to over-value dispositional or personality-based explanations for the observed behaviors of others while under-valuing situational explanations for those behaviors. In short, people tend to assume that other people’s behavior automatically reflects their personality when in reality, it really reflects the situation.
  • Truthfulness bias – tendency of people to assume other people’s statements to be true even when they’re false.
  • Persuasion effect – when people are distracted it increases the likeliness that the people will be persuaded or the message is more persuasive.
  • Denial-innuendo effect – tendency of people to positively believe in things that are being categorically denied.
  • Hypothesis testing bias – people, when testing a theory, instead of trying to prove it wrong, they tend to look for information that confirms it.


Why You Can’t Help Believing Everything You Read

Wikipedia: Fundamental Attribution Error

Full reference: 

Explorable.com (Apr 5, 2010). Understanding and Belief. Retrieved Jul 20, 2024 from Explorable.com: https://explorable.com/understanding-and-belief

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