Are we getting smarter?

Hello everyone, sorry for the lack of blogging over the last month or so – I’ve been doing some extra work in my free time which I’m sure I’ll share on here once it’s published! But I’ve got a bit of a break between deadlines, so I’m back with this post about intelligence and IQ tests which will aim to answer the question: are we getting smarter?

Let’s start off with a bit about IQ tests. There are several which are regularly used in scientific research, such as Raven’s matrices, the Weschler Intelligence Scales, and the Stanford-Binet Intelligence Scale. See how you get on with these example questions and scroll to the bottom for answers!

Raven’s Matrices:

This is a progressive IQ test, with questions becoming harder as you progress through the test. Easier questions at the beginning are used to test children – I’ve done used this before for a research project and it’s relatively simple to explain meaning young children can’t be confused by long written instructions. It is a non-verbal test made of 60 multiple choice questions which measures ‘fluid intelligence’ – or reasoning. Participants are shown a geometric design with a missing piece, and have to choose from multiple options which piece fits best. Have a go at these and see how you get on..

a)

RAPM2

b)

RAPM31

Weschler Adult Intelligence Scale

This test measures cognitive abilities, with the most recent edition – the WAIS-IV, including 4 IQ sub scales: Verbal comprehension, Perceptual reasoning, Working memory and Processing speed. Like the Raven’s matrices, this scale has been adapted for use with children and is also used in a clinical setting, for example when testing for developmental disorders or dementia. See an example below:

c)WAIS-IV_Visual_Puzzles

So how did you get on? Composite scores from answering all of the questions in these intelligence tests are combined to give a score of Intelligence Quotient, or IQ. IQ tests such as the ones above are developed to give a median score of 100 with each standard deviation of 15 IQ points. This is often illustrated in a bell curve, as shown below:

bell-curve-normal-distribution-iq

But are we getting smarter? A scientist called James Flynn has documented the fact that as a population, we are performing better at IQ tests over time. This has therefore become known as the Flynn Effect. Using Weschler tests, it has been estimated that IQ increases by about 3 points per decade. IQ tests such as these have undergone several revisions over time (the first Weschler test was developed in 1939), and scores are standardised using testers to give a median of 100. When these new test subjects take the older versions of the test, they usually score significantly higher than 100, implying our intelligence is increasing. Possible explanations for this increase include better schooling, better nutrition and health. However, there is some debate about whether people are really  getting more intelligent, or are just getting better at taking intelligence tests!

Thanks for reading, I hope you enjoyed this post. I should be back to regular uploads soon!

Answers: a) 3, b) 8, c)1,3,6.

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Confirmation Bias

Hi everyone, this week’s post is an expansion of a brain teaser that I wrote a few months ago about whether we are innately logical – to read that and see how you get on in a test of logic check here. In this, I explained that we tend to fail at classic logic tests because we look for information that supports what we already know, rather than taking all available information into consideration to make our judgments – this is called confirmation bias. It operates in 2 ways: by selective searching for information, and biased interpretation of information.

Once you think about it, it’s surprisingly common in everyday situations. People have superstitions because they notice a link between a certain action and a result, so every they will continue to carry out that action. They do this even if it doesn’t always work – these instances are ignored, but every time the superstition ‘works’ it sticks in their memory and reinforces their actions.

Although this is a relatively simple example, the way we use reasoning has important implications, for example in the criminal justice system. Members of the jury must consider all the information presented to them in order to come up with the correct decision. However, several psychological studies have shown that people’s judgments are easily affected by prejudice and personal expectations, or by a piece of evidence which seems to fit.

For example, Ask & Granhag (2005) asked both criminal investigators and students to read facts about a murder case, but manipulated information so that half of the participants had background information suggesting that a prime suspect had a motive, while the other half were told there might be someone else involved. They found that the students thought it was more likely to be the prime suspect, but only when they had a motive. The investigators showed a similar effect and were less likely to consider problems with the evidence when a prime suspect was identified, rather than if there was someone else – but importantly only if they had a ‘need for cognitive closure’ (basically time pressure and emotional investment in the decision). This shows the imprecise nature of our decision making and how our emotions and initial thoughts can easily cloud our judgments.

In order to avoid confirmation bias, it is important to take into account any information which goes against what you originally thought. In science, people need to actively look for information to go against their theory, because when you’ve disproved alternatives you can be sure that your theory is correct. So it might be worth keeping this in mind..

confirmation bias

 

Are we logical?

If I asked you if you were logical, you would probably say yes. But how rational actually are we? According to some studies.. most people are pretty irrational – let’s see how you get on.

Wason Card Selection Test (Wason, 1966)

Each of these cards has a letter on one side and a number on the other. Your task is to decide which of these cards (choosing the minimum number possible) needs to be turned over to find out whether the following rule is true or false.

Rule: If the card has an A on one side, then there is a 4 on the other side.

Here are your cards, have a look and then scroll down for the solution…

wason

The logical way to solve this problem is to try to find a counterexample to the rule – for example an A card which doesn’t have a 4 on the back. Therefore, the only way to test this rule is to turn over the A card. Only 4% of participants tend to choose this option, suggesting that we aren’t very rational! Instead, most people choose to turn over the A and 4 cards, which is an example of confirmation bias – they look to show that the rule IS true, and don’t look for an example of one of the variables without the other.

So how did you get on?!