Fair? You are so biased.
Tim Dingle Dingle 
Are you ready for some cognitive bias and conjunction fallacy rap?
Are you ready for some cognitive bias and conjunction fallacy rap? I saw a great show in Edinburgh that pushed all my cognitive buttons: neuroscience, comedy, rapping and religion. The brilliant Baba Brinkman, (Rap Guide To Religion / The Rap Canterbury Tales / Off The Top) performed some freestyle rapping while his fantastic neuroscientist wife, Dr. Heather Berlin set him various cognitive tasks (in the lab she uses various electrodes)… Yes, she experiments on her husband. Nice.
This is one of those tests (called the Stroop effect) where he succeeded while freestyle rapping (which is incredibly hard). Read the words out loud and see where you go quicker or slower. Baba passed this with flying colours (see what I did there)…
He failed (by the way) while rapping and doing a simple memory test. This experiment led me to investigate the neuroscience basis of this psychological test and I came across another of Baba’s thoughts and insights about ‘bias’. Consider this…
Mark is 31 years old, single, outspoken, and very bright. He majored in contemporary art and music. As a student, he was deeply concerned with issues of race, discrimination and social justice, and also participated in many demonstrations.
Which is more probable?
1. Mark is a teacher
2. Mark is a teacher and is a rapper.
The majority of those asked chose option 2. Did you? You are biased, I knew it! I am particularly fond of this example [in the original research it is called the Linda problem] because I know that the [conjoint] statement is least probable, yet a little part of my brain continues to jump up and down, shouting at me, he must be rapper.
However I also know the mathematics. The probability of two events occurring together (that is they are in conjunction) is always less than or equal to the probability of either one occurring alone. For the two events A and B this inequality could be written as:
For example, even choosing a very low probability of Mark being a teacher, say Pr (Mark is a teacher) = 0.05 and a high probability that he would be a rapper, say Pr (Mark is a rapper) = 0.95, then, assuming independence, Pr (Mark is a teacher andMark is a rapper) = 0.05 × 0.95 or 0.0475, lower than Pr (Mark is a teacher).
This example of a fallacy originated with two psychologists called Amos Tversky and Daniel Kahneman. They called it the Linda problem and I have shamelessly amended it to the Mark problem (and the rapping problem given in Baba Brinkman’s show). They argue that most people get this problem wrong because they use a heuristic (an easily calculated procedure) called representativeness to make this kind of judgment: Option 2 seems more representative of Mark based on the description of him, even though it is clearly mathematically less likely.
Suppose Andy Murray reaches the Wimbledon finals in 2015. Please rank order the following outcomes from most to least likely.
- Murray will win the match
- Murray will lose the first set
- Murray will lose the first set but win the match
- Murray will win the first set but lose the match
What did you rate first and second?
On average, participants rated Murray will lose the first set but win the match more highly than Murray will lose the first set.
Which, I hope you now know is massively wrong. He obviously pulled out due to a back injury. So where does bias come from? It seems to arises from various processes that are sometimes difficult to distinguish. These include
information processing shortcuts (fast brain thinking)
the huge amount of mental noise around us (social media, TV, radio, people)
the mind's limited information processing capacity (we are both amazing and stupid)
emotional and moral motivations (education, religion and more)
social influence (peers, elders, systems, religion etc)
But that makes a huge problem for our legal system. A fair jury trial, for example, requires that the jury ignore irrelevant features of the case, weigh the relevant features appropriately, consider different possibilities open-mindedly and resist fallacies such as appeal to emotion. The various biases demonstrated in these psychological experiments suggest that people will frequently fail to do all these things.
These complex biases are also related to the persistence of superstition (too many to name), to large social issues such as racial prejudice, stereotypes and they also work as a hindrance in the acceptance of scientific non-intuitive knowledge.
Oh and the Stroop test? It is a demonstration of brain interference in the reaction time of a task. The effect is named after John Ridley Stroop who first published the effect in English in 1935. Now super modern Brain imaging techniques (including the one I love so much), Functional Magnetic Resonance Imaging (fMRI), and Positron Emission Tomography (PET) have shown that there are two main areas in the frontal lobe that are activated by the Stroop effect. They are the anterior cingulate cortex, and the dorsolateral prefrontal cortex. More specifically, while both are activated when resolving conflicts and catching errors, the dorsolateral prefrontal cortex assists in memory and other executive functions, while the anterior cingulate cortex is used to select an appropriate response and allocate attention resources. Yes really.
You can go further with this by introducing the Emotional Stroop Test.If you are given negative emotional words like, grief, violence and pain mixed in with more neutral words like clock, door and shoe. Just like in the original test, the words are coloured and the individual is supposed to name the colour. Research has revealed that individuals that are depressed are more likely to say the colour of a negative word slower than the colour of a neutral word. Tricky.
Or try this…
So you are biased (as we all are) but at least you know that your are…and go watch /l listen to this.
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