Bias in Thinking and Decision making

Cognitive Biases

• Cognitive biases are systematic cognitive dispositions in human thinking that often do not comply with logic, reasoning, and plausibility

• These intuitive and subconscious tendencies are at the basis of human judgment and behavior.

• System 1 makes assumptions (heuristics), with little or no thought and generates a ‘probable’ answer, prone to errors

• Understanding common errors in the way people think helps us to anticipate poor decision-making

• Major heuristics / biases that humans use: the representativeness heuristic, the availability heuristic, and the adjustment and anchoring heuristic (Tversky & Kahneman, 1974)

Anchoring bias

• Anchoring bias is a cognitive bias that causes us to rely on the first piece of information we are given about a topic.

• When we are setting plans or making estimates, we interpret newer information from the reference point of our anchor, instead of seeing it objectively.

• This can skew our judgment, and prevent us from updating our plans or predictions as much as we should.

Bias study

English and Mussweiler

English and Mussweiler Aim

To determine the effect of a prosecutor's suggestion for sentencing on the decision-making of a judge.

English and Mussweiler Procedure

• 19 young trial judges (15 male 4 female) with an average of 9 months of experience

• First had a pilot study with a group of law students

• They were presented the case and asked to give what they thought an appropriate sentence for the crime would be

• The average recommended prison term was 17 months

• This was then used as a basis for determining the anchors

• There were two conditions

• In one the prosecutor recommended a 2-month sentence

• In the other the prosecutor recommended a 36-month sentence

• The participants were given the case material along with the penal code

• They read through it and had to form an opinion within 15 minutes.

• After they were given a questionnaire, which asked:

• Do you think that the sentence was too low, adequate or too high?

• What sentence would you recommend?

• How certain are you about your sentencing decision? (1 – 9)

• How realistic do you think this case is? (1 – 9)

English and Mussweiler Results

• The average rating for the realistic nature of the case was 7.17

• The judges' certainty about their responses were not as strong, with an average rating of 4.53.

• When presented with a low anchor of two months, the average sentence was 18.78 months.

• In the high anchor condition of 34 months, the average sentence was 28.70 months

English and Mussweiler Conclusion

The prosecutor’s recommendation swayed the participant’s recommendation.

Link to Dual Process Model

• The use of a pilot study allows English and Mussweiler to demonstrate both systems of thinking

• The pilot study used system 2 thinking – there was no time constraint or prosecutors recommendation

• Both conditions of the experiment used system 1 thinking, they relied on what they knew from their experience as a trial judge