Cognitive Biases and Cognitive Ability

A question that arises is whether tasks that measure cognitive biases are measuring general cognitive ability. Stanovich and West (1998) investigated performance on tasks representing 28 cognitive biases (some based on prior literature and some first identified for the study) and found that for roughly half the tasks, there was no correlation with general cognitive ability. However, the denominator neglect problem is an example of a task for which there was a correlation: Participants are told they will win money by choosing a black marble in a tray of white and black marbles mixed as either 1 black in 10 marbles (10 percent chance of winning) or 8 black in 100 marbles (8 percent chance of winning). Participants tend to choose the 100-marble tray despite it being longer odds, perhaps with the idea that having 8 black marbles is interpreted as having 8 chances of winning, which is better than having only 1. However, participants with a higher general cognitive ability tended to choose the option with the better odds of winning, thereby demonstrating resistance to this type of cognitive bias. Another cognitive-ability-related task is the probabilistic reasoning task, in which respondents are asked to predict the number on the down side of 10 dealt cards when they are told that 7 cards have the number 1 and 3 cards have the number 2 on the down side (Stanovich and West, 1998). Most participants choose a strategy of predicting which 7 are 1 card and which 3 are 2 cards, even though a winning strategy is to predict 1-card status for all 10 cards. However, participants with higher cognitive ability are less likely to make this error.

An example of a task in which the cognitive bias is not correlated with cognitive ability is the anchoring effect task (Stanovich and West, 1998). In this task, participants are asked two questions, such as “Do you think there are more or less than 65 African countries in the United Nations?” and then “How many African countries do you think are in the United Nations?” Instead of “65” in the first question, half the participants were given the number “12.” For those who were given “65” in the first question, the mean of their responses to the second question was 45.2; for those given “12” in the first question, the mean of the responses was 14.4. This discrepancy illustrates the anchoring effect, in that the information presented first heavily influenced the later decision. In this test, there was no correlation between SAT score and the size of the estimate in responding to the second question.

Another example of a task where the cognitive bias does not correlate with cognitive ability is the sunk cost task (Stanovich and West, 1998). Participants say that they would be more willing to drive an extra 10 minutes to save $10 on a $30 calculator than they would to save $10 on a $250 jacket, despite the fact that in either case the $10 savings is exactly the same.