As we continue our series on cognitive biases, I thought I’d begin with one that is a little quirky – the Ikea Effect. This is defined as “the tendency for people to place a disproportionately high value on objects that they partially assembled themselves, such as furniture from IKEA, regardless of the quality of the end result.” Come on, you know you suffer from this one!
Cognitive psychologists have demonstrate that self-assembly impacts the evaluation of a product by its consumers. Their studies suggest that when people use their own labour to construct a particular product, even if done badly, they value the end result more than if they had not put any effort into its creation.
To test this, researchers gave their subjects the task of assembling some IKEA furniture. Participants were then asked to price their furniture, along with some identical pieces which had come pre-assembled. In a series of experiments, they demonstrated that people attach greater value to things they built than the very same product that was built by someone else. In fact, the studies showed that the subjects were willing to pay 63% more for the former. This is particularly surprising given the quality of the assembled furniture I know I usually produce!
When it comes to biblical interpretation, a cognitive bias that may be influential is the illusory truth effect. This essentially involves the tendency of people to identify a statement as true simply because they have heard it before, irrespective of its actual truthfulness. In other words, people have a tendency to believe information to be true simply because they have been exposed to it previously; we are more likely to believe a familiar statement than an unfamiliar one.
This effect was first identified in a 1977 study in which participants were given a list of sixty plausible historical factoids, which they were required to identify as true or false on a scale from one (definitely false) to seven (definitely true).  Examples of the factoids include “The People’s Republic of China was founded in 1947” (false, it was established in 1949), “Lithium is the lightest of all metals” (true), and “The largest museum in the world is the Louvre in Paris” (false, either the Hermitage Museum in Saint-Petersburg, Russia or the Smithsonian could lay claim to this title).
The participants were required to take a total of three such tests, with a two week gap between each. Of the sixty factoids included in each test, twenty were repeated and forty were new. The researchers discovered that participants increased their rating of the truthfulness of the repeated statements across the three tests: in the first test these statements were given a mean truthfulness rating of 4.35, which increased to 4.67 in the second test and 4.74 in the last. Their belief that the statement was true increased on each occasion they encountered the repeated information. This effect was particularly noticeable when contrasted with the forty new questions in each test; the mean truthfulness rating for these factoids did not increase over time (4.25 in the first test, followed by 4.22 in the second and 4.13 in the third).
This effect may result in exegetes thinking that a certain interpretation of a passage is correct simply because they have encountered it before, especially if they have encountered it on numerous occasions. In other words, interpreters are likely to adopt as their default understanding of the passage, the interpretation with which they are familiar. While this may be appropriate, a tendency to uncritically default to the popular understanding can be problematic. Consider, for example, the common suggestion that Matthew 19: 24 (“Again I tell you, it is easier for a camel to go through the eye of a needle than for someone who is rich to enter the kingdom of God.”) refers to an actual gate in Jerusalem called the “Eye of the Needle” through which a camel could only pass if it stooped down and had all its baggage removed. Although such an interpretation may have been repeated oft-times throughout history (it seems to date back at least to the fifteenth century, and possibly even the ninth), there is no historical or archaeological evidence that such a gate existed; its “existence” appears only to have been accepted due to the repetition of the story. Thus, while such an interpretation may have made great sermon material – which is perhaps the reason for its frequent repetition in the first place – it is, at best, an illusory truth.
In my next post, I plan to look at how we can perhaps reduce the influence of some of these biases.
 I. M. Begg, A. Anas, and S. Farinacci. “Dissociation of Processes In Belief: Source Recollection, Statement Familiarity, and the Illusion of Truth,” Journal of Experimental Psychology: General 121/4 (1992): 446-58.
 L. Hasher, D. Goldstein, and T. Toppino, “Frequency and the Conference of Referential Validity,” Journal of Verbal Learning and Verbal Behavior 16 (1977): 107-12.
 See, for example, W. Barclay, The Gospel of Matthew: Vol 2, rev ed (Philadelphia: Westminster Press, 1975), 217.
Dr Aaron Chalmers
Head of School, Ministry, Theology and Culture