Psychology Experiment: Anchoring Bias

Thinking is a process of using knowledge and information to make plans, interpret the world, and make predictions about the world in general. There are four components of thinking: Problem-solving, creativity, reasoning, and decision-making. In particular, decision-making is a process of identifying and choosing alternatives based on the values and preferences of the decision-maker. As humans are cognitive misers, strive to avoid ego depletion, and experience cognitive overload, their preferences may not always be based on truths or be rational, instead, it may be subjected to bias. A cognitive bias is defined as errors in thinking and decision-making that distort thinking, influence decisions, and impact judgments and beliefs. One example of cognitive bias is anchoring bias. Anchoring bias causes us to rely too heavily on the first piece of information we are given about a topic – serves as an “anchor” for subsequent decisions. This article will discuss anchoring bias and its effect on memory with reference to a lab experiment by Plassmann et al. (2008). 

Plassmann et al. (2008) was a lab experiment utilizing fMRI with 20 subjects, aiming to demonstrate the role of the anchoring bias on wine tasting in a measure of neural mechanisms affecting decision-making. They had participants sample wine while in an fMRI. Participants were told they were tasting five different Cabernet Sauvignons. The different wines were identified only by their retail prices. But, in reality, there were actually only three different wines. The fourth wine was the same as the first wine, and the fifth wine was the same as the second one. Wine one was represented as a $90 bottle, the next at $5, then $45, $35, and a $10 bottle of wine last. Through this experiment, they were able to find out that the price served as an anchor for deciding on the pleasantness of the wine – when the wine was thought to be $90, not only did the participants report it was a better wine, but they showed more activity in their medial orbitofrontal cortex, an area that is associated with experiencing pleasure. 

This experiment suggests that increasing the price of a wine increases subjective reports of flavor pleasantness as well as blood-oxygen-level-dependent activity in the medial orbitofrontal cortex. This links back to the explanation of anchoring bias by demonstrating that humans rely too heavily on the first piece of information they receive early in the decision-making process, and people estimate the problem in an uncertain situation by using the first presented information.