Skip to main content

Information Cascades and Conformity

In class, we discussed, mostly in terms of technological adoption, how information about technology spreads over a network and how signals about a product influence its adoption over a large group of people.  This concept relates directly with the concept of social pressure and conformity in crowds and the idea of “groupthink” or “following the herd”.  Several psychological experiments were done throughout the years in an attempt to address this question and determine why and how this phenomenon exists.  One of the most famous of these psychological experiments was Asch’s card “line-matching” study (an article of Asch’s entitlted “Opinions and Social Pressure” is available here:  In the study, students are placed into groups whereby everyone but one of the students is told to pick a wrong answer to a question – the question involves comparing the sizes of two lines as you can see in the following image:

(One of the pairs of cards used in the experiment. The card on the left has the reference line and the one on the right shows the three comparison lines. – from

After a few “normal” rounds whereby each participant selects the correctly sized line, everyone but the subject begins selecting incorrect answers.  The key here is that every other individual in the group picks the exact same incorrectly sized line.

“Of the 123 put to the test, a considerable percentage yielded to the majority. Whereas in ordinary circumstances individuals matching the lines will make mistakes less than 1 per cent of the time, under group pressure the minority subjects swung to acceptance of the misleading majority’s wrong judgments in 36.8 per cent of the selections.”

This phenomenon can be very easily explained using the information we have about cascades!  As the last person to choose the correct answer, the subject assumes that along the way each participant has weighed his or her own thoughts with those of the person before.  This assumption continues down a long chain of “thinking that the other person thought” – ultimately the last person assumes that given every person before him or her has made the same decision, this overrules whatever judgement he/she might have.

What does this mean in terms of our decision making?  If anything, the rule we learned in class is a reflection of our reliance on other people to make decisions.  As a society perhaps we should value more our own judgement and trust ourselves more – in other words, weight our own judgement much more than we rate the judgement of others.

Here is a rather humorous take on conformity, a video of Asch’s “elevator experiment”:


Leave a Reply

Blogging Calendar

November 2011
« Oct   Aug »