Strengthening Information Cascades with Uniformed Individuals
During lecture, Dr. Easley warned against the inherent weakness of information cascades — that they could very often be “false” cascades and cause the majority of people to make the wrong decision. Research conducted by Iain Couzin at Princeton University hints at ways a cascade might be strengthened against making poor decisions.
A assumption we’ll make: when deciding what everyone wants, the majority’s wishes should be followed and decision making shouldn’t be left up to a minority.
The study involves a species of fish called golden shiners, which naturally gravitate toward yellow light. We’ll consider the decision to gravitate towards yellow light as being the wrong decision. The right decision would be to gravitate towards blue light, which the researches in Dr. Couzin’s lab trained a small minority of the fish to do, though it was assumed that since this was not a natural tendency for the fish, the preference for yellow light would be stronger in the untrained fish than the preference for blue light in the trained fish. When put in a school with a minority of fish which preferred yellow light, the more deeply entrenched preference for yellow light by the minority ended up ruling the entire school’s decisions. In terms of information cascades, those that want what they want most are more likely to set out in their own direction before everyone else has a chance to make up their mind, leaving the others to follow.
In the next stage of the study, the scientists added a bunch of fish untrained fish without a strong preference for either light. The interesting thing is that these fish were able to shift the school’s decision to the majority preference of blue, guarding against the strongly opinionated minority. Again in terms of information cascades, this sort of an outcome would be expected because the weight that each individual pays to the decision of others is greatly diminished when they know that person could just be making a random ignorant decision, and so even if a few start of strongly supporting the wrong decision, a majority will slowly overwhelm.
Sources:
http://www.bt.com.bn/science-technology/2011/12/17/minnows-reveal-true-power-uninformed
http://content.time.com/time/health/article/0,8599,2102612,00.html