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How logical are you? You might consider yourself more logical than most – you hope to be a trusted adviser to your friends and colleagues.
However, this doesn't make you immune to a quirk of human nature that can fog your judgment, according to Niro Sivanathan, LBS Associate Professor of Organisational Behaviour.
"The truth is far too often we see people speak up, but fail to influence," says Dr Sivanathan. "The message was sound, but the delivery proved faulty."
Imagine two students and consider which will achieve the most: Tim spends 31 hours a week studying outside of class. Tom spends 31 hours a week studying outside of class, has a brother and two sisters, visits his grandparents often, once went on a blind date and shoots pool once a month.
"The truth is far too often we see people speak up, but fail to influence. The message was sound, but the delivery proved faulty."
Prior research has shown that on average people rate Tim to have a significantly higher grade point average than Tom. It is an irrational conclusion, so what is going on?
"Turns out in this context, when we're presented with such information, our minds utilise two categories of information. Diagnostic and non-diagnostic," explains Dr Sivanathan. "Diagnostic information is information of relevance to the evaluation that is needed. Non-diagnostic is information that is irrelevant or inconsequential to that evaluation. And when both categories of information are mixed, dilution occurs. The fact that Tom plays pool dilutes the weight of the diagnostic information, namely that he studies for 31 hours outside of class."
The psychological explanation for this is one of averaging, according to Dr Sivanathan. In this model, we take in information and those pieces of information are afforded a weight or score. And our minds do not add those pieces of information, but rather, average them out. So when you introduce irrelevant, or even weak arguments, those weak arguments reduce the weight of your overall argument.
"This quirk has important implications for our ability to be heard and listened to," adds Dr Sivanathan. "When we speak out against authority, speak against the grain of a shared opinion among friends, or speak truth to power."
Dr Sivanathan’s own research has also found this argument dilution effect in circumstances where the individual's judgment is highly motivated to make the right call.
“The next time you want to speak up in a meeting it is important to note that the delivery of your message is every bit as important as the content.”
In the US the FDA compels TV drug adverts to spell out all the side effects in the final few seconds of air time. In TV and radio, a hurried voiceover reels off a long list of effects, starting with heart attack and stroke, and concluding with minor effects like itchy feet. The dilution effect is undimmed. Itchy feet dilutes the perceived risk of the more serious side effects.
"In one study we reproduced this phenomenon with a print ad. One real ad was presented in its entirety to half of the participants and to the other half we removed just four words – the minor side effects," explains Dr Sivanathan "Both groups then rated the risk of taking the drug. The first group rated the risk significantly lower than the group who didn’t see the minor side-effects. A follow-up study with that same group, who read all the side effects, also found they found the drug significantly more attractive and were prepared to pay more to buy the drug compared to the group who read the ad with just major side-effects."
It is hoped the regulation will prompt the FDA to look at the regulations around the listing of minor side-effects.
For Dr Sivanathan the take-away for communicators is to focus on quality over quantity.
"You cannot increase the quality of an argument by simply increasing the quantity of your argument," he warns. "The next time you want to speak up in a meeting it is important to note that the delivery of your message is every bit as important as the content. Stick to strong arguments. Because your arguments don't add up, in the minds of the receiver, they average out."
Niro Sivanathan is Associate Professor of Organisational Behaviour at LBS. This article is based on Dr Sivanathan’s talk at TEDxLondonBusinessSchool 2019.