This is a named principle rather than a measured effect. The logic is sound, and the documented cases keep bearing it out. Trust the direction, and treat the boundaries as open.
The writer C. Northcote Parkinson illustrated a strange feature of how groups spend their attention with an imagined committee meeting. On the agenda were two items: approving the plans for an enormously expensive nuclear reactor, and approving a bike shed for the staff. The reactor was approved in minutes, with very little discussion. The bike shed, costing a tiny fraction as much, consumed the bulk of the meeting in heated debate, everyone had opinions about the materials, the roof, the colour. The reason is simple and human. The reactor was so complex that few people felt competent to question it, so they deferred and moved on. The bike shed was something everyone understood, so everyone had a view and wanted it heard. Attention flowed not to what mattered most, but to what people felt most able to have an opinion about. It became known as the law of triviality, or the bike-shed effect.
Groups spend the most time and energy on the things they find easiest to understand, not the things that matter most, because people engage where they feel competent to have an opinion. The genuinely important, complex decisions often get waved through precisely because their difficulty makes people hesitant to weigh in, while trivial, graspable matters generate endless debate. Watch for this in your own meetings and your own attention. When a discussion is consuming enormous energy, ask whether it is consuming that energy because it is important, or merely because it is easy to have opinions about, and whether the decision that really mattered slipped through while everyone argued about the bike shed.
In software and engineering teams the same pattern is widely known as bikeshedding. The term was popularised in October 1999, when the Danish developer Poul-Henning Kamp sent the FreeBSD mailing lists a message titled "A bike shed (any colour will do) on greener grass", written after a thread arguing over whether the sleep command should accept fractional seconds had already run for a couple of weeks. It appears whenever an agenda mixes items of very different difficulty. A hiring budget or a systems decision passes in a few minutes, and then the office layout, the name of a feature, or the wording of a policy takes the rest of the hour. The cheapest item on the list is often the one that generates the longest discussion.
The better known law from the same book, on why administrations grow regardless of the work, is Parkinson's law.
Source: C. Northcote Parkinson, Parkinson's Law, 1957, in the chapter High Finance, or the Point of Vanishing Interest. The book grew out of his satirical essay in The Economist, 1955.
C. Northcote Parkinson, 1957
The witty original on how organisations misallocate time and attention, bike shed and all.
Every Saturday, one idea worth your time, with an honest account of how far the evidence really goes and where it stops. Free, a few minutes to read, and it leaves you with questions rather than instructions.
Draw your own card. It does not take long, and it rewards taking your time.