Improving objects, ideas or situations—whether a designer seeks to advance technology, a writer seeks to strengthen an argument or a manager seeks to encourage desired behaviour—requires a mental search for possible changes^1,2,3. We investigated whether people are as likely to consider changes that subtract components from an object, idea or situation as they are to consider changes that add new components. People typically consider a limited number of promising ideas in order to manage the cognitive burden of searching through all possible ideas, but this can lead them to accept adequate solutions without considering potentially superior alternatives^{4,5,6,7,8,9,10}. Here we show that people systematically default to searching for additive transformations, and consequently overlook subtractive transformations. Across eight experiments, participants were less likely to identify advantageous subtractive changes when the task did not (versus did) cue them to consider subtraction, when they had only one opportunity (versus several) to recognize the shortcomings of an additive search strategy or when they were under a higher (versus lower) cognitive load. Defaulting to searches for additive changes may be one reason that people struggle to mitigate overburdened schedules¹¹, institutional red tape¹² and damaging effects on the planet^13,14.

改进对象、想法或情况——无论是设计师寻求推进技术，作家寻求加强论点，还是经理寻求鼓励期望的行为——都需要在精神上寻找可能的变化^1,2,3。我们调查了人们是否会考虑从对象、想法或情况中减去组件的更改，因为他们会考虑添加新组件的更改。人们通常会考虑有限数量的有前途的想法，以便管理搜索所有可能想法的认知负担，但这可能导致他们接受足够的解决方案而不考虑潜在的更好替代方案^{4,5,6,7,8,9,10}. 在这里，我们表明人们系统地默认搜索加法变换，因此忽略了减法变换。在八个实验中，当任务没有（相对于确实）提示他们考虑减法时，当他们只有一次机会（相对于几次）认识到加法搜索策略的缺点时，或者当他们处于较高（相对于较低）的认知负荷下。默认搜索附加更改可能是人们努力减轻负担过重的时间表¹¹、机构繁文缛节¹²和对地球的破坏性影响^13,14的原因之一。