Our brain is only able to retain a certain amount of information at any particular moment—this is called our “cognitive capacity.” Different cognitive tasks require different amounts of our brain’s cognitive capacity. 

Our cognitive abilities and restraints are determined by the availability of our attentional resources—such as working memory (i.e., the amount of information we can mentally hold at any given time) and fluid intelligence (i.e., the ability to solve new problems). 

The thing is, attentional resources are limited, and using them for one cognitive task leaves fewer available for other tasks (and, in turn, reduces available cognitive capacity). Given the overwhelming abundance of information at our fingertips and our brains’ limited capacity to process that information, we need to be incredibly selective with how we’re allocating our attentional resources.