The Curse of Knowledge and Logical Gaps
Your reader cannot read your mind. They only have the words on the page.
When we write, we know exactly how all the pieces connect, so the connections feel obvious to us, and we skip over them. To the reader, those skipped connections are logical gaps: moments where the logic is clear in the writer's mind but missing from the text.
The Curse of Knowledge
We inadvertently create logical gaps because we have a cognitive bias called the Curse of Knowledge: once you know something, you can no longer imagine what it feels like not to know it. The information feels so obvious that it doesn't need to be explicitly stated. So you don't — and you leave the reader to fill in the gap themselves.
The more expertise you have, the harder it is to explain your expertise to someone else. We can't imagine what it feels like to not know what we know, so we tend to under-explain and over-estimate the reader's background information.
The curse of knowledge affects everyone, even experienced writers.
What a logical gap looks like
A logical gap appears when two sentences don't visibly connect. The writer sees the connection in their mind, but they don't show it on the page.
This example from psychology can be fixed by making the difference explicit:
Participants were randomly assigned to the control or experimental group.
Participants were randomly assigned to the control or experimental group. The experimental group completed an additional two-hour session each week, and drop-out rates in this group were higher.
This example from environmental science can be fixed by making the reason explicit:
Nitrogen runoff from agricultural fields increased significantly between
1990 and 2020.
Nitrogen runoff from agricultural fields increased significantly between 1990 and 2020. Because nitrogen is a key nutrient for algal growth, blooms became more frequent in the lake.
This example from law can be fixed by making the threshold explicit:
The regulation required companies to disclose emissions data annually.
The regulation required companies to disclose emissions data annually. The exemption threshold was set at fewer than 50 employees, so small businesses were exempt.
This example from software engineering can be fixed by making the reasoning explicit:
The API rate limit was set to 100 requests per minute.
The API rate limit was set to 100 requests per minute. During peak hours, traffic regularly exceeded this limit, causing several users to report failed requests.
Most logical gaps can be resolved by applying old to new consistently: start each sentence with something the reader already knows before introducing something new.
How to find your own logical gaps
You cannot reliably spot your own gaps. Because you already know the missing information, your brain fills it in automatically as you re-read. The text looks fine to you because in your mind, it is.
The most effective solution is to ask someone outside your field to read your text and mark every place they had to stop.
Ask someone who is not familiar with your work — not your supervisor, not a close colleague. People who know your field will automatically fill in the gaps rather than flag them. To make this work, find someone outside of your field and listen to what they have to say.
A reader will stop reading when they are confused about how the parts all fit together. These moments of confusion happen when the connections are not explicit, so the relationship does not appear to be logical to another person's mind: logical gaps. If you can figure out where these logical gaps happen, you can fill them in for the reader using given to new.
At each gap, try asking yourself: "What do I know here that I haven't written down?" The answer is usually what you need to add.
Why does this work?
Readers learn by connecting new information to what they already know. If a new idea arrives without a visible link to what came before, the reader has to stop and figure out the connection themselves (or give up).
When you fill in the logical gaps, you do that work for the reader. The text flows because all the connections are on the page, and the reader doesn't have to do any guesswork.
How important is it to overcome your curse of knowledge and fill in logical gaps?
On a scale of 1-10, it's a 9: very important. A logical gap stops your reader completely. No amount of good writing elsewhere will save you when a reader simply cannot figure out how two ideas connect to each other. Are you finding logical gaps in your writing? Ask for help!