The use of an em dash (—) instead of a hyphen (-) can be a sign that a text was written by ChatGPT?

In fact, proper typography favours the em dash over the hyphen in many cases - especially when separating clauses or adding emphasis. However, the standard keyboard layout favours the hyphen, making it the default choice for most people.

So who's really to blame for the widespread use of the hyphen over the em dash? Is it AI, or is it the limitations of our keyboards and habits shaped by digital convenience?

The history of why keyboards lack the em dash (—) and only have the hyphen (-) is rooted in the technical limitations of early typewriters and computers.

Why is the hyphen (-) used everywhere instead of the em dash (—)?
Typewriters. Early typewriters had no dedicated key for the em dash. People either used a hyphen (-) or two in a row (--), which became the standard "two hyphens instead of an em dash," later inherited by computers.

ASCII and character encoding. Early computer systems (such as ASCII) simply didn’t include the em dash. The hyphen (-) was the only available character and was used for everything: hyphenation, subtraction, and dashes.

Keyboard layouts. Even after Unicode introduced support for the em dash, it wasn’t added to standard keyboards—simply because people were already accustomed to using a single or double hyphen (--). As a result, most users don’t even know that the em dash (—) can be typed using key combinations (Alt+0151 on Windows, Option+Shift+- on Mac).

Typography on the internet. Web page rendering and basic text editors didn’t always handle em dashes correctly, so developers avoided them.