Her blond hair is her signature look; people apparently have a hard time recognizing her as a brunette. And they seem to prefer her blonde.
Here's a link to the article:
Consumers Prefer Beyonce as a Blonde
http://adage.com/article/adages/hey-beyonce-consumers-hair-blonde/241363/
Here's a link to the article:
Consumers Prefer Beyonce as a Blonde
http://adage.com/article/adages/hey-beyonce-consumers-hair-blonde/241363/