I have been meaning to answer this question since I started the blog so a recent email prompted me to do so finally!
Q: What does science say about the hair typing system?
Well it was invented by Andre Walker who is a hair stylist and it was based on his experience. It is not a scientific system but it is very definitive. My google research says that over the years people have added in categories such as 3c and 4z. For the newbies/transitioners, if you haven't heard of the hair typing system - just google it!
I do not think the system was meant to be as restrictive and rigid as some naturals make it. You can have multiple textures and additionally, sometimes hair doesn't quite fit the exact definition but comes close to it
Q: Is 4b hair really just dry 4a hair?
No this is not always the case. If you experience a mass of tiny little spiral curls when your hair is wet, then after styling (stretching) they disappear, then you most likely have 4a hair. However, there is hair which never forms coils/curls. 4b hair is supposed to be z shaped but sometimes it is more s shaped, it just never forms spirals.
Great shots of 4a and 4b hair - Click here for Mwedzi's fotki
Hair with no curling (4b) - See Sera's video where she shows her hair dripping wet and points out it has no curls (but it is not straight) - Click here for Sera's Youtube
Are you able to identify your hair twins using the hair typing system? Do you use the typing system or do you prefer not to?