Traits are like perks, except they typically have a downside (whereas perks are usually solely beneficial). Lastly, Doc Mitchell will ask you to fill out a form about your medical history, which allows you to pick your traits.
Again, this is all covered in greater detail in the Character Creation section of the guide, but for those who can’t be bothered to read it, start out by tagging the Science, Lockpick and either Speech or Survival (only Tag! Survival if you plan to play the game in Hardcore Mode).
These skills get a +15 bonus when starting out, making them most likely your highest skills at the moment. Once done, follow Doc Mitchell into another room and endure a word-association test and a rorschach test which serve to set your Tag! skills. You’ll get a chance to modify your characters shortly.
Assign your SPECIAL Attributes as you see fit (left) and assign whatever traits you wish to begin the game with (right).
