error.full_messages does indeed call human_attribute_name. Did you check the source for that method in the link you posted?
http://ar.rubyonrails.org/classes/ActiveRecord/Errors.html#M000311 full_messages << @base.class.human_attribute_name(attr) + " " + msg -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To view this discussion on the web visit https://groups.google.com/d/msg/rubyonrails-talk/-/VS02Sjms5v4J. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
