UCSB does not offer an undergraduate cognitive science major.
Why Cognitive Science? What track/specialty within cognitive science are you interested in? UCSB has a Psychological & Brain Sciences which is more of the neuro emphasis of cog sci.
While USCD was the first UC to offer Cognitive Science, it has been at UC Davis for close to a decade. If you are sure about cog sci, I would add UC Irvine, UC Davis, and UC Santa Cruz to your list. If possible, plan a visit to the campuses this year.