'Big Brother 15' Racism: CBS President Was 'Mortified' by Comments; Defends Casting Process [VIDEO]

CBS president Nina Tassler addressed the Big Brother racism controversy Wednesday, revealing the show's future plans in screening for new contestants.

Big Brother 15 was a headline-making season for the long-running reality series, but not in a way that CBS would have hoped. Several of the show's houseguests made some racially-charged slurs in the house, but the biggest offender, 23-year-old Aaryn Gries, was criticized the most for it.

"I was mortified by the comments that Aaryn made," Tassler revealed to critics at the TCA press tour Wednesday. "We also have to look at last summer as this sort of confluence of events between what was going on with Trayvon Martin, what was happening with Paula Deen. It was this extraordinary series of events that were dominating the news waves."

While Tassler did not defend the comments, she admitted that the incidents were part of the overall social experiment that is Big Brother.

"You're talking about people from very disparate walks of life and confining them in a house for a finite period of time," Tassler noted. "You have to recognize yes, this is that show. It is a social experiment."

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Tassler also acknowledged that she sits in on auditions for prospective Big Brother contestants, explaining that people are often different in their interview persona than they are when the get inside the house.

"You ask probing questions and you develop an opinion about that person. You do the requisite background checks on everybody ... but it's not a science," she admitted. "You go into a season hoping you picked the right people. How someone comes off in a one-on-one interview ... sometimes the way they behave in the context of that room is very, very different [from what you see on the show]."

Big Brother 15 Cast Racism Controversy Leading to Season 16 All Star Edition?

Big Brother 16 premieres in summer 2014 on CBS.

Watch a supercut of all the racist comments said on Big Brother 15 here.