The legacy of this weekend's box office seems certain to be a victory for a visual-effects-heavy event movie over a sophisticated adult comedy and a children's animated tale.

"Tron: Legacy," Walt Disney Studios' big-budget resurrection of the 1982 cult favorite, is a sure bet to be the most popular movie this weekend in the U.S. and Canada. People who have seen pre-release audience surveys say it should take in about $50 million, a solid but not spectacular start for such a highly anticipated movie.

Warner Bros.' animation/live-action hybrid "Yogi Bear" is appealing mainly to families with young children and is expected to kick off its run with a so-so $20 million.

The weekend's big question, however, is just how poorly Sony Pictures' "How Do You Know" will do. The costly adult comedy, directed by James L. Brooks and starring Reese Witherspoon, Owen Wilson, Paul Rudd and Jack Nicholson, is generating very soft interest and will likely open to only about $10 million.

It could even get beaten by two low-budget specialty films expanding into nationwide release this weekend. After a strong start in five theaters last weekend, the Mark Wahlberg boxing drama "The Fighter" is expected to gross between $12 million and $15 million. The dark ballet fantasy movie "Black Swan" will play in just under 1,000 theaters, fewer than half as many as "How Do You Know." But following two strong weekends in limited release, it should collect about $10 million this weekend.

Sony spent a little more than $100 million to produce "How Do You Know," a very hefty budget for an adult comedy, and will likely lose millions of dollars if ticket sales are in line with expectations. It appears likely to perform similarly to director Brooks' last picture, the 2004 comedy "Spanglish," which opened in mid-December to $8.8 million and ended up with $42.7 million domestically and only $12.3 million from foreign countries.

Middling reviews could hurt "How Do You Know" with its target audience of adult women.

Disney is hoping that "Tron" will be a "four quadrant" movie that appeals to men and women young and old. But tracking surveys indicate that on the film's first weekend, at least, it will draw primarily men. Women appear to be more hesitant about the science-fiction sequel starring Jeff Bridges, Garret Hedlund and Olivia Wilde.

The studio spent an estimated $170 million to produce the movie, and its sibling divisions have invested millions more on the brand for products ranging from video games to an animated television series, making it critical that the film perform well. Disney is also spending about $150 million to market the movie worldwide. An opening in the $50-million range would still necessitate that "Tron: Legacy" perform strongly over Christmas and that it bring in even more money overseas to be profitable.

The movie could perform well internationally -- particularly in Asia, where films loaded with special effects tend to be particularly popular. It debuts this weekend in a small number of foreign countries, including Argentina, Australia and Greece.

"Yogi Bear" is an effort by Warner Bros. to duplicate the success of 20th Century Fox's "Alvin and the Chipmunks," the 2007 surprise hit based on another cartoon that opened to $44.3 million. Although movies that appeal mainly to young children are difficult to track, it appears that "Yogi Bear" will fall far short of the "Alvin" opening.

Warner spent about $80 million to produce "Yogi," in which all of the animal characters are computer-generated, making it important for the film to prove popular with families over Christmas in order for it to become a big hit.

Also competing for the family audience this weekend, though for slightly older children, is "The Chronicles of Narnia: Voyage of the Dawn Treader." After a soft domestic opening last weekend, Fox and Walden Media are hoping its second-weekend decline is modest.

In limited release, Lionsgate will debut "Rabbit Hole," starring Nicole Kidman and Aaron Eckhart in an adaptation of the Pulitzer Prize-winning play about a family coping with loss, at five theaters in Los Angeles, New York and Toronto.

-- Ben Fritz