Over the last decade, which two kinds of created-for-film characters have achieved the most critical and popular success? The answer: single parents (think Erin Brockovich) and the mentally challenged (à la Rain Man and Forrest Gump). If you were to blend both character types for the lead role, you would get a surefire hit, right?

This line of reasoning must have been going through the minds of Kristine Johnson and Jessie Nelson when they wrote I Am Sam, an improbable story of an autistic man who fights a custody battle for his daughter. Nelson, who is also the film’s director and co-producer, flopped with her last script (the universally despised The Story of Us), and seems so eager to atone for that disaster that she pulls out all the stops for I Am Sam. The first-time director cast the versatile Sean Penn as the lead, the sassy Michelle Pfeiffer as his lawyer and an adorable little girl (Dakota Fanning) as Penn’s daughter. If that weren’t enough, Nelson fills the soundtrack with catchy Beatles tunes. (You may recently have heard Aimee Mann and Michael Penn’s Two of Us on the adult contemporary airwaves.) All of this adds up to a pop movie—an entertaining treatment of a formulaic story.

I Am Sam opens with a whirlwind introduction into the life of autistic Sam Dawson (Penn). We quickly learn that Dawson’s relationship with a homeless woman has produced a newborn baby for him to look after by himself, because the mother inexplicably abandons the child soon after delivery. Dawson names his daughter Lucy Diamond, after the Beatles song (this is only the first of a multitude of Beatles references that grow wearisome by the second hour). Not knowing how to take care of a baby, Dawson asks his neighbor (Diane Wiest) for parenting advice. Dawson’s shortcomings—he has the mental capacity of a seven-year-old—are played for laughs at the movie’s onset (he fastens Lucy’s diaper with large pin-on buttons), but it soon becomes evident that Sam’s mental incapacity threatens Lucy’s development. Social Services intervene and put Lucy into foster care on Lucy’s seventh birthday.

Not giving up without a fight, Dawson enlists the reluctant Rita Harrison (Pfeiffer, an uptight personal injury lawyer), to represent him at his custody hearing. Harrison’s struggle to construct a compelling argument for Dawson, made more difficult by his continued follies, make the case appear increasingly hopeless. Yet the man’s love for Lucy is unassailable and it seems that this might be the key to getting Lucy back. Dawson’s fatherly devotion certainly makes a strong impression on Harrison, whose relationship with her own son is predictably in tatters. Soon, Harrison is fighting for Dawson’s cause with a passion.

This may seem like a lot for a first-time director to juggle—it is. The first act has an unsure, all-over-the-map feel about it. It tries to strike a balance between comedy, pathos and the harsh reality of Sam’s condition, but these tones frequently conflict; the pairing of hand-held camera footage with mellow string passages in the score seems particularly incongruous.

Perhaps the most major flaw is in Penn’s character. Let it first be known that Penn is absolutely convincing as an autistic—he reportedly observed autistics for 90 days in preparation for this role. Penn convincingly portrays Dawson as he fouls up the coffee at his job at Starbucks, falls down on the floor and gives hugs to people indiscriminately. Still, it is unfortunate that so much of the script is preoccupied with this stereotypical behavior. In the third act of the film Dawson is finally given some depth and, for his part, Penn convincingly injects pathos into his character.

One reason for this delay in character development may be that the film’s first half focuses too much on the father-daughter relationship. Unfortunately, this is hindered not only by the lack of chemistry between Penn and Fanning, but also by the fact that the audience may have difficulty relating to Penn’s character. In the second half, the movie shifts focus to the relationship between Dawson and Harrison. Because the audience shares Harrison’s reservations about Dawson, Dawson is allowed to develop in response. This is similar to the character dynamic in Rain Man—because the audience empathizes with Tom Cruise’s character, the growth of Dustin Hoffman’s character (stemming from the Cruise-Hoffman conflict) is facile.

Although it is largely predictable, I Am Sam does enjoy some refreshing breaks from formula. For a change, the foster mother (Laura Dern) and the state attorney in Dawson’s custody battle are not antagonistic, but rather want what is best for Lucy. Dern delivers a fine performance, as does Pfeiffer.

I Am Sam may not win any Oscars (Russell Crowe’s performance in A Beautiful Mind outshines Penn’s) and may not even get a decent showing at the box office but, to its credit, it manages to portray a mentally challenged person in an entertaining yet dignified manner. It’s true that the protagonist and the schmaltzy movie he leads find wisdom in Beatles lyrics, but hey, nobody’s perfect.

I AM SAM

starring

Sean Penn

Michelle Pfeiffer

Dakota Fanning

Fine Line Pictures