ABC's Men in Trees is averaging 7 million viewers and finishes third in its time slot.

Yet both shows were extended for full seasons late last week in a strange TV season that has seen a couple of breakout hits but plenty of other series that are still sticking around despite middling ratings.

"We're trying to be patient," ABC Entertainment president Steve McPherson says. "Creatively, everyone feels, across the networks, that this crop of freshman shows is strong."

Networks typically order 13 episodes of new series in May, then wait to see how they perform before committing to the additional nine episodes required for a full season.

And borderline ratings make the decisions more difficult.

"This year there's been very few clear successes," says NBC Entertainment president Kevin Reilly, who boasts one of them in Heroes.

Tipping the balance for also-rans: Their creative potential, ratings trend and how they compare with lead-in shows or former time-slot occupants.

"You get to a batch of shows that are either shows you believe in and want to stick around ... or others that are fighting for their lives and you have creative issues to work out," he says. "You can only nurture so many."

Some serialized dramas have faced a particularly tough time, with Kidnapped, Vanished and Six Degrees gone or on the way out and The Nine, Friday Night Lights and others struggling. That has led programmers and advertisers to question whether the commitment they demand asks too much of viewers.

"The transcendent theme of the new season is that the quality is one of the best in years, and quantitatively it's one of the most disappointing in years," says ad-buying chief John Rash of Campbell Mithun in Minneapolis.

"The very nature of what made the season so compelling — ambitious and addictive serialized dramas — has made many viewers adopt none of them because their media menu is so full."

Confounding the trend, serialized Heroes is this season's biggest hit, and CBS' Jericho is a sleeper, suggesting viewers are willing to dive into some series.

But McPherson theorizes it's not the format but the tone that may have made others off-putting: Heroes and Ugly Betty are "fun, wish-fulfillment, lighter, really enjoyable rides," while several faltering dramas are "tougher subject matter."

"You do feel like society now is in a Depression-era mentality, even though we're not in a depression. People seem to be so down on things, maybe there's a desire to get more escapism."