When the television series Numb3rs premiered in 2005, it was greeted as a unique show, a source of entertainment that required the brain to be turned on. The main character, Charlie Eppes, was a rarity in TV land: a math professor at a prominent California university. I’m sure I wasn’t the only viewer who marveled at such a programming concept having been successfully pitched at a meeting of CBS executives.

The first two seasons were brilliant much of the time, as each episode depicted how Charlie was able, through the wizardry of advanced mathematics, to help his older brother, an FBI agent, solve baffling crimes. The series was so special that the Math Department at Northeastern University started a Numb3rs blog to follow Charlie’s intellectual exploits as he introduced and explained such mathematical wonders as the Fibonacci Sequence and the Golden Ratio.

But as time went on, the show became less and less about math and more and more about car chases and shoot-em-ups.

Numb3rs eventually lost so much of its original quality that the Northeastern team wrote, “The mathematical relevance and excitement of the show has waned, and the characters and plots have become more stylized and less interesting”.

Now in its second season, the Fox network series Lie to Me may, I fear, be headed down the same road toward mediocrity. Its main character, Dr. Cal Lightman, is — like Charlie Eppes — an intellectual specialist, a scientist whose expertise resides in analyzing micro-expressions, subtle movements of the face and body that provide physical indications of a person’s emotions and mental state. He is a human lie detector able to tell, sometimes at a mere glance, when someone is dissembling. The only people who can dodge his sublime scrutiny are psychopaths.

Lightman, played brilliantly by British actor Tim Roth, is based on real life UCSF psychologist Paul Ekman, an acknowledged expert on body language and facial expressions. According to a September 2009 article in the San Francisco Chronicle, “Ekman, who is employed as a scientific adviser to the show, said the series gets most of the science of micro-expressions right but agreed that it oversimplifies their use. In a blog on Fox’s website, he corrects the show’s errors and discusses the complexities.”

The series started out much the way Numb3rs had, focusing on the science at least as much as on the bad guys. But lately I’ve noticed a marked shift toward turning Lightman into a bizarre kind of action hero. Instead of evaluating data — pictures of faces and videotaped interviews — and employing acidic verbal wit when consulting with educated colleagues, which is what scientists really do, Lightman has been morphing into a kind of rumpled Rambo teaming up with a former IRA member out for revenge, playing poker with gun-toting gamblers in Las Vegas, and spelunking through caves in Afghanistan.

The next episode of Lie to Me will air Monday night, July 12th, and the show has been renewed for a third season. I hope the producers reconsider their recent path and focus again on the cerebral sleuthing that made the series so interesting to viewers like me always on the lookout for something beyond the usual TV fare.