What separates man from other creatures? Thinkers both religious and secular have been wrestling with this question throughout history. The three-part series “The Human Spark” (7 p.m., PBS, check local listings) offers new theories about the origins of human behavior, the ability to think, plan, anticipate and record thoughts with language and art.

While the legendary cave paintings of Lascaux, France, have long been seen as the earliest evidence of a civilizing genius, new finds in Africa push back the date of inspired creativity by 100,000 years.

Host Alan Alda does a good job presenting the evidence, combining meditative asides with a folksy presentation. He has experience in this field, having hosted “Scientific American Frontiers” for years.

• Millions of Americans can’t find work, but popular celebrities have no problems passing themselves off as minimum-wage employees on the second installment of the candid-camera comedy special “I Get That a Lot” (7 p.m., CBS).

Regular folks seem incredulous when they see Snoop Dogg posing as a parking-lot attendant or Julie Chen working at a yogurt shop. Some insist they recognize them. Hence the show’s theme and title, “I Get That a Lot.”

Pardon me if I find this more condescending than amusing. The presence of Paris Hilton (who pretends to toil at a gas station) and her “Simple Life” history only underscores the show’s message that real working people are a bit of a joke and that celebrity, no matter how notoriously achieved, is the only status worth attaining.

• Turner Classic Movies devotes every Wednesday in January to films about Russia and our complicated relationship with that country, from the czars to the U.S.S.R. Highlights include “Rasputin and the Empress” (9 p.m.) from 1932, featuring Hollywood’s own royal family — John, Ethel and Lionel Barrymore.

Over the course of the month, the 20-film shocker will present comedies spoofing communism (“Ninotchka,” Jan. 13), Cold War dramas (“The Kremlin Letter,” Jan. 20) and even pro-Soviet propaganda movies (“The North Star” and “Mission to Moscow,” Jan. 20) made at the behest of the American government during our military alliance with the Soviet Union during World War II.

While produced for the war effort, these last two films were later used as evidence of the Communist infiltration of Hollywood.

Tonight’s other highlights

• A patient’s crisis distracts Veronica from her troubles on “Mercy” (7 p.m. NBC).

• A visit from Gloria’s ex (Benjamin Bratt) sends Jay into sleepless anxiety on “Modern Family” (8 p.m., ABC).

• Lisa Kudrow guest-stars as a mean dermatologist on “Cougar Town” (8:30 p.m., ABC).