Collecting comes in all flavors. For some people, it involves picking up snow globes on business trips. For others, it’s an affinity for hotel shampoos and shower caps.

But when it becomes impossible to part with souvenir soap, “collecting” begins to move into the realm of hoarding … especially if the soap resides within a pile of newspapers, chipped dishes and 1970s clothing.

Often dramatized on television, cases of hoarding have made occasional appearances in literature since at least the 13th century.

In modern times, one of the first true and most famous cases of hoarding involved a set of brothers known as the Collyers. They were found dead in their New York City brownstone in 1947, surrounded by more than 100 tons of toys, car parts, boxes, newspapers, light fixtures, and, by most definitions, trash.

Only now are scientists beginning to suspect that hoarding is not a typical compulsive behavior.

Using powerful scanners that record changes in the brain during social interactions, scientists affiliated with Hartford Hospital and Yale University compared the brains of patients with hoarding disorder and patients with obsessive-compulsive disorder, or OCD.

The investigators discovered people with hoarding disorder can easily vanquish other people’s credit card offers, coupons, magazines and photos. But the prospect of shredding their personal junk mail caused a neural uproar.

Two brain regions in particular lit up when people with hoarding behavior considered the fate of their belongings.

Healthy volunteers and people with OCD, which involves repeated behaviors, such as handwashing or incessantly checking whether the refrigerator door is closed, did not have the same brain response at all.

The discovery may influence how doctors view these behaviors … the concept of hoarding being thought of as OCD with a twist may have to be tossed out with the trash.