SEASONAL AFFECTIVE DISORDER

With Christmas in full swing -- if you can say that of a time when almost everything shuts down -- it is obvious there has been a shift toward subtlety, believe it or not, in holiday decoration.

This is counterintuitive, since the season now begins immediately after Halloween with industry blandishments to buy, buy, buy; The New York Times can fill a full page with Christmas music releases (all new, save for a few reissues); and holiday television specials have become so important that TNT is willing to run the same movie over and over again for an entire 24 hours. It truly has become a season more than a holiday, very nearly supplanting those quaint old notions of “fall” or “autumn.”

So why is it that the arms race of lights and decorations has wound down so dramatically, no matter what is seen on sitcoms such as “Married to the Kellys” (in which the most extravagant display ever seen only ties for tenth place in the local community newspaper’s list). Around the parts of Boston and Cambridge I’ve traveled in the heat of this season, which is meant both ways, such displays are rare to the point of freakishness, sort of like the sad little king in “Start the Revolution Without Me” who “thought it was a costume ball.”

Around Porter Square, the homes are radiant in their holiday calm, most displaying no decorations at all and many others choosing just one to mark the occasion: here a wreath or a white light in each window; there lights dangling like icicles from the top of a porch; in the most garish display, green and red Christmas tree balls hover between porch top and railing with what appears to be fishing line.

It is almost pleasant to think that this is the inevitable result of what Ivan Pavlov seemed to variously call “the law of transition” or “reciprocal induction.” Pavlov famously taught dogs to salivate just by hearing a bell, but only because the dogs had grown conditioned to consistently being given food immediately after hearing it. But Pavlov found that sometimes stimuli, such as the bell, produced the opposite effect after a period of reliable results -- that the result “passes into a state of inhibition.”

See, now they’ve done it, our mad holiday sentimentalists and salespeople: By pushing Christmas so aggressively, they’ve caused an increase in our passivity. One could almost say they’re turning the holiday into one of peace.