A giant spider crawls on the wall of a Milton Street house in North Cambridge. A few houses in North Cambridge are decorated elaborately for Halloween, but residents don’t seem to go to as much effort for the December holidays. (Photo: Marc Levy)

Cambridge Day is part of a project called Voices of MainStreet — a weekly, nationwide Q&A in which editors at the money and lifestyle site MainStreet.com ask questions and bloggers answer them. This is the third entry, in which I discuss how Cambridge handles its holiday decorations.

A few years back, I noticed something peculiar about Cambridge — or at least Porter Square and the rest of North Cambridge: There are no garish, over-the-top Christmas displays, no one-upping the neighbors with lights and inflatable objects or endless recorded Christmas carols. Where there are signs of Christmas observances, it’s most commonly the classic look of a candle in a window that can be seen from the street.

The homes are radiant in their holiday calm, with most displaying no decorations at all, and many others choosing just one thing to mark the occasion: Here a wreath, there lights dangling like icicles from the top of a porch. And in the most garish display, green and red Christmas tree balls hover between porch top and railing with what appears to be fishing line. Still, it’s all pretty subtle.

Just to get all intellectual about it, I remember wondering whether this modesty resulted from what Ivan Pavlov seemed to 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 being given food immediately after hearing the sound. 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.”

In this case, the growing intensity with which Christmas is celebrated — the sales at big-box stores starting as early as summer, larger number of all-Christmas music stations on the radio, increasingly aggressive war by confused Christians on the use of the phrase “happy holidays” — seems to have created at least one pocket of humanity that withdraws from the hype to move instead toward a more restrained and private observance.

Where has the energy gone? Into Halloween, possibly. There are several houses in the area where residents go all out, draping giant webs in the trees (occupied by giant spiders), ramming witches into trees and even, in a move that might go a little too far, putting rubber rats atop trash cans. In the Dudley Street area, neighbors have held Halloween parties drawing up to 800 people a night. The annual parties have been held for about a decade, and now even have their theme song.

Writer Fran Cronin surveyed the parties in October, quoting resident Susan Dillard in a line that might easily be mistaken for a Christmas sentiment: “If it weren’t for Halloween, I would not know my neighbors as well as I do,” Dillard says. “Our Halloween spirit lasts all year.”

Portions of this post appeared before here.

Update: The current photo was posted Dec. 5, replacing one found via Flickr of an elaborately decorated home on Orchard Street, just over the town line in Somerville.