It's hard to think of many instances where something is designed perfectly, but downtown commercial holiday displays are one.

No matter that they are a little hokey; it's a quality essential to evoking the intended reaction: a momentary soaring of the spirit, a damp eye, and a fuzzy warmth toward humanity, the holidays, and the store furnishing the free show.

Luckily, Philadelphia happens to be a living museum of the holiday display genre. Its materials range from papîer-maché to pixels and its delivery systems from windows to high-resolution screens. But they all have form and content in common. They are short and sweet, they feature familiar tropes (Santa, snowmen, reindeer, and rosy-cheeked children), and they reflect the "eye-mindedness" - or the lens through which we perceive our surroundings - of the time they were created.

While Philadelphia may be lacking the ornate department-store window displays that first sprang up in cities at the turn of the 20th century - see New York's Fifth Avenue for that - the city has a rare complete inventory of the rest of the century's offerings. I've been checking them out with my daughter.

She's only 2, but like a seasoned lifer, she demonstrates a Pavlovian response to Macy's Christmas Light Show, breathing a little faster as we wedge ourselves through the store's heavy front doors. Inside, she "wows" at Julie Andrews' soothing narration and the lights blinking over the seven-story Grand Court. The atrium, considered a marvel when John Wanamaker squarely planted the building downtown in 1910, has always been transformed during the holidays. A display manager introduced the towering, electric Christmas tree in 1955 - the trunk was a thick electrical strip with color-coded plugs. Before that, the displays were all stage-carpentry, tapestries, greenery. And in some years, huge candles lit atop the organ.

Wanamaker, called the "P.T. Barnum of the retail business," was wedded to the arts as a means of promoting his stores. He started a kind of holiday-display arms race that traveled Market Street for most of the rest of the century. Gimbels, Lit Bros., and Strawbridge & Clothier all got into the act.

When the 1930s ushered in the next iteration of holiday displays - the walk-through village with mechanical figures - Strawbridge introduced Dickens Village (now at Macy's) and Lits got the Enchanted Colonial Village (now at the Please Touch Museum, and one of only two still on display in the U.S. that were made by the legendary Christian Hoffmann company in Germany). By that time, the public, primed by Hollywood's new moving pictures, was developing a new type of eye-mindedness that prepared it for kinetic displays. But despite the new technology, designers still took their references from literature.

According to Smithsonian curator William Bird's excellent book, Holidays on Display, the miniature architecture of these Christmas villages tended to be a mixture of Tudor Revival and storybook style, with half-timbering and mullioned windows that mimicked medieval cottages and English country houses. The twee buildings and people in the villages made you feel as if you were walking through a storybook, because literature was the most common vehicle for entertainment. Bird thinks they still tug at heartstrings because books remain a sweet and integral part of childhood - "maybe it's from remembering sitting on your parent's lap and having them read you a story."

Wanamakers Grand Court displays shifted from static to electric in 1955, a few years before televisions started appearing in people's living rooms. Then in 2006, Macy's updated the show with LED lights, lighter materials, and automation - but not in a way that detracts from its pre-digital-era charm. The slightly scratchy soundtrack and cartoonish bulbs still feel as unslick as the 1964 animated Rudolph the Red-Nosed Reindeer classic.

Now, a hundred years after Wanamaker built it, the Grand Court remains a successful public spectacle. In 1910, no one was so informal as to sprawl across its floor, but today it accommodates the modern masses arranged in a jumble of joy, fatigue, and winter jackets.

A few blocks away, the Comcast Center's Holiday Spectacular is the only one of its kind - it plays on the world's largest, highest-resolution screen. Brian Roberts, Comcast's CEO, grew up going to the Wanamaker Holiday Light Show, says John Demming, a Comcast spokesman, and he wanted to create something to complement it.

The result is today's sort of eye-mindedness: People are most literate in pixels. Yet the Comcast show shares some traits with its predecessors. Most of the content remains the same year to year.

"We want people to come back and see it again and again," says Demming, "just like how you watch the same holiday movies over and over." (Cue TBS's 24-hour loop of A Christmas Story every Christmas Eve.) On any given weekend, the scene is similar to the jumble of joy and jackets that you find at Macy's. There are just as many "wows."

It's funny that despite the progress of technology and design, today's kids seem to respond as eagerly to the cookie-cutter graphics outlined in red and green bulbs as they do to highly produced montages on a cutting-edge, flawlessly crisp screen.

There are exceptions. My own kid, who is so charmed by the creations of yore, was terrified this year by the Comcast show. The designer should take it as a compliment - it was just too real. And she hasn't had much screen time in her short life. We'll try again next year.