Let’s hear it for the toys: Ever since the success of the 1964 creation of G.I. Joe, action figures have been an integral part of collector culture as well as a childhood staple. Currently, the Star Wars: The Force Awakens figurine play-set is the best selling “action and toy figures” item on Amazon, part of the chunk of plastic change that is expected to produce Disney and Hasbro $1.5 billion in toy earnings by the end of 2016.

Star Wars has had a long, financially rewarding relationship with the toy industry because the franchise showed up at the right moment — G.I. Joe was still largely unopposed on the plasticine battlefield — and George Lucas saw potential. This year’s resurgence in action figure interest — largely a product of Force Awakens and Marvel movies — harkens back to an earlier, less digital era of stocking stuffing.

The military man had a good run as the premier figurine — credited as the first action figure G.I. Joe began as a 11.5 inch not doll, that quickly became an awkward icon of failed militaristic tropes when the Vietnam War hit its peak. It got rebranded in the 1970s as a kung-fu adventure cool-guy and then was redesigned again in the 1980s as an almost-four inch plastic terrorist-fighter. The main reason for the reboot? Competition from the incredibly popular Star Wars action figures.

A G.I. Joe Adventure Team -- Man of Action with Kung-fu grip.

The original Star Wars action figures produced by Kenner Toys were so popular that millions of children were okay opening up an empty box on Christmas morning, save for a certificate guaranteeing that four action figures would be available in the first months of 1978: Luke Skywalker, Princess Leia, Chewbacca, and R2-D2. This was called the Star Wars Early Bird Kit and by the time Kenner ended their toyline in 1985, an estimated 250 million Star Wars figures had been sold around the world. This original set of action figures was the first of over 20 different reboots leading up to the most recent film.

A 1995 Luke Skywalker figurine.

But something interesting happened between 1978 and 1995: Luke Skywalker got beefy. Now manufactured by Hasbro (a company that, while still called the Hassenfeld Brothers, created G.I. Joe) the Star Wars characters from the early 1990s were given “Hero Age” sculpts — super muscular chests and arms set on lithe hips.

He-Man and Battle Cat.

The action figures of late 1980s through the 1990s were big on bulk. Two of the six best-selling toys of 1985 were humanoid guys with body-builder frames — He-Man and G.I. Joe in his most COBRA-fighting stage. He-Man of He-Man and the Masters of the Universe was so popular in 1985 that the line outsold Barbie and earned $400 million dollars. Not to be out-done, muscle-clad Power Ranger toys generated about $1 billion in revenue in 1995, hot off their best-selling toy spree of 1994. In 1998 a Wolverine action figure debuted with a bicep measurement equal to the size of its waist and a chest double the size of the waist.

Wolverine and Wonder Woman.

Why did our heroes get so buff? Capitalism and product differentiation. In the early ‘80s G.I. Joe was being beat out in sales by Star Wars — before the intergalactic franchise the purpose of the action figure was the same as the doll, a tool of imaginary play that let children create a narrative entirely on their own. The Star Wars toys changed the market into a series of media-franchised creations set with their own storylines and pre-packaged looks. G.I. Joe needed to compete.

Just like brand twisted itself (then hurriedly untwisted itself) to fit the culture of the Vietnam War, G.I. Joe was able to tap into the political atmosphere of the Reagan-administration and create a new legion of hyper-masculine figures that would in turn influence the design of action figures to come. Between 1982 and 1985 the National Coalition on Television Violence reported a 350 percent increase in the sale of war toys — predominantly because of the success of G.I. Joe’s new look.

G.I. Joe's Sergeant Slaughter in 1985.

That action figures appear to have changed in stature since 1964 is a fact; research conducted by the University of Massachusetts, McLean Hospital, and Harvard Medical School found that from 1964 to 1994 action figures grew more muscular and developed increasingly sharp muscular definition. These figures, they emphasized, had bodies that far exceeded the muscle mass of “even the largest body builders.” Case in point: The first G.I. Joe didn’t even have abs.

While these mega-men look almost comic in their proportions, the implication of how they were styled had and still has real effects. Studies have found that playing with these hyper-muscular action figures significantly decreases the body esteem of actual humans. A 2005 study went to find out how a group of 18-year-old Midwestern male college students would react when asked to mess around with the action figures — turns out, it made them depressed about their own physique.

How action figures make young boys feel about themselves is not known.

What is known is that toys are highly gendered. Girls toys are consistently associated with beauty, nurturance, and domestic skill while boys’ toys are described as “violent, competitive, exciting, and somewhat dangerous.” In related news: There’s not enough new Rey toys to meet the demand.

Rey and BB-8.

Because toys reflect the times and we live in a kale-drinking militaristically turbulent decade, action figures are beginning to slim down to normal size. Hasbro decided to have their Star Wars figurines become more natural when the Phantom Menace premiered and the newest figures look essentially like the bodies of the actors. But before the mad rush of these new Star Wars figurines, action figures weren’t doing so well. In 2014 Hasbro’s fourth-quarter net income fell 15 percent from the previous year, while Mattel’s net income only rose because it wasn’t dealing with legal expenses anymore. In 2013 there was six percent drop in sales of action figures which, while the number seems low, was a shock to an industry that had become accustomed only to growth.

What could be a boon for action-figure lovers and a nightmare for franchises: the rise of 3D printing. Increased accessibility to 3D printers means a world where you can create characters to any specification that you want. No need to wait for a franchise to tell you what is the hot toy of Christmas, just let kids make the coolest thing they can think of.