Fashion statement I figure. Bug's gotta eat: they'll go through your socks if they know there's fresh meat to be had!

I prefer taller socks for compression. Pushes fluid from my ankles. Joints seem to ache less.

In answer to the subject title: No.
As you discovered empirically, they often seem to prefer areas covered by socks as well as other tight garments. They also like belts and tight underwear (and I can tell you that sometimes the relief of scratching feels so good I'm surprised it hasn't been condemned as some kind of special sin).
A long time ago, when we went blackberry picking we'd dust ourselves with 'flowers of sulfur' or sulfur dust. There might actually be some preventative value to that mess but today I prefer to just live with them. I don't even bother with insect repellant (besides, chiggers are mites, not insects). Scratching a little now and then is just fine by me, all the other monkeys do it.

Two options, ScoutFish

1) Spray da outside uppers of your socks with permethrin. Permethrin is a semi-permanent insect repellent for clothing. Spray it on once, let dry, stays for about 20 washes or so, keeps da bugs from biting through clothing. For socks, though, keep it on the outside and uppers (outside of the boot) only, because the stuff will irritate your skin.

2) Wear gaiters.

B

When I am in major bug areas I use leg wraps. Original boy scouts used them and they serve a purpose. Yes they are hot in warm weather, but the trade off is worth it. It also keeps out the ticks that come from the ground. You're on your own for ticks on tall bushes. Long sleeves and duct tape the cuffs. Necker also helps, but they are pretty persistant and occasionally one will get through the defenses. I'm not into the use of chemicals.

Stosh

I think it depends on the weave. I find the green Thorlo scout socks help a little but the weave is so open that they get through.

I use Permethrin on my boots and socks, and 100% DEET on exposed flesh. I also wear lightweight long pants and sleeves on occasion.

100% DEET is scary stuff. Melted my plastic watch band--took an hour to get that thing off. Do not spray near plastic glass lenses either! And DO NOT spray in your open mouth by mistake! But man the Mosquitos hit that stuff and died on contact.

Finally I always hike near a tastier scout.

from an entomology extension guide

http://extension.missouri.edu/p/g7398

"Avoidance

The best defense against chiggers is to avoid them. Avoid wearing shorts, sleeveless shirts and sandals when going into chigger habitats. Tightly woven fabrics reduce the threat of chiggers penetrating clothing. Tuck pant legs inside boots, and button cuffs and collars tightly to keep chiggers on the outside of clothing. This increases the time that chiggers are exposed to any repellents you have applied to your clothes. Remove clothing as soon as possible after exposure to chigger habitats, and launder it before wearing it again. A warm shower with a vigorous skin massage, taken within an hour or two after exposure, greatly reduces the number of irritating bites. If itching has already started, however, it is probably too late for bathing to do much good.

Repellents

If you must enter chigger-infested areas, chemical repellents can be used with good results.

Any insect repellent containing DEET (diethyl toluamide) or picaradin will be effective. Apply it to clothing from the feet up, and reapply every two to three hours to maintain its effectiveness.
Sulphur powder is also effective when applied to clothing but has a strong odor that makes it less desirable.
Permanone, also sold as Coulston's Permethrin Tick Repellent, contains the pyrethroid insecticide permethrin and should be sprayed on clothing and allowed to dry before the clothing is worn."

The knee socks are a left-over from the style of the Brits (but we never went for the kilts), they really are good protection from brush wacking your legs on the trails in camp. After seeing many ugly legs of adults with the short socks, both genders, I sort of wish more folks wore knee socks.
Permethrin use: I've been using the stuff on my clothing for 30+ years, several brands of this insecticide available. Even the BSA catalog now sells the stuff. I spray a couple of sets of my summer hiking underwear, the entire sock, cuffs, waist and even the fly of all my pants. I spray my summer hiking shirts, it does not hurt any nylon or poly material. Have done lots of reading of material on backpacker.com and the companies that make the stuff. They claim it is not harmful to spray on you, it just doesn't work on human skin because there is some enzeme that neutralizes it. Some folks spray on the tent doors and screens to repel skeeters, no harm to tent. I've done summer trail marking thru high grass next to rivers and returned to trailhead with my pants and shirts red, covered with dead chiggers and ticks. I would no more wear gaiters to repel chiggers in the summer than I would wear a wool sweater here in Missouri in the summer - a bit hot and sticky. I've seen several differing claims about how many washings the clothes can take before the Permethrin is neutralized, several seems to be good number, good enough for the summer. Our Challenge Course and Climbing training really pushes the use of Permethrin because our programs are in heavily wooded and brushy areas. We have lots of happy Scouters who have followed our advice.
A bit of a disclaimer: a recent adult climbing student of ours does not trust the manufacturers of this stuff and had several articles doubting the safety for humans. She and they claim that not enough science has been done, she is also a pretty "organic" person. If you have any doubts about the safety spend some time on the net, I didn't keep the articles.

Knee socks give chiggers somewhere to hang out between snacks...

Dust your socks down real good with flower of sulfur...

I used flour of sulfur as a kid. Works for both ticks and chiggers.(This message has been edited by eisely)

"Do tall socks stop chiggers?"

No, but they certainly stop chicks.
;-)