Has any research been done on personality?

[MintyMyndi]

Nothing (that I can find) on the site says anything about a Chao's personality. I've found sites that seem to have in-depth information, but when you read it, you can see that it is mostly untrue, detailed things somebody obviously made up.
The reason I am asking is that recently, I obtained a Chao with no personality. This is a normal thing, but one of my oldest Chao also has been without a personality since her transfer shortly after birth. She is now an age 3 adult, and her personality remains nonexistent. I originally blamed it on the fact that she was born on SADX, and the Chao on there act blander than plain, uncooked ramen (but their faces are more fun than SA2B), but this Chao was born on this game. The older one is related to the younger one, but they are separated by 6 generations, so...
I don't think it's genetic, is it? Or is it influenced by genetics and how you hatch the egg? Because I have found correlation between hatching methods and personality; I have only gotten energetic and short tempered Chao from throwing only. Although the latter only showed up a few times, the former was one of the most common personalities when hatching the eggs that contained the unsaved siblings of the younger Chao; this was done more that 50 times, and possibly over 100, long enough for me to be annoyed at the cracking sound the egg makes when it breaks (to be honest, I'm almost scared to find the exact number of times I bred them), so the results can be used as a rough guide. The second most common personality was the big eater personality, present in the Chao's lime parent and in the other parent's grandfather. The grandfather would shift to crybaby, but this would only be visible on his chart and not in the garden. It seems he would shift just before and after getting it checked. I don't know. The lime parent is consistently a big eater, and was fittingly made to be a sumo Chao. Several of my Chao shift between naive, crybaby, and curious, very rarely having carefree. Most seem to lean toward crybaby. Since I started paying attention, none of my personality-less Chao have shifted. The same applies to my energetics. The crybabies seem to be all over the place; most of them weren't born crybabies, but shifted in adulthood. One of my sister's Chao was born crybaby and raised with a lot of mine, giving the illusion of crybabiness being contagious. I just don't know.
Is there any hope that my new Chao will shift? How long will it last? What are the specifics of each personality? Where is Waldo? Why am I asking you all these questions?
Just... Tell me things from your personal experience. I am so confused about something that barely matters.

[Albedo]

Actually, most chao have different personalities based on how they're hatched. I hope this helps. P.S. Some chao shift personalities depending on how they are treated.

[krzys2]

Well some personalitis can change like big eater-ifeed alot, carefree-if pet to much, crybaby-when was a baby was peted ALOT

[Mamkute]

To answer your initial question in the title: Not much. But it sounds like you just did, and a sizable amount, too.

I have heard a lot of mixed things about personality, and as you said, a lot of it is completely false, or at least without support.
They do shift personalities, although treatment correlating to that is not certain. In my experiences, my chao are inclined to have no personality after reincarnation. I don't know if others have observations similar to mine in that regard. Also, most of mine are Naive, Carefree, and Big Eater and Crybaby as the ones that I note by just watching the chao interact. I don't throw my chao to hatch, and fittingly either have few or no Short-Tempered and Energetic.

[MintyMyndi]

Well, I guess I should report some things I've found.
Throwing the egg has a higher chance of energetic and short-tempered personalities. This proves the rumor that throwing the egg produces an active Chao partially true.
Some personalities shift more often than others. I haven't found any correlation between treatment and shifting, but that doesn't mean anything. I have paid little attention to this.
And some things I've found about the personalities:
None: Really bland, default Chao. Tendency to be very uncooperative, but this may just be my two.
Big Eater: ALWAYS scarfs its food, even when not hungry. Yes, it will even throw the fruit while making the faster animation. Hunger also seems to deplete faster. I have them grab fruit all the time. They may also do that randomly.
Crybaby: Kind of annoying. It's quicker to cry when hurt, underfed, overfed, etc. (like if you have to do it five times as something else, it might cry at like 3 times as a crybaby. That's just a random example, as I don't have any numerical anything when it comes to this. It works the same way, though.) Will cry more often when it has the same as a "normal" Chao. Will also cry for no reason. I've had them make the "overfed" cry then immediately make a hungry animation.
Energetic: Timer seems to work faster. Does things more often than a "normal" Chao. Also seems to sleep more often, but for shorter times. Most of the time while sleeping, they snore very loudly. I've only had one make "normal" sleeping sounds a few times. I don't recall snoring since my original SADX card, and at the time all of my Chao were thrown because I thought that they wouldn't hatch otherwise. Hmmm, seems like a trend. They were probably mostly energetic.

Now, for some speculation:
Short-tempered: A rarer personality. Probably similar to crybaby, but with anger instead of crying. This personality seems like it would only make sense on dark Chao, because (as far as I know) they are the only ones that make angry animations. Nonetheless, I have had Chao born with it (but unsaved newborns, so no research).
Picky eater: A rarer personality. I'd imagine it being the opposite of big eater, always making the slower eating animation. I don't remember clearly having this, but I think I may have seen it once while playing without a memory card. If so, it was still an unsaved newborn, so no behavior observation took place. For the most part, I am taking the internet's word that this exists. I probably haven't seen it.
As for carefree, curious, and naive, I haven't seen anything that seems different. Any other personalities that exist but I forgot are also unknown.
Attention paying, AWAY!!

[Delta5]

Wow you have given this a lot of thought. My observations agree with the conclusions that you have thus far. Just to put my 2 cent in, don't know how true this is, but from what I have seen, the character you play as seems to play a role in it as well. just another factor that I think should be put in the equation

[The_Awesome_Chao]

Seems pretty accurate but i doubt that hatchting methods affect personality (or anything for that matter)

[Shining Chaos Chao]

I can say with a fair amount of confidence that hatching methods don't change anything. All evidence points to any egg already existing in garden yields the same chao every time.

Every time I have let two chao breed, or let an egg into the garden from the character's inventory, then saved and hatched in different ways has led to identical personality/face/colour/etc

Personalities(/face/etc) do seem to be influenced in some way when breeding - but I don't think I'll ever have the drive to come up with anything more detailed than that.