There were enslaved people that did exactly that. White enslavers feared poison almost as much as an uprising, because enslaved people prepared all their food. After Nat Turner’s rebellion was put to a violent end, the terror inflicted on the enslaved population is hard to overstate.

On top of potentially having never left the square mile or two of the plantation they were born on, dogs were used to hunt enslaved people who ran. Those who were recaptured were often physically mutilated to prevent further escape attempts. These acts were typically carried out in front of the other enslaved people. The cost was too high and the barriers too difficult to surmount for many people. Add to that, they may have had children or a spouse they might be forced to leave if they ran.

For some who were extremely clever (Henry Brown mailed himself to freedom) or who were able to make contacts with people who could hide them on the Underground Railroad, they were able to make it. But everyone who didn’t run was kept in place by a system of racial terror, not out of a lack of desire for freedom.

i'm not a historian, but can tell you that slaves were treated as if they were helpless toddlers-- they were made to believe that their existence was entirely dependent on their "owners." in other words "if it weren't for your owner, you would suffer even worse than you already are, and you would die." they were prohibited from learning how to read and write. they were born and raised with the mindset that if they did leave the plantation, the only thing that would happen would be they would be caught, whipped, and brought right back to where they were, to be whipped again, or very likely worse. when you're born and raised in this kind of environment, the idea of "walk off the farm" doesn't even occur to you

and where would they go? they were prevented from knowing that there was such a thing as abolitionists, or places where they could escape to and not be slaves. and even if they heard about this possibility, they were brainwashed to think they were offending god by defying "master" or some shit. it was self-preservation, not fear. the frederick douglasses who taught themselves how to read, beat up their owners, and escaped to the north were rare.

if you're really interested, i recommend douglass's own book , as well as Caste by isabel wilkerson. the burning hate and racism of whites is still here

tl;dr: mind control

edit: since we're on the topic, i'm going to rant

the argument "you can't judge people in the past according to today's societal standards" is bullshit. yes i fucking can, and yes i fucking do. "slavery is wrong" is not a "welllll...." or "but....." statement. slavery is fucking wrong, and always has been. and there have always been people who know this simple fact, regardless of what century they lived in. this is evidenced by the fact that there would still be slavery if not for the people at the time who recognized its wrongness, and fought to end it.

if you want to dive deep, read up on Bartolomé de las Casas, a person from the 1400s who, through the course of his life, went from "slavery is normal," to "only africans should be slaves," to "NO ONE should be enslaved." because of the horrific things he saw and experienced in the new world. yea, they don't teach de las Casas in school, because of systemic racism, and so they can continue to push the bullshit "they were products of their time" narrative.

As other people have already said, most of it was fear, the other large piece was manipulation. Make them afraid of running, mutilate anyone who tries so badly that others wouldn't even risk it. Make them think that running is pointless. You're gonna get caught anyway, where would you go, it's better here than "there". Not to mention that (often) the whole town was involved in stopping escapes. If anyone saw or heard about a slave escaping then they did everything they could to help because 1. They were viewed as property, if someone saw an escaped livestock or a missing farm tool, they'd try to return it if they could, keep it if they couldn't. 2. If a slave escaped from one farm, it was likely other slaves would hear about it and try escaping too. If someone owned slaves it was in their interest to make sure nobodys slaves escaped, because it held the image up. The more stories that got around about slaves escaping or the underground railroad, the bolder slaves might be willing to be.

That said, these were all awful ways to treat a human being. But slavery is an awful thing.

Just the framing of the question is insanely insulting nonsense and almost makes me believe this is not a question being made in good faith.

In an attempt to reduce my blood pressure, how bout we go ahead and assume the people enduring slavery were, largely, the same as you and I. Wouldn't you know, they probably could've figured out how sneaking away in the goddamn night works.

Now, let's say you found yourself enslaved, AND knew the one weird trick slave owners hate (waiting until night time). What might keep you from fleeing slavery in this situation?

Maybe, vicious dogs? Or perhaps the threat of being scourged within an inch of your life with a whip? Maybe it's just the fact that any random what person within 300 miles is going to string you up from a tree if they see you out at night?

If all else fails, literally the entire state apparatus will hunt you to the end of their jurisdiction and beyond and make an example of your ass.

There was no getting out. You were property, someone's farm tool. If you didn't understand that, they'd make your life more of a living hell than it already was.

This is why the runaway slave Patrol exists, the predecessor to the modern police force with largely the same mission

Consider that them being seen anywhere they wouldn't be able to blend in, because they're black. It's not like they could find clean clothes and blend in and start over.

There were the occasional slave uprisings, but none of them were successful, and the punishment for anything like that was so harsh that it was hard to get support. In addition, the slaves knew that anyone who reported a burgeoning uprising would get handsomely rewarded, so it was almost certain to be reported. Nobody could be trusted.