By psychological effects of alcohol, I mean the effects from 0.060–0.099 Blood Alcohol Content % by volume (according to this Wikipedia article), but not the physical effects, like alcohol poisoning.

The humans would most likely have these symptoms:

  • Lack of reasoning
  • Euphoria
  • Disinhibition
  • Extroversion
  • Lack of depth perception

If humans were like this (without Alcohol poisoning, liver failure etc.) would they be able to survive for as long as we have and, how different would they be compared to our current level of advancement (tackle depth perception issues)?

Because of some confusion: They were drunk from the start (caveman era etc.), It's not like humans randomly got permanently drunk in the middle of 2015.

  • 1
    $\begingroup$ If everyone is just a bit drunk all the time it would probably be like the 17th century, during which time we managed to more or less survive and actually got some cool stuff done re science. $\endgroup$ Commented Jun 26, 2015 at 15:20
  • 4
    $\begingroup$ Ah, reminds me of college. $\endgroup$ Commented Jun 26, 2015 at 18:01

6 Answers 6


Just my own musing on each symptom:

Lack of Reasoning

Alcohol doesn't prevent reasoning, but it does cause it to be much slower and be prone to mistakes. Our ancient ancestors most important use for reasoning was probably for hunting, to figure out how to find the prey and then how to trap it and kill it. Less successful hunts means less food, and less people that are able to survive. If the lack of reasoning is so important that hunts will fail entirely, humans may not be able to spread quite as far as we did and would have to survive more as scavenger/gatherers in ideal climates rather than hunter/gatherers across the globe.

Lack of Reasoning would certainly slow us down, a lot - but it wouldn't necessarily kill us as a species.


The euphoria experienced is, in my opinion, what causes people to be somewhat more immune to pain while drunk - but this is more negative than positive. Pain is meant as a warning that your body is under stress and can't take the beating forever. As a one-time circumstance, like during a fist-fight, this could be a good thing - but if people are naturally stressing themselves over that limit every day, they won't stop until their body is seriously harmed. The other negative aspect of euphoria is that it makes it harder to have motivation to do other things. Such as finding food. So not only are we worse at finding food due to lack of reasoning, but we probably feel hunger later from the slight immunity to pain, and then are less likely to act on the hunger for a bit after that. The good news is, small pain wouldn't stop us from finding food, even if it eventually kills us.


From a societal point of view, this would probably balance out. People would do things or say things more easily, but also be more accepting of things. From a survival point of view, it means we are more likely to try new things. Most of those things will not work - but the things that do work will be found more quickly. The trade-off here is that more people will probably die, but we will find new things faster - though the lack of reasoning takes away from this substantially.

Extroversion and Lack of Depth Perception

are secondary effects, in my opinion. The extroversion is a result of all three of the above traits. We feel more willing to share and connect to others and are more willing to overcome emotional insecurities because of the euphoria and disinhibition. The lack of reasoning helps prevent jealousy or making connections like, "If I help him, it makes it harder for me." The lack of depth perception comes from the lack of reasoning - it is harder to connect what we are seeing now to what we have experienced in the past for how far away something is or how much motor control to use. The overall effect on our survival is that we are more accepting of others and again - suffer negative aspects to the hunting part of our culture.

Overall, if we are living in a region where food is easy to find and there aren't a lot of things around to kill us through careless accidents, I think we would survive, though with less numbers. Technology would probably advance more slowly, and we would be stuck in certain global climates until technology advanced enough to move out farther. Society might be more careless, and more forgiving of its members when careless doesn't get someone killed.

  • $\begingroup$ The "alcohol kills brain cells" thing is a myth, and even if it were true, what's the basis for saying that it is the source of euphoria? psychology.about.com/od/biopsychology/f/… However, while alcohol doesn't kill off existing neurons, it does harm the formation of new neurons, both in the brain and the body generally. This is very harmful to the fetus, but can effect adults too, who, contrary again to popular belief, do grow new brain cells. psychology.about.com/od/biopsychology/f/… $\endgroup$ Commented Jun 29, 2015 at 9:11
  • $\begingroup$ a good discussion, but I think you forgot to discuss predation. A drunk human in the wild, without modern technology, would be a very very easy dinner for almost any predator the size of a dog or larger. Frankly, despite all my research into evolution I still think it's surprising we managed to not be eaten long enough to develop sufficent technology and cultural techniques to defend ourselves. Put us in the same boat and too drunk to think up good tools fast, and too unsteady on our feet to run..... $\endgroup$
    – dsollen
    Commented Jun 30, 2015 at 19:33
  • $\begingroup$ @dsollen To be honest, it had occurred to me - but I was unsure what kind of predators we would have to worry about - and how we even dealt with them in the far past without being drunk. Using items on the ground to hit with or throw doesn't take too much "thinking" - drunk or not - but if we depended too much on running or climbing, our terrible sense of balance may sink the boat. $\endgroup$ Commented Jun 30, 2015 at 20:04

I'm going to look at this under the assumption that this has always been the case, and isn't an emergent trait.

Given the lack of inhibition and reasoning capacity, we'll be looking at lower populations. Natural selection will have plenty of opportunities to weed out the gene pool. But because of that, the humans that do survive will likely be a lot more resilient. Getting knocked around will probably fairly common, so the survivors will have to be able to take it. Heck, they might might even heal a little quicker.

Populations would have a much lower average age. Birth rates would be high, but so would death rates. Once you're past your prime, the odds of you falling prey to accident and injury would skyrocket. Actual old people would be quite uncommon.

Social structure would be completely different. Between the extroversion and the lowered inhibitions, society would be very communal. You wouldn't get strong hierarchies forming, and the family unit would likely boil down to "Everyone I know". Also, you'd have a lot of fights between people, but they'd be fast and blow over as quickly as they start. Which might actually help prevent wars in general, along with a low chance of forming larger centrally controlled societies. They'd be very decentralised in general.

As for advancement, it'd be erratic, but I suspect okay. Poorer reason would probably slow down advancement somewhat, but they'd be better suited to make unrelated jumps to new ideas, and they wouldn't get as stuck on a single technological path as standard humans. One main difference though, is that most of their tools and technology would be designed to require less manual dexterity. Lots of big easy to use controls, and absolutely no fiddly bits.


Not Very Long

Given how common alcohol related accidents are, if all humans exhibited those symptoms, they wouldn't live long. At any point in history, a lack of depth perception would make tool use difficult or impossible. Given that human's evolutionary advantage is tool use and reasoning skills, we wouldn't survive long.

Also, a lack of disinhibition leads to such comical tales equivalent to "Hold my beer, I'm gonna go pull that lion's tail".


"a species has the psychological effects of alcohol"??? Question is somewhat unclear.
Do you mean a species of which every individual, all the time, experiences the symptoms that humans get from alcohol intoxication? How can you even measure that? Human alcohol intoxication effents are only defined by Deviation from how unintoxicated human Brains work.

A species whose Brains are inherently wired in such a way that they can never function better than humans at the alcohol Level you mentioned, would be somewhat less likely to survive or have evolved.

Or, the other way, a species that somehow(?) has effects of alcohol, would have evolved to inherently, by how their Brains are wired, have superhuman concentration, Inhibition, reasoning, depth perception, what have you, so they would always compensate and have competitive abilities like humans


Bro, after the Renaissance, our tolerance was like, so high that it didn't even affect us anymore. I mean, as a species we're pretty buzzed right now, and we're still having a perfectly intellilli... liggib... gib... coherent conversation, here.

More seriously, when does this effect kick in? Because if it was in caveman times, we'd go extinct almost immediately. Have you ever tried to catch an antelope... stoned?


Always? Like since the early branch of homo sapiens? As others have pointed out, the psychological effect would have a great negative impact on inventing and using tools, which is something our ancestors' success relied on heavily. My bet is that our progress would be generally slower. The journey from Africa to the world would go much slower as we would have trouble adapting to new environments - to new climates, build shelters from new materials, hunt new kinds of prey etc. Development of societies would be much slower and who knows if any civilization would ever be formed. In those hard times, when we cleared the world of most of the megafauna, the sober homo sapiens invented agriculture and the population levels afterwards increased. The population level of drunk homo-sapiens would probably drop greatly and stay low for a very long time and a lot of areas would be completely uninhabited by drunk homo :)

But there is also the possibility that drunk homo sapiens would keep its population lower right from the beginning thanks to generally being less flexible, successful and adaptable. With worse tools and worse hunting techniques, the megafauna could maybe never die out and drunk homo sapiens could just always stay in the hunter-gatherer phase.

  • $\begingroup$ What do you call "megafauna"? The most significant "big" species that has become extinct is the mammoth, which was not a carnivore. Other big species that have been hit pretty hard are the cetaceans, the elephant and the bison, but none of them appears to me as a significant competitor. More significant could be the decrease in the populations of wolfes and big felines (lions, tigers), but I would not call that "mega". $\endgroup$
    – SJuan76
    Commented Jun 26, 2015 at 18:05
  • $\begingroup$ There were a lots of others than mammoth - see here en.wikipedia.org/wiki/Pleistocene_megafauna $\endgroup$ Commented Jun 27, 2015 at 6:47

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