I'm in the rough outlining stages of this story, and found myself a bit stuck trying to turn this particular corner.

Firstly, here are the basics of this world:

In the future, it's a common practice to genetically alter embryos, rendering them immune to incurable diseases and protecting them from genetic defects.

As time went on, this procedure also included physically enhancing these future children, by ways of increasing height, increasing their ability to gain muscle, more appealing facial structures, etc.

However, in some of the seedier corners of society, people have experimented with changing the germline of offspring so as to make them not quite human anymore. This was done by testing the limits of what could be accomplished physically (keep in mind that this technology is still in its relatively early stages; the test-subjects would still look somewhat human-esque, not like some sort of eldritch horror). Since a physically-altered human already stirs plenty of unfavourable images in someone's mind, there's plenty of creative room to draw from there. The important thing is that, though potentially traumatized, they would still be fundamentally human on the inside, however skewed they may be physically.

At some point, these bootleg engineers realize they can experiment with the psychology of a human as well, making their subjects' behavior and thought processes fundamentally different from what we would normally experience. They could create a being with little regard for anything other than hedonism, or on the opposite end of the spectrum, a being that feels crushing numbness that no experience could ever lift the weight of.

The protagonist of this story is among the first people to be subjected to these experiments. However, I find it difficult to imagine what sort of subtle changes could be made to one's psyche that would make them appear slightly different, without it being hand-waved away as a normal point on the spectrum of human behavior. Somewhere beyond the box, if that makes sense.

As straightforwardly as I can put it, my question is:

Via altering their genetics, what kind of psychological changes could be made to a person that would make them subtly different from a human? Think trans-humanism, as in a sort of braching off in human's evolution.

EDIT: made the question less about mental illness, as it wasn't what I was trying to compare this to

  • $\begingroup$ Hi Graviti, welcome to Worldbuilding! You've got an interesting question here that seems to get at the heart of the nature-nurture debate. Given that we're not really sure how much of the human experience is genetic and how much is a consequence of upbringing, answering this question objectively is quite difficult. Are you hoping for well-known mental disorders that have a strong genetic component? $\endgroup$
    – Dubukay
    Commented Aug 13, 2019 at 20:50
  • 1
    $\begingroup$ Unless you're going to have a controlled experiment, by definition it is impossible to draw any conclusions. In this case, you have a single data point, your protagonist, to attempt to extrapolate a conclusion from. This is not good science. Without having at least three controls: One who underwent the same modification but was raised properly (i.e. with loving parents), one who was raised like an experiment but with no modification, and one who was raised properly with no modifications, it is impossible to draw any conclusions from your protagonist. $\endgroup$
    – stix
    Commented Aug 13, 2019 at 21:15
  • $\begingroup$ Thank you both for the comments. I actually wasn't intending for these changes to be perceived as mental illness, more like a trans-humanism concept, though now that I think about it there is quite an overlap between mental illness / any deviation in psychological behavior, genetic or otherwise. It's pretty hard to draw a distinction between the two. This actually gave me a few good ideas for how I could direct this story. Either way, I'll try to make the question a bit less broad. $\endgroup$
    – Graviti
    Commented Aug 13, 2019 at 21:17
  • $\begingroup$ As for what you're saying, Stix, I completely agree. I'll try to edit my question accordingly. $\endgroup$
    – Graviti
    Commented Aug 13, 2019 at 21:19
  • 1
    $\begingroup$ That was a poorly thought out example on my part. Thank you for telling me, Kleer, I'll edit it out $\endgroup$
    – Graviti
    Commented Aug 13, 2019 at 22:55

6 Answers 6


My best suggestions would be:

  • Making your character impervious to betrayal. They can be betrayed in the most gut-wrenching way but they seem able to shrug it off as if it's just a disappointment on a par with, say, finding that the library doesn't have the particular book they want.
  • Having them react similarly to power. Taunts, power-plays enacted against this character, pulling rank at times that would be infuriating to a regular human, just seems to be water off a duck's back to your character. They genuinely seem to see it for what it is without feeling affronted by it. Either that or they seem strangely keen to comply, as if they're tweaked for a more hierarchical life than a regular human.
  • Rather than having ambitions for themselves, to have them for another individual. Perhaps whoever's in charge, or a given group (such as your character's government, the business they work for, their family as a unit, etc.)
  • To have a flawless ability to be inter-dependant. Inter-dependance is the ability to take one's own strengths and weaknesses, to notice another person's, and to work as a team with them. While different people have this skill to varying degrees, perhaps your character could have a preference for doing this right off the bat?

I hope those help!

  • $\begingroup$ Thank you, these are the sorts of suggestions I was looking for! $\endgroup$
    – Graviti
    Commented Aug 13, 2019 at 21:47

Psychological changes are ineviteably physiological changes of the brain. The brain has sections dedicated to specific tasks and nerve connections that connect and influence these partitions. If you rewired your own brain's connections right now without changing the brain partitions you could make yourself smarter, dumber, capable of a single task or many at the same time and more. This quickly becomes a problem that we simply cant answer correctly unless you narrow it down.

Example: your scientists want to make someone more resilient to loss so they dont grieve as long or suffer ill effects from losing a friend, relative or loved one. Especially handy for the ineviteable supersoldier project right? Except that like the brain all emotions are connected. Loss is connected to things like love, friendship, ownership, empathy, morality and more and reducing the feeling of loss has an impact on all those things. The same for all emotions, they are there for a reason and we use all emotions in some capacity every day. And psychology would ineviteably be a terribly murky part of this type of change "just" making people smarter would already change their personality!

What you could do for yourself: imagine an altered psychological state you might be interested in, then look on the internet and find the associated mental disorder(s). Genetic defects already cause many altered states and it is likely that anything you can think off has an associated mental disorder. Autism for example is marked by the brain not streamlining the brain's connections, reducing the processing speed of many brain processes but often increasing the level of detail this can give you, which is incidentally also why people with Autism can be overloaded, it takes more time to process and you can keep heaping more processes on that till the brain doesnt know what to do and requires time and lack of outside stimulants to get through it all.

  • $\begingroup$ The second paragraph is incorrect. You can easily trigger a lesion in the right part of the brain and cut loss (and a few related emotions) without cutting out friendship, morality, etc. Destroy the amygdala for example and you've completely removed fear in all forms, and yet a person without that part of their brain would still cry if their parents died. $\endgroup$
    – forest
    Commented Aug 14, 2019 at 6:06
  • $\begingroup$ @forest ofcourse they can still feel other emotions, what I'm saying is that removing (parts of) an emotion affects the personality and emotions that are left. A person without amygdala would cry about loss but work through the loss differently than with the amygdala. There are many ways to work through the stages of grief in an orderly fashion. $\endgroup$
    – Demigan
    Commented Aug 14, 2019 at 6:17
  • $\begingroup$ Oh I see what you mean. I thought you meant that removing one emotion would also remove all others. $\endgroup$
    – forest
    Commented Aug 14, 2019 at 6:18
  • $\begingroup$ @forest I'll try to edit it as I don't blame you for interpreting it that way, especially the wing analogy does not help. $\endgroup$
    – Demigan
    Commented Aug 14, 2019 at 7:06
  • $\begingroup$ Indeed the wing analogy is what confused me. It makes more sense now! $\endgroup$
    – forest
    Commented Aug 14, 2019 at 7:08

TL;DR - Make your protagonist think in ways that are clearly alien thought processes, but are still logically self-consistent on some level.

Mental illness is defined by society, and tends to be very subjective. Just a few decades ago, homosexuality was listed in the DSM as a "mental illness." Even today certain sexual fetishes are listed as "mental illness" that seem more along the lines of societal taboos than objectively "bad."

However, an objective definition of mental illness is that it is a deviation in an otherwise normally functioning mind that is detrimental to or causes dysfunction in the possessor of that mind or his/her peers. Being depressed is objectively a mental illness, it causes pain to the person suffering it; gender dysphoria is objectively a mental illness, it is a thought process that causes pain to the person suffering it; schizophrenia is objectively a mental illness, as the lack of a proper understanding of reality creates dysfunction for the sufferer. These all have the common characteristic that they present as a person showing no outward or obvious pathologies of their physical bodies, but their mental states show something is clearly wrong.

Previously, it was assumed that mental illnesses did not have a physical cause. Ultimately, we are likely to find that this is not the case, perhaps even in situations where it is caused by environment stresses rather than genetics (for example, schizophrenia has been linked to brain dysfunction, it is possible to induce pathological apathy in a person through traumatic brain injury, gender dysphoria is likely caused by brain anatomy not being appropriate for the gender of the person's body, etc, etc...).

Humans are intelligent creatures, and we are not strictly bound by our genetics. In addition, the way a human is raised is likely to cause physical manifestations that affect their behavior.

It is then perhaps more appropriate to say that mental illness is merely a deviation from a physical "norm" that we are unable to detect as pathological. This is unfortunate as it likely implies all mental illnesses as we define them are idiopathic (unknown cause), which means it is all the more difficult for you to say your character's traits are nature or nurture.

The only way you're going to get any real traction on your question is to try to re-frame it in more objective terms. Look at how the human thought process works, and how you can make it more alien but still self-consistent. A common theme with mental illness is that there is a logical contradiction of sorts at play. I feel sad, but I clearly have no reason to, I feel as though I am male/female but my body is clearly not, I feel like the government is spying on me, even though it can be shown empirically that they aren't, etc...

Viewed this way, it is much easier to define it as a mental illness when one's perceptions do not match an objective, physical reality. They all represent dysfunction in what we would call common sense human thinking.

However, if you want your character to be "off" and seem "off" without being "crazy," you need to have him/her think from a point of view that is not human, but still consistent with reality.

One of the biggest problems that faces astrobiologists and xenolinguistic scholars is how we would communicate with an alien species. The entirety of our experience in communicating with others has been with our own species, and it is reasonable to assume that, since we all evolved together, that no matter how different our languages are, our thought process is the same. This is evidenced by the fact that a child can pick up any language, even languages as incredibly different as say, Japanese and English, or Chinese, and Swahili.

Contrast this with, say, a dolphin. It's generally assumed that dolphins are intelligent enough to have some rudimentary concept of culture and language, yet in all of the millions of years we've shared the Earth, no human has ever been able to "speak" with a dolphin, nor vice-versa. No matter how young a human or dolphin child is raised with the other species, it will never learn to speak their language, and is unlikely to understand their culture. This is the problem that xenolinguists face: Is it possible for two species who have evolved under incredibly different circumstances to have a frame of reference similar enough to enable communication.

All human languages, without exception, have the concepts of verbs and nouns. All human cultures have a very similar underlying concept of morality, which may even be objective. This is likely due in no small part to our genetic programming and our evolution as a communal species.

However, it is entirely possible, and perhaps even likely, that a species evolving differently may not have the "universal vocabulary" to communicate with humans, or we may find their way of thinking so different from ours we are unable to make sense of concepts they take for granted.

So if you want your protagonist to seem less human in an objective way that isn't tied to mental illness, look at how you can change his/her thought processes in a way that is still self-consistent and obviously not dysfunctional, but in a way that causes someone to say "I would have never expected a human being to think that way."

Have him/her reach conclusions in a way that seems chaotic and/or roundabout compared to how a "normal" person would reach them. Have him/her be able to think so many steps ahead that he/she seems to be clairvoyant. Think of ways to "break common sense." All of these will make your protagonist seem more "alien" and less human. A pig can never fly no matter how well it jumps, but if you see a pig flying one day, it's not necessarily inconsistent with itself or reality, it just means that it's not a normal pig, or that it's not a pig at all.

  • $\begingroup$ In addition to the concept of Human basis, OP should check out the back of Steven Pinker's book "The Blank Slate". There's a few pages of cross cultural constants, things that are present in every Human culture. $\endgroup$
    – kleer001
    Commented Aug 14, 2019 at 16:45

Start with the big five (or HEXACO) personality dimensions. These are the closest science has gotten us to personality/behavioral sliders.

Here's a couple light primers:



Start with one of those and crank them around to get what you want. Thing is I bet you won't find lots of extreme settings that go along with your plan, but instead it'll be better to have a nice balance of things for whatever you want to do.

You didn't mention what the plan for this person was, but I'll assume you want a perfect assassin just for arguments sake.

For example (using the HEXACO model):

honesty? Turn it all the way up. This way you've got a person you can trust to the end of the earth as long as they hold you in trust.

extraversion? middling? Too outgoing and they're too flexible in seeking attention, too intraverted and they'll be out of line with their peers. But maybe low side is good too. Unless you want a James Bond type charmer, then you want a bit on the higher side of normal.

agreeableness? On the very high side. These kind of people are easy to convince to do what you want them to do and less likely to revolt. Too low and you get an instant rebel.

openness? Too high and they're likely to find holes in your plan and even side track it if they're not too distracted by the latest new and shiny thing. Too low and they're too dumb to follow directions. A little on the low side of high and you have a better balance, just smart enough to justify what they're doing, but not high enough to really reason past the wall of logical fallacies built into the rest of the human psyche. And no, you can't get rid of them, they're part and parcel with being a sentient being in the chaotic universe.

conscientiousness? Probably really really high, but not high enough to have OCD kick in. This kind of person has all their ducks in a row and rarely makes mistakes. Their living quarters are clean and they stay away from contamination. Think of the situational control of a Navy Seal, think Bat Man.

neuroticism? Probably really really low? Not so low that they don't have any emotional response, but low enough that random chaos won't throw them for a loop. This is probably one of the only ones that'll you'll likely want really low.

Then again, nature is going to alter those traits as the human grows...

Some more models, but none scientific except the big 5 / Hexaco (unless they are important to your story):




The question is basically what components of human psychology are defined by our genetics. The simplest answer to this is, well, everything. Our brains are entirely defined by our genetics. Millions of years of evolution have developed a thinking machine optimized to make copies of itself. Everything our minds are capable of exists, at least originally, for that purpose. From that perspective, it’s all on the table for manipulation, but I suspect that such a broad answer isn’t generally helpful for your purpose so let’s try to break it down further.

When most people see a baby’s face we find it pleasant. It makes us happy, it makes us smile. Why? Because it is evolutionarily advantageous for us to instinctively enjoy our offspring. Is there anything objectively pleasant about a human baby’s face? Of course not, beauty is entirely subjective and those things most people agree are pretty, such as flowers or rainbows, represent a genetically encoded preference. We can extend this for any human preference, be it for a sight, a smell, a taste, a touch, a sensory input of any sort is entirely subjective and has a fundamentally genetic basis. Importantly, if something has a genetic basis then it follows that it can be manipulated by genetic engineering.

But even moving past our basic reactions to external stimuli, what is happiness and why does it make us smile? What is sadness and why does it make us cry? Our feelings exist to guide our behaviors in evolutionarily advantageous ways. Feeling happy when “good” things happen encourages us to facilitate more “good” things and to avoid “bad” things in order to help us survive and procreate. Our external displays of our internal mental states serve to communicate our feelings to other humans to aid in communication and cooperation. All of these features of our minds have been developed and refined by evolutionary processes and are encoded by our genetics.

So, with this understanding that ultimately our thinking developed to serve an evolutionary purpose, we can examine all of the different aspects of human psychology and see that they all serve evolutionary purposes and therefore are genetically encoded and manipulable. All of the below are examples of mental capabilities that could be weakened, strengthened, or manipulated in any way conceivable given sufficient understanding of the genetic mechanisms:

  • Justice and fairness
  • Envy and vengeance
  • Belonging and companionship
  • Love and lust
  • Respect and approval
  • Fear and anxiety
  • Anger and wrath
  • Language
  • Memory and recall
  • Logic and mathematics
  • Boredom
  • Curiosity

I'm going to assume the question is 'What changes are possible?', and not 'What changes should we make', as the latter is opinion based.

Brain development is interesting to say the least. But here's the deal - you're approaching it from the wrong end. It's much easier to mess with the human brain after it develops using surgery than before hand using genetics - in theory, anyway. Strokes have been known to rewrite personalities, there are ways to make people optimistic with magnets, and then you have straight up mental disorders, all of which take place after development.

So what's easier to do from a deleopment standpoint? Natural inclinations. Based on the optimism paper, you can try rewrite DNA to produce or not produce parts of the brain responsible for emotion. For instance, imagine a human without the capacity for a pessimistic thought. It's also possible to enlarge certain areas, at least theoretically. Image a human with his math section tripled. Or you can adjust the balance of emotion/reason.

The odd thing is, I'm not entirely sure you can induce transhumanism if you're just messing around with the normal balance of human thought and emotion, because humans are very varied within their emotional patterns already, far more so than their physical abilities. There are individuals (though rare) who just don't have strong emotions and are able to coldly apply logic to everything, there are people who are just naturally strong optimists. So, while you could create a generation of people who have emotions in some areas, but not others entirely, perhaps you design a batch which don't have any form of altruism, you wouldn't wind up with a batch of humans that the normal human race couldn't produce.


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