Starting with a creature and its environment, how does one create its psychology?

Evolutionary biology and evolutionary psychology attempt to explain attributes that we observe in our fellow humans and in the animals that inhabit Earth in terms of ancient fitness. Explanations come in the form of "<Trait X> exists because of <Environmental Pressure Y> or <Competition Z>". With a well established evolution history for a planet, it's possible to work out where a particular mental or physical attribute came from. Remember also, that every single creature you see, from the smallest single-celled creature to the blue whale are always the sum of their ancestors. So this is all well and good for our planet. What if it was for someone else's planet?

On WB, we often get questions asking something like "I have this really odd creature, how would it behave?" or "I have an alien with these attributes, how does it interact with its peers or the environment?" In some cases these questions are unanswerable because our experience is only with how life and evolution worked once. We don't know the universe of how life might work only how it has worked on our planet. Still, any understanding of how life has evolved may inform some educated guess about how it might evolve.

It's common for an author to start with an alien's appearance and immediate environment. However, this starting information often isn't enough to develop a rich psychological model for the alien. What is a method for deriving a creature's psychology from its environment, evolutionary history and physical morphology? If this isn't possible, what additional information is required?

Acceptable answers will provide a series of steps describing how to gather and incorporate whatever information is required to complete the process. If there are repeated steps, provide a way to know when the process is complete.

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    $\begingroup$ The reputation of evolutionary psychology is mixed, to say the least. And remember that natural selection is only one of the forces driving evolution; there are also sexual selection and genetic drift; for "large" species, such as mice and men, drift is at least equally important as natural selection. $\endgroup$
    – AlexP
    Dec 29, 2016 at 15:39
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    $\begingroup$ I'm positive any valid answer to this question can be developed into a full fledged scientific paper. There's a lot at play when it comes to morphological evolution, like @AlexP said, and evolutionary psych would be even more complex. $\endgroup$ Dec 29, 2016 at 15:59
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    $\begingroup$ @MalharKhushu, I realize that if taken to an extreme this question describes a process for developing an entire ecosystem. And publishable too. One would need to run some experiments to show what kind of information is really useful though. $\endgroup$
    – Green
    Dec 29, 2016 at 16:01
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    $\begingroup$ I'm going to be following this question closely, it sounds absolutely fascinating. Maybe we could at least run a few thought experiments? But we'll have to define parameters, given that we can only think of or experiment in Earth or Earth-like conditions. Let's settle on carbon based, proton gradient using organisms, with similar chemical make up, and nucleic acid like information transfer for now (who knows how silicon-based beings might think) $\endgroup$ Dec 29, 2016 at 16:06
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    $\begingroup$ I just came at it from a writing perspective, as it's a fictional creature, and no science tag. Earth is what we have to draw on, but there's certainly a lot that's strange on earth. My focus was more on what the creature must DO in order to live and thrive, with their environment and biologic track informing that. My angle wasn't about building the environ, it was about building the creature. $\endgroup$ Dec 29, 2016 at 16:58

5 Answers 5


Everything relates to everything else, so I don't believe this is a process that goes step 1, 2, 3. I think that you can start with any of these points and build from there.

My approach is dynamic, focusing more on answering questions about what the creature has to do in order to survive and thrive (which pushes their evolution), with their physical morphology and environment informing the answers.

All of these categories are based on evolution. Answer them and you have a start.

Mating, Pregnancy & Child Rearing. How does the species reproduce? What is the process used in order to get to mate and reproduce? Informing the answer will be what their evolutionary track is--bird evolution and eggs will produce a different cultural track than, say, a mammal-based live birth. This has to make sense biologically in order to track culturally. The answers to these questions will help get you to their psychology and societal structure, because it answers questions about general relationships in childhood and for romance, whatever that might mean. The physical characteristics of your creature, will help to inform this, from whether they are repilitain or birdlike or more like a mammal.

Questions to ask:

  • How is mating achieved? What must they do in order to be considered
    as a mate? Look to biologically similar creatures on this planet and the rituals involved there. You can then build cultural custom out of this. You can gather this info by researching similar animals on this planet.
  • How long is pregnancy? What are the difficulties? Are any special resources needed to accommodate it? Again, look to animals as your model. Here I would widen research, looking at groups at large, such as mammal and reptile. Google is your friend.
  • How many children are there?
  • How long is the child cared for by the parents, if at all? Is extended family or the group involved, as it would be in a chimp troop?(This will track into how developed they are at birth and some of their societal interaction).
  • How are the responsibilities generally divided? Answer this based on biology, as well as you can, finding an analogue in our own biosphere as a starting point. (True, they can be alien, but we only have our own biosphere to start with and the experiences of this planet. We can reach beyond that, but if we are writing fiction it has to make sense to the reader, who will also be from earth, as far as we know).

How much do they change over a lifetime? Do they look completely different when they are younger, like pupa and larva? Maybe spotted like a fawn until adulthood? These changes will be incorporated into culture--you might say a deerperson never really lost their spots to indicate immaturity. Those phases and the state of mind in those phases of development are going to be important to the underlying psychology.

What do they eat? Eating is a big part of the day and an important thing, so these questions determine societal cues you might not realize come from biology.

  • Omnivore? Carnivore? Herbivore? Insectivore? What do they eat and how did they get it when they were more primitive--this informs behavior. Look at other creatures which share this taste for things.

  • If carnivore or omnivore,do they hunt cooperatively? Solo? Is there a division along gender lines, as there is with the big cats? (females mainly hunt)

  • What physical characteristics do they have, which help them to get food, whatever food that may be? This can be anything from eyes that move independently of one another and a tongue which catches prey, to fast twitch musculature or a mouth shape built to efficiently eat grass. Ask too, when you're thinking about this, how these adaptations might effect how they interact with the world, each other and societal and cultural aspects.

  • What do they have to do in order to compete with each other for resources? Look into territorial behaviors or lack thereof for your species. This will effect psychology, ability to cooperate, and possibly their monetary system.

What eats them? In this category, this is anything that kills them, or did when they were primitive. This includes things that don't literally eat our creatures--like cold weather and disease.

  • What defenses does the creature have against the things that could kill them?

  • Same as above on physical characteristics, this time as applied to defense.

    That reaction to those things will inform their evolution, and later, some of their behaviors, culturally.

The sea in which they swim This covers the environment in which they developed. Underwater, on the plains, or in the jungle--their environment determines how they look at the world, which, in turn determines their psychology, as well as their evolution.

  • Think about the environment. What's different? Underwater creatures will think more 3-D than plains creatures, and jungle creatures might not be very good at perspective (understanding that things in the distance are smaller, because the jungle is so dense, you don't ever get much perspective). The environment can color everything--how they hunt, mate, rear young, but that doesn't mean you should determine this first--it just means that if you come up with it last, you should make sure it fits with everything else you've done. Look at all the animals you can in that environment.

  • Think about the adaptations needed in body, and how that affects their interaction with the world.

Lifespan. Knowing how old your species gets and if they get infirm is critical to societal structure. If, like salmon, they tend to die post spawn, this will effect everything, as will species which tend to have a place in their society for the aged (chimps often do, but it is dependant on gender).

  • How old do they get?

  • What happens when they get past breeding age, biologically?

  • Do they have a role to fulfill when they are older?

Are there any periods of time when the species is especially vulnerable? For humans, we have a long childhood, but for an alien species, this can be a chrysalis, or shedding skin or anything really. It can happen because they are old, or any number of biologic reasons. Ask what the species does/did during this time, and how that effects their way of looking at the world, as well as how others in the species react to it.

Are they dependant on/do they need any one thing/creature? Do they have a relationship with any other species biologically? Even a crocodile has birds that clean his teeth. Are they the bird? Or the crocodile? Or neither. This relationship can inform their psychology...Is there something specific they need in order to survive? Most specialists die out, but kolas need eucalyptus--it's all they eat...your creature might have to eat stones for better digestion, or eat a particular type of plant periodically. Horses, for example, do need salt, so they end up licking each other sometimes to fill that need. Look at the need/dependance through a social and psyche lens, once you understand what it is. It can have a huge cultural impact on custom.

When will you be done? Well, you might not be. There's always something new you can discover about your creature. Gathering the info is just a matter of google, the library, and answering questions. Each of these questions and steps will be informed by the others, like a giant damn circle. Just pick a place to start and come back around. I know you were hoping for something more step-by-step, but a creature creation is part research and part creative process.

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    $\begingroup$ I really like your answer... Also, you're barfing rainbows. You should have that looked at. $\endgroup$ Dec 29, 2016 at 17:24
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    $\begingroup$ This answer is fantastic. If i could +2, I would. It's excellent advice for anyone putting together a wholly new race. $\endgroup$
    – BaseHobo
    Dec 29, 2016 at 18:16
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    $\begingroup$ @XandarTheZenon My symptoms have progressed. Now my eyes have turned into eggs and my mouth is sealed with bacon. $\endgroup$ Dec 29, 2016 at 18:54
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    $\begingroup$ You might expand your mating section with r/K selection theory [en.wikipedia.org/wiki/… and your environment section with the question of "what is the main limiting factor in the environment to further population growth?". $\endgroup$ Dec 30, 2016 at 10:11
  • $\begingroup$ @MarkRipley Any of it can be expanded or focused on narrowly, but I didn't want this answer to be 80 pages long! Thank you very much for the link, it is helpful to the process! $\endgroup$ Jan 2, 2017 at 0:30


As some comments have pointed out, this question could be its own field of study. For the sake of brevity, the following answer does not take into account ecological balance of atmosphere, random environment events (read: asteroid impacts), complex food-chains and the like. It also necessarily condenses hundreds of thousands of years of evolution into single sentences, thereby unavoidably simplifying concepts that could themselves be their own fields of study. Unfortunate but necessary to avoid the "too long, didn't read" stamp.

First, some condensed background:

Evolution, prior to the never-guaranteed rise of intelligent life, is driven almost exclusively by environmental factors. Environmental factors on Earch include (but are not limited to) availability of water, food and breeding mates. On Earth, possibly the most important factor that has shaped behavior of all life is the competition for resources. This competition combined with Darwinian trial-and-error through random mutation gives rise to "dominant" species for a given environment. "A given environment" is an important point because the environment can change over time and life must adapt to the changes. In the long run, plants are very good at this and at competing with each other. In non-plant life, this competition for resources has endowed it with life's two pre-programmed instinctual pillars: Preservation of self and preservation of species. Those two instinctual drives ultimately act as the foundation for all of the emotional behavior that we observe in the natural world. No matter how complex the emotional response or the uniqueness of the emotion to a particular species, you can trace its origins back to one of those two precepts. It isn't until the rise of self-awareness and higher intelligence that environmental factors cease to be the most driving force as we become better and better at living in, predicting, controlling and shaping the environment - to a point.

So to your question: "What is a method of deriving a creature's psychology from its environment, evolutionary history and physical morphology?" Along with its evolutionary history, you need the corresponding environmental history. With those, the method is to chart the instinctual and then behavioral history of your creatures along with any changes to morphology within the time-span. This is hard though, particularly if your creature's environment is manifestly different from your own familiar frame of reference and point of view. For instance, what if your creature evolved on a world where competition for resources simply was not a factor? For instance, perhaps they live in a water world (physio-chemical needs), derive all nourishment from photosynthesis (energy) and their population growth was slow. This would create an entirely different set of instinctual drives, emotions and then higher thought processes - drives, emotions and thought processes that would be...well...alien to us and difficult to understand and relate to. But then that would make the aliens and the story all the more interesting if you do it well.

One caveat though: competition of resources, through a complicated evolutionary history of human emotion, has given rise to xenophobia. Something truly alien won't ever have the "warm fuzzies" from readers unless there's something interpreted as a positive that people can relate to. It's something to keep in mind if being able to relate is important to the story.

As I think on it, one short story from 1934 does a decent job of this is "Who Goes There" by Joseph Campbell. It's the source material for the two "The Thing" movies but the story, though dated, is far better than the resultant movies. The creature in question shares the desire for self-preservation - something we can relate to - but the similarity ends there.

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    $\begingroup$ 'what if your creature evolved on a world where competition for resources simply was not a factor?' There is always some limiting factor for a population in an environment. If there is no limiting factor, the population would keep growing until they found one, even if that factor was lack of living space, or in the case of your photosynthesis animals, lack of surface area where they could find sunlight to absorb. $\endgroup$ Dec 30, 2016 at 10:00
  • $\begingroup$ @MarkRipley. True, unless their reproductive cycle / life-span self-adapts to the environment without any conscious (or even sub-conscious) decision-making. Liter-size would be one mammalian example in some species and for amphibians, the west African reed frog will spontaneously change gender if there are not enough males in the local environment. $\endgroup$
    – Jym
    Dec 30, 2016 at 13:00
  • $\begingroup$ @Jym In general the gender changing has an immediate advantage to the one doing the switch though (it can find mates). As soon as one life-form decides to stop co-operating and just reproduce it will drive out all of the others unless there is some defense against that or they start competing back. $\endgroup$
    – Tim B
    Dec 30, 2016 at 16:22
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    $\begingroup$ @TimB But the frog doesn't decide to change gender. It just happens. "As soon as one life-form decides to stop co-operating and just reproduce it will drive out all of the others..." What if there are no others? What if reproduction is governed by the same mechanics as the frog's gender switch or the size of a wolf's litter? Such a biological mechanism responds to the environment but lies below even instinct. $\endgroup$
    – Jym
    Dec 30, 2016 at 18:47
  • $\begingroup$ @Jym Look at cancer as an example. The cells of the body are all working well together co-operatively. Then some start dividing selfishly. The end result is very unhealthy and often even kills them - but they don't care. They just want to multiply. $\endgroup$
    – Tim B
    Dec 30, 2016 at 21:34

This answer proposes a method for an author to derive a creature's general psychology based on the characteristics and historical environment of its ancestors. While the method describes a linear process, there are actually many opportunities within the method to provide feedback into previous steps which will feed forward into later steps. The degree of recursive feedback is bounded only by the author's willingness to explore.

A couple rules to remember about evolution: - Minimize metabolic costs while maximizing utility - Changing existing features is much easier than creating a feature from scratch - Unused features may go away over time - Features that incure no undue cost and don't decrease fitness may survive for long periods. - All features must be continuously and continuously helpful. Discrete jumps from a simple structure to a more complicated one are not permitted. - Evolution is a constant contest between raw strength and sneakiness

Background Prep

In order to make an educated guess at a complete evolution tree for a planet, one should be familiar with how evolution works on our planet. Phylogenetic Tree

Berkeley has an excellent (and short) program called Understanding Evolution that explains in detail how to analyze and create phylogenetic trees.

Simplified Phylogenetic Tree with common traits highlighted (Photo Credit)

The Method

  1. Figure out the most basic and primitive life form on this planet and its environment. The closer to a single celled organism, the more the author will be able to make decisions about fundamental biochemistry. Starting with a more complicated creature such as early land creatures with bones and muscles helps to focus attention on morphology and primitive psychology. The author has broad discretion where to start.

The earliest creatures won't require significant amounts of detail about their morphology or environment beyond the essentials. For example, the description of an early creature might be "simple six legged creature residing on broad mud-flats". Reducing the amount of early details does a couple of things. First, lots of detail about early species will likely be overwritten by adaptations in later species. No sense going into more detail than you need to. Second, if Earth is any measure, there could be hundreds of millions of years between this earliest species and the creature of interest. So much change is possible on those time scales.

  1. Trace milestone species from this first life form to the current creature. At this stage, the author will be creating a phylogenetic tree for this world as well as a rough history of the environment. Include the how, why and when describing mass extinctions, environment changes, new morphological features (eg: bones, amniotic sacs, lungs, mammary glands, etc) and corresponding forks in the phylogenetic tree, and development explosions (eg: Cambrian Explosion). There may be other features to account for the above list is a really good start.

  2. Describe in as much detail as desired what physical and mental attributes each of these milestone creatures possessed to thrive. Earlier creatures will require less detail. These might be as simple as "can think in 3d", "has bones", "understands concept of in-group". For each milestone, you'll need to work out the creature's environment too since this is critical in deciding fitness.

Starting with the last million years of a creature's history, explore in increasing detail its morphology and psychology. If the creature of interest has changed significantly in the geologically recent past, pay close attention to that period of change.

  1. Each of these intermediate life forms will have something that makes them competitive in their environment. We see that decedents will share this feature unless it reduces fitness or is superseded by another, more fit feature. Maintain a list of features for the creature of interest.

  2. Examine the various aspects of life of this creature. How is it conceived? How is it born? Does it require significant nurturing or is it precocious? Does it work in groups or alone? How does it acquire its food? Is it food for other things? Is there a long standing environmental danger? Are there significant changes in morphology as the creature ages? Does the creature age? Does it use tools? Does the environment force some kind of extreme adaptation (hot, cold, wet, dry)? Is this ambush or pursuit predator? Where in the food chain is this creature? The possible list can go on for a long time. Make as many useful question as desired and answer them.

  3. Harmonize the inherited feature list with the creature's feature list from the previous step. If there are discontinuities or features that just don't match up or make sense, go back to the previous steps and correct them.

  4. There should be enough information from the previous step to write a brief description of what will motivate this creature and how it will interact with its environment.

  5. After summing up the mental characteristics, you should have a pretty good idea of how this creature came to be and why it might behave in a certain way.

The degree of detail and the number of iterations is left completely up to the author to decide. Happy exploring!


I find the most powerful tool for understanding how a creature will act is to look at what doesn't change. The reason for this is somewhat circular. We tend to give the title of "creature" to things that exhibit what Aristotle called entelecheia, which is energy/motion of something being itself. A fish must expend energy to continue being a fish. We call it metabolism. If the fish stopped doing this, it would quickly become "meat," consumed by animals and single celled organisms. The thing which interested us in the first place is that which is kept still.

We can further break this concept up into "naturally stable" structures which do not change much on their own and "naturally unstable" structures which require continuous expenditure of energy. Everything else a creature does will fill in the gaps with things that do change, and they will change until they best suit the creature.

Naturally stable things are concepts like teeth, claws, and other structures which generally are not trying to continuously decompose. These are interesting because the creature had to spend an initial amount of energy constructing them, and after they are constructed they have very little control over them. The creature will generally find ways to use these stable structures to their fullest extent possible. A tiger's claws are extraordinarily good at clawing prey. To protect them, the tiger has muscles that retract the claws when not in use.

The key thing to remember about these naturally stable things is that they always have a use. It took energy to create them, and the creature doesn't have much control over the process. For evolution to have decided "this is the best path for this creature," there must be a use in the environment that warrants the energy expenditure.

Naturally unstable things are more interesting, in my opinion. These are patterns that are valuable to the creature, but only exist because of a feedback loop controlling them. Emotions are an excellent example. Emotions serve to help us cope with the world around us, but they themselves are unstable unless controlled by a "higher" brain function. These naturally unstable things are what are the difference between a tiger from the wild and a trained tiger in the circus. They are adapted to the environment, and they're held still by continuous expenditure of energy to keep them the same (entelecheia).

Of course, the control loops which support these naturally unstable characteristics, themselves, must be explained. This can be done iteratively, until you get to the "core" of a creature. This is it's "self." When you get to this layer, you truly understand the creature from the outside in, and can then understand it from the inside out.

Now while this can be a very unstructured process, typically we assume some earth-like structure to it. This is where answers such as Erin Thurby's answer come in. Consider mating. The species needs to procreate. It spends energy to continue being itself (entelecheia, at a species level this time). The nature of the species can be captured here.

Basically, you can refine any psychological estimate of a creature simply by running a mental simulation of how the creature behaves, and observe what doesn't change. If, in support of maintaining it's "self," your creature appears to choose not to mate, there's a good chance that psychological estimate was not the right now. If it looks like it's not using its beak or its claws or some other stable structure, it's wasting that energy and is probably not a good estimate.


Starting with environment and morphology should give you plenty to work off of for psychology. Think of it like this - the psychology becomes a strategy to survive in the given environment with the given morphology.

My answer is formatted a bit different than others; I will work through an example:

Using real-life wolves as an example: wolves are moderately sized carnivores. They have a relatively weak sense of smell for a canine, which makes it harder for them to hunt small prey. They tend to live near and hunt larger prey that move in herds, like deer and bison.

Now we can start with the psychology. Since wolves have evolved to hunt prey that is much larger than they are, it makes sense for them to hunt in groups. We can assume several wolves should be able to bring down a large animal more easily than a single wolf (Wikipedia reports that isn't true, but we'll pretend it is for simplicity). Furthermore, one kill should provide enough food for several wolves.

Already we have a reason for our wolves to have some basic social behaviors. Let's consider further on the fact that wolves often prey on herd animals. They can use cooperation to hunt more efficiently - a simple strategy could be to split into two groups, and have one group try to divert some of the herd directly into the other group. The more coordinated the pack is, the more successfully they should be able to hunt. This level of teamwork promotes a tightly knit community. Now we're moving toward a cooperative social structure, with groups of wolves living and working together. From here, you start thinking about the way they form into groups - in this case, by family.

Temperament can also be derived from environment. Let's say your wolves only see one herd of prey a week and have to compete with bears for the meat. They are likely to be suspicious of, or fiercely aggressive towards, unaffiliated packs, bears, and anything else that might eat their food.

You can get a very good on a creature's psychology by answering a few simple questions.

  1. Does the creature's morphology/environment make it more likely to be successful operating independently or in a group?
  2. Is the creature more likely to be successful if it defaults to flight or to fight (or passive observation or subservience or...)?

Research analogous creatures on Earth when you aren't sure how to answer a question or can't come up with enough details. If your creature survives by eating a toxic plant which no other creature in its environment uses as a food source, you could research koalas (which survive on toxic eucalyptus) to see how their diet affects their behavior.

A few things to consider when writing a story:

  • It's a story, and sometimes the needs of the story supersede the environment and morphology you've come up with. If your alien species needs language or trade, they need some element of civilization, so you can't design them in a way that promotes isolation and prohibits community. Think of environmental or morphological reasons for them to have cooperated enough to develop those qualities of civilization.
  • If you're trying to make your alien species interesting, try to think of a unique psychological characteristic that will be novel or counter-intuitive to your readers. For example, the smallest and frailest member of the tribe is the most honored and revered, because it is the only one light enough to climb the ralthis trees and pick the treasured sarak fruit. When your human character throws up, the alien mistakes it as a marriage proposal because their species regurgitates food to attract mates. I'd say that if you're devoting this much time to fleshing out the species, this should be one of the first things you address.

provide a way to know when the process is complete.

The process is complete when you have enough information to fill your needs. If you're writing a story, it's complete when you know how to answer any questions that come up when you're writing the text. If you're making a game, it's complete when you have enough information to design the creature's appearance and behavior. Any time you run into a question you didn't think of ('how would this creature decorate its cave?') you simply go back and flesh out what you've already come up with.


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