The Mystery of Personality
Great white sharks don’t have personalities.

Let me rephrase that: great white sharks all have the same personality. As one fictional scientist put it:
Out there is a Perfect Engine, an Eating Machine that is a miracle of evolution. It swims and eats and makes little baby sharks. That’s all.
MATT HOOPER, JAWS
They hunt. They eat. They mate. End of story.
And it honestly isn’t strange. Most animals are like that. If you were to perform a Freaky Friday style body swap on a great white shark and, say, a butterfly, how would that play out?
Honestly, I doubt there would be a noticeable difference. The butterfly in the body of the shark would have to learn new skills, like swimming and breathing water, but once it figured out how being a shark works, it would just go on following the instincts of its body, much like it always does.
Most animals have the same goals and drives, and you can hardly tell one from the other. Which makes sense, since most animals are merely trying to survive.
It’s the exceptions that are weird.
Yes, I’m Sure
Your first objection is really easy to dismiss, so let’s get it out of the way right now.
Of course there is the possibility that all animals have personalities that are only visible to other animals of the same species. For all I know, great white sharks have moods and quirks that other great white sharks can detect.

Perhaps that species is home to a cast of colorful characters with fascinating backstories and individual preferences and personas. That could all very well be true.
But it doesn’t matter.
Because other animals exist whose personalities are human-recognizable. If, as a rule, personality can only be discerned by a member of one’s own species, why are there so many exceptions to the rule?
It’s safe to say that any “member’s only” personality traits—if they exist—are a different phenomenon than typical personality. These secret handshakes are so subtle that, for human purposes, they might as well not exist.
There is a difference, is what I’m trying to say. And it is in the animals that provably have personality that I take interest. Because there are commonalities among them.
Peer Pressure
In wild animals, certain flavors of sociology seem to accompany the development of individual personalities.
Of course, other forms of sociology do the opposite, stifling individualism. Take, for example, an ant colony.

An individual ant has less personality than perhaps any other animal. And maybe that has something to do with the crushing sociology of an ant colony. A rigid caste system decides an ant’s destiny. The peons have no personal goals or aspirations. They exist to serve the colony.
Thus we see that merely having a sociology is not enough to cultivate personalities. But consider cases where social animals develop individual characters. Animals like wolves or dolphins or crows. What common thread runs through their social structures?
Allow me to make the case that that the defining social force for creating personality is peerage.
In an ant colony, there are no peers. There are only those who command and those who obey. The workers have no relationships with each other.
Contrast that to a wolf pack, where peer circles are formed along generational lines. The geriatric wolves form one peer group, pups another, and young adults also have their peers.
It’s easy to see how any system that allows peer groups to form also requires members of that group to differentiate. Otherwise, individuals get lost in the crowd.
Solitary animals have no need for personalities because each one is the only member in its sphere.
Hive animals have no need for personalities because one individual is interchangeable with another, and individuals are sorted by caste rather than by peerage.
But animals whose sociology requires interaction between members of equal status require some other way (aside from status) to distinguish themselves. Thus, the need for individual personalities arises.
Humans Make It Worse
All of this, or course, gets complicated by domestication.

When humans tame and transform an animal species, it changes not only the forms of their bodies but the shapes of their personalities.
Don’t believe me? Just look at dogs.
Dogs certainly inherited some of their personality from wolf ancestors, but is there any denying that human intervention has led to an explosion of personality types in dogs, many of which cannot be found in wolves? We selectively breed dogs to be meaner or nicer, smarter or more faithful, better with children or better against intruders.
There are, simply put, more flavors of dog than there are of wolf. And when you look at other species humans have tamed, you can’t help but wonder how much of their personality is natural and how much is man made.
What Does any of This have to Do with Writing?
I used to think that creating lively characters was a blind spot in my own writing skill. Inventing new personalities is something that does not come naturally to me. Like many writers, I had to learn it through observation.
And I’m afraid that humans are no different from animals in this regard. We form our own personalities as a way of staking our claim within a peer group and serving human society in our domesticated roles.
There is much that we wish to do but can’t because we have, effectively, tamed ourselves. Likewise, there is much we don’t wish to do, but will, because we have a need for peerage.
I do not doubt that, given enough time, humans will domesticate all other species, and thus, invent new personalities for them. I’ve gotten much better at character creation in the meantime. And when I create them, I wonder if I’m simply inventing a personality for the character, or cultivating one through selective breeding.
Maybe there is no difference.

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If this is the extent of your understanding of animal personalities, and human ones, then I gear for how you render personality in your fictional characters.
For starters, great white sharks do have personalities that are obvious to people who spend any amount of time around them… Did you really just cite Jaws as a reference on shark biology? You are officially the worst scholar ever.
Social insects have personalities too, and some of those workers, who you describe as interchangeable will defy their queens by laying eggs of their own, for no apparent reason other than just because they can.
Your argument completely ignores any genetic aspect to personality, which is well demonstrated in many animal species, from mammals to invertebrates.
Octopuses have personalities observable to humans, and these are solitary creatures, totally lacking any form of society.
Different personalities have an evolutionary explanation. In certain environments some personalities help an individual survive, while that same personality is maladaptive in other environments. But environments vary in time and space, thus Harboring a diversity of personalities can lead to the longevity of a population.
The only reason humans were able to domesticate other animals in the first place was because there was already a variety of naturally occurring personalities present in the wild population to choose from. Individual animals that were more docile, were better suited for domestication and were bred for these personality traits.
So we see that the generation of a diversity of personalities is an evolutionary process. Divergence of personalities arises naturally in virtually all populations of higher multi-cellular animals.
And another thing, personality can change in an individual over time. Experiences can mold personality. Chemicals can also alter personality.
There is so much complexity to this thing we call personality, and virtually all animals exhibit differences in personality. Sea sponges, not so much, but practically everything else. These are not exceptions at all!
I would of course expect a marine biologist to project a personality onto any creature he studies. It is an extremely human thing to do.
Much like how a sailor will ascribe motive or mood to the sea, it reassures them that the object of their devotion can return their attentions.
But even at its most innocent, it’s a delusion. A worker ant that lays its own eggs is a malfunctioning cog, not a rebellious free spirit. Personality requires more than devious behavior. It requires that the correctness of behavior become subjective.
Likewise, intelligence is not personality. An octopus may possess the intelligence to navigate a maze, but so does a computer. True, many have been deluded into ascribing personalities to their computer, or their car, or their house or their toilet or their air conditioning unit. Yet these are correctly understood as personality quirks within the person and not their possessions.
I suppose next you’ll assert the existence of personality in jellyfish or amoebas, as those species also experience genetic selection pressure, and therefore (according to you) require a variety of personalities to ensure survival.
You think I’m anthropomorphizing sharks? I am not.
For a long time scientists were afraid to ascribe personalities to animals, for fear of letting their own human biases cloud their ability to be objective. However, in recent years most animal behaviorists have caved to mounting evidence that animals, both domestic and wild, do in fact display individual personalities and even possess feelings.
There is a book out called: Personality in Nonhuman Animals (https://link.springer.com/book/10.1007/978-3-319-59300-5) And there is an entire chapter in it about elasmobranchs… that is, sharks n’ stuff.
I am more familiar with personality studies in bony fishes than cartilaginous fishes, and there is a rich literature showing intra-specific variation in many personality traits. One of the easiest to test empirically is boldness. In Salmon, for example, the age at which freshwater juveniles (parr) dare to swim downstream to the ocean and become marine varies quite a lot within populations. Amazingly, if you administer an anxiety reducing drugs to the salmon (e.g. oxazepam) they transition to the marine environment at a much younger age (see Hellstrom et al. 2016. Nature Communications 7: 13460).
If this sounds like junk science—giving medication to fish—it isn’t. Fish that lose their fear and migrate to the ocean too early end up food for predators much more often than if they’d waited. You could decimate an entire population of salmon by polluting the water with chemicals that act as GABAa receptor agonists, like oxazepam. Sadly, this has happened. Salmon populations are valuable resources that need to be protected, and that is one reason why animal personality studies are important.
A quick google scholar search turned up a study about boldness and stress reactivity in port jackson sharks (Byrnes & Brown 2016. Journal of Fish Biology), and it seems there is ample evidence for variation in these personality traits. I didn’t find anything published about great whites, but I know people.
Hermit crabs also show distinct variation in boldness. Some come out of their shells much more quickly than others. Carl Safina (TV scientist) does this bit where he gives prozac to the hermit crabs and they lose their fear and don’t go into their shells at all. Isn’t that amazing that a drug meant for humans has a similar effect on a crustacean? Humans and animals have a lot more in common than most people realize. There’s also a case where humans have been able to stop mosquitos from feeding by giving them appetite suppressants. It sound too crazy to be true, but apparently it is real.
Octopuses are intelligent. They can figure out mazes. But did you know that they can also recognize human faces? Many aquarium keepers have noticed that octopuses are much more friendly with the people that feed them than the people who clean their tanks. And some octopuses are more interested in people than others. And some octopuses show playful tendencies that others of their same species don’t appear to have. If you ever watch the PBS program, Nature, there is a recent episode on octopuses that might change your mind about animal personalities.
So you see, your opinions about animal personalities are about 15-20 years old. You’ve missed a lot of the conversation, and you need to know that science has moved on from the views you’ve expressed in your blog post.
Salmon broods appear to be a peer group, in that they all hatch in the same season, and all return to their breeding ground in the same season. Your example only supports my original argument.
Though I wouldn’t use behavior-altering drugs as an example of “personality”. On the contrary: changing an animal’s behavior through use of a drug is more akin to programming a computer. You are superseding whatever individual behavior the animal has and bending it to your desire. Surely, that is the opposite of personality.
Salmon broods are not peer groups. To an extent they do act as a cohort, and exhibit a strong natal homing tendency, but some individuals will ignore the tendency, apparently just because that’s their personality. Yes, even salmon have their nonconformists.
It would be a mistake to try and divorce personality from behavior. What is a personality if not a unique collection of behavioral proclivities? Also the term “personality trait” is quite an appropriate and useful term, with which we can associate the basic components of a personality with individual behaviors.
Manipulation of personality traits, using drugs or other methods, is therefore insightful to the study of personality. This is true for both humans and animals alike, and is in fact more fully demonstrated in humans.
Look no further than the famous account of Phineas Gage (https://en.m.wikipedia.org/wiki/Phineas_Gage) for a human example in which alteration of the brain resulted in a causal change in personality.
Thus we see that both humans and salmon have personalities that are subject to tampering. If salmon are little computers to be programmed then so are people.
Both salmon and humans are born with free will, of course. But that can be taken away with enough programming. But unlike salmon, humans often stupidly program themselves to the point where change becomes extremely difficult.