The Nature of Cognitive Impairment

In one episode of Invader Zim (focused on a laughably-incompetent alien invader named Zim and the conspiracy-obsessed kid Dib who sees through Zim's disguise), Zim shrinks himself and pilots a very tiny ship that travels inside Dib's body. There, he heads for Dib's brain, with two goals in mind - wiping out Dib's knowledge of where he hid proof of Zim's identity, and making Dib stupid. After accomplishing his first goal, Zim turns a dial that goes from smart to stupid, and begins charging his machine, while announcing 'now, to unleash stupidity upon your entire brain!' Fortunately for Dib, however, Zim gets defeated just in time, and Dib's intelligence remains intact.

Obviously, intelligence does not work that way. We don't have a 'dial' that goes from profound cognitive impairment to profound giftedness. Intelligence is also not like height, in that we can't clearly identify a single dimension that people of different intelligence levels vary along in a linear fashion. Cognitive tests involve a wide variety of specific cognitive functions which, in NTs, emerge at many different ages, and individuals are scored based on how many of these cognitive functions are operational and how consolidated they are (as measured by whether they perform certain tasks correctly).

But what is different in the cognitive process of an intellectually disabled person as opposed to an NT? There are hundreds of different possible etiologies of cognitive disability. Even if you only look at genetic causes, genes that are implicated in cognitive development may perform many different specific tasks. LIS1, on chromosome 17p13.3, influences a process called 'neuronal migration', which takes place early on in brain development - deleting this gene causes lissencephaly, where the brain is smooth instead of wrinkly, and results in profound cognitive impairment, severe intractable seizures and severe cerebral palsy. In contrast, the DLG3 gene on Xq13 influences how neurotransmitter recepters are clustered, and mutations cause moderate cognitive disability in males. And MECP2, on Xq28, doesn't do anything directly, instead regulating the activating of a wide variety of other genes, and mutations in MECP2 can cause a wide variety of different cognitive disabilities depending on the specific kind of mutation - in males, MECP2 mutations have been linked to a severe neurodegenerative disorder with death in infancy at the one extreme, and mild cognitive disability at the other extreme. Each of these mutations have very different effects on the structure and function of the brain, but they all cause cognitive disability of varying degrees.

So my question is, what specific cognitive processes, if impaired, could cause wide-ranging, pervasive effects on development?

Koike et al (1992) studied 22 individuals, ranging from 8 to 57 years old, who were all identified as profoundly intellectually disabled, with a wide range of underlying causes. None had independent mobility, only one had any useful handskills, and all were profoundly impaired in both receptive and expressive language. Important to the testing procedure is the fact that none of them showed any visual impairment and all of them blinked when an object moved rapidly towards their eyes.

Each participant was seated in front of a blind and a teacher held the participant's head in position to watch it. At each trial, the blind was removed and they could see an object with one of two patterns (a circle or a cross) on it move slowly back and forth. Their visual tracking of the object was recorded by two experimenters as well as by electrodes attached to the participants' faces. Each individual saw the first pattern on six trials in a row, and the second pattern for the last two trials.

In most people, if you present them with the exact same thing over and over, they get bored. This is measured as a reduction in response to the stimulus - in this study, reduction in visual tracking - and is known as habituation. If you then change the stimulus in some way that the person can perceive, they will 'perk up' and responding will increase - this is dishabituation.

Eleven participants showed that exact pattern, of habituation followed by dishabituation. Since this pattern is shown even by newborns, that's not all that surprising. What is surprising is that the other 11 didn't. Two showed habituation, but then didn't dishabituate when the stimulus was changed, and the other 9 didn't habituate - in other words, they showed just as much interest the sixth time they saw the stimulus as they'd shown the first time. These eleven, incidentally, had significantly poorer communication skills than the participants who habituated.

Now, there are many possible explanations for the observed failure to habituate. Maybe they had more subtle visual problems that interfered with perception of the two patterns. Maybe visual tracking was automatically elicited by movement whether or not they were interested in it. Or maybe they have severe difficulties remembering visual shapes.

But let's go on a thought experiment. What if a child was born, who was almost completely normal in cognitive potential, except that the child couldn't habituate to repeated stimuli? In other words, to this child, newness doesn't 'pop out' and catch his/her attention because everything feels 'new' even if he/she has seen it a hundred times. And not because the child can't remember seeing it before, but because seeing it before doesn't make it any less inherently interesting to this child.

If you attend to a stimulus, you can learn stuff about it. But within a very short time, you run out of things you can learn from a single unchanging stimulus. At this point, most children will disengage from the stimulus and start ignoring it, or else do something to change the stimulus in some way. Furthermore, when they've got something tuned out, they no longer expend any significant mental effort in processing it.

So the net effect of habituating is that two things happen: you stop expending effort attending to something when there's no benefit to attending to it, and you shift focus to some new stimulus that can teach you something else.

If a child does not habituate, therefore, they'll spend an awful lot of time paying attention to the exact same things. (Like a norn pushing the elevator button over and over.) And they will spend less time attending to new things - things they can learn from. As a result, their overall learning opportunities will be reduced.

In addition, the desire for novelty provides a strong motivation to learn certain skills, because many skills help a child expose him/herself to something new. Reaching allows the child to get tactile stimuli from objects within reach, and grasping enables them to move the object: maybe chewing on it, maybe throwing or dropping it, maybe banging it against something. Mobility allows the child to bring things into reach that weren't previously in reach, and to change what appears in their visual field and possibly the texture of the surface they're on - and not only that, they get kinesthetic stimuli from performing the movement! Communication skills allow them to request that others provide them with stimuli (eg giving them an object they can't reach), and also allows them to get novel information from the messages that others convey.

A typical young child will quickly realize that learning new skills will bring them opportunities to explore new things more easily, and will try very hard to learn those new skills. A child who isn't interested in new things, in contrast, won't try as hard to learn new skills. He/she may try to do so for comfort reasons, such as shifting position so he/she doesn't have one arm twisted underneath his/her body, or learning how to say 'no' so people will take things away that the child finds upsetting, but he/she will have one less motivation to learn skills, and will therefore be less willing to exert a lot of effort to learn those skills.

This might set off a cascade of missed opportunities throughout the child's life, such that the child falls further and further behind in development. Could this result in some cases of profound intellectual disability?

Instincts, Predators, and Animal Rights

I'm a supporter of animals rights, but not in the way most people frame it. For example, I'm not, and am not planning to become, a vegetarian, even though that means that animals die to feed me. The big reason for that is simple: I don't think my cat is like Jeffrey Dahmer, even though both of them torture, kill and eat other living creatures for fun. (My cat gets plenty of cat food. Hunting mice is not a matter of survival for her. If it was, she'd be quicker about killing them.)

Recently, I mentioned this to an animal rights vegetarian, and she said that there's an important difference between my cat and Jeffrey Dahmer - cats act on instinct, while humans have choices.

It would be a great argument, if it actually fit the facts. But it doesn't. It's wrong on both counts.

First, let's clarify what having instincts means. A lot of people, when they think of instinctive behavior, think of something like a songbird who, having never heard his species' song before, reproduces it perfectly upon adolescence. Or a duckling following the first thing he/she sees upon hatching.

Those are certainly instincts, but most instincts are more subtle. They're more on the level of certain connections being easier to learn, certain stimuli producing emotions that nudge you into certain actions, and so forth.

And it's mostly the more subtle instincts that humans have. Think of the most dangerous things a modern person is likely to encounter - cars and electricity. Most electrical outlets have several hundred times the amount of electrocity needed to kill us. And car accidents are one of the most common causes of accidental death. Yet the number of people who are afraid of cars or electricity is greatly outnumbered by the number of people who fear snakes or spiders. The simple reason is that we're genetically programmed to be more likely to fear spiders and snakes. Therefore, it takes a lot less to teach us to fear spiders and snakes than to fear electricity or cars, both things that cave men didn't have to worry about.

Sexuality is another example. It used to be that sex education was very poor, with many young couples marrying without either person knowing how babies are made. Yet they managed to make babies nonetheless - in fact, lack of sex education increases the likelihood of a teenager getting pregnant, instead of decreasing it. The reason? Sex is instinctive. You find yourself craving the touch of the other person, and the exact same sexual actions that are most pleasurable for the majority of people are also the ones most likely to cause pregnancy. The majority of people most enjoy heterosexual penis-in-vagina intercourse. Other activities may be fun, especially for a bit of variety, but standard intercourse, the only sexual activity that results in pregnancy, is also the most enjoyable one. Teens with no sex education will, by simple experimentation, end up figuring this out soon enough.

Language is another instinct. Attempts were made to explain language development in children by learning alone, but none of those theories could explain how good most children are at it - and the specific kinds of errors children make when learning, such as overregularization (eg 'haded'). The current theory is that children have an inborn 'language module' that leads them to expect a certain kind of structure to language, and they apply these rules to the specific language they're exposed to. If you look at all the languages in the world, they all have certain things in common, despite their vast differences. (Incidentally, children with specific language impairment seem to have genetically based abnormalities in the language module. One gene, FOXP2, has been found to be particularly important for learning how to do the rapid complex movements needed to say words.)

Another instinct is particularly relevant to the likes of Jeffrey Dahmer - instinctive morality. Children as young as 3 or 4, if asked, will tell you that some things are wrong only because an authority figure forbids them, and others are inherently wrong. The things that are inherently wrong are things that the children believe causes harm to other people. (These things can be justified by appealing to greater harm if they're not done, but that's another matter.) All cultures make this distinction, even if religious beliefs cause them to predict harm in different circumstances. And the only groups who don't draw this distinction are psychopaths and people with a specific kind of brain injury. Psychopathy, incidentally, seems to bear little relationship to the child's environment (abused kids are mostly normal on this particular test). Instead, psychopathy is genetic - for example, identical twins are much more similar on psychopathic personality traits than non-psychopaths. And though most psychopaths aren't serial killers, most serial killers are psychopaths.

So, though Jeffrey Dahmer did indeed have choices, his actions weren't simply a matter of choosing differently from most people. He most likely lacked certain instincts that strongly discourage the average person from doing the horrific acts that he did. On the other hand, one of the main reasons that I am not a serial killer is not a matter of what choices I've made, but the presence of certain instincts that make me feel horrified and disgusted at the thought of murdering in cold blood. It would take considerably more to push me into murder than it takes for a psychopath, and that's not something either of us have chosen. Instincts, or the lack of them, can have a considerable influence on a human's life - despite the common belief that we're above instincts.

And, conversely, cats can make choices, too. Certainly, attacking and killing rodents is largely instinctive (though it is affected by learning, since cats raised on mice hunt differently from cats raised on birds). But there are many cases of cats who befriend rodents. I had such a cat myself, a kitten named Hermes. The urge to attack his rat friends was clearly strong - he'd put his paws on them, lick them obsessively, and watch them with that 'predator focus' that cats have. But he never once hurt them, despite his instincts pushing him that way. He knew they were friends, and even though they were delicious, he must not eat them.

So, we're not really that different. Sure, our behavior is much less instinctive than cats, and we're much better at learning. But it's a difference of degree, not of kind. That argument may work with an insect, I don't know, but it certainly doesn't work with a cat.

Character Descriptions

I'm taking a creative writing class, and I finally got the textbook for it several weeks in. And, quite bluntly, it sucks. The class is great, but the textbook seems to have no clue what good writing actually is. If you know absolutely nothing about creative writing, you'll benefit from some of the more obvious advice in the story, but for much of the more complicated aspects of good writing the book leads you in the exact wrong direction. (For example, it recommends against including details that don't advance the plot, when the absence of such details makes your plot transparent and gives the impression that the entire universe revolves solely around the protagonist. A good example of an author who breaks this rule very well is JRR Tolkien.)

One particular bit of advice is about character outlines. These are basically a form-based description of a character, something like the following:

Full Name: Marie Kockaert



Nick Name(s): Moonbeam


Gender: female


Age: 400 or so years old, turned into a vampire at 17


Birthday/Year: 1650s


Marital Status/Sexual Preference: unmarried, probably heterosexual but too precoccupied to think about it


Spouse: n/a

Origin: Belgium


Language(s): English, French, Flemish


Height: kinda short but not unusually so


Weight/Body Structure/Physical Faults: very skinny


Physical/Mental Health: believes drinking blood is bad so is constantly starving herself, accident prone due to lack of concern for own well-being, extreme black-and-white thinker, obsessively religious, suffers from unrecognized PTSD due to the Spanish Inquisition, feels like she should punish herself, longs to die but thinks suicide is a sin


Race: white


Clothing: she usually just puts on whatever, though she avoids revealing clothes because she considers them sinfull


Parents/Guardians: she was a farmgirl with Catholic parents who had mixed feelings about the Spanish invading (at first rooting for them in their efforts to rid Belgium of heretics, then more and more alarmed at how far they were taking it). Her vampire parent was Bjorn, an Icelander who believes in honor, kinship and raiding/pillaging, and who agreed to turn her in exchange for sparing her family after his son was killed


Siblings: an older brother, who killed Bjorn's son and was killed himself in revenge

Usually they're much longer, but you get the point there. There are two potential purposes I can see for such an outline - to keep from forgetting little details (eg having your character's eyes brown in chapter 1 and blue in chapter 3), and to flesh out your character. The first is a pretty good reason for an outline, at least containing any such niggling details. The second, though, is a very bad idea.

See, what character outlines do is chop the character into a bunch of little pieces. It's very tricky, when looking at a character outline, to pull those together into a coherent whole. If you already have a good sense of the character, an outline won't hurt, but it won't really help either. But if you don't have a clear idea of them, you'll end up with a bunch of disconnected pieces and no easy way to turn these into a real character. At worst, you may have contradictory traits, such as describing one of a character's strengths as 'easy-going' and one of their weaknesses as 'hot-tempered'.

But the reason these are so widely appealing, I know, is that they give struggling writers something concrete to do to flesh out a character. So I'm going to offer something concrete for a writer to do if they need to flesh out a character, that should give you someone much more well-rounded than a character outline will provide.

Gordon Allport, one of the early personality theorists, suggested that personality traits can be divided into three main categories - cardinal dispositions, central dispositions and secondary dispositions. Secondary dispositions are minor, unimportant traits, more akin to habits, such as a student who always chews on his/her pencil when pondering a multiple choice answer. People have an uncountable number of secondary dispositions. Central dispositions are relevant to multiple situations and show up in multiple different behaviors, but are not the most crucial traits to a person's personality; typically you can identify 5 to 10 of these. And lastly, cardinal dispositions are the defining traits that tell you who this person truly is, and each person has only one or two of these.

In sketching out your character, start by identifying their cardinal traits. For example, Moonbeam's cardinal traits are her self-hatred and her fanatical Catholicism. Just knowing that about her tells you a lot. (Of course you'd need to know that she's a vampire, too, but that's not a personality trait, it's a background detail.)

Incidentally, if you have no clue what your character's cardinal traits should be, you can look at your intended plot for ideas. Their personality will shape their actions, and their actions will shape their plot, so identify specific things your character has to do in order for the plot to unfold as intended, and figure out what personality traits might lead them to do that. For example, one character in a different story, Terald, has to help a friend of his murder her villainous sister, then once he discovers the sister alive and severely brain-damaged, he has to spare her and take care of her. This led me to the realization that he's an extremely forgiving and highly moral person who has been sorely tested by this villainous sister, and reluctantly decides that he needs to take drastic measures to ensure that she will cause no further harm. As a result, I realized that Terald's cardinal dispositions are his strong moral code and his logical reasoning, which are often pitted in conflict with each other. (Note that if you have to chose between a well-fleshed-out character and a desired plot, I'd pick the character first. Only go from plot to character if you don't have a fleshed-out character yet.)



Once you've identified the cardinal dispositions, flesh them out. You can do this is two directions. Firstly, go back in time. Where did this trait originate? Is it part of their inborn temperament, or was it shaped by their environment? In Moonbeam's case, she was Catholic but not a fanatic as a girl, and then after a couple decades of being a vampire, she was tortured by the Spanish Inquisition. She decided they were in the right, and this belief led to both of her cardinal traits. (Note that formative events can change cardinal traits, but this is tricky to do convincingly in-story.)

Secondly, look at this cardinal trait in different situations. What specific thoughts, feelings and behaviors are involved? In the case of Moonbeam's self-hatred, this means painting out what, exactly, Moonbeam hates about herself. She hates that she's a vampire. She hates that she's hurt people. She hates that she's immortal, which to her means being cut off from God and from the natural order. She hates her unacknowledged anger and fear at the torturers, and love (parent-child love, by the way) for Bjorn. She hates that she's been miserable for so long. In terms of her fanatic Catholicism, this would mean deciding what, specifically, she believes, but you get my point already.

At this point, chances are you already have some central dispositions. Moonbeam, for example, has shown in this bit that she is quite determined and doesn't flinch away from unpleasantness, because rather than trying to forget her sins she's trying to atone for them. She's also a caring person, as shown by her concerns about hurting other people. She is highly anxious, as a result of her traumatic experiences. All of those come directly from fleshing out her cardinal traits.

Then, you can add other things which fit well with both your existing characterization and your intended plot. For example, since Moonbeam's role in the plot is as a supernatural detective, she has to be an intelligent person - a stupid person wouldn't be much good as a detective.

Around this point, you probably have thought of secondary dispositions too. But don't put too much effort into fleshing these out, unless they're plot important or add realism to the character. For example, Moonbeam's shoulders always start to hurt whenever she prays, which is a sensory flashback to a particular torture technique that tends to dislocate the victim's shoulders. This detail is included mainly as one of several hints leading to the eventual reveal that she was severely traumatized. Another kind of plot important secondary disposition is one that causes someone to recognize them when they don't want to be recognized, such as when they're disguised - the brain-injured villain in Terald's story is eventually recognized by her sister due to her favorite food and her love of climbing (she used to climb things all the time as a small child and eventually outgrew this behavior, only for it to re-emerge when she's at the same cognitive level once again). But you won't be able to flesh out every single secondary disposition, so don't even try.

I hope people find this helpful.

The Line

One thing that psychopaths often don't seem to understand about empaths* is that we each have a line, a set of rules that must not be crossed. A psychopath can push an empath a certain amount, but once they cross that empath's line, the empath will lose all sympathy and tolerance for them.

An example: My uncle, who I suspect was a psychopath, spent much of his life counting on my father, among others, to bail him out of trouble. See, there was a family rule in my father's family that everyone was supposed to take care of this person. My father followed this rule, doing things like lending my uncle money that he knew he'd never see again, paying my uncle's bail so he wouldn't have to spend a few nights in jail, forgiving my uncle for various wrongs he did to my father, and so forth.

Then, my father had his niece and nephew over for a visit, and his niece revealed that her father, my uncle, was sexually abusing her. My father's behavior to his brother changed immediately - he turned him in to the police, did his best to ensure no contact between my uncle and his children, and for the rest of my uncle's life he had as little contact as he could with my uncle. (Which, for the period of time I can remember, consisted of seeing him once at a funeral, where my father did not acknowledge his brother and turned away when his brother tried to talk to him.)

My uncle never seemed to get that it was over. He kept trying to mend the relationship, to convince my father to forgive him. At court at one of the custody hearings, he apparently ordered his lawyer to say that he just wanted everyone to get along. Even 15+ years later at a relative's funeral he tried to talk to my father, hoping to patch things up. After all, my father had always forgiven him before.

You see this clearly in a lot of fiction. There are many heroes who engage in transgressive behavior, like beating people up or in some cases killing them. But if they cross a certain line, they will cease to be considered a hero. (Admittedly, rules in real life are usually stricter than in fiction, because people don't have to face the real-life consequences of the actions such as making a mistake, setting a precedent, etc.)

Dexter, for example, despite being a serial killer, manages to be a hero, because he has certain lines he never crosses. The big one is that his violence to others is proportionate to the violence they have engaged in. He only kills people who have killed multiple people themselves. The times that he faces foes who have never killed, such as his girlfriend's ex-husband (a physically and emotionally abusive drug addict), he deals with them through methods other than murder. Even Doyle, who found him out and was planning to expose him, he was not able to bring himself to kill.

Another line he never crosses is that he never kills children. Once, he contemplated killing a budding serial killer teenager, but the plot conspired to ensure that he changed his mind. This is important because children, even when they have done wrong, are not considered to be as responsible for their actions as adults are. And because children are designed to elicit maximal levels of empathy - all immature mammals have certain physical and behavioral traits that mammals are instinctively predisposed to consider 'cute', in order to elicit nurturant behavior from them. Dexter's caring behavior towards children, therefore, serves as a signal to viewers that despite being a serial killer he is still a hero.

There are other uncrossable lines for many people, such as betrayal or sexual violence, but those are the main ones. Furthermore, each empath is somewhat unique in this regard - while the big things tend to be universal, every person draws the line slightly differently. For example, people who hold strong views about tolerating diversity may lose all sympathy for someone who expresses a racist, sexist or homophobic view, while other people think it's wrong but not unforgiveable. Some people see infidelity as unforgiveable, others do not. My father did not consider reporting his brother to the police to be crossing the line (provided he'd done something bad enough, which he had), but his family did. Often if you ask a person what they consider unforgiveable, they can name specific things, though sometimes people don't know that they find something unforgiveable because it hasn't occurred to them that anyone would do that.

And an important point: this line tends to be mostly the same regardless of whether the wrong was done to them, to someone they care about, or even to someone they don't know or don't like. The one exception is that many people tend to make excuses for the wrongs done by people they care about and therefore may require a higher standard of 'deserving victim' if they liked the victim. But for the most part, it doesn't make much of a difference. My father reacted similarly to my uncle abusing his own children as he'd have reacted to my uncle abusing me (which he did not have the opportunity to do, fortunately). He'd have been more emotionally distraught about me being abused, but he'd have taken exactly the same measures. Furthermore, if he had not known the children at all before discovering they were being abused, he'd likely have reacted similarly.

* Non-psychopath - includes NTs plus people with other brain differences that are unrelated to psychopathy.