Scientists who study large populations have uncovered several risk factors for aggressive behavior in autistic children—lack of sleep, poor social and communication skills, irritability, etc. (see my last post). In contrast, autistic people are less likely to focus on general risk factors than to describe their own personal experiences during childhood: the specific situations in which they threatened or injured others, and the way they felt at the time. Nevertheless, there are many commonalities among their experiences, commonalities which do not always correspond with what scientists have described. For example, while scientists tend to assume that all aggression is intentional, many autistic people report having engaged during childhood in unintentional aggression. One type of unintentional aggression is what I call reactive “aggression”—and I am using quotation marks because I am not sure that what is described below truly qualifies as aggression at all.
I have an instinctive fear of snakes. It’s not a phobia. If I have time to think about it, I can talk about and look at snakes. I even petted a snake once, to show my kids that reptiles aren’t dangerous. But if I am out walking and a harmless little garter snake wiggles across the sidewalk in front of me, I immediately find myself jumping a foot in the air and then running away. And if—God forbid—a snake were to fall out of a tree onto my shoulder, the poor thing would get whacked hard to get it off me, even though I have no conscious intention of hurting it. My reaction is purely instinctive.
Many autistic people report a similar response to being touched by other people, which they may find intensely painful: “The pain I feel when someone touches me is like feeling needles that sting my flesh.” Or if touch is not exactly painful, it may still be intolerable in other ways:
I don’t feel pain but I cannot tolerate pressure, which is what I feel physically when touched, to the point where my brain perceives being touched as being crushed, and transmits a threat response. I also feel a complete sense of psychological invasion as others have said, and I get an immediate irresistible sense of nononono that I have to get away from. Can’t abide being touched.
Averse to touch, autistic people may be able to avoid lashing out if they get some advance warning. But if they are taken by surprise, they respond instinctively, in the same way I would respond to a snake suddenly landing on me:
i have often hit people who have touched me without warning, particularly if they touch me from behind, a sharp elbow flies backwards. however this is not advisable as people take offense to it & some hit back! it is a reflex reaction for me, i have no concious control over it.
It is common for autistic students to hit out wildly when they get touched, and schools often interpret these reactive behaviors as aggressive. The result is punishment, usually in the form of suspension or (for repeated incidents) expulsion:
I got suspended for hitting kids when they got too close (I can feel people’s energy or “chi” when I get close to them or they get close to me and it is physicaly painful) 
However, autistic writers often remember these childhood reactions as uncontrollable:
Until about the age of 12 or 13 I’d regularly scream and hit people for touching me. Not so bad these days but I still hate unwanted touch. When I was younger kids at school thought it was hilarious to poke me until I lost my temper. Being poked is extremely painful, I’m very sensitive to touch. I try telling people this and they think I’m exaggerating.
Did any of you have a problem as a kid where if a kid hurt you (even unintentionally), you would hit them without thinking? I used to get suspended multiple times year for punching other kids because they pinched me between a desk or bumped me while playing soccer. It was a reflex I was unable to control until I was older.
As both of the last quotations indicate, some children learn to control their reactions as they grow older. However, even for adults this may require a tremendous amount of effort:
if someone touches my face, my cheek especially, i can barely control myself from hitting that person. being stuck in a slow moving crowd, i feel trapped and want to scream my lungs out. i feel like pushing people aside violently, i don’t do it because it’s wrong, but i slam my fist in an open palm and growl like an animal. i go crazy and no one notices.
Children in general have a much more limited ability to maintain control over their reflexes.
The reflexive childhood “aggressor” usually does not intend to hurt anyone, knows perfectly well that hitting others is wrong, and after the fact often feels very badly about the way they have behaved:
When I was a kid-I was at a friends house when a friend of his . . . came up from behind and grabbed me-now I do not like to be touched or grabbed from behind-now I know its because of AS-I did not know it was him and I turned around and punched who ever it was in the mouth and it was him-he ran crying and I felt so bad that I hurt this boy who was just playing and meant no harm but I thought I was being attacked and hit this poor kid-I felt really bad,so bad I pledged I would never hurt anyone for any reason ever again and I still live up to that to this day.It still upsets me to think about the incident and the thought of hurting an innocent,harmless person.
Should reactions which are instinctive, difficult to control, engaged in with no intent to harm, and often deeply regretted afterwards be consider “aggression”? I would have to say “No.” Certainly there will be a need for behavior interventions, to help these kids learn not to react so strongly to unexpected touch, but punishment seems inappropriate in such cases.
 In what follows, I will be drawing primarily on posts from the Wrong Planet website, which has thousands of autistic subscribers. Like other quick posts on social media sites, these may contain errors of spelling and grammar. This is simply the nature of such posts, which are usually composed in a hurry.
 Kairi96, in in the “I Feel Pain When Other People Touch Me” discussion:
 C2V, in the “I Feel Pain When Other People Touch Me” discussion:
 Sally, in the “About Hating Touch..” discussion: http://wrongplanet.net/forums/viewtopic.php?t=48437.
 PunkyKat, in the “Aspies—Ever Get Suspended/Expeled” discussion:
 Squirsh, in the “Do You Get Irritated When People Touch You?” discussion: http://wrongplanet.net/forums/viewtopic.php?t=169499.
 bluecurry, in the “What Were You Like in Elementary School” discussion: https://wrongplanet.net/forums/viewtopic.php?t=226220.
 Felinesaresuperior, in the “Odd Things That Make You Feel Irrationally Angry” discussion:
 Radiofixr, in the “Did Anyone Else LIKE Being Bullied?” discussion: http://wrongplanet.net/forums/viewtopic.php?t=129369.