When a neurotypical (a person without autism) walks in to a store, restaurant or office building, they might notice a change in sound level. They adapt quickly, and extraneous, sensory stimuli fade into the background.
A person with autism, has a very different experience. Sounds, smells, the humidity or dryness of the air and bright lights, all combine to make an uncomfortable symphony of stimuli that quickly becomes unbearable.
As if that weren’t enough, they are then expected to be sociable and on their best behavior.
Some autistic people cope better with the sensory overload than others, but most can only tolerate it for short periods of time.
A friend or business acquaintance sitting in the next seat trying to carry on a conversation, might be the noise that provides the final sour note that leads to an emotional meltdown. This is when an autistic person might be accused of being unfriendly or mean.
For an autistic person, the world is a sensory battlefield.
Dripping water can be deafening, mechanical noises make the head pound. A sound as benign as a cat meowing can startle them and make it difficult to function.
Depending on the circumstance or the sensitivities and tolerance level of the individual, avoidance or retreat is often the only way to deal with the situation. This is when the autistic person might snap and make an angry remark, or an individual with less developed social skills might hit, bite or simply, run out of the room.
This is not about rude behavior. The autistic at this point, is sensing danger; adrenaline is pumping and they are in “fight or flight” mode.
A person fleeing from a hungry bear won’t stop to chat with bystanders as they run past. Social interaction, for a person with autism, can feel just that dangerous.
Particularly, when they have reached their sensory limits.
“What is normal for the spider is chaos for the fly.” -Charles Addams