Aren't we the normal ones for noticing everything??

i notice things like dog poo bags swinging from trees a rabbit thats about 100 meters away and such

It’s a question I am quite interested in.

To me my autistic brain is normal because it’s the only brain I have ever, and will ever have. The non autistic brains that filter out much more data via sensory gating processes, are the majority brain type but that doesn’t mean the same thing as “normal” to my mind. 

I spend a lot of time thinking about what it would be like to have much higher sensory gating and information filtering …. 

I agree that this is a really useful book.

I also really like the Olga Bogdashina book “sensory perceptual issues in autism and Asperger’s syndrome”. It seems very important to read the second edition not the first though! The language in the first edition is not something i enjoyed and it’s not got a lot of the up to date research.  She does a really good job of gathering together all the research on the subject. The thing that really stood out for me was how much sensory gating non-autistic people do - their brains are disregarding a much higher amount of the data their senses send to their brains. So that’s why they can’t feel the clothes they are wearing unless they draw their attention to the feeling and it’s not that they can’t see the details in their environment it’s just that their brains unavoidable filter more of the details out of awareness. There is not a lot they can do about it apparently. 

I read a book which explains this - A field guide to earthlings by Ian Ford.

Yes, NT brains filter out some sensory inputs, which allows them to cope better in busy environments and multi task. Babies don't have this, it develops over time and is usually complete by adulthood if I understand correctly.

It's interesting and I thought about it too. My idea, from things I've seen and read over the years, is something like this:

Most people think of their eye like a camera. You see with your eye, but the eye is a sensor and you see with your brain.

Your eye sends stream of data. It is high resolution. The centre is higher resolution and you have a blind spot in each eye due to the optic nerve, so you move them around. Your brain creates an image piecing data together.

It is a lot of information to process in real time. Even though you have a disproportionately large amount of your brain allocated to processing visual information it throws most of the data away. There is an interesting experiment that prove this with basketball players.

It creates a 3D mental representation of what is there, based at on edges and colour, there is pattern recognition. This is how you can reach out and pick something up or point without looking or get close. It is how you move around without walking into things, or throw things accurately.

If you close your eyes, open them for half a second then close them, then think about what you saw or tried to draw it, you'll notice how much detail and the sorts of things that get noticed a first glance.

If you look at a pile of books you won't notice the titles of each one in in a quick look, even if the image in theory has enough data and resolution. Over time you can fill in more detail.

I think difference between people is how much detail is in the models, how much you fill in by looking closely, and the level of detail that stands out as important and is worth noticing. I think it is a difference in degree. The more mental power put into image processing the less to put to other things, like communication. It is harder to talk when looking at something in detail.

Even if you notice more than most it is still only a fraction of what is there. I notice things other don't, but I still miss a lot.

To take short cuts you have pattern recognition. It is why you see shapes in clouds or faces in random pattern. It is to detect a tiger hiding in the grass.

You look for edges, which is why camouflage works because it breaks up the edges and the shapes spoiling your pattern recognition.

You are highly biased towards noticing movement, which is change in some pixels. This is a survival thing, to detect something coming towards you.

The more your nervous system is on edge, which is a lot of time in ASD, the more the movement, edge detection, pattern recognition etc. will be turned up.

Try observing if you see the same when relaxed and when anxious.

I think this is probably a major cause of difference in the real world. If you are more relaxed, the threat detection system is turned down, so your brain can put less effort into processing images. NT may just be more relaxed. 

As far as smell is concerned, discovering this explained why colleagues didn't notice smells I made comment on. It can be helpful, but when mine is particularly heightened it means I smell more than I need to.

I have also noticed at work that others don't notice subtle changes. Sometimes I have to decide whether to comment if they are unimportant. I have discovered I can be intrigued in things that others do not think about.

In respect of sound, others around me notice annoying sounds like neighbours dogs who bark for a long time. The sounds that only I notice are often very subtle sounds. 

That is interesting about eye contact, I suppose that is why it uses more energy. 

I think everyone does seem or feel these things, it's just that their brains either choose to ignore them or that it is deemed to be unimportant so it just gets filled away.

A random example of my own experience. I'm very aware of the pressure on my skin, clothing, my watch, wedding ring or even the weight of my body on the bed etc 

Everyone must experience this but it just doesn't seem to be a factor in their lives.

The whole sensitivity thing, is it because we feel certain things more or is it because we are just so much more aware of those sensations that make them difficult to live with?