Optical and auditory illusions

Svartalf · **#21** by **Svartalf** » Mar 26, 2020 11:14 am

Interesting, to me they are fascinating, at least until I've figured out what's wrong in my perception.

archibald · **#22** by **archibald** » Mar 26, 2020 11:47 am

Svartalf wrote:Interesting, to me they are fascinating, at least until I've figured out what's wrong in my perception.

I'm not going to claim to be able to understand or fully explain such illusions (which of course, being different, may have different explanations) but I'm going to have an amateur crack at an idea in general.

Our perceptions have to be reliable, for evolutionary reasons. They don't have to represent what's 'actually out there', but they do have to work pragmatically in order for us to respond in a way that enhances our chances of survival.

Now, nature, the world outside our brains, tends to manifest and function in certain repeatable ways, there are patterns and a great deal of apparent order. Our perceptions will tend to respond to that. They are less likely, I think, to have evolved to deal with very unusual situations (which I think is what illusions tend to involve) because the drivers for doing that are weak. In a way, I think it's about priorities and trade-offs. Better to adapt and respond to (make useful guesses about) what almost always matters than be equipped to constantly waste processing energy trying to analyse everything in detail, including outliers.

In other words, your perception is arguably working very well indeed.

archibald · **#23** by **archibald** » Mar 26, 2020 11:57 am

The McGurk Effect seems to be an example of where vision takes priority over hearing:

https://www.youtube.com/watch?time_cont ... e=emb_logo

newolder · **#24** by **newolder** » Sep 04, 2021 9:46 am

A x4 version of an earlier jelly twister. View it here because my attempt to attach the file does not work...

The_Metatron · **#25** by **The_Metatron** » Sep 04, 2021 3:34 pm

It's a big file, over 21 MB. Almost hurts my eyes.

newolder · **#26** by **newolder** » Sep 04, 2021 6:06 pm

Aha, makes sense and its effects are very strange indeed. :crazy:

don't get me started · **#27** by **don't get me started** » Sep 05, 2021 1:02 am

I read this a few years back.
A really good introduction to visual perception, and immensely readable.
Some of the processes involved in these optical illusions are described in accessible terms.

Basic Vision: An Introduction to Visual Perception - Robert Snowden, Peter Thompson, Tom Troscianko

https://www.amazon.co.jp/-/en/Robert-Snowden/dp/019957202X/ref=sr_1_1?dchild=1&keywords=basic+vision&qid=1630803512&sr=8-1