I know that the concept of working memory may be subject to discussion. Still, there is a storage capacity limit. This is a real mystery to me. Working memory is known to be positively correlated to various tests (IQ for example). Why did natural selection not grant us a better storage capacity?
Before asking this question, I read some hypotheses by Cowan: The Magical Mystery Four: How is Working Memory Capacity Limited, and Why? Two camps are presented: capacity-limit-as-weakness and capacity-limit-as-strength. Basically the first camp explains this weakness from a neuronal point of view, claiming that keeping many items active is greedy and can cause interference. The second camp pretends that the lesser the number of items accessible is the quicker the cognitive processes are (chunking, searching, etc.). Honestly I don't know what to think. More than that, I don't feel its very convincing. If our neural system has evolved toward some incredibly powerful processing modules and can't even keep 10 items active at the same time, there must be a reason. I am more inclined to think that the capacity limit is a kind of strength somewhere, but I don't feel very convinced by the examples provided in the short passage I mentioned.
Do you have any extra arguments for/against any of these theoretical positions?
My preconception is that this limit constrains us to encode the real in the most powerful fashion. In short, we are always forced to learn more complex patterns. Is it relevant or not? Do you have any source which could challenge or back up this view?