Summary for those who are either in the UK and unwilling to use a proxy, or very short on attention span: Your sensory mechanisms, like any other means of dete

Summary for those who are either in the UK and unwilling to use a proxy, or very short on attention span: Your sensory mechanisms, like any other means of detecting anything, are less than perfect. Therefore you're going to get some false positives (thinking your phone is vibrating when it isn't) and/or some false negatives (not noticing when your phone really is vibrating). It's possible to trade off between these by adjusting the threshold for detection. There's no reason why the optimal point (or the approximation to optimality that your brain actually chooses) should give no false positives; more likely it will give some false positives and some false negatives. The end. (This tradeoff occurs all over the place. One interesting example, due to Justin Barrett, is the suggestion that (1) one thing our brains are set up to detect is signs of agency -- something purposeful acting in our vicinity, and (2) it is generally better for us to be too sensitive (thinking there is a tiger hiding in the trees when there isn't really) than not sensitive enough (not noticing the tiger, and getting eaten). And that this is the mechanism underlying a lot of belief in the supernatural: we see something, have the feeling that someone or something must have made it that way on purpose, and on looking closer fail to find any good candidates ... and are then liable to conclude that something we can't directly detect made it so.)