I'm the youngest, so my mom would go through my sister, my brother and sometimes the pets before getting to my name. My sister and I get it the worst, though - we can be sitting NEXT to each other and she'll still call us the other's name.
I think it's something to do with vocal patterns - they've been calling out a particular name so much that the pathway gets worn down in your brain, and it's hard to fire a different memory neuron that hasn't been used, or they've all been used so much that the signals are garbling... or something. You know, something like that.
