Jonah Lehrer explains the science behind Girl Talk:
Let’s say you’re listening to that catchy Wu-Tang song, with the chorus “And let’s start it like this, son, rollin’ with this one / And that one, pullin’ out gats for fun”. Once the acoustic snippet enters working memory, individual neurons in the prefrontal cortex will fire in response to the stimulus – they are the neural representation of the song. Here’s where things get interesting: even when the stimulus disappears – you’ve now started listening to a different song, perhaps that Boston song “Foreplay/Long Time” – those working memory cells continue to fire. They’re still holding on to the Wu-Tang clip, which is why working memory is a type of memory. This echo of activity only lasts for a few seconds, but it’s long enough so that our thoughts get blended together, as seemingly unrelated sensations overlap.