Time is objective—except between your ears, says neuroscientist Dean Buonomano. Each of us intuitively feels what has been written about since at least 1890, in William James' 'The Principles of Psychology': a warping of our internal clock that is inconsistent with the notion of time as a constant force. Here, Buonomano explains our paradoxical experience of time. In the moment, pleasure is fleeting, while pain and boredom seem to last forever. But that's just one way our brain interprets time: prospectively. In the opposite view, retrospective timing, the tables are turned, and the good times are rebuilt to hold much more weight in our memory while that six-hour delay at the airport fades into oblivion. How we remember time is vastly different to how we experience it. Dean Buonomano is the author of Your Brain Is a Time Machine: The Neuroscience and Physics of Time.