Why Does Time Fly? | theDiagonal

[div class=attrib]From Scientific American:[end-div]

Everybody knows that the passage of time is not constant. Moments of terror or elation can stretch a clock tick to what seems like a life time. Yet, we do not know how the brain “constructs” the experience of subjective time. Would it not be important to know so we can find ways to make moments last, or pass by, more quickly?

A recent study by van Wassenhove and colleagues is beginning to shed some light on this problem. This group used a simple experimental set up to measure the “subjective” experience of time. They found that people accurately judge whether a dot appears on the screen for shorter, longer or the same amount of time as another dot. However, when the dot increases in size so as to appear to be moving toward the individual — i.e. the dot is “looming” — something strange happens. People overestimate the time that the dot lasted on the screen. This overestimation does not happen when the dot seems to move away. Thus, the overestimation is not simply a function of motion. Van Wassenhove and colleagues conducted this experiment during functional magnetic resonance imaging, which enabled them to examine how the brain reacted differently to looming and receding.

The brain imaging data revealed two main findings. First, structures in the middle of the brain were more active during the looming condition. These brain areas are also known to activate in experiments that involve the comparison of self-judgments to the judgments of others, or when an experimenter does not tell the subject what to do. In both cases, the prevailing idea is that the brain is busy wondering about itself, its ongoing plans and activities, and relating oneself to the rest of the world.