Last time on "A Moment of Science" we looked at how our internal, biological clocks, left on their own, would have approximately a twenty-five hour cycle, and how they must be reset each day to keep in synch with a twenty-four hour day.

Today we will look at what happens if people are removed from the influence of the sun and from all markers that would let their bodies know what time it is.

Rutger Wever's Isolation Experiment

In an experiment by researcher Rutger Wever, human subjects were placed in isolated rooms for a month.

With no windows, clocks or television sets, these people, each in a separate room, had no way of knowing what time it was.

Alone In Isolation... What Happens?

Wever found that these subjects extended their sleeping and waking cycles each day, without any knowledge of doing so.

Sleeping

Some would sleep as long as seventeen hours at once, and then stay awake for as long as thirty hours. Though the sleeping and waking cycles of the subjects extended far beyond the standard twenty-four hour period, the biorhythms of the subjects' bodies kept approximately a twenty-five hour internal clock.

Temperature

The subjects' temperatures were routinely monitored and the rising and falling of these temperatures never varied much from their twenty-five hour clock. These results showed Wever that the rising and falling of a subject's temperature is dictated by an internal clock and not by sleeping and waking patterns.

The Results

At the end of the experiment, subjects often would be astonished to find that the month was over because, according to their own calculations, based on their sleep cycles, they had only been in isolation for two or three weeks. They were convinced that thirty days had passed only after being shown newspapers that appeared to be from their future.