A now is about two seconds long
What we experience as "now" has a certain duration in time. In each perception we are presented with a now that lasts one or two seconds. There is also a now in the memory. We relive impressions of sights and sounds in sequences of several seconds.
So claims philosopher Jan Almäng at University West. In a physical sense, the now has no duration in time, but he is talking about a different kind of now, the experienced now. He explains using a memory of an accident involving an elk that took place three years ago. He remembers the event as several sequential moments. Starting with him hearing the driver of the car shouting. Then he sees the elk in front of him on the road. Then he hears the bang as it hits the car. The car slows down and then in the rear-view mirror he sees two or three more elks cross the road behind him. (None of those in the car were injured.)
"When I play this back to myself, it takes maybe ten or fifteen seconds, but in each particular moment of the memory, I experience only one or two seconds of the whole," says Jan Almäng.
According to brain researchers, the same brain cells are activated when we experience something for the first time as when we later recall the scene for our inner vision. It is a kind of simulation, and it consists of several sequential nows. At the same time, we know that this now is being played out in the past.
Another important part of our perception of time is that there is an order for what takes place during a now. For example, we can hear someone sing "do re mi" and keep all three tones in our consciousness at the same time. We hear them together, you could say, but there is still an order.
"When someone sings "mi", I hear "mi" as now and "re" as in the past and "do" as a little further still in the past," says Jan Almäng.
In a recently published paper, he analyses our perception of time. He also discusses the conclusions of other philosophers and gives his opinions on these. Not everyone agrees that we experience a now when we remember events in the past, but Jan Almäng presents his argument for this. He will be developing a new theory of time perception in an upcoming research project.
Sometimes a person's time perception is disrupted and this can result in major problems. For example, old persons who confuses now with then has difficulty managing by themselves. An analysis of our time perception could be an important step in understanding what has gone wrong when time perception is disrupted.
"Theories about time perception can help us to ask the right questions when conducting research on the brain," says Jan Almäng.
Reference: Time, Mode and Perceptual Content, Almäng, J. Acta Analytica 2011, in press