All vertebrates and insects have a clock within their brain, their nervous system. Scientists attribute this clock to our sense of the passage of time. Human perception of time, slow or fast, may be tied to this internal mechanism. This internal mechanism is closely tied to the metabolic rate of the living entity. Time appears to go very fast for a youth than for an old person. Metabolic rate slows as a person ages. Now scientists are zoning into a property of this internal clock mechanism which enables the brain to ignore flickering light and view it as a steady source of illumination (Article in The Guardian).
A dog’s metabolic rate is much faster than that of a human. Dogs brain can detect higher frequency flicker than human brain. The entire mechanism of television transmission and reception is designed to cheat the human brain into thinking that movements on the screen are smooth which in reality it is a slide show presentation! Dog brains can notice flicker on the TV making looking at TV to be boring. Dog are sure to find it strange that humans spend so much time in front of a flicker box. Insects are capable of detecting flicker to a even higher rate. Insect brain is four times sensitive as human brain in detecting flicker. Time passes really slow for them and gives their brain the ability to notice even the slightest motion of a person’s hand to squash them.
Vedic tradition had five sets of units of time. This is very interesting. Colonial scholars translating Vedic time units were often confused. The five sets of units of time are related to human brains ability to switch into modes of awareness of time based on the activity one engaged in. The names of one of these five units of time measures related to archery demanding keener perception of time. Sri Sri Ravishankar in his book on Time discusses the five sets of time units. Modern science is beginning to quantify human brain’s time skills.