Slow-motion world for small animals

Smaller animals tend to perceive time as if
it is passing in slow-motion, a new study
has shown.
This means that they can observe movement
on a finer timescale than bigger creatures,
allowing them to escape from larger
predators.
Insects and small birds, for example, can see
more information in one second than a larger
animal such as an elephant.
The work is published in the journal Animal
Behaviour .
"The ability to perceive time on very small
scales may be the difference between life and
death for fast-moving organisms such as
predators and their prey," said lead author
Kevin Healy, at Trinity College Dublin (TCD),
Ireland.
The reverse was found in bigger animals which
may miss things that smaller creatures can
rapidly spot.

Speedy goalkeeper
In humans, too, there is variation among
individuals. Athletes, for example, can often
process visual information more quickly. An
experienced goalkeeper would therefore be
quicker than others in observing where a ball
comes from.
The speed at which humans absorb visual
information is also age-related, said Andrew
Jackson, a co-author of the work at TCD.
"Younger people can react more quickly than
older people, and this ability falls off further
with increasing age."
The team looked at the variation of time
perception across a variety of animals. They
gathered datasets from other teams who had
used a technique called critical flicker fusion
frequency, which measures the speed at which
the eye can process light.
Plotting these results on a graph revealed a
pattern that showed a strong relationship
between body size and how quick the eye
could respond to changing visual information
such as a flashing light.
"From a human perspective, our ability to
process visual information limits our ability to
drive cars or fly planes any faster than we
currently do in Formula 1, where these guys
are pushing the limits of what is humanly
possible," Dr Jackson told BBC News.
"Therefore, to go any quicker would require
either computer assistance, or enhancement of
our visual system, either through drugs or
ultimately implants."

Confused woodlice
The current study focused on vertebrates, but
the team also found that several fly species
have eyes that react to stimulus more than
four times quicker than the human eye.
But some deep-sea isopods (a type of marine
woodlouse) have the slowest recorded reaction
of all, and can only see a light turning off and
on four times per second "before they get
confused and see it as being constantly on", Dr
Jackson explained.
"We are beginning to understand that there is
a whole world of detail out there that only
some animals can perceive and it's fascinating
to think of how they might perceive the world
differently to us," he added.
Graeme Ruxton, of the University of St
Andrews, Scotland, another co-author, said:
"Having eyes that send updates to the brain at
much higher frequencies than our eyes do is
of no value if the brain cannot process that
information equally quickly.
"Hence, this work highlights the impressive
capabilities of even the smallest animal brains.
Flies might not be deep thinkers but they can
make good decisions very quickly."