18 | New Scientist | 30 November 2019PsychologyBots can check pipes
while water still runsSWARMS of floating robots
could help map underground
pipe networks and detect leaks
and blockages in plumbing.
Peter Baltus at Eindhoven
University of Technology in the
Netherlands and his team have
developed golf ball-sized sensors
that can gather information as
they float through pipes.
Each robot has a microprocessor,
a sensor, memory boards and aWhy sex is especially
memorable for fliesFEMALE fruit flies get a boost in
their long-term memory after
mating thanks to a molecule
found in male fly semen.
The substance involved, called
the sex peptide, binds to the sperm
of male flies and is passed on to
females, where it travels from the
reproductive tract to the brain.
It was already known that this
molecule, which is unique to
fruit flies, alters behaviour. After
mating, it changes what females
prefer to eat and makes them
reject future mating partners,
for example. It normally does
this by acting on nerve cells
that are connected to the uterus.
Now Thomas Préat and his
colleagues at PSL University,
France, have found that this
molecule also enhances long-
term memory by targeting cells
in the brain responsible for it.
To test fruit fly memory, theAnimal behaviour^ RoboticsIF YOU were watching a basketball
game and a person in a gorilla suit
walked across the court, you would
notice, right? Earlier experiments
showed that only about half of us
would, and now it turns out that if
you don’t notice within 1.5 seconds,
you are unlikely to catch it at all.
The effect is called inattentional
blindness. But Katherine Wood and
Daniel Simons at the University of
Illinois wondered if lengthening the
time a new visual cue is in our field
of view helps. To test this, they
asked people to watch black and
white shapes moving in straight
lines across a computer screen
and bouncing off the screen edges.
The people were told to count
how many times objects of one
colour bounced. While doing this,
a new, cross-shaped object passed
over the screen for either 2.67 or 5seconds. People failed to spot it at
around the same rate in both cases.
Next, the cross appeared for
either 1.5 seconds or 5 seconds.
Slightly more than half noticed it if
it was displayed for 5 seconds, and
slightly less than half when it was
shown for 1.5 seconds. There was
just a 13 per cent greater chance
of noticing it if it was displayed for
5 seconds rather than 1.5 seconds.
“The most natural thing to
assume is that the longer it’s there,
the more opportunity you have to
notice it, so we were quite surprised
when it turned out that it seems not
to help you very much,” says Wood.
The team found that 1.5 seconds is
the time beyond which most people
will have noticed something like
this if they are going to spot it
(Royal Society Open Science,
doi.org/dfk4). Chelsea WhyteLook sharp or you’ll miss
the gorilla on the court
battery. They can be programmed
to detect sound, temperature,
pressure, acceleration, rotation
and magnetic fields.
To save power, a sensor can be
activated by a sudden change in
conditions, such as hissing sounds
associated with water escaping, or
increased rotation, which could be
a sign of turbulent water flow. The
robot would then increase the rate
at which it takes measurements.
One use the team has in mind is
to improve sketchy maps of ageing
water distribution networks below
cities. “The documentation is
spotty and incorrect, or at least
very approximate,” says Baltus.
The advantage of these robots is
that they can work without having
to shut down the networks they
travel through. “It makes many
people unhappy if you have to
switch off drinking water to
inspect pipelines,” says Baltus.
Similarly, the robots could
inspect piping in a chemical plant
without the need to shut the plant
down entirely. Donna Luteam conditioned females to
pair certain smells with electric
shocks. Flies that had mated
could remember to avoid smells
associated with shocks, but flies
that hadn’t mated forgot after four
days, showing they couldn’t retain
this training in the long term.
The researchers found that
females who mated with males
modified to lack the sex peptide
didn’t have better long-term
memories, but flies that hadn’t
mated but were injected with
the peptide saw a memory boost
(Science Advances, doi.org/dfk5).
In nature, flies that are yet to
mate might lack such a memory
in order to make them braver and
more likely to search out mates. In
contrast, long-term memory may
mean flies that have mated can
remember safe spots to lay eggs.
Stuart Wigby at the University
of Oxford says he is surprised
that the sex peptide can migrate
all the way to the brain and affect
learning. “It’s kind of amazing,”
he says. Gege LiCH
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