Manatees’ exquisite sense of touch may lead them into dangerous waters
A manatee’s entire face is about as
sensitive as your fingertip, according to
research presented at APA’s 2011 Annual
Convention by New College of Florida
psychology professor Gordon Bauer, PhD.
That’s an important finding because it
helps explain why the endangered Florida
manatee so often gets ensnared in fishing
nets, hooks and traps, said Bauer.
“Their strong tactile orientation
may be at the root of their problem
with fishing gear,” he said. “It’s how they
Bauer and his colleagues tested
two manatees’ sense of active touch by
presenting them with pairs of plastic
plates with vertical grating, and rewarding
them for selecting the one with the wider A manatee’s entire face is as sensitive as your fingertip, research finds.
ridges. The manatees investigated the
plates by rubbing them with their faces,
which are covered in fine hairs, and
the less sensitive manatee was able to
distinguish between gratings that were
just 0.15 millimeters apart — about one-tenth of the height of a grain of sugar.
(The more sensitive manatee detected
gratings just 0.05 millimeters apart.)
Motion-sensing hairs cover the entire
body of the manatee, though they aren’t
spaced as closely on manatees’ backs and
bellies. The body hairs help manatees
detect slight vibrations in the water,
according to a second experiment by
Bauer. In that study, Bauer blindfolded the
manatees and muffled their facial hairs
with a mask, then set a ball vibrating in
the water. Using their body hairs only, the
animals detected very slight vibrations
between 15 and 150 hertz.
This highly developed sense probably
helps manatees navigate by detecting
the surface, bottom, current and objects
in the water — though, unfortunately,
it hasn’t helped them steer clear of the
motor boats that are decimating their
population, Bauer said.
Building a better tomato
What does psychology have to do with the efforts by
horticulturists to create a better tomato? At the APA
2011 Annual Convention session “From Psychophysics to
Horticulture: Understanding and Increasing Palatibility
of Nutritious Foods,” Linda M. Bartoshuk, PhD,
described her work with “supertasters” to isolate the stuff that dream tomatoes
are made of.
Supertasters are people with many more tastebuds (or, fungiform papillae)
than average tasters. “Supertasters live in a neon food world. The rest of us live
in a pastel world,” she said. Supertasters and regular tasters were tapped to help
with the project. But the first step was to figure out what flavor elements of the
tomatoes — called volatiles — influence the fruit’s taste. Some volatiles make
tomatoes taste sweet, others salty — or worse.
“Since 1989, all the people working to make tomatoes taste better were using
the wrong volatiles,” she said. Working together, researchers were able to isolate
the correct volatiles. When those volatiles are intensified through cross-breeding,
tasters perceive the tomatoes as sweeter, and it’s this sweetness that people
associate with a better tomato.
Bartoshuk called it “an extremely reachable goal” to break through the ceiling
of what people perceive as the best tomato they’ve ever tasted to the nirvana of
someone’s absolute favorite food. “We can’t add sugar,” she said, “but we can add