May 2020, ScientificAmerican.com 5LETTERS
[email protected]BRAIN EXERCISES
In devising recommendations for exercise
regimens to enhance cognition in healthy
individuals and those experiencing cogni-
tive decline, as discussed by David A.
Raichlen and Gene E. Alexander [“Why
Your Brain Needs Exercise”], scientists
would do well to talk to experienced older
runners, cyclists and dancers. For example,
many runners and cyclists participate in
group runs and rides, where social interac-
tion might provide enhanced mental stim-
ulation more than exercising solo.
Also, expecting older runners to take up
trail running if they do not already do so is
unrealistic. For someone like me, who has
osteoporosis, trail running has risks. Sim-
ply varying one’s route while running, par-
ticularly in a city, would be a better option.
Roxane Sismanidis Washington, D.C.
Raichlen and Alexander conjecture that
physical activity outdoors such as running
on trails may yield as good or better bene-
fits as indoor treadmill work. This would
hardly be surprising because our hominin
ancestors exercised outdoors with con-
stant physical and cognitive challenges.
I run on city sidewalks, and I’m con-
stantly challenged by weather, pedestrians,
traffic, traffic signals, uneven pavements,
dog waste, the gooey residue of gingko fruit
and—when I run with a partner—manag-
ing a conversation on top of everything else.
Researchers might do well to test vulnera-
ble subjects under a version of these condi-
tions, such as jogging in an exercise yard
with a simplified obstacle course while fol-
lowing instructions from a coach. A model
closer to square dancing might also prove
useful to test because group dancing in-
volves cooperative social stimulation in ad-
dition to vigorous and changing activity.
Martha Cornog PhiladelphiaLONELY PLANET
“The Galactic Archipelago,” by Caleb
Scharf, argues that we have likely not found
other spacefaring civilizations because our
planet is in an out-of-the-way spot during a
lull in waves of exploration or settlement.
For me, the critical question is whether
H. G. Wells was right, and our native eco-
system would probably destroy invaders, or
whether invasive species more often have
the advantage. We still don’t know wheth-
er life on Earth sprang up spontaneously
from nonliving matter or whether it evolved
once and spread from there. If the latter is
the case, then Scharf ’s model sounds omi-
nous. We may be out on a galactic limb and
vulnerable to a huge array of pathogens.
J. Gunn Coolidge Chevy Chase, Md.Sending our massive selves on an interstel-
lar journey requires huge energy at any-
thing near light speed, and at a more mod-
est speed, journey times to even fairly near
stars could be hundreds of years. Surely we
will instead send out very small spaceships,
at a few kilograms of mass, that can report
back with pictures after a few years? That’s
what we should be looking for: small space-
ships zipping through our solar system!
Stanley Waterman Hitchin, EnglandScharf ’s article presupposes that technolog-
ical life will be widespread. Such ideas tell
us more about ourselves than about the uni-
verse: Life arose quickly on Earth, and pro-
karyotes did their stuff successfully despite
the vagaries of the environment, which sug-gests it may be common. Complex life, on
the other hand, to the best of our knowl-
edge, arose only once. The implication is
that it’s an extremely improbably event.
James Fradgley Wimborne, EnglandSCHARF REPLIES: One of the great chal-
lenges of addressing the question “Where is
everybody?” is that there are endless cave-
ats and propositions that can seem abso-
lutely necessary. The problem is that we just
don’t know how to weight their importance.
Our own sense of agency and terrestrial
bias gets in the way. The model I describe
attempts to strip things down to a simple
premise that also offers a constraint from
Earth’s paleontological record. I think it’s
good that there is incompleteness to this
model. It represents a kind of theoretical
minimum, a starting point in a vast array
of cosmic possibilities. Indeed, it can—and,
I hope, will—be developed to quantitatively
evaluate the effects of further assumptions.NO-CONFIDENCE VOTE
“One Phone, One Vote,” by Wade Roush,
discusses software developed to ensure
votes are counted correctly. But technology
will never make elections more secure. And
praising Senator Mitch McConnell of Ken-
tucky for initially releasing a mere $
million for election security (since followed
by a woefully still inadequate $425 million),
without any provisions banning hackable
voting machines, is off base.
Our elections are under attack from so-
phisticated adversaries, foreign and do-
mestic. They must have analog audits, not
digital ones. Procedures must be in place
for hand counts of hand-marked paper
ballots to ensure that any electronic vote
count is accurate.
Allegra Dengler
Citizens for Voting Integrity New YorkWHO’S A PRETTY BIRD?
In “The Surprising Power of the Avian
Mind,” Onur Güntürkün writes that his
study with Eurasian magpies demonstrat-
ed the first observation of a bird exhibiting
self-recognition in a mirror test.
This is simply false. Almost four decades
ago I and my colleagues, including noted
Harvard University psychologist B. F. Skin-
ner, published a paper in Science showing
the same behavior in pigeons. Birds used aJanuary 2020
“Our elections must
have analog audits,
not digital ones.”
allegra dengler
citizens for voting integrity new york