BRAIN EXERCISES
In devising recommendations for exercise regimens to enhance cognition in healthy individuals and those experiencing cognitive 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 interaction might provide enhanced mental stimulation 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. Simply varying one's route while running, particularly in a city, would be a better option.
On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
ROXANE SISMANIDIS Washington, D.C.
Raichlen and Alexander conjecture that physical activity outdoors such as running on trails may yield as good or better benefits as indoor treadmill work. This would hardly be surprising because our hominin ancestors exercised outdoors with constant physical and cognitive challenges.
I run on city sidewalks, and I'm constantly challenged by weather, pedestrians, traffic, traffic signals, uneven pavements, dog waste, the gooey residue of gingko fruit and—when I run with a partner—managing a conversation on top of everything else. Researchers might do well to test vulnerable subjects under a version of these conditions, such as jogging in an exercise yard with a simplified obstacle course while following instructions from a coach. A model closer to square dancing might also prove useful to test because group dancing involves cooperative social stimulation in addition to vigorous and changing activity.
MARTHA CORNOG Philadelphia
LONELY 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 ecosystem would probably destroy invaders, or whether invasive species more often have the advantage. We still don't know whether 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 ominous. 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 interstellar journey requires huge energy at anything near light speed, and at a more modest 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 spaceships zipping through our solar system!
STANLEY WATERMAN Hitchin, England
Scharf's article presupposes that technological life will be widespread. Such ideas tell us more about ourselves than about the universe: Life arose quickly on Earth, and prokaryotes did their stuff successfully despite the vagaries of the environment, which suggests it may be common. Complex life, on the other hand, to the best of our knowledge, arose only once. The implication is that it's an extremely improbably event.
JAMES FRADGLEY Wimborne, England
SCHARF REPLIES: One of the great challenges of addressing the question “Where is everybody?” is that there are endless caveats and propositions that can seem absolutely 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 Kentucky for initially releasing a mere $250 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 sophisticated adversaries, foreign and domestic. 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 York
WHO'S A PRETTY BIRD?
In “The Surprising Power of the Avian Mind,” Onur Güntürkün writes that his study with Eurasian magpies demonstrated 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. Skinner, published a paper in Science showing the same behavior in pigeons. Birds used a mirror to locate a spot on their body that they could not see directly. Although this kind of behavior has traditionally been attributed to a self-concept or other cognitive process, our experiment suggested an environmental component.
Further, it's clear there are different degrees of self-awareness/self-recognition. For instance, we didn't report in our paper that the pigeons attacked their own reflection in the mirror. Indeed, we humans are often as oblivious to certain aspects of who we are as those birds were.
ROBERT LANZA Wake Forest University
GÜNTÜRKÜN REPLIES: I do not think that Lanza's study—or a successful replication of it published by Japanese researchers in 2014—shows self-recognition in pigeons.
Using operant conditioning, organisms can be brought to do various behaviors. In both experiments, pigeons were stepwise conditioned to peck a dot on their body that they could see only in a mirror. In Lanza's paper, that result was achieved after first training the birds to peck on visible dots on their body, then conditioning them to peck on dots on the wall and then going through several intermediate steps involving the mirror.
This process is completely different from the procedure used in apes, elephants and magpies. Here the animals are first accustomed to a mirror for some hours. During this time they are not trained to touch their body or to attend to the mark. Then the mark is placed, and the behavior of the animal is observed. In the case of the magpie study, my colleagues and I used various control conditions (no mirror and/or a black mark that wasn't visible to the birds).
Our magpies were never conditioned to, for example, scratch the area under their beak, attend to a mark or look behind the mirror. They acted spontaneously. This is the critical difference between our study and Lanza's, and these papers therefore require different interpretations. To give an extreme example: we could condition monkeys to type “to be or not to be,” but we should not subsequently infer that they think about classic literature.
I agree with Lanza that there are possibly different degrees of self-awareness/self-recognition. But I disagree that conditioning the animals can solve this point.