I was amazed at the article by Amanda Boxtel, “Walking 2.0,” and at her undaunted courage in her efforts to walk after being paralyzed in a skiing accident. Her story of learning to use an exoskeleton is truly remarkable and a great example for everyone faced with disabilities.

I was particularly interested in Boxtel's story because I suffer from some wearing out of lower back vertebrae. My ailment is commonplace in the aging population, and the only solution seems to be tailored exercises and painkillers. Given that medical technology today can circumvent some of the spinal problems with this impressive exoskeleton support, I believe that within the next 100 years technology will be able to replace worn-out or broken spinal disks.

Charles G. Roy
via e-mail

Although the article about the exoskeleton was very interesting, I would like to point out that there are other options for exoskeletons that may be more suitable for other people. For example, Rex Bionics has one that does not require the use of crutches and can be used at home without a physical therapist being present. In fact, there are at least two or three other exoskeletons that were not mentioned in the article.

Michael Landau
via e-mail

THE EDITORS REPLY: Landau is correct that there are more manufacturers and devices available than we could detail. We focused on devices that are available in the U.S. and approved by the FDA. Currently the Rex Bionics exoskeleton for home use is not available in the U.S. We hope that when we return to this topic in the future, we will have an opportunity to take a more global look at the subject.


The tired mantra at the conclusion of thousands of psychological studies that “more research is needed” certainly applies to research on the effects of violent video games, as stated in “How Violent Video Games Really Affect Kids,” by Greg Toppo. More important, the mantra should also read that “better research is needed.” Most research on this topic uses correlational designs, small samples, laboratory conditions, and self-report indices of aggression or violence proneness. Such weak causal inference research has not been very helpful in getting the answers the public needs. These studies have also focused on what I call “small v” violence, indexed in those self-report questionnaire measures of violence and aggression that are usually poorly validated, or not validated at all, against real-world actual violence—that is, “big V” violence.

As a psychological researcher myself, I think job number one is to conduct this research out there where the actual violence is, where the pain is and where the possibilities of remediation are strong. It will be a challenge to our ingenuity to conduct violent video game research beyond the monastery walls, but it is essential that it be done, and replicated, and replicated.

Frank Farley
Temple University


The first sentences of the article “Before the Trauma,” by Moises Velasquez-Manoff, grabbed my attention with a flashback of my own. Like an explosive device concealed diabolically underneath a tray of cookies, when I was eight, my 12-year-old brother hid a rubber cockroach between two slices of roast beef at our Sunday dinner, which until then had been my favorite meal. There were many other abuses at my brother's hands that my parents did nothing to prevent. Velasquez-Manoff writes, “A consistent finding is that early-life adversity increases the risk of PTSD many years later.” This is a true statement. I suffered PTSD as a young bride of 22 after being raped by a trusted boss. My early experiences taught me I was not valued; these experiences were followed by others. I've never been in the military, but I've fought my own wars. Thanks for this challenging article. I'm sure many others in recovery will benefit from the research.

Kathryne B.
via e-mail


The presumably intentional hyperbole in the final sentences of Christof Koch's “Intelligence without Sentience” [Consciousness Redux] notwithstanding, the only trouble with his article is the failure to define “intelligence.” The implied definition seems to be along the lines of “able to be made to carry out a defined task (in some cases through a ‘learning’ mechanism).” Yet by that definition, very many things count as intelligent—yet appear to lack what we're really after. The laser sensor at the supermarket is very good at opening the door for me just as I approach, and as Daniel Dennett once pointed out, a home thermostat quite intelligently monitors the heat in my home and operates the furnace to keep me comfortable. Deep Blue, Watson and DeepMind are all examples, I think, of what John Searle has famously called “weak AI”: a simulacrum of intelligence, not the genuine article.

True intelligence requires meaning. The system must know, must understand, what it is doing to count as being truly intelligent. I do not know if consciousness is a necessary part of this equation, but I do believe it harms AI research itself to label systems such as DeepMind as intelligent. To do so sets the bar too low. True artificial intelligence, whether it possesses the ever elusive consciousness or not, will, at the very least, know what it is doing. Before we declare that there can be intelligence without consciousness, we need to make sure we've found real intelligence to begin with.

Benjamin J. Stenberg
Oregon State University

KOCH REPLIES: I fully agree with you on the crucial difference between weak and strong AI, as I spelled out in my essay in the September/October issue of Scientific American Mind. The extent to which strong intelligence, whether of the human or of the computer variety—and defined as the ability to achieve a variety of goals within a range of natural and artificial environments—requires either “meaning” or consciousness is an open question. Unlike many other questions in philosophy, however, we may know the answer before the century is out.


I found “Adapt and Overcome,” by Michael T. Ullman and Mariel Y. Pullman [Perspectives], very interesting. In 1990 my then four-year-old daughter was diagnosed with Tourette's and attention-deficit/hyperactivity disorder. Her school years were traumatic, with teasing and bullying. In an attempt to alleviate the situation, she and I tried to identify what other body movement, something that would be less visible, could provide the necessary relief from the tic impulse. Another way of scratching the itch!

For instance, when she had a facial tic, she tried to move the reaction to the impulse down her neck to her chest or diaphragm to internalize it. When she had a vocal tic, she turned it into snippets of song humming. As the tics waned and returned, she discovered that they would always start in the original site again. Her ability to move the tic would then kick in. She still uses this method whenever tics arise. Today she is a well-adjusted, socially confident 30-year-old.

An interesting aside: when I told her neurologist and general practitioner what she was doing, they told me not to encourage it because it was too stressful and cruel!

Judy S.
via e-mail


“Before the Trauma” incorrectly stated that the insula and dorsal anterior cingulate cortex are part of the prefrontal cortex. These are three distinct brain areas, all of which are affected by early childhood maltreatment.

“Out of Sync,” by Emily Laber-Warren [September/October 2015], misstated Brant Hasler's specialty. He is a psychologist.