The cover illustration for the story “Dating in a Digital World,” by Eli J. Finkel, Paul W. Eastwick, Benjamin R. Karney, Harry T. Reis and Susan Sprecher, places the two people in perfect position for the function of the vomeronasal organ. This tiny structure hides about one centimeter inside the nose in each nostril along the middle wall, where it can sample each inhalation for pheromones. Mating involves exchanging pheromones, which provide information used by the brain outside of conscious thought.

Until we develop some technique to transfer pheromone information via the computer screen, we will be at a loss to complete the biological process that initiates the mating protocol for our species.

Martin Zane
Hidden Hills, Calif.

Editors' note: For more information on the vomeronasal organ, see “Sex and the Secret Nerve,” by R. Douglas Fields; Scientific American Mind, February/March 2007.


In “Building Better Brains,” John Jonides, Susanne M. Jaeggi, Martin Buschkuehl and Priti Shah summarize findings that they interpret to indicate that “fluid” intelligence—the ability to solve novel problems and adapt to new situations—can be increased to a statistically and practically significant degree through working memory training.

The scientific jury is still very much out on whether working memory training truly increases fluid intelligence. With our colleagues, two of us (Hambrick and Redick) recently published a failure to replicate the authors' widely cited 2008 finding, which they describe in “Building Better Brains,” that working memory training increases fluid intelligence in young adults. A report of our study appeared online in June in the Journal of Experimental Psychology: General.

In a study in Developmental Psychology in May, a meta-analysis of the quantitative findings of 23 studies on working memory training—including studies by Jonides et al.—researchers Monica Melby-Lervåg and Charles Hulme found no convincing evidence that working memory training improves either adults' or children's fluid intelligence or scholastic outcomes.

It may turn out that working memory training has generalizable benefits for only some people, under only some circumstances, but it is far too soon to tell even that much. In the meantime, scientists should avoid portraying evidence for the efficacy of working memory training as more definitive than it is.

David Z. Hambrick
Michigan State University

Frederick L. Oswald
Rice University

Thomas S. Redick
Indiana University–Purdue University Columbus

THE AUTHORS RESPOND: Hambrick and his colleagues' failure to replicate our findings must be taken in the context of research from at least three other independent laboratories that have successfully replicated our original work. As we pointed out in our article, inconsistent results across studies do not necessarily mean that the original finding is false but instead can provide a valuable opportunity to learn more about the underlying phenomenon.

The study procedure used by Hambrick et al. has several notable weaknesses. For instance, the time to administer each of the 17 tests was so short that measurement quality was probably somewhat questionable. Participants got the best score possible on some of the pretests, thereby giving them no opportunity to improve as a function of cognitive training. Finally, the training curves of their participants were notably shallower than those of ours, and we have shown in published research that transfer is related to how well people train. Although we value failures to replicate that are scientifically sound, we have reason to doubt that the cited paper is one of these.

The current body of scientific literature that focuses on training of working memory is still rather small, as is shown quite impressively by the recent meta-analysis, which included only 23 studies with small sample sizes. The studies vary in procedures and subject populations, including children with ADHD and stroke patients. With that in mind, we think it is simply too early to conclude that working memory interventions are not effective. In “Building Better Brains,” we acknowledge that there are many questions regarding the breadth and durability of training effects, but we argue that the prevailing evidence supports optimism that intelligence is not entirely fixed.

Editors' note: For more information about this topic, including a new study from the journal Intelligence that found working memory training did not result in lasting improvements, see “Best Evidence for Brain Training Falls Short,” a blog by Scientific American editor Gary Stix, at


Regarding “Hard to Swallow,” by Dwayne Godwin and Jorge Cham, the assumption of such a condescendingly dismissive attitude toward nonmainstream health care modalities reflects badly on a publication founded in scientific principles. One narrative caption makes the blanket statement that “alternative medicine practices, which have no scientific basis, may just be relying on this placebo mechanism.” Although this is surely true of some practices, it is irresponsible to imply that such a description applies across the board.

The cartoon betrays a profound ignorance of the perspective being mocked (“I can feel my karmic energy flowing!” cries the acupuncture patient. Seriously?), not to mention the amassed evidence regarding Chinese medicine and various other modalities that at the very least merit more credit and intellectual curiosity than this comic gives them. What I see here demonstrates no scientific effort toward objectivity but rather the dogmatically barred and narrow outlook that so often poses on the pedestal of science.

Karli Nabours-Palermo, R.N.
Lake Charles, La.


I wouldn't hasten to thank television's increasing portrayal of mental health issues for any apparent drop in associated stigmas, as Daisy Yuhas does in her article “Psychology: As Seen on TV!” Many of the TV shows cited in Yuhas's article depict mental illness in an extreme fashion, with no attempt to represent the humanity of mental illness sufferers let alone the complexity of their conditions. For this I doubt the creators of such shows are motivated by little else than ratings, which would explain their preference for the psychotic disorders and cases of OCD. I recently watched my first episode of Criminal Minds. Never have I been so quick to grab the remote control as when a character on the show pronounced: “Listen, doctor, my mother is a paranoid schizophrenic who's been institutionalized, so I know very well what mental illness looks like.”

As long as there is no genuine exploration of mental health issues, with attempts to challenge rather than confirm the assumptions we uphold, it could hardly be considered progress if each and every TV show this century were to suddenly feature a shrink.

Chini Ogundare
Sydney, Australia


Tori Rodriguez's article about personality changes linked to cats and toxoplasmosis hardly seems to qualify as news. As the writer notes, the connection with schizophrenia and the advice that pregnant women not clean cat litter boxes have been around for a long time, so more common personality changes linked to Toxoplasma infections can't really be unexpected.

The big question is why can we not somehow end our culture's addiction to keeping cats as pets? Or at least find a way to ensure they and their owners (servants, staff?) are not infected. Isn't there a hue and a cry whenever any other popular part of our culture (for example, tobacco, trans fats) poses a significant health risk? How is it that cats are somehow immune to criticism but Toxoplasma gondii is not?

Joseph R. Sullivan
via e-mail