The news is chattering over a new paper by Smet and Byrne entitled “African Elephants Can Use Human Pointing Cues to Find Hidden Food” [link]. The lede is frequently the typical one for comparative cognition studies. Take this example from VOA:

Elephants are able to recognize human gestures without any sort of training, new research shows. Scientists believe the finding indicates that elephants are able to understand humans in a way most other animals do not.

They might be excused for this since the authors themselves write, in the Results and Discussion section “Here we found elephants capable of responding spontaneously to pointing gestures that require attention to subtle differences in the position of the forearm and hand.“. This is, however, a tired and old problem with this type of study.

Even Carl Zimmer, writing in the NYT, makes most of his post about this wonderous “spontaneous” property of all elephants. Still, to his credit he does include the critical caveat.

Diana Reiss, an expert on elephant cognition at Hunter College, wondered if the elephants had already learned about pointing by observing their handlers pointing to each other.
“In these elephant camps such opportunities can easily go unnoticed by their human caretakers,” said Dr. Reiss.

The authors themselves point this out, although they try to handwave it away:

All of these elephants have lived in captivity since infancy: they have had the opportunity to witness pointing used between humans. However, observation of human interactions does not automatically translate into aptitude at interpretation of these interactions.

Whoa dude. Whoa. Hold up. Extraordinary claims require extraordinary evidence. Except, apparently, in comparative cognition when we are just sooooo keen to believe findings that show species X is “just like humans” in some cognitive or behavioral property.

I have at least one observation in the archive that points out where not thinking hard about the study design can lead to unsupported conclusions being widely disseminated. This post was originally published Feb 25, 2008.

In the midst of World War I, Wolfgang Köhler conducted a famous series of experiments to investigate problem solving ability in chimpanzees. The lasting impression of these experiments, reinforced by just about every introductory Psychology text, was Köhler’s assertion that the chimps demonstrated “insightful” learning.
Did they now?

Read the rest of this entry »

Abel Pharmboy of Terra Sigillata has a recent post covering Sol Snyder’s NEJM commentary (currently free) on finding god in the brain, an overview of some neuroscience thinking on religiosity. Abel and Sol both touch on a 2006 study by Roland Griffiths and colleagues [available to all from the MAPS site here] which reported on a study of the “mystical-type” experiences of humans following a dose of psilocybin. I’ll try to expand a bit on this since it was a very interesting study in many ways. Even though this is a bit dated by now, I wasn’t blogging back then so I’ll give it a whack. It should be obvious where this touches on some of my own scientific interests. Read the rest of this entry »

A recent commentary in Nature by Barbara Sahakian and Sharon Morein-Zamir discusses the ethical questions arising from the use of cognitive enhancing drugs to improve intellectual function in “normal” people. This follows a prior piece in Nature arguing that science-enhancing drugs may not be just acceptable but indeed laudable, which I covered previously. A couple of blogs are already on it, including Adventures in Ethics and Science (natch), Retrospectacle and Action Potential. [Update: 12/21/07: More from the Silverback , Corpus Callosum and Munger.] Commentary on the first two Borg blogs is already quite brisk. People seem to love discussing brain doping! Read the rest of this entry »

The 15 Nov issue of Nature has a most interesting editorial in which they propose that artificial performance enhancement is not cheating but in fact highly laudable.

Of all the arguments levelled against taking drugs for human enhancement, the idea that it is cheating has least power. …What is sure is that opponents of enhancement are, to a degree, whistling in the wind. They raise other spectres — unfairness of access (although today’s enhancing dose is cheaper than a cup of coffee), possibilities of employer coercion and the loss of human dignity or of the ‘natural’ — but ultimately, to little avail. Many healthy people still opt for chemical enhancements of all sorts, as suppliers of cosmetics and some pharmaceuticals know well. Such actions betoken an ethical argument on the other side: the pursuit of personal liberty. Read the rest of this entry »

Dave Munger at Cognitive Daily comments briefly on a recent NY Times on the positive effects of exercise on brain function. [Update 8/22/07: Jake at Pure Pedantry waxes pedantic about the Morris Water Maze and data interpretation thereof, jeez.]  The Times starts off with the findings from Rusty Gage’s lab at the Salk Institute which focus mostly on evidence of improved neurogenesis, decreased cell death and improved cognition in spatial memory tasks in mice and rats. The pubs started with van Praag et al. 1999 , got a particularly big splash with a finding of improved learning in aged mice (van Praag et al. 2005) and the most recent is van Praag et al. 2007 showing beneficial effects of a plant-derived flavinol in combination with exercise.

[As a sidebar for regular readers of DM, I should point out that San Diego is not only cycling paradise but biomedical research paradise as well. We’re home to the University of California, San Diego, the Salk Institute for Biological Studies, The Scripps Research Institute, The Burnham Institute, The La Jolla Institute of Allergy and Immunology, San Diego State University (not only perennial Playboy top party school but the “top small research institute”), and bunch of smaller or less-well-known institutes. Of course, you knew that already… BM Disclosure: Yes, I work for one of these places. It is no accident that DM and I talk science on occasion.]

Getting back to the exercise-hippocampal neurogenesis-spatial learning stuff, the new finding is a report (Pereira et al, 2007) using MRI to evaluate how much blood was rushing (Cerebral Blood Volume; CBV) through the hippocampi of humans before and after a 3 mo aerobic exercise regimen. Findings were that CBV was increased in dentate gyrus after exercise, the increase was correlated with individual changes in VO2max (a good proxy for the physiological benefit of the exercise program; measured on cycling ergometer, heh!) and, importantly

a correlation between CBV and VO2max was not observed for any other hippocampal subregion, including the entorhinal cortex Fig. 4b), confirming that exercise has a selective effect on dentate
gyrus CBV.

better yet:

we found that changes in VO2max correlated exclusively with postexercise trial 1 learning… Additional analyses showed that the orrelatcion between changes in VO2max and cognition was selective to trial 1 learning (Fig. 4b), thereby confirming that, despite apparent increases in other cognitive measures (i.e., delayed recognition, as shown in Fig. 4a), this particular measure was selectively influenced by exercise.

The rest of the paper is laden with similar and more-invasive mouse findings similar to the Gage studies, in fact Gage is a co-author on this study.

Pretty cool. It starts to put to rest the suspicions of old-time Experimental Psychologists that rodents studies were confounded by the old “impoverished/enriched environment” deal. Basically, the complaint is that normal lab housed rats are not likely to be getting a normal amount of sensory stimulation and thus the “control” group is the abnormal one. Not a huge deal until you want to apply it to humans since there may be ceiling effects. This study tends to confirm the effects in a relatively normal human sample.

BikeMonkey has a question though:

Eleven subjects (mean age, 33 ranging from 21–45 years; 2
males and 9 females) who fulfilled the American Heart Association
criteria for below-average aerobic fitness (VO2max, <43 for men
and <37 for women) were recruited (51). The 11 enrolled subjects
engaged in an exercise training protocol for 12 weeks at Columbia
University Fitness Center at a frequency of four times a week. Each
exercise session lasted ~1hr: 5 min of low-intensity warm-up on a
treadmill or stationary bicycle, 5 min of stretching, 40 min of aerobic
training, and 10 min for cool down and stretching. During the 40
min of aerobic activity, subjects were permitted to select from
cycling on a stationary ergometer, running on a treadmill, climbing
on a StairMaster, or using an elliptical trainer.

So how many chose the bike and who got the best V02max improvement???!!!!

First, I’ll tip the hat to Shelley at Retrospectacle for starting a “tour of the vaults” with the classic LSD in elephants study. Today, I’m reaching way back for “A study of trial and error reactions in mammals” by G. V. Hamilton, Journal of Animal Behavior, 1911 Jan-Feb 1(1):33-66. This study is worth reading because it provides an often hilarious insight into the conduct of science at the turn of the past century but also because this study is a root (perhaps the taproot) of a relatively current subfield on spatial working memory and spatial search. Read the rest of this entry »