Spindle cells, a type of cell previously thought to be found only in great apes, have been found in large whales. Spindle cells are also called Von Economo neurons.
In the provocative-hypothesis-of-the-week department:
Kevin Lafferty, a parasitologist, has put forth the idea that a fairly ubiquitous parasite (infecting O(10%) of Americans, and up to 2/3 of people in places like Brazil) is responsible for some of the diversity of human culures (1). The parasite uses common housecats to increase its transmission to the next host in the life cycle, and has a subtle effect on human personality, with some studies claiming that it even causes neuroticism, and even schizophrenia. (One clinical report (2) claims that “subjects with latent toxoplasmosis had higher intelligence [and] lower guilt proneness.” Hmm!)
Anyway, Lafferty noted that toxoplasmosis varies in prevalence from world region to world region, and then tries to draw correlates between these prevalences and local cultures:
“Drivers of the geographical variation in the prevalence of this parasite include the effects of climate on the persistence of infectious stages in soil, the cultural practices of food preparation and cats as pets. Some variation in culture, therefore, may ultimately be related to how climate affects the distribution of T. gondii, though the results only explain a fraction of the variation in two of the four cultural dimensions, suggesting that if T. gondii does influence human culture, it is only one among many factors.”
I wonder how one could test this hypothesis? Look for recent immigrants from one culture to another, who have lower Toxoplasmosis incidence? (Preferably finding populations that go in opposite directions, as a control.) Track culture change vs. migration vs. climate change?
Unlikely, perhaps. But nice that people are still thinking big 🙂
(1) Lafferty, K
Can the common brain parasite, Toxoplasma gondii, influence human culture?
Proceedings of the Royal Society B: Biological Sciences
Picked up by the popular press here
(2) Flegr J, Havlicek J.
Changes in the personality profile of young women with latent toxoplasmosis.
Folia Parasitol (Praha). 1999;46(1):22-8.
Interesting read on the return of personality psych (and the use of the term “personality”) to ethology.
It was back in 1991 that Anderson and Jennifer Mather, a psychologist from the University of Lethbridge in Alberta, Canada, first decided to undertake a joint personality study of 44 smaller red octopuses at the aquarium as a way to begin to codify and systematize what they thought they had been observing. Using three categorizations from a standard human-personality-assessment test – shy, aggressive and passive – their data would ultimately show that the animals did consistently clump together under these different categories in response to various stimuli, like touching them with a bristly test-tube brush or dropping a crab into the tank.
“The aggressive ones would pounce on the crab,” Anderson told me. “The passive ones would wait for the crab to come past and then grab it. The shy animal would wait till overnight when no one was looking, and we’d find this little pile of crab shell in the morning.”
Anderson and Mather’s resulting 1993 paper in the Journal of Comparative Psychology, entitled “Personalities of Octopuses,” was not only the first-ever documentation of personality in invertebrates. It was the first time in anyone’s memory that the term “personality” had been applied to a nonhuman in a major psychology journal.
Alison Bell has done related experiments with sticklebacks. It has long been clear to researchers that fish that have lived for many generations in the proximity of dangerous predators are less bold and less aggressive than animals that have lived relatively risk-free. What Bell discovered is that those cautious tendencies outlast the presence of risk, even by a generation. When she moved sticklebacks who had always lived in a high-risk environment into a low-risk environment, she found that not only did they retain their cautious tendencies, but so did their offspring. Even fish raised from birth in a low-risk environment behave more fearfully if raised by a particularly vigilant father from a high-risk background.
“There’s definitely the effect of genetic difference,” Bell explained, “but there’s also the effect of what is experienced as they grow up. Genotype and environment interactions make it difficult to detect the effects of genes, because you have to take the environment into account. This is annoying to geneticists.” To scientists like Bell who are studying the interplay of genes and environment, however, it is of profound interest.
So, Edge has a new question for 2006 for its All-Stars of Academia to answer: What is your dangerous idea? (Suggested to Edge by Steven Pinker, who perhaps got the idea from a colloquium series at his old haunting grounds.)
Offhand, one might expect a broad range of perceived dangerous ideas, varying by research interests and such. What’s surprising is that many of the luminaries think that the “most dangerous idea” is this particular, same idea: As neuroscience progresses, popular realization that the “astonishing hypothesis” — that mind is brain — will create a potentially cataclysmic upheaval of society as we know and have profound (negative) moral implications as people claim less responsibility for their actions.
Of course, this just isn’t true. But, would you believe that
John Allen Paulos,
and, in a more genetic context, Jerry Coyne and Craig Venter
are all very worried about this issue? (And I didn’t even read 50% of the Edge dangerous ideas… there might be even more… ) Is this really the most dangerous idea out there to all of these talented thinkers?
I feel strongly that science and morality have always been separate domains and that any worry that, by “debunking” the mind, we automatically become immoral machines is just ridiculous. Through this scientific knowledge, we might gain some humility, maybe better see our close relatedness to nonhuman primates and place in nature, etc., but we’re not going to flip out and become crazed zombies. This just isn’t going to happen.
Does anybody else think that this just isn’t a truly dangerous idea (although certainly an “astonishing” one, in the Crick sense)? Or am I wrong here?
Samples of academic worrying after the jump.
This nytimes article describes an experiment in which
1) In front of chimps, human researchers demonstrate opening a box, but they throw in some unnecessary steps. The box is constructed so that an onlooker can figure out which steps are unnecessary just by watching. The chimps learn to open the box, but skip the unnecessary steps.
2) In front of human children, the researchers do the same thing. The children learn to open the box, but are careful to do exactly what the demonstrator did, including the unnecessary steps.
The children’s awareness of which steps were unnecessary in condition (4) is shown by having some children who do not get to see a demonstration of how to open the box. These children are able to figure out how to open it (without the unnecessary steps, of course).
Thus, human children, as compared to chimps, are more likely to imitate exactly what they see.
Victoria Horner, Andrew Whiten. Causal knowledge and imitation/emulation switching in chimpanzees (Pan troglodytes) and children (Homo sapiens), Animal Cognition, Volume 8, Issue 3, Jul 2005, Pages 164 – 181
Somebody debunk this before it blows my mind.
“We’ve been observing gorillas for 10 years here, and we have two cases of them using detached objects as tools,” said Thomas Breuer, from the Wildlife Conservation Society (WCS), who heads the study team in Nouabalé-Ndoki National Park in the Democratic Republic of Congo.
“In the first case, we had a female crossing a pool; and this female has crossed this pool by using a detached stick and testing the water depth, and trying to use it as a walking stick,” he told the BBC.
The second case saw another female gorilla pick up the trunk of a dead shrub and use it to lean on while dredging for food in a swamp.
She then placed the trunk down on the swampy ground and used it as a bridge.