Author Archives: Jason Whitaker

About Jason Whitaker

J.W. is a studying Psychology, Anthropology, and Biology at the University of California, San Diego. His current research includes quantitative methods, perceptual fluency, and mate preference in humans.

New reserach suggests mammals are tunned to the crying calls of infants, even when these don't come from members of their species. Photo: Flickr Commons

The primal call: mammals may respond to baby cries even when they’re from another species

New reserach suggests mammals are tunned to the crying calls of infants, even when these don't come from members of their species. Photo: Flickr Commons

New reserach suggests mammals are tuned to the crying calls of infants, even when these don’t come from members of their species. Photo: Flickr Commons

Crying is a baby’s principal means of communicating its negative emotions, yet no matter how annoying and painful it may be to hear those high pitched screams, humans are naturally drawn to this call. Well, it seems our brains are hard-wired to respond strongly to the sound, making us more attentive and priming our bodies to help whenever we hear it. A new study by biologists at the University of Winnipeg, Canada suggests that this isn’t a solely human trait. Their findings suggest there’s a common element among the cries of most, if not all mammalian species that draws adults to investigate as a primal instinct, ignoring any risks in between.

The call

Susan Lingle, a biologist at the University of Winnipeg, and colleagues recorded the calls made by infants from a variety of mammal species when separated from their mother or otherwise threatened. These were then played our in the Canadian prairies from hidden speakers to wild mule deer (Odocoileus hemionus). The researchers noticed that mother deer quickly moved towards the source of the sound when the cry of an infant deer was played, but same held true whether the cries came from infant fur seals, dogs, cats or humans. All these species call at roughly the same high pitch. Even the ultrasonic calls of infant bats attracted the mother deer, of course after being tuned to a lower frequency using software.

The findings suggest there’s a common acoustic element that some mammals are hard-wired to respond to and investigate, at the cost of taking risks. It may be that this common element was kept across species, even in those whose lineages separated more than 90 million years ago.

“These are calls that are generally made in a life-or-death situation,” Lingle says. “I think the advantage of securing survival for your offspring outweighs the potential for error.”

Findings appeared in the journal American Naturalist.

 

Adelie penguins going about their way. Photo :Peter & J. Clement/

New bird flu infects Antarctic penguins

Adelie penguins going about their way. Photo :Peter & J. Clement/

Adelie penguins going about their way. Photo :Peter & J. Clement/

It’s so cold even penguins get the flu in the Antarctic. Seriously, researchers report in a paper published in the journal mBio how they identified a new strain of influenza that infects Adelie penguins which breed in huge colonies on the rocky Antarctic Peninsula. The virus itself seems to be dormant as the penguins don’t exhibit any visible flu symptoms, yet the findings do raise important questions like how influenza spreads over the world in extremely isolated regions such as the Antarctic.

Bird flu strikes penguins

Researchers at a World Health Organization flu lab in Australia, led by Aeron Hurt, trekked down to the Antarctic Peninsula a year ago and collected oral samples from two distinct colonies. Using a laboratory technique called real-time reverse transcription-PCR, the researchers found avian influenza virus (AIV) genetic material in 3 percent of the samples.

[NOW READ] Climate change causes penguin colonies to decline by a third

The researchers managed to culture four viruses, demonstrating that live infectious virus was present. All of these were H11N2 influenza viruses that were highly similar to each other, yet when their genomes were compared with those from a database spanning all known animal and human influenzas there was nothing quite alike on the planet. Apparently, this penguin influenza is unique.

This suggests that it has been isolated for many decades — presumably hiding out in the penguins’ digestive and respiratory tracts, or possibly frozen in Antarctic ice. So where did they come from and in Antarctica of all places?

[ALSO READ] Dutch researchers create super-influenza, with the capacity to kill billions

Four of the gene segments were most closely related to North American avian lineage viruses from the 1960s to 1980s. Two genes showed a distant relationship to a large number of South American AIVs from Chile, Argentina and Brazil. Using a molecular clock to incorporate the evolutionary rate of each AIV gene segment, the researchers estimated that the virus has been evolving for the past 49 to 80 years without anyone knowing about it.

Concerning this South American connection, it may be possible that long distance migratory birds are the root of the virus’ spreading. The yellow-billed pintail duck, for instance, is known to stray from South America and end up on the Antarctic Peninsula. This coupled with penguins’ utter contempt for hygiene, despite their tuxedo, fancy-like appearance, may have helped spread the virus.

“The large amount of penguin feces in colonies during summer, which in some cases is so significant it can be observed on satellite images, presumably facilitates (viral) transmission by the fecal-oral route,” the scientists note.

While the penguin influenza hasn’t caused any illness yet, it’s still interesting to follow. Scientists might gather from this how often, for instance, infectious viruses can reach isolated communities and far away places like Antarctica and what animals are most vulnerable.

Disturbed Sleep Promotes Appetite

Depicted above: The “why am I so hungry? I drank, like, 10 beers and it’s 7am” Effect.
Photo:.bbc.co.uk

 

Lack of sleep adversely affects a plethora of bodily functions,where typically most of these effects are thought to be cosmetic or fleeting: bags beneath the eyes; an obvious  state of dehydration;and if you’re a student during finals a developed sense of disregard for constructing full sentences.

Well, as it happens the excess skin around your eyes and the excess skin around your gut can be partly attributable to disrupted sleep.

In “Acute Sleep Deprivation Increases Portion Size and Affects Food Choice in Young Men” Hogenkamp, et al., finds their results mirror that of previous literature- acute sleep deprivation increases appetite- and refines an understanding of the phenomena by investigating distinctions between how much one plans to eat as opposed to actually how much one eats.

The findings were that those having undergone Total Sleep Deprivation (TSD) ate more than their rested peers, opted to chose more when selecting meals and snacks a and that these “optimal  portion sizes” correlated well with actual food intake of sleep deprived persons recorded in other studies.

It was found, also, that plasma grehlin increases after TSD. Grehlin is a hormone that affects short bursts of appetite. Intravenous injections of grehlin has been found to  increase activation in areas involved in hedonic appetitive control, or in laymen’s terms, that overwhelming desire to eat until your pants don’t fit.

What’s more, is that our body seems ill equipped to adapt our appetite in the face of TSD. For example, those working the graveyard shift will experience shifted sleep patterns, yet the act of altering one’s sleeping pattern increases appetite in the same manner as though one hadn’t slept.

One hopes Nabisco or MacDonald’s hasn’t heard of these findings, lest all our prepackaged foods will come with “free taurine;”

 

“Why is Redbull cornering the instant waffle market?”
Photo:theaustralian.com.au

 

Memory Beyond Decapitation

 

A fluorescent planarian
Photo: http://www.mcb.ucdavis.edu/faculty-labs/scholey

 

Even the most untrained, layperson neuroscientist has the correct sense to recognize memories are realized by the brain, that the brain resides in the head, and so it follows removing the head displaces the memories ostensibly to wherever the head now resides.

Now introducing the planarian (c. Elegans), a standard organismic model in behavioral and biological research along  with rats and undergraduates. The planarian is a flatworm, approximately 1 cm.. Long They are one of the simplest creatures to be endowed with a brain; possessing exactly 302 neurons,it is capable of basic sight, detection of chemical gradients, electrical fields, magnetic fields, and vibration. With these abilities c. elegans is able to be trained, albeit only to perfrom simple tasks. 

Also, it can regenerate parts of its body. This is important.

In the ’60s it was discovered- presumably by a scientist with a maniacal laugh- that c. elegans were not only able to survive decapitation and then regenerate its head but, also, that these trained worms possessed memories that, by all convention, should be locked away in the severed head. The head was removed but the memories remained.

Research on this phenomena carried on for some time. However, training, decapitating, then measuring the behavior of thousands of minuscule worms proved extremely difficult. Further, many dissenting findings occurred and so interest and research on this phenomena all but ceased.

So do planarians perform such a remarkable feat? Had they ever been capable of such a task, or had this quirky behavior been a result of statistical anomaly?

The latest research evidences, yes.

Shomrat and Levin out of Tufts universisty devised an automated manner of measuring the behavior of trained/decapitated/ regenerated worms. 20- to 40 worms were trained over 10-11 days in a custom built fully automated training apparatus (ATA). Planarians naturally possess strong aversion to light (negative phototaxis). During the course of training researchers placed pieces of liver, which planarians apparently love, under a “strong blue lED light… thus, no worm would stay in this quadrant {of the ATA} unless its desire for the liver overcame its natural light aversion.”

Worms who had been trained to appreciate the blue LED light as an indicator of liver navigated the ATA quicker and tolerated the light longer than their untrained counterparts. The worms with re-grown heads had undoubtedly retained their memories; and due to a new high-tech means of recording and training the dispute seems all but over. But how does a creature a retain memories belonging to an appendage which had been removed?

In the first place, planarians possess a nervous much unlike us vertebrates. Their nervous system is a much less dynamical and much less complex, rendering the whole system a highly specialized amalgam of distinct neural tissues. So, although the organs pertaining to phototaxis- the eyes- are situated in the head it does not necessarily follow that the memories and instincts related to those organs are stored completely in the ganglion (bundles of nerves) most associated with the eyes.

Delineation of neuron types in the planarian head Photo:http://www.scholarpedia.org/article/Planaria_nervous_system

 

Where are the neurons that contain memories, then? It isn’t known. And how are memories which are stored in the body coordinated with a newly grown head and pair of eyes? This isn’t known either. The most compelling theory is that the Peripheral Nervous System (nervous tissue of the body) is where memories are stored and the Central Nervous System (nervous tissue of the head) manages behavior. Given that a decapitated worm produces no behavior, other than regrowing a head, this theory is plausible. And if so, it’s a brilliantly simple adaptation for a miniature creature whose very likely to be squished within its lifetime: if the body is damaged, only memories are lost; and if the head is damaged, only behavior is lost briefly.

Wouldn’t it be interesting if  humans exhibited such a modular schematic of our Nervous system: “I’m sorry. I seem to have forgotten your name. You see, the other day I cut the tip off the end of my left thumb in a carpentry accident and now I can’t remember the names of my acquaintances whose first names start with the letters j-m.”

 

“Sexual Sweat” is Recognized as Novel by the Brain


Put down that clump of Whale vomit*, there’s a better kind of perfume now: “Sexual Sweat.”

In a possible attempt to level the field for scientists everywhere, researchers Wen Zhou and Denise Chen of Rice University presented 20 women with samples of human sweat, both produced from times when male volunteers viewed either pornography or a documentary (The documentaries weren’t sexy documentaries, but used as a control measure.). The aim of the experiment being whether humans are sensitive to pheromones, and if so, where the information is processed in the brain.

The sweat produced from these viewing were collected and stored; and then presented to female subjects who were asked how pleasant, if at all, were the stimuli and how intense. In addition to “Sexual Sweat” and “Neutral Sweat,” the putative sex pheromone(PSP), androstadienone, and “PEA,” a control chemical were used.

 


How pleasant is the smell of sweat produced from a guy watching porn? 
Apparently, somewhere between "unpleasant" and "neutral."

 

While subjects were smelling stimuli they were also have their brains scanned via fMRI– it’s a technique much like a PET scan, but instead of rendering a detailed tomographic visualization, fMRI can monitor alterations in brain state concurrently. It can monitor thoughts (and unconscious processes) as they happen.

The results were that presentation of the Sexual Sweat activated areas of the brain other stimuli failed to. The areas of note are the right orbitofrontal and right fusiform cortices (OFC and RFC, respectively), along with the hypothalamus. The OFC is a secondary olfactory processing region, in addition the author’s note the OFC is “…widely implicated in socioemotional regulation and behavior.” This, along with activation of the RFC- the certain area activated not normally being associated with olfaction- indicates that Sexual Sweat is recognized as novel; not simply a smell but one imbued with particular importance. Additionally, that most subjects did not identify the sweat as human, indicates the areas activated were prompted by an intrinsic quality of the “chemosensory cue” and not simply the recognition of “people smell.”

There. Some more evidence our choices are swayed by the nudging of mother Nature– often to the dismay of our irrational sense of a rational self.

 

*It’s called Ambergris. Perfume makers use the products of the whales’ digestive tract as base for expensive fragrances. Remember that next time your’e necking…

Remotely Controlling Neurons: Using Nanoparticle Actuators to Remotely Activate Neural Tissue (or, “Why Standing in Front of a Microwave Whilst Possessing Nanoparticles in your Brain is a Bad Idea.”)

Not quite yet-- but close...

Neuroscientists are always looking for new and interesting ways to manipulate individual neurons and neural networks– shooting magnetic waves at our brains may be the best route yet.

Research in recent years has produced measures for producing and silencing activity of neural regions, which are far more efficacious than classical physiological measures, i.e. electroshocking brain material. “Optometrics,” is the technology of shooting certain light at neural tissue to produce a reaction. This method is attractive because it is far more noninvasive and precise than previous techniques; however, due to the thickness of of our skulls, Optometric techniques can only pierce topical brain tissue, leaving much of the interesting brain organs (the Limbic system, by example) out of purview. This is unless researchers drill holes through the skull to implant light carrying fibers to specific regions– but any process that leaves holes in the subject’s skull seems to defy the notion of, “noninvasive.”

And this is where the nanoparticles come in.

Arnd Pralle and colleagues out of the University of Buffalo reported a new (and mostly noninvasive) method, described as, “Magnetogenetic.” The researchers combined manganese ferrite nanoparticles with proteins on the membrane of certain cells that have been genetically altered to express the temperature-sensitive transient receptor potential V1 (TRPV1) ion channel. Or, in simpler terms, Pralle and colleagues placed nanoparticles within specific sites, which, when exposed to heat, create activity. See, neurons need to be provoked in order to fire. This provocation usually comes in the form of a “neurotransmitter;” neurotransmitters are released from one end of a neuron- which alters the calcium ion balance of the extracellular space – and is taken up by another neuron. It is the process of endless chattering neurons that is responsible for all our thoughts and actions.

Instead of releasing an egregious amount of your average neurotransmitter (dopamine, for example), these researchers opted, instead, to take a “hyrbid” approach, first genetically engineering certain cell proteins to be heat activated, and then supplied the, “membranetargeted superparamagnetic nanoparticles.” When the particles are exposed to a magnetic field that is continuously switching their magnetization it causes these particles to increase in heat– and this heat- coupled with the genetically engineered, heat sensitive neurons- causes activation in the affected part of the brain.

The technique was tested on the species of flatworm , C. elegans ( a mainstay species for biological experimentation). Researchers placed nanoparticles on the ends of thermosensory neurons in the head regions of the worms. Exposing the worms to a magnetic field activated the nanoparticles, which activated the neurons and caused the worms to perform athermal avoidance reflex, “ by moving backwards.

C. elegans

Notably, also, are the immediate possibilities to test the Magnetogenetic method on mice, which do not congenitally possess the specific genes required, but have been engineered in the past to accrue the necessary genetics. And this compels one to wonder, firstly, how easy it would be to genetically engineer heat sensitive neurons in humans’ brain, and secondly, just how difficult is it to place nanoparticles in a person’s brain?

Whatever the answer to these questions, it is certain a somewhat crazed neuroscientist has already undertaken the task.

The Relationship of Reproduction Strategy and Mental Pathology: The Curious Complexity of Personality

It’s often remarkable the ways in which seemingly disparate characteristics of personality mingle. Whether this interaction is remarkable due to the vast complexity and multifaceted nature of the human persona or instead because our understanding of such matters is so paltry, our library of the “psychical” patterns that give rise first to cognition and then secondly to a personality is so lacking, is yet determined—the author’s opinion falls somewhere in the middle; where the former explanation is fact and thus is largely responsible for the second explanation. But whatever the reason for our surprise at such phenomena, it’s always a delight to find another connection between two “nodes” in our “Personality Circuitry.”

Personality characteristics run in packs, as if “you” and “I” are an aggregate of  slightly- and sometimes not so slightly- overlapping circles in a Venn diagram, where  each circled is labeled, “intelligence, “neuroticism (antiquated terms aren’t disregarded in this little hypothetical model), “creativity, ” ad infintum (in fact, if we wanted to have fun with this model, we could replace the 2d model of a Venn diagram with a 3d model of interacting agents in a phase space, but this is geeky, useless digression).

And so often it’s discovered- in our little personality-by-Venn model- that two circles overlap non-intuitively; or at least overlap when it wouldn’t seem obvious, which is what research from the Weill Medical College of Cornell University has discovered: The circle,  “reproductive strategy” and the circle “mental pathology” overlap.

First, what is meant by “reproductive strategy? No, it’s not the repertoire of pick up lines one has at his disposal; nor is it a closetful of matching shoe-handbag combinations.  “Reproductive strategy” can be taken to mean a few things, but in terms of this article, the term refers to the r/K theory, first posited by E.O. Wilson. r/K represent to sides of a continuum– imagine one side is labeled, “cad” and the other side, “dad.” r equals Cad and K equals Dad. An elaboration of the K strategy:

A high-K strategy in humans is theorized as a specific and cohesive fitness strategy, in which the individual invests somatic and parental effort to produce a fewer number of “fitter” and more competitive offspring. Measures of high-K strategy have been shown to correlate with offspring quality and with resultant fitness.

As such, it’s easy to imagine then the converse implications of an r strategy: the parents (or parent, if you’d like to imagine a highly volatile characteristic for two partners to be discordant with) is not so much interested in having few children to which he/she/ they will proffer the requisite amount of  affection and capital upon their child/children in order to thrive, but instead the r strategist is inclined to have many children of whom he/she/ they will only invest the least degree of energy.

Before going on a brief note is required: it’s one thing to apply such a theory as the r/K reproductive theory to birds, hyenas, or even apes, but when attempting to map such a construct onto humans the task becomes trickier; for, whereas, most wouldn’t have any theoretical qualms with equating the complex behaviors of mate selection, reproduction, and child rearing with simple behavioral heuristics as it concerns non-human animals, humans, however, tend to disagree with this view. After all: “animals aren’t conscious, not like us anyway. Animals don’t have a choice in such behavior, whereas humans, equipped with introspection, do have a choice. We are able to deliberately choose who we are going to have children with and the ways in which we will raise those children.” This is all true, of course. The defense is valid: humans possess such cognitive abilities that would seem to preclude the possibility that our behavior could be explained by simple reproductive theories that are applicable to other animals; and it’s not here an extended attempt to convince the reader to what degree human behavior is the result of unconscious, preprogrammed reproductive strategies forces will be made. However   to deny that some of our behavior is not swayed by such forces would be to deny a large literature that indicates otherwise. The point is: the idea that humans go about their “reproductive strategies” in a largely unconscious way, that is, by instinct, or, “gut feeling,” is not a radical idea; and as such to apply the r/K theory to humans is, also, neither a radical idea.

Back to the topic: as mentioned, the Cornell researchers found overlap between the circles, r/K reproductive strategy” and “mental pathology.” What’s this means is that a correlation was found between and aspect of r/k reproduction strategies (the “r” strategy) and mental pathology–  which is to say that a correlation was found between the measures that indicate the degree that a  person theoretically exhibits ” r strategy behavior” and some version of mental pathology, e.g., depression, anxiety, bi-polar disorder, etc.. In finding this correlation the researchers tested “…a sample of 1400 disaster workers who had exposure to a singular traumatic event [World Trade Towers attack] and who underwent psychological evaluations.” Those evaluations are divided into two subgroups: Interview style and self measure evaluations. Of the Interview evaluations, there were: Clinician-Administered PTSD Scale; and The Structured Clinical Interview for the DSM-IV: a semi-structured clinical interview designed to determine DSM-IV diagnoses. Of the self evaluations, there were: High-K Strategy Scale, a 26-item scale tapping into various indicators of high-K strategy behavior; The PTSD Checklist, a DSM-correspondent, 17-item self-report measure of PTSD; Brief Symptom Inventory, a 53-item checklist that assesses a broad range of symptoms of psychopathology; The State Trait  Anger Expression Inventory-2: version 15-item STAXI, which provides concise measures of the experience, expression, and  control of anger; and, The Sleep Index, a Sleep Quality Index that assesses sleep disturbances and their frequency.

After the data were collected, each of these measures was correlated against one another and against demographical factors (sex, age, etc.). Below is the correlation matrix (“matrix” being a table where each combination of correlations is presented. So, for example, if one wanted to know the correlation coefficient (number) between, “age” and “marital status,” he or she would look at the indice of row 1 and column 2.). The higher the number, if positive, the larger the degree these two factors are related, so that is if one increases so does the other. The lower the number, the less these two factors are related. If the number is negative, these rules still apply but just in the opposite direction, so that if one factor increases the other decreases. The stars indicate at what level a respective correlation is significant. “Significant,” basically, means that such a result is likely to not be a product of chance at 95% or, say, 99%.

As one can see, “High-K” correlates significantly and negatively with many other factors. If we take the opposite of the High-K strategy to be the r strategy, it becomes blatant that there is a relationship between r strategy and different machinations of mental pathology.

And why might this occur? Unfortunately, the authors do not hypothesize post- results what may account for their results, however, they posit in their introduction:

Because a high-K strategy is associated with greater somatic effort [i.e., investment in child rearing]  as opposed to reproductive effort, “slow” strategists should manifest the benefits of this in terms of better mental  and physical health. Likewise, low-K (“fast”) strategists should exhibit increased psychopathology and increased physical illness, because these individuals do not allocate sufficient somatic effort to prevent such problems. Indeed, in one of   the first studies on this topic, high-K strategy was shown to be an important negative predictor of depressive symptomatology, accounting for 20% in the variance in the Beck Depression Inventory scores, after controlling for risk factors in depression such as demographics, prior trauma, prior psychopathology, or recent negative life events.

And so with these results, we may shift a few circles of our hypothetical and proverbial Venn diagram of personality atop on another. But there’s one last point to be made. The idea of personality as a great Venn diagram wasn’t capricious inspiration; instead this analogy was chosen –amongst serving a decent means of transmitting an idea- to illustrate a key point of correlation studies, which is, the direction of a correlation can very rarely be deduced—that is, we do not what causes what, only that two phenomena are related. Just as two overlapping circles of a Venn diagram only illustrate a mutual relationship, devoid of illuminating causation, so are the nature of correlations. The authors responsibly iterate this sentiment:

First, as in any correlational study, the direction of causality cannot be established with certainty. One can argue that people score highly on the high-K precisely because they enjoyed better mental health in the first place and their resources could thus be channeled to the indicators that make up the high-K factor. This is a legitimate claim and testing the direction of causality is not a small feat.

Never the less, such findings, if not yet explainable, are welcome to the observers of that swirling mess of interacting characteristics referred to as, “Personality.”

Finger Length Ratios Indicate Sexual Orientation

d2-d4

In a meta-analysis study (a study that combines the results of many studies whose hypotheses are similar), researchers from the University of Ontario, Penn State, and the Centre for Addiction and Mental Health found that the second to fourth finger length ratio (2D:4D) serves as an indicator of sexual orientation.

“…lesbians had a smaller, more masculine 2D:4D than did heterosexual women, whereas gay and heterosexual men did not differ significantly in 2D:4D. The right-hand 2D:4D difference between lesbian and heterosexual women was estimated to be small to medium in size.This difference was robust,” the authors write.

But why might this ostensibly menial measurement correlate with such a multifarious and prominent aspect of the human psyche? And further, at the expense of coming off myopic, if this is true, why might have no one ever noticed this effect before? After all, who’s heard of the happily heterosexual female carpenter who after accidentally shortening either her second or fourth digit in a skill-saw accident suddenly turned lesbian? Or vice versa if she were one already.

In answering these questions, we’ve to remember that, “correlation is not causation.”– thus, while these findings certainly reveal a relationship between second and fourth finger length ratio and sexual orientation, they cannot, by definition, remark on the nature of the relationship. Take a breath: You can relax around Skill-saws again.

As to why these correlations exist, the researchers have penned androgen – steroids implemented in the regulation of male characteristics – as the culprit:

…our results support the hypothesis that prenatal androgen exposure affects sexual orientation in women. These results corroborate other evidence that androgen affects sexual orientation orientation, such as sexual attraction to males in persons with CAIS and sexual attraction to females in women with CAIS [Complete Androgen Insensitivity Syndrome] and prenatally normal males whose gender was reassigned near birth.

Other interesting findings of the study were: sampling location had an effect, where gay men had a lower ratio in Europe and a higher one in North America when compared to Heterosexual controls in both hands, but this effect was only observed in women in the left hand; and higher proportions of white homosexual subjects tended to have more masculine second to fourth finger length ratios.

If only one thing is to be contemplated and taken from this study, it should not be the results, but rather the means by which these results where obtained. Which is to say, quite blatantly, one should understand the nature of the mathematical processes that are utilized in compiling and analyzing such data. In this case we are reminded that, one, correlation is not causation: though two phenomena may be behave identically, so as to give the impression that one is causing the other, this is not necessarily the case; and two, in many instances when a correlation is observed there is often a third factor that is responsible for the observed other two, e.g., prenatal androgen having an effect on both 2D:4D and sexual orientation; and  lastly, while meta-analysis studies can be powerful, if the protocol by which a study is either included or omitted is compromised, so that a few studies that shouldn’t have been included are included or vice versa, the results may become eschewed. This is especially worrisome since the lead authors are relying on both their protocol and the research skills of many other researchers to obtain valid data.

Or more simply: finger length ratios don’t “cause” shifts in sexual orientation, but still, please be careful when handling your skill-saw.

The Domesticated Dog’s Ability to Interpret Human Social Cues is a Result of Millennia of Selective Breeding

man-looking-like-bulldog

As if the domesticated dog’s position as, “man’s (or woman’s) best friend” was not entrenched in the human zeitgeist enough, research from Brian Hare out Harvard’s Anthropology department indicates that not only are dogs far more adept than Chimpanzees- our closest genetic, extant relative- at interpreting human social cues, but that domesticated dogs are superior to wolves- their closest genetic, extant relative- in this respect, too.

The explanation reached by Hare is thus, “…dogs’ social-communicative skills with humans were acquired during the process of domestication.;” which occurred, because, “…dogs that were able to use social cues to predict the behavior of humans more flexibly than could their last common wolf ancestor … were at a selective advantage.”

In coming to this conclusion, Hare et al. performed four experiments, each pertaining to three hypotheses concerning the genesis of the domesticated dog’s social cognition. The experiments were centered around the Object Choice Task (OCT), where a subject- be it a dog, puppy, or chimpanzee- is presented with two boxes. Hidden underneath one the boxes is a treat (usually a piece of food); and because the box eliminates the possibility of detecting the food by either sight or smell, the subject relies on its ability to interpret the researchers indication (any combination of a gaze, point, or tapping of the box) to choose correctly.

The first of the three hypotheses, The Canid Generalization Hypothesis, posits that many canids, especially wolves, should perform well at OCT tasks because, “…[wolves] typically live in cooperative hunting social groups, making it likely that they need to exploit the behavior of conspecifics [other wolves] and quarry alike, and this ability may then generalize to humans.” The second, “Human Exposure” hypothesis, places the domesticated dog’s ontogeny forefront, implicating their social cognition as the result of having been exposed to humans for their entire lives. Lastly, the Domestication Hypothesis attributes dogs and humans pre-historic relationship as the vehicle of dogs developed ability to interpret human signals: the ability to interpret correctly human intentions, or at least more so than other individuals, was a positive trait. And that over the course of dog and humans 10 millennia long shared history (or, “paraell phylogeny,” if you’d like to be technical), these traits were exacerbated and honed.

Each of these hypotheses possesses logical corollaries. For example, it follows from Canid Generalization that wolves should to as well, or very nearly so, as dogs in OCTs; according to the Human exposure hypothesis puppies reared by humans should outperform their kennel reared peers in OCTs; and if the Domestication Hypothesis were true, dogs should perform well at OCTs regardless of age, since the ability to distinguish human social cues should be greatly inborn (and outperforming Chimpanzees doesn’t hurt to bolster this hypothesis either). By systematically comparing adult dogs and wolves, human reared puppies and kennel reared puppies, and adult dogs and chimpanzees performances at combinations of OCTs, Hare and colleagues were able to shed two of the hypothesis, which left the domestication hypothesis as the clear winner.

Of course, and this is the author writing, our ancestors probably did not selectively breed their dogs on the basis that they could find a hidden piece of food (which is undetectable by direct smell or sight) based on their gesticulations. The most conspicuous answer is that this specific trait (adeptness at OCT tasks) is a function of a dog’s ability to do work. After all, what good is the herding dog that herds on caprice, indiscriminately of his or her owner’s wishes? Simply, humans and canines have benefited from one another for thousands of years, and this relationship is based (like any good relationship) on clear communication. The fact that dogs have retained this ability (because it’s doubted that many of us use our “labradoodles” to herd) is a testament to the two species intimately intertwined lineage. And in the author’s opinion, so long as man (or woman) want their best friend by their side, this trait will persist for another ten millennia.