I found and was tempted to post horrifying videos of vicious attacks by non-pit bull type dogs, but I didn’t think that would encourage  further intelligent discourse. .It appears to me that the core questions  are  a). Is canine impulsive aggression a heritable factor?  b.) Is it caused by, (or does it perhaps result in) unique structural changes within the brains of particular breeds such as pit bulls, which are in turn sequelae of genetic manipulation to achieve a consistent suite of behaviours and physical conformation? Are there other factors implicated? Is this unique alteration of structure present in all members of the breed (which would strongly support BSL legislation? Are there (biochemical) facilitators,moderators or mitigators of this behavior.

In reading Ms. Semyonova’s article (which  is footnoted, but I can find no evidence of its having been peer reviewed and published in a scientific or veterinary medical journal), I found a number of flaws and failure to take into account the more recently recognized complexity of canine cognition, as well as research findings on canine brain plasticity and biochemical influences. I won’t detail them all here as it would take several very boring pages, but things that particularly stood out for me include: 

No one would dispute that we have bred dogs over hundreds of years to have conformation, physical abilities and behaviour suites suited to do various specialised jobs – she referenced Border collies, hunting dogs and so on. However, I disagree with her contention that dogs ‘feel good’ – thus self-reward – when they assume ‘natural’ postures and movement that are actually demanded (in terms of it’s the easiest way for them to stand and move) by their conformation and musculature.  There is no scientific evidence that they ‘feel good’ doing so and are thus reinforced to continue the behaviour. Hence, I think the implication that pit bull types ‘feel good’ when they are attacking and killing because they were bred for bear baiting is unfounded conjecture. (And, PS, I believe Mastiffs were used for this purpose at times as well – shall we ban them?). Interestingly, the breeds most frequently implicated in impulsive aggression are English Cocker Spaniels and English Setters ( ahem…bred as HUNTING dogs).

Many breeds are no longer bred to perform their original jobs, so there is a great deal of genetic diversity within breeds. In her study:  “That Dog Is Smarter Than You Know: Advances in Understanding Canine Learning, Memory, and Cognition, Karen L. Overall, MA, VMD, PhD, Dipl. ACVB, ABS Certified Applied Animal Behaviorist

Volume 26, Number 1, February 2011

Dr. Overall said:

“A number of studies have begun to focus on differences in

performance, problem solving, and cognitive capabilities

across canid species.34-37 It is important that we interpret the

studies to date with the limitations of the studies and their

foci in mind. Although dogs were originally selected on the

basis of their behaviors—and specific tasks gave rise to

breeds—most dogs are no longer “worked.” This means that

there is a large amount of divergence in populations of any

breed that can be reflected in both their behavior and genetics.

38 We should not expect dogs, even within a self-labeled

“breed,” to be homogeneous with respect to behavioral capabilities,

even if those results are not dependent on the rearing

and learning environments, simply because dogs selected

for work and those selected to not work may look the same

but may not be the same. Studies within one culture have

shown that at some level dogs’ responses to basic cognitive

tests do not vary by breed or age39; however, they may vary

by culture. Pet dogs in one culture may have been developed

under a different set of expectations than those in another

culture. Specific expectations about performance (e.g.,

whether the dog is capable of being a trained detection dog or

a service dog) are, themselves, also affected by culture. This

means that source, culture, trainability/capability of the parents

(for dogs bred to be working dogs), early experience, and

in utero and early brain development may all be sources of

variation that may need to be considered.

cognition in domestic dogs is finally written”.

Next, let’s look at causes of changes in structure/size of areas within the canine brain. MsSemyonova references research done in the a930’s through ‘60’s, when it was believed that brains of humans (and the more ‘primitive’ brains of dogs) lost plasticity (the ability to change and develop) in adults. Research now shows that experience and learning can alter brain structure  and size of various areas as well as growing new synapses (in dogs and humans).

Current research shows that both experiences and learning can cause physical and biochemical changes to the brain.  As Dr. Overall’s research shows: “Learning is generally defined as the acquisition of information

or behavior through exposure and repetition. At the

cellular and molecular level, learning is defined as cellular

and receptor changes that are the result of stimulation of

neurons and the manufacture of new proteins. It is these new

proteins/receptors that then change the way the cell responds

when next stimulated. It is important to remember that no

cell/neuron acts on its own: region of the brain, neurochemical

tract, and interactions with other cells are critical for

determining response

3 Finally, when examining the rates of gene

expression mutations in regional brain tissue, the only species

studied to date that has comparable rates with those found for

humans is the domestic dog.14 Such data, when taken together,

strongly suggest that dogs can be excellent models for many

aspects of human social behavior, cognition, and pathological

behavioral conditions, including those involving anxiety.

Other research has shown that dogs suffer from psychological ailments such as depression, OCD, fear aggression, anxiety, panic, and so on that are analogous to human issues and are now used as models for these disorders.

Glutamate and inhibition of  Serotonin are also implicated in poor impulsive aggression. However, again, learning through good training (learning) and experiences seem to be able to mitigate these and change brain physiology and chemistry.

Hence, my conclusion is that there is a hereditary component, but it is not breed specific, and it can be mitigated through selective breeding and creating positive learning experiences.

So here is another video to show that pit type attacks are different than most other attacks by other breeds on average. Not to inflame, but to show how pit types disregard most visual signals & cues, that most other breeds would use to break off an attack.

Pits have been known to continue an attack on an already dead animal. This is what was being described in part in the earlier articles.

Aggression per se is not the issue, it is the quality of the impulsive behavior and the oblivious nature of the pit, once the attack begins. This genetic element can also appear in other breeds, so not just confined to the pit. But it is the amount of this genetic factor that must be our concern, since it appears to be focused & concentrated in pit types. This is clearly evidenced in the countless numbers of attacks recorded on film and in police records of the quality of such attacks.

We would never deny the high agitation & energy level of many terrier breeds, yet when we cross terriers into other breeds, why would we expect a zero net effect, regarding that level of excitability in the new product from such crosses?

Yet, we deny that pit types would have any different genetic factor influencing their core temperament en masse, just because we find it politically distasteful to do so!

ST. LOUIS — Ten-year-old Rodney McAllister was no match for the stray dogs that neighbors had complained about for days.

The fourth-grader was found mauled to death by a pack of dogs Tuesday, bite wounds on most of his body, pieces of his clothing scattered around the park across the street from his home. The attack has horrified many in St. Louis and led to the jailing of the boy's own mother for not keeping closer watch over him.

"He was literally eaten by the dogs," Police Chief Ron Henderson said. "They fed off of him."

Neighbors told police they heard the sounds of "suffering" Monday, two hours after Rodney told his mother he was going to play basketball in the park.

Before Rodney's death, neighbors had complained about stray dogs in the area around Ivory Perry Park. Just a few days earlier, two officers from the city's Animal Control division had responded to the complaints.

"We did not see anything," said Richard Stevson, Animal Control program manager.

Two-person crews are usually sent to investigate complaints, but Stevson said Rodney's death prompted the agency to evaluate its procedures to see if larger crews should be used.

On Tuesday and Wednesday, animal control officers rounded up 10 dogs in and around the park — two chows, a German shepherd, a Rottweiler and several mixed breeds. It was unclear how many of the dogs were involved in the attack.


Lorain County Coroner Paul Matus said Michael Winters, 30, was bitten “hundreds” of times during the attack by as many as nine of the family’s dogs. Winters’ clothing was torn off during the attack, which caused extensive bleeding, Matus said.

Seven other dogs were euthanised at the scene, Chief Deputy Dennis Cavanaugh said. A 10th dog that was inside the house at the time of the attack was spared, he said. Barker said authorities had no choice but to put down all of the dogs, which varied in size and breed, but included a mastiff and a Rottweiler.“All the dogs are going to be euthanised,” he said. “There’s no way to tell which ones were involved.”

LOS ANGELES, California (Reuters) -- Massive dogs belonging to "Mission: Impossible" star Ving Rhames attacked and killed a live-in caretaker at the actor's Los Angeles home Friday, police said.

The caretaker, whose name was not released by authorities, was found dead on the front lawn of Rhames' gated home in an expensive Brentwood neighborhood, covered in dog bites, a Los Angeles police spokesman said.

Several large dogs were running loose on the property when police responded to the scene shortly after 7:15 a.m. (10:15 a.m. ET) and animal control officers took three huge bull mastiffs and an English bulldog into custody.

"It appeared that the person suffered a number of injuries as a result of the dog mauling," Sgt. Lee Sands said. "There were numerous dog bites all over his body, but the exact cause of death is pending the coroner's ruling."

Sands said four dogs, the largest weighing nearly 200 pounds, were being quarantined as part of an investigation into the attack.

Moving right along to aggressiveness and genetics, I don’t think I stated that aggression – particularly impulse aggression -- (or other attributes of temperament) has no genetic component.  What I said was, “ Hence, my conclusion is that there is a hereditary component, but it is not breed specific, and it can be mitigated through selective breeding and creating positive learning experiences. To that I would add: Positive learning experiences via good training, socialization, and so on do create biochemical and structural changes at the cellular level that mitigate against aggression. Further I certainly did not suggest that breed specific behaviours do not exist within breeds. I referred to these as ‘suites of behaviours’ . I simply think that breed specific aggression unique to pit bull types does not exist.

What research is showing  is that genes do not directly control aggressive behavior--they affect the behavioral regulators known as neurotransmitters, that in turn may influence the probability of certain kinds of aggressive behavior.

Association of dopamine- and serotonin-related genes with canine aggression

1. J. Våge¹,
2. C. Wade^2,3,4,
3. T. Biagi²,
4. J. Fatjó⁵,
5. M. Amat⁵,
6. K. Lindblad-Toh^2,6,
7. F. Lingaas^1,*

Aggression in dogs comprises a group of complex behavioural phenotypes, often with a continuous, rather than discrete distribution. Large differences in breed-specific risks of aggressive behaviour coupled with high estimates of heritabilities (Liinamo et al. 2007; Pérez-Guisado et al. 2006) strongly indicate that canine genetic architecture significantly influences the risk of exhibiting human-directed aggression.

We observed significant allelic associations between human-directed canine aggression in ECSs (English Cocker Spaniels) and alleles at 4 of the 16 loci studied. In addition, haplotypes having both high and low OR for aggression were observed. All of the studied genes are related to neurotransmitter systems in the brain and are highly relevant to behavioural alterations both in normal and diseased states. Although the mechanisms for their actions are not fully understood, Siever (2008) describes a model in which reduced serotonin and enhanced dopamine decrease cortical suppression of aggression and reduced GABA activity in the limbic system can modulate limbic ‘drives’ for aggressive behaviour. As expected, we did not identify any single locus with specific alleles/haplotypes completely associated with the presence of the recorded phenotypes. Although the study identifies haplotypes associated with a risk of aggressive behaviour, it supports a complex nature of canine aggression, and the associated loci studied are only partly explaining the observed variation in the aggressive phenotype. This is also shown by the ‘attributable risk’ (risk if haplotype minus risk without haplotype) of aggression from risk haplotypes, varying between 0.21 and 0.36 for the four genes within the study population of cases and controls.’

One of the unique features of springer’s with this form of dominance aggression is the lack of warning before the aggression.  The “glazed look” noted by owners is actually a very intense stare and dilated pupils.  This is caused by sympathetic nervous stimulation, part of the fight or flight response.  Whereas most dominant dogs gradually escalate the level of threat in social situations, moving from a stare, to growl, to lip curl, to snap and finally to bite, springers seem to move from stare to full-blown attack, skipping the intermediate stages.  These dogs lacked impulse control and over-reacted in situations they perceived as threatening

 Genetics of Impulsive Aggression in the Dog

A New Research Project

We are genetic researchers from the University of California, San Francisco.

We are working on the Canine Behavioral Genetics Project, investigating the

genetics underlying various anxiety-related behaviors such as noise phobia,

separation anxiety, fear aggression, and impulse control problems. As members

of the Department of Psychiatry, our hope is to identify genetic markers that may

predispose dogs to certain behavioral traits, with future goals of applying this

knowledge to better treatment of affected dogs as well as learning more about

related pathways in human disorders.

One of our projects involves studying aggression, a complex behavior that is

probably influenced by a combination of genetic and environmental factors.

We work under the assumption that many aggressive behaviors are related to

underlying anxiety conditions. Specifically, we are interested in maladaptive,

anxiety-based fear-aggression, and impulse control aggression. Dogs with this

type of inappropriate aggression exhibit abnormal, aggressive behaviors that

are grossly out of proportion or out of context with the external environment.

We are very interested in the genetics and biology behind this trait.

We realize that this is a very controversial trait to research and want to assure you

that our entire group has publicly criticized breed-specific legislation. It is clear

that this type of inappropriate aggression is seen throughout all breeds of dogs.

It is our hope that by identifying genetic markers for predisposition to this type

of aggression, we might better address the need for modified training practices

at a young age and improved breeding and puppy-raising practices, which we

hope will remove the negative stigma associated with particular breeds

.

The dog provides a unique opportunity to study the genetics underlying different

behaviors. Because dogs from the same breed are more genetically similar than

dogs from different breeds, studying single-breed groups makes it easier to find

genetic markers that may predispose certain dogs to behavioral traits. Discoveries

made in one particular breed can then be extended to other, closely related

breeds for confirmation of findings (e.g., Australian Shepherds vs. Collies).

Given the strong interest in genetics within the Australian Shepherd community,

we have sought to initiate these studies with a breed where the importance of

genetics for understanding the breed is well-established.

Pit Bull Mastiff-Mix Kills 10-Year Old Boy in Mexico

'Impulsive' Gene Identified in Finnish Men

CREDIT:

Being impulsive at the shopping mall is one thing, but the personality trait at the extreme is linked to violence and criminal behavior. Now scientists have found a gene mutation behind such impulsive behavior.

The gene mutation affects the action of the neurotransmitter serotonin, a hormone known to be related to self-control, according to the researchers.

The mutation, which is found only in Finnish populations, shows up three times more often in violent criminal offenders than in psychologically healthy Finns, the study found. However, the researchers caution that the mutation itself does not cause impulsivity, but may play a role along with factors like gender, alcohol consumption and stress.

 

"We've known that impulsivity is strongly influenced genetically, but here's a severe genetic variant that does contribute to it," study author David Goldman, a geneticist at the National Institute on Alcohol Abuse and Alcoholism (NIAAA), told LiveScience.

Impulsive genes

Earlier studies have found that low serotonin levels are associated with impulsive behavior. Research also has suggested a heritable component to impulsive behavior and to disorders involving impulsivity, such as attention deficit hyperactivity disorder (ADHD).

In the current study, researchers recruited 96 Finnish men who were in jail for violent offenses and 96 psychologically healthy Finnish men who were not incarcerated. Finns were chosen for the study, because the Finnish population is more isolated than other populations and therefore hosts a less-diverse array of genetic mutations.

Goldman and his colleagues analyzed each man's genome, focusing on 14 genes known to be related to the function of the neurotransmitters dopamine and serotonin. They found a mutation on a gene called HTR2B was associated with impulsive, violent behavior. HTR2B contains the instructions for a serotonin receptor found all over the brain, especially in the frontal lobe, the seat of impulse control. The mutation in HTR2B is a misplaced "stop codon," or genetic code that halts the transcription of a gene into a functional product. The stop codon prevents the expression of the serotonin receptor.

History of violence

Seventeen of the 96 inmates had the gene mutation, a rate three times that of the non-incarcerated participants. On average, the prisoners had committed five violent crimes apiece, 94 percent of which occurred under the influence of alcohol. The crimes were not premeditated and were usually an overreaction to a minor incident, the researchers report. The study also revealed that 70 percent of participants with the mutation had displayed suicidal behavior.

To better understand the role of the gene, the researchers bred mice with the same mutation. They found that mutated mice were more likely to show impulsive behaviors when exposed to new objects or environments than were regular mice. The mice with the mutation also had higher testosterone levels, a trait they shared with human men with the same mutation.

Genes aren't destiny, the researchers were quick to warn.

"The [mutant] allele can be regarded as one determinant of behavioral variation," the researchers wrote. "However, the presence of [the mutation] was not in itself sufficient: male sex, testosterone level, the decision to drink alcohol, and probably other factors such as stress exposure, all have important roles." (An allele is a gene variant.)

In other words, Goldman said, the gene isn't sufficient to turn someone to a life of crime.

"What we've extrapolated is that over 100,000 Finns carry this variant," he said. "Most of them will never commit any highly impulsive act, much less a criminal act."

The fact that the mutation is only present in Finns is a reminder of the genetic diversity of complex traits like psychiatric disorders or propensity toward impulsivity, University of California, San Diego psychiatrist John Kelsoe wrote in a News & Views article accompanying the study.

"But although this specific mutation is absent in non-Finnish populations, different mutations in the HTR2B gene might operate in other populations," Kelsoe, who was not involved in the study, wrote.