I had my camera running at just the right time this week. I just love this clip of Summer interacting with…wildlife. Nobody got hurt. But I should add that it was rather foolish of me to allow this interaction at all. You never know what might be living in the detritus under your hose reel–but the dogs knew there was something.
So….comments are open and let’s hear your speculations about what is going on with Summer! She is fearful and jumpy, but what else? Do your best to base your comments on observations of specific actions.
I’ll participate in a limited way in the comments (no spoilers from me!) then publish a followup blog with my own observations and a bit of history. Enjoy!
Thank you to Debbie Jacobs and Randi Rossman who made suggestions about this. All conclusions and any errors are my own.
Have you heard the term “opposition reflex” used in dog training? It’s used pretty often. But recently I got to wondering whether the opposition reflex was really a reflex. (Quick answer: “No.” Shortest blog post I’ve ever written.)
Would you like to hear the story anyway?
First, some context. I gathered the following quotes about the “opposition reflex” from a selection of dog training articles.
The dog’s opposition reflex [is the] instinctive reaction to push against a push.
Dogs have a natural resistance to pressure called the opposition reflex.
If dogs are pulled in one direction, they will automatically pull in the other direction.
The opposition reflex is your dog’s natural instinct to resist pressure.
Wow. Instinctive! Natural! Automatic! But then I started looking for the term “opposition reflex” in lists of actual reflexes. I looked in biology, physiology, and learning theory textbooks. I looked in scholarly articles.
Results: nothing.
Virtually all mentions of the so-called “opposition reflex” are in lay articles about dog and horse training. So where did this term come from and why do we use it? It’s not in the textbooks.
History
We have Pavlov to thank for part of the confusion about the opposition reflex. Interesting, since he was a physiologist. Pavlov came up with the term “freedom reflex” for the escape behaviors of a dog who strongly resisted the harness he used in his laboratory. He generalized it to all organisms. (It turns out that Pavlov liked to call all sorts of things reflexes. That is a whole other discussion.)
Most scholars agree that Pavlov grossly over-generalized from the actions of the dog, and was mistaken in calling what was essentially resistance to coercion as a reflex. As one of his critics states:
There is of course no reflex of freedom, although it is easy to see resistance to coercion in animals and humans. Herding cats is nearly impossible, and it is equally hard to keep male dogs from sniffing females in heat. Wild horses resist taming, and most animals cannot be domesticated at all. Human beings fiercely resist unwanted control. But struggling against coercion is not a reflex — it is nothing like a simple atom of behaviour. –Baars, Bernard. “IP Pavlov and the freedom reflex.” Journal of Consciousness Studies 10, no. 11 (2003): 19-40.
But decades after Pavlov, trainers grabbed onto the concept of the freedom or opposition reflex. Mentions start to appear in the mid-1990s in training literature, first applied to horses, then to dogs, as far as I could tell. Some authors connected the two terms, as in this article: “Opposition Reflex in Horses.” It’s pretty clear that what many people refer to now as the opposition reflex is a direct descendent of Pavlov’s freedom reflex. The problem? It never was a reflex and it’s still not a reflex.
What Is a Reflex?
Reflexes are involuntary, discrete, and consistent behaviors. As Baars mentions in the quote above, they can be thought of as “atoms of behavior.”
A reflex is an automatic response to nerve stimulation. –Alters, Sandra. Biology: understanding life. Jones & Bartlett Learning, 2000.
Some examples of reflexes in dogs are:
the scratch reflex (dog’s leg kicks when you scratch them on certain parts of the body);
the palpebral reflex (dog blinks when the skin below the corner of the eye is tapped);
the pupillary light reflex (the pupil of the dog’s eye contracts when a bright light is shined on it);
the withdrawal reflex (dog pulls foot away when toe is pinched);
and many more, including at least 10 other reflexes having to do with stimulation and response of parts of dogs’ legs.
These are immediate, involuntary responses.
Pavlov’s so-called freedom reflex consists of much more varied behavior, sometimes chains of behaviors, which comprise methods of escape or regaining balance. These behaviors vary to the extreme by species and individuals. A large, gentle animal might just walk away if you tried to restrain it without any special equipment. But anyone who has ever tried to handle feral kittens knows that their methods of trying to escape are typically painful and actually dangerous (because of the possibility of infection from scratches and bites) to humans.
What are typical situations in which an animal might exhibit these compensatory or escape behaviors?
The animal is trying to get to something and is being restrained
The animal is trying to get away from something and is being restrained
The opposite can also occur: the animal is being forced to move and is resisting, as when a trainer tries to force a sit by pushing the dog’s butt down.
The animal has been knocked off balance and is trying to regain equilibrium.
(I’m omitting situations where the animal has been trained to create or maintain pressure, such as a roping horse who can hold a cowboy’s line taut, or all sorts of animals that pull sleds or carts.)
Do you see the pattern here? In all cases, the animal is resisting force, confinement, or physical discomfort. When we use the phrase “opposition reflex,” we are often neatly sidestepping the fact that we are trying to get the animal to do something it doesn’t want to do. It’s a shortcut, a label that unfortunately encourages us to leave out our agency in the matter.
When Is This Discussed in Dog Training?
The so-called opposition reflex is generally brought up in discussions about leash walking, molding behaviors, and play.
Leash Walking
Countless writers highlight a dog’s supposed opposition reflex when discussing why a dog won’t yield to leash pressure, but instead, might pull the other way. Reducing the reasons a dog might not yield to leash pressure, or will take action to create it, to an “opposition reflex” is simply applying a label. It gives us no insight into the situation. Many writers grab onto the phrase without considering the many sources and reasons for this behavior:
First and foremost, many dogs naturally travel much faster than we do. They want to get moving. This creates a taut leash as our slowness holds them back.
They are trying to get to something interesting, and we are passively or actively slowing them down. Again, this creates a taut leash.
We are trying to get them away from something interesting, and they want to stay there. This time, we are actively creating the taut leash.
They are frightened and trying to get away from us, the leash, or something else they perceive as threatening.
Positive reinforcement-based trainers try to avoid these situations anyway. We don’t want to drag our dogs around. To me, it seems much more helpful to understand that the dog is wanting to go at a different speed or to a different location than to reduce it to “opposition reflex.” The “opposition” part can make them sound downright contrary, instead of being creatures with their own agency and interests. On the other hand, the “reflex” part obscures that their behavior may be a visible indication of what they want or intend. Reflex sounds like they pull because they can’t help it, not because they are motivated by something.
Training by Molding Behaviors
The second place you read about the “opposition reflex” is in discussions of molding as a training technique. This is not a method that positive reinforcement-based trainers use, but it bears mentioning because people who do use it bring up the opposition reflex. It’s found in the old “push the dog’s butt down to teach him to sit” method. If you’ve ever tried it, you’ve probably experienced what people call the opposition reflex. It is an instant resistance by the dog to being pushed. It’s very common. It’s resistance to being thrown off balance and/or coerced. But again, labeling it “opposition” can even make it sound like this resistance is naughty or defiant.
Play and Restrained Recalls
A final situation in which people discuss the opposition reflex is in activities that involve drive and enthusiasm. For instance, some agility trainers use what are called “restrained recalls.” A partner restrains the dog while the handler calls her. The dog’s struggle to escape can result in a faster recall when she is released.
Note that the latter situation matches my description #1 above: the dog is trying to get to something and is being restrained. If you have a play history with your dog, this can be fun for the dog. But it’s pretty obvious it’s not a reflex–they are trying to get to something.
Here’s an example where I am restraining my dog in a training/play situation. Check out 0:26 in the video.
I contend that Summer’s pushing against my hands as I pull her backward is not a reflex. We’re seeing a dog who wants to run forward and get to the garden hose.
Thigmotaxis
Oxford Reference defines the term thigmotaxis as “Movement towards or away from a solid object in response to tactile stimulation.” Several readers suggested this as an explanation for the opposition reflex.
The classic example of positive thigmotaxis is rodents’ tendencies to walk staying in touch with walls and other vertical surfaces. Negative thigmotaxis is a movement to avoid certain stimuli, and is seen in fish and unicellular organisms.
The idea that the “opposition reflex” is some kind of thigmotaxis appears to come from the work of Steven R. Lindsay. In Volume 1 of his Handbook of Applied Dog Behavior and Training, he suggests that the opposition reflex is an example of thigmotaxis. But in Volume 3, he rescinds his recommendation of the term thigmotaxis for response to leash pressure and returns to using the term opposition reflex. It’s pretty clear that his original citing of thigmotaxis was an educated opinion, not based on experimental literature. And he changed his mind.
Positive thigmotaxis (turning **toward** touch or pressure) is seen in neonate puppies in the behavior of rooting for a nipple. Other than that, I haven’t seen it listed as present in dogs.
What’s the Problem With the Phrase?
I think we should question our use of the phrase “opposition reflex” because:
It’s a label—it can stand for dozens of different behaviors.
The behaviors it is used to describe are generally not reflexes.
It discourages us from analyzing and asking why the behavior is being performed. (E.g., the leashed dog simply wants to go faster.)
It discourages us from looking at our role in setting the stage for the behavior.
It discourages us from determining the consequences that are driving the behavior.
It sounds automatic, nonvolitional.
It also sounds negative. Opposition sounds like defiance.
It promotes confusion about respondent and operant behaviors.
I don’t think the term is going away anytime soon. But I hope we can get better at actually observing and describing behavior and understanding its causes and consequences. If we did that, this term would be left behind.
Have you heard the phrase in more contexts that I have listed? Have you ever seen a true reflex mentioned when discussing the opposition reflex?
Addendum
Wow, opposition in the trenches. (I’m going to avoid the obvious joke there.)
To anyone who wants to claim that the opposition reflex in dogs is a true reflex/respondent behavior/thigmotaxis, the burden of proof is on you. I have already tried and failed. You may succeed, then I’ll retract appropriate statements and amend my post. To provide evidence you will need to do the following:
Cite a source listing the “opposition reflex” as a true reflex from a canine anatomy/physiology, neurology, or another veterinary textbook.
Show that near 100% of neurologically healthy dogs demonstrate it in the same way.
Show the body part that can receive the stimulus and nerve group involved.
Show that the same physiological response is consistent.
Show that it can’t be punished or reinforced (though it could be attached to a new stimulus).
As I mentioned, I have already tried and failed to find these things. Please let me know if you find them.
It’s the start of tick season here in the Northeast and I’ve been reflecting on last year’s tick season and how we almost lost our sweet BooBoo. So in the interest of raising awareness and saving lives, I share with you our story.
It was a beautiful Sunday in April 2015, one of the first nice days of the spring. My husband and I decided to take our two rescues, Mr. Barbo and BooBoo, for a hike and before we headed to bed that night, we did our standard post-hiking tick check and everyone checked out clean.
The next day we let the dogs out and as they chased the squirrels, BooBoo’s rear legs slipped and she fell. Did she trip on the pool cover? Maybe her hip dysplasia was acting up after our hike? I wasn’t really sure but she wiped out and then just kept going.
By dinnertime she was non-weight bearing on her right rear leg and I immediately worried she had an ACL injury from her earlier slip. I knew that non-weight bearing was a classic symptom so I put an afterhours call into our vet and immediately started her on some Rimadyl.
Over the next five days she improved and regressed. We brought her to the vet to rule out an ACL injury and our vet suggested we could re-run a Lyme test, even though she had just had one two months ago and even though we use Vectra 3D monthly. We declined the test and suspected it was an injury from the slip that was causing her limp.
Our first red flag that we were dealing with something else came Saturday evening when she was curled up on the couch and whimpered as she adjusted herself. We left a message for the vet saying we would need an appointment first thing after the weekend because the Rimadyl wasn’t working.
But, that plan changed Sunday morning when we woke up and she wasn’t in bed with us. We found her on the floor, lethargic and reluctant to move. She wouldn’t eat, not even her favorite treat and her temperature was well over 105. We rushed her to our local emergency facility, calling ahead so they were prepared to receive her. When temperatures are that high, the chance of a seizure is a real risk.
BooBoo in the hospital
We arrived at the ER and they immediately started cooling her. We explained the weeklong history since our hike and they suggested a Lyme test, as our vet originally did. So we did the in office “snap test” but it came back negative. Despite the negative results, she was symptomatic of a tick disease and they suggested a full antibodies panel and PCR test for all the tick illnesses. We started Doxycycline right away and ran bloodwork and everything came back normal. The tick panel would take several business days for results but if it were a tick disease, the Doxy should start to knock it out. They admitted her for IV antibiotics and fluids to stabilize her and then said we could take her home. After midnight, they called, said her temperature had been stable since 10PM and we could take her home with oral Doxy and Tramadol for pain.
We followed-up with our regular vet on Monday and she agreed with the ER’s diagnosis. BooBoo was on the meds, still lethargic and not eating well but her temperature seemed to be controlled.
But then Tuesday evening her temperature spiked back over 104 again and we rushed back to the ER where they admitted her again, this time for several days. We consulted with the internal medicine specialist to discuss the all possibilities from cancer to autoimmune issues to tumors and other super scary things since the Doxy didn’t seem to be working. We ran additional diagnostics including ultrasound and x-rays and she got the all clear. No cancer. No tumors. All of her organs were the right size and everything looked perfect. A glimmer of good news in a sea of uncertainty. But her fever was still fluctuating and they were struggling to keep her stable. The 5 doctors now on her team were all brainstorming to figure out what was causing our sweet Boo to be so sick.
Later in the week, the antibodies results returned a “high positive” for Rocky Mountain Spotted Fever. I was thrilled to know what we were dealing with but I was baffled. We hadn’t been in that area of the country, so how did she get it? But then I learned that despite its name, only 5% of the cases were actually from that region1. As I researched, she fit much of the epidemiology. RMSF is called “the great imitator” because clinical signs are often vague and symptoms are often confused with other infections but high fever, joint and muscle pains are usually observed within 3 days of exposure. And with delayed diagnosis and treatment, within days the effect on the central nervous and vascular systems can be devastating including death within a very short period of time. I was beginning to realize how close we were to losing her.
So with the RMSF on the radar, the vets changed the drug regimen within 24 hours she stabilized and we were able to bring her home Friday. The bad news was the PCR test came back negative, which meant either she had been a carrier of RMSF for a long time and it was a red herring that was throwing off what we should actually be treating or that the DNA wasn’t in her bloodstream because it had attached to things like cell or artery walls. Since RMSF typically attacks the vascular system the latter option was a possibility, but we had no way to be sure.
We stayed the course and remained vigilant for any additional symptoms and completed the prescribed 3 weeks of medication. She progressed little by little but never got to 100% by the time the drugs ran out. She was still reluctant to jump up and was still very tentative on the stairs.
So what now? Retesting the tick panel at this point wouldn’t give us any new information. We could do additional diagnostics like joint taps to rule out things like autoimmune polyarthropathy but doing invasive procedures like that brings its own risks. Would she now be lame forever?
We opted to started her on Prednisone to see if her mobility improved. After 2 days of Prednisone, she had mobility improvement but also was experiencing the known side-effects of steroids – increase appetite (not really bad for her at this point) and increased thirst/urination. We continued the Prednisone for months, dropping the dose as advised but noticed that even though we were dropping her dosage, her need to urinate very frequently wasn’t subsiding. This caused our vet to begin to worry about liver, kidney and diabetes risks. We ran additional bloodwork and now her liver values were dangerously high. We continued to step down the Prednisone as quickly as we safely could and added in Denamarin, to help support her liver.
It would take over six months after her diagnosis to completely step her down off the medications before her liver values returned to normal and she got a clean bill of health.
BooBoo feeling good again
So here we are, a year later at the beginning of a new tick season. She’s healthy and happy but is a changed dog and we’ve made changes as a result of this experience. We still hike – our dogs love it and even through almost life ending experience, I wouldn’t want to keep them from that joy. After all my research on RMSF and the recent Powassan virus, I discovered that some of these tick-borne diseases only take a few hours to be transmitted and that is truly frightening to me. Unlike Lyme, where the tick needs to be attached for 24-48 hours to transmit the disease, RMSF can be transmitted in as little as 5 hours. This means hiking a full day and not checking for ticks until before bed will no longer do. We now do a mid-hike tick check every 2 hours if we’re out for a long day in the woods.
As I reflect back on this ordeal, I’ve got several important takeaways that I’d like to share.
Know your dog inside and out. Know how to take your dog’s temperature and pulse. Just like people, dog temperatures vary and knowing what is normal for your dog could help you spot an early warning sign. Know your dog’s normal vitals (body temperature, average resting pulse), appetite pattern, coat texture and sleeping habits.
Be your dog’s advocate. Don’t just wait it out to see if it gets better on its own, as tempting as it might be. Time is of the essence. Seek out care right away and be your dog’s advocate. Don’t wait for organ failure or hemorrhaging – it very well might be too late to treat at that point. Be proactive in the care your dog gets.
Pet insurance. We purchased insurance soon after adoption so there would be no excluded pre-existing conditions. Having the peace of mind knowing that everything would be covered allowed us to focus on BooBoo and do whatever the doctors recommended and not have the financial strain as a deciding factor in her medical care. Yes, the monthly premium is a lot but insurance is exactly for cases like this. We received 100% reimbursement of over $6500 in vet bills (minus our $100 deductible.)
Topical treatments. Although we are generally holistic, we do apply a monthly topical tick preventative. When I approached the manufacturer about how she could be infected with being on preventative every month, even through the winter, they stated it’s only 97% effective in repelling. So some ticks will get through. I suspect we never found the tick that infected Boo because it bit her and then the Vectra killed it, and the tick fell off before we did our evening check. We still use the topical but now also supplement with an essential oil spray. Also, having proof of purchase of tick preventative was necessary for our insurance claims to be paid 100%.
Have a regular vet. As tempting as it is to bounce around to low cost clinics for vaccines, this reinforced how it’s far more important to have a solid relationship with a regular vet, who sees your pet at least once annually, whether they are sick or not. We have an amazing vet and we trust her implicitly. When ER vets were throwing out all sorts of tests and things they could do, we relied on our regular vet’s advice and knowledge of the history of our dog to help us decide a course of treatment. Our regular vet worked in tandem with the ER staff and the specialists, reviewing all the lab reports and treatment plans. They sent her daily updates and reports. It’s easy to be overwhelmed when your pet is in medical crisis and having a regular vet as an ally helps you make decisions and not feel like the ER vets might be taking advantage of your compromised state.
Have an ER vet. You never want to need to use it, but in an emergency you don’t want to lose precious minutes looking up who your closest ER facility is. Know where they are, know how to get there and have the phone number programmed in your phone so you can call them on your way so they’re ready to take you in for a real emergency. In our case, getting Boo’s temperature down was critical to saving her life and preventing a seizure. The hospital knowing we were on our way gave them advance warning to prepare a room for her so there was no delay when we arrived.
I am forever grateful to the medical team that saved our girl but I know our quick action also played a part. Many dogs do not get diagnosed with RMSF until it is too late to save them – until they are hemorrhaging or some other equally awful symptom appears. It wasn’t her time but it easily could have been if I hadn’t taken her temperature or if the ER vets hadn’t started her on drugs at that moment. There are so many things that could have altered our outcome. Our sweet Boo came to us as a feral dog from Kentucky and is now a certified therapy dog and I like to think the world needed her around for a while longer. I hope that others hearing our RMSF story will bring awareness to tick-borne illnesses and help people notice the symptoms early on to help save lives.
For now, we will keep hiking but checking for nasty ticks often and cuddling as much as possible to enjoy every moment that we have left together.
For more information, please check these RMSF resources
Kate LaSala, CTC is an honors graduate of The Academy for Dog Trainers and owns Rescued By Training in Central NJ. She is also a certified AKC Canine Good Citizen (CGC) Evaluator and trainer for the NJ Chapter of Pets for Vets. She shares her home with her husband John and their two rescue dogs, Mr. Barbo and BooBoo. Kate and BooBoo are a certified therapy dog team, visiting nursing and rehabilitation homes locally. Follow her on Facebook for training tips and helpful information.
Copyright 2016 Kate LaSala
Related Post from Eileen
My dog Clara also had Rocky Mountain Spotted Fever. Here is her story and a video showing her symptoms:
My friend Kelly Viscosi has stepped forward to share how she prepared Dennis, her 9-year-old vizsla, to meet Saya, the new vizsla puppy. But actually, the story starts long before they meet, because Kelly did a ton of very clever preparation with Dennis.
Here are her words.
When we were expecting a puppy last summer, I asked the breeder to send me audio of the puppies crying and whining at their loudest (which happened to be right before breakfast time for them). She video taped it with her smart phone and sent it to me.
First I classically conditioned Dennis to just the sound of the crying puppies. Once I was getting a good positive conditioned emotional response to this, then I set up a stuffed dog in a crate, placing a small, wireless speaker under the stuffed dog. At random times throughout the day, I would play the audio and treats would rain from the sky right in front of the crate with the stuffed puppy.
Before long, Dennis would just choose to park himself in front of the crate, waiting for the “puppy” to cry. From here, I also began putting the stuffed puppy in an ex-pen (also with wireless speaker under stuffed puppy). We repeated the same thing: puppy cries, treats rain down. This worked very well to prepare Dennis, who is sound sensitive AND fearful of dogs outside the family.
When we brought the real puppy home a month later, he was very well prepared for all the extra noise his baby sister made. She would cry/bark, and it sounded just like the stuffed puppy had, because he had been listening to his sister and her littermates for several weeks now. I still tossed treats to Dennis every time his sister cried or whined, and he would park himself a few feet away from the ex-pen, waiting for her to cry so he could get treats.
Yes, he gained some weight during this time, but it was well worth it because he had a positive association and we just reduced his calories a couple months later.
Classical Conditioning Done Well
I just have to editorialize about this, to elaborate a bit on all the things that Kelly did right.
She got a recording of the exact sounds that Dennis would be exposed to.
She used classical conditioning: she played a few seconds of the crying, then rained the treats down. Notice that she did not just leave an audio recording going. She played a short segment and followed it with treats.
She played the noise (and followed it with treats) at random times throughout the day. She made it clear that the noise, and the noise alone, predicted the special treats.
She then made a further association: she made the sound source appear to be the stuffed dog. Even though Dennis doubtless knew that this was not a real dog, it gave a focal point for the sound and a visual that was similar to what he would later see with the real puppy.
She did the “noisy puppy” show in two different locations, the crate and the ex-pen.
She didn’t skimp on the quality of the the treats.
This work she did made a huge difference for Dennis. He could have been miserable from the noise and the new stranger. But with Kelly’s careful preparation, the arrival of the puppy meant enrichment opportunities for him. How cool is that?
But Wait–There’s More!
Here’s some other great training Kelly did before the pup came. She set up a group mat exercise for Dennis, the future puppy, and Trixie, her other senior dog. She used the faithful stuffed dog as a stand-in for the puppy. Again, Dennis surely knew this was not a puppy. But the exercise helped create a routine. He learned that the object on the adjacent mat getting a treat predicted his getting a treat. Learning the routine was another thing that helped him adjust faster to the real dog when she came. (Kelly mentioned that Trixie, the black and tan senior dog, was gregarious and happy with other dogs, so this exercise was just a bonus for her.)
One of my favorite things in life is seeing the imaginative and thoughtful things that people all over the world do to make their dogs’ lives better. I hope Kelly’s work with Dennis plants some seeds of ideas out there for others who are preparing resident dogs for a newcomer.
Care to share? I bet there are some other great stories out there.
This post is not directly about dogs, but it’s about something we see happening in the dog world very frequently. That is the misunderstanding and misapplication of research results. This particular example caught my attention because it involves something I have a bit of expertise in: sound.
In the past few years there has been a rash of articles about how important silence can be in our lives. Many of them center on a campaign by the Finnish Tourist Board that promoted the restful silence of that country. I’ve been there, and it’s true!
The silence thing got my attention. I’m a fan. I’m an auditory person, musically trained. I’m very sensitive to my auditory environment and dislike unnecessary background noise, including music. When I have music, radio, or the television on, I am actively listening. When I’m done they go off. I need and enjoy quiet.
Likewise, I am quite attuned to the “background” sounds that are present even when it’s very quiet. I am sitting in my study now. I’m aware of traffic noises, neighborhood dogs, the occasional creak of the house, the furnace and refrigerator when they cycle on, my neighbor’s sump pump, and Clara snoring. She’s got a funny little whistle sound in her nose. Plus I can hear some of the common urban mashup of low frequency noises. The 60-cycle hum of power lines is audible, although we habituate to it. We can hear even lower frequencies generated by industrial equipment. Most of us city dwellers are unaware of these lower frequency, deeper noises, although sometimes we notice their absence if we get out “beyond the sidewalks,” especially at night. But even with all that going on, my environment right now definitely qualifies as quiet, if not exactly silent.
Frequency and magnitude breakdown (FFT) of the noise in my study
How different would it feel if **all** that noise were gone?
Silence is Golden?
The articles I ran across praised the value of silence in our lives and cited a scientific study that had “proved” the value of silence.
In the study, the effects of different auditory stimuli were tested on mice with the goal of analyzing whether they affected the creation of new brain cells. The scientists were looking at adult neurogenesis in the hippocampus. They exposed the mice to five different acoustic conditions: the ambient sounds of the facility, white noise, some Mozart piano music (thoughtfully transposed to the normal hearing range of the mice), the calls of rat pups, and silence. Most mice were exposed to one of the auditory stimuli for two hours a day for three days inside an anechoic chamber. After one more day they were killed and their brains were studied. Some mice were exposed for seven days, then killed.
The Mozart music and the silence resulted in the largest increase in precursor cell proliferation after three days of exposure to the sounds. (Precursor cells are new, blank cells that can develop into different kinds of cells. For example, stem cells are one type of precursor cell.) And after seven days of exposure, only silence was associated with increased numbers of precursor cells. Edit 4/3/16: I deleted some incorrect comments I made about the control of the study.
Back to the articles. They claim, and cite this study to support, the idea that periods of quiet, perhaps “down time,” are beneficial to our brains. The articles evoke images of calm contemplation and taking breaks from mental activity. This is a potent meme in our sometimes noisy, frenetic lives.
Such periods probably are beneficial. The problem is that that is not what this study is about. The term “silence” in the study refers to a specific state that is virtually never replicated in normal life. And it was probably not a pleasant state for the experimental mice, despite the article title. Here’s what it really involved.
Walls of anechoic chamber–photo source, Wikimedia Commons
All of the mice experienced the sound exposure inside an anechoic chamber. Anechoic chambers are enclosed spaces in which the amount of reflected sound is reduced almost to zero. They are built of absorptive material installed in patterns designed to break up sound waves. They are also insulated from exterior noise. When there is sound being generated on the inside, as with the recordings used in the experiment, only the original sound wave reaches the organism’s ears. There are no reflections. This is an abnormal situation. In real life, we almost always perceive some reflected sound. Any noise would without reflection sounds “dead.”
This is a highly disturbing auditory situation if you don’t understand what is going on. I’ve been in an environment that approximates that. It makes your ears feel funny and you lose senses you didn’t even know you had. You can no longer sense where objects are in relation to your body (the rudimentary human equivalent of echolocation).
For mice, being trapped in an anechoic chamber and exposed to its unique qualities could well have stressed them out of their minds. We can’t explain it to them. So we need to get rid of the positive connotations of the word “silence” in the case of this study. This was not restful or calm. It was foreign and strange, something that no animal could be prepared for from previous life experience.
We should note that the mice who were exposed to other auditory stimuli were also placed in the anechoic chamber. There was doubtless also some strangeness for them. But since sound was being played, they would not experience the strangeness of absolute silence.
The Results
If you read far enough in the study, there is discussion about silence being a stressful state.
But of the tested paradigms, silence might be the most arousing, because it is highly atypical under wild conditions and must thus be perceived as alerting. Functional imaging studies indicate that trying to hear in silence activates the auditory cortex, putting “the sound of silence”, the absence of expected sound, at the same level with actual sounds. The alert elicited by such unnatural silence might stimulate neurogenesis as preparation for future cognitive challenges.–Kirste, Imke, et al. “Is silence golden? Effects of auditory stimuli and their absence on adult hippocampal neurogenesis.” Brain Structure and Function 220.2 (2015): 1221-1228.
No kidding. In other words, the level of silence was novel and probably uncomfortable and scary. The apparent increase in neurogenesis in the mice’s brains correlated with a time when they were suddenly thrust into an eerily quiet, unnatural environment and couldn’t escape. They weren’t in the equivalent of a pleasant, peaceful, mousie yoga studio.
A more accurate title for an article about this study might be, “Being trapped without the possibility of escape in a strange, frightening environment may help generate new brain cells.”
The Big Picture
I am not weighing in on the methods and results of the study. Neither am I arguing against the value of relative quiet in our noisy human lives. I am highlighting the way this study is being incorrectly referenced. The results of the study do not connect with the spin of the articles about it. And we can’t blame it only on the journalists. Note that the scientists themselves prompted this, in part, with the reference to “Silence is golden” in the title. Catchy, but misleading. (Also, to be fair, most of the articles cite other studies as well, studies that may support the claims about restful silence.)
Humans love to take mental shortcuts, and articles about the “value of quiet” are attractive in our noisy, hasty world. They resonate, if I may use another auditory figure of speech. But we need to be careful.
This particular example jumped out at me since I have a background in acoustics. I was curious about how the “silence” was created, and as soon as I saw the mention of an anechoic chamber, I was on the trail. But in this study, you don’t actually have to understand acoustics to see the problem, as long as you read the whole thing. The paragraph I quoted above is one of several in the “Discussion” part of the study where they make observations and theorize about the findings. The fact that the silence was a highly stressful condition is discussed in detail. But you have to read far enough to get there, and to drop your automatic warm fuzzy thoughts about silence and calm states.
I’d love to know whether anyone has been in an anechoic chamber or experienced other sensory deprivation. What was it like? When I was in graduate school we bought the materials to build a chamber and I messed around with the stuff, so I know what even a small exposure to the noise absorptive materials made my ears feel like. Creepy!
Reference
Kirste, I., Nicola, Z., Kronenberg, G., Walker, T. L., Liu, R. C., & Kempermann, G. (2015). Is silence golden? Effects of auditory stimuli and their absence on adult hippocampal neurogenesis. Brain Structure and Function, 220, 1221-1228.
