Just read an absolutely fascinating study called “Enriched environment experience overcomes learning deficits and depressive-like behaviour induced by juvenile stress“, that Dr Sophia Yin made reference to recently on Facebook. It’s an absolutely fascinating read, especially after writing about the over-emphasis of socialisation just days ago. I almost have to eat my words… Almost…

Dogs yawn when they’re stressed – I don’t know if rats do, too, but this study used biochemistry to measure rat-stress.

Basics of the Study

This study used rats to investigate the role of stress on adult behaviour (particularly surrounding anxiety and depression).  Two groups of rats were stress during their juvenile period (27-29 days) through ‘forced swimming’, elevation, and restraint. (A third group of rats was used as a control.)  One group of the ‘stressed’ rats was given environmental enrichment, by enhancing their cage environments with toys, shapes, colours, and allowing them activities outside of their cage.  The other groups did not receive environmental enrichment.

The Findings

In short: Environmental enrichment seemed to ‘neutralise’ the anxiety experienced by the stressed rats, and sometimes reduced their anxiety further than rats with no stressful incidents and no environmental enrichment.

In long:

Weight Gain

Stress affected weight gain.  The stressed rats all had ‘less weight gain’ than non-stressed rats.  However, in a week, those stressed rats who also received environmental enrichment, were on-par with weights to control rats.  This shows that environmental enrichment was starting to help reduce the signs of stress even within the first week.

Anxiety

Rats that were exposed to juvenile stress had high anxiety rates, but rats with environmentally enriched environments had less anxiety than their non-environmentally-enriched counterparts and, indeed, even the control!

Exploration

The rats that were living in an environmentally enriched environment were more willing to explore near environments, even compared to the control. It was suggested that the juvenile stressed rats with no environmental enrichment had some symptoms of learned helplessness.

Concluding Quote

A quote from the study: “Overall, [juvenile stress] appears to trigger anxiety- and depressive-like behaviors; [environmental enrichment] was found to be able to reverse these effects. Moreover, [environmental enrichment] not only reversed most of [juvenile stress]-induced disruptions but rather, in some parameters made the animals less anxious, more motivated and with better learning abilitities compared also with [control] animals.”

What does this mean for dogs?

Obviously, rats are not dogs, so we can only speculate what implications this study actually has for dogs.  I have no knowledge of critical periods in rat development, and what bearing critical periods in puppy development may have on the implications of this study. However, we can speculate…

Events in puppy hood aren’t the be-and-end-all for dogs.  This study explains, in some ways, why puppies raised in puppy farm environments can still grow to be well adjusted dogs. If owners enrich the environment enough (if they take the dog out for walks, give them toys at home, play with them, etc) then the stress from early events can be nullified.

Furthermore, it speaks loudly on shelter dogs and the benefits of environmental enrichment.  Shelter dogs will almost invariably be stressed, and environmental enrichment has a serious role in reducing stress (and associated anxiety and depression).  Stressed animals often develop behavioural problems that make them unadoptable, and in turn, these behaviours often then provide an excuse for the animal to be euthanised. Stress has a pretty major role in shelters, and reduction of stress is crucial in improving the welfare of kennelled rescue dogs.

Indeed, any stressed dog would probably benefit from environmental enrichment of some sort. At the very least, it may reduce stress and anxiety. At most, it may make the dog better than dogs that aren’t stressed.  A pretty exciting suggestion!