Study: Rat Cognition and Environmental Enrichment. It Turns Out Freedom Makes People Smarter!

study on rats found that when they were given “enriched” environments to explore, their brains physically grew, and the rats displayed better problem-solving skills. They didn’t have to be forced to interact with their environment. They were naturally curious. It doesn’t make sense to push your children towards particular things that you want them to learn, or that public schools say they should learn. Instead of signing them up for piano lessons, for example, put a piano in their environment. If they express interest, offer to get them more help and instruction.

The Sudbury Valley School in Framingham Massachusetts has a 50-year history of teaching students in this way. They have a beautiful, sprawling campus, with a pond, woods, and fields. They have books to read, and games to play, sports equipment, kitchens for cooking, and labs for experiments. They have teachers available so that when the kids do want help learning or creating, they get it. But students plan their own days, they are not forced to study anything in particular. And with such a history, the school has amassed piles of anecdotal evidence on the results. It suggests simply giving children the freedom to pursue their own intellectual activities makes them more self-assured, more successful, and happier in childhood, and later in life.

Rat Cognition and Environmental Enrichment

Environmental enrichment is broken down into general categories such as sensory, structural, food-based, and social. One of the less discussed options is cognitive enrichment, which is any form of enrichment that “engages evolved cognitive skills by providing opportunities to solve problems and control some aspect of the environment [and] is correlated to one or more validated measures of well-being.”1

Cognitive enrichment grew out of studies of rat’s cognitive abilities, which used a free operant procedure. The rats might be shown a discriminative stimulus (e.g. red light), and learn that if they perform the correct response (e.g. press the lever on the right) they will receive a reward (such as a sweet food). One finding from this work was that rewarded operants produce a state of positive anticipation. And time spent in positive and negative anticipation combines with the naturally excellent episodic memory of rats2 to producing a prevailing state of good or impaired welfare.

Examples of cognitive enrichment include group housing, puzzle feeders, and clicker training, but many other options could be developed to suit the animal, staff, and facility. Two important areas to consider are interactions with people and managing sensory experiences.

Interactions with People

Domesticated animals will naturally become attuned to humans as a source of information and an environmental resource–but this can lead to both positive or negative welfare states (see: the “Clever Hans” effect,3 “Maze Bright” rat study).4 A few procedures can help create beneficial effects, for example a gentling program that seeks a behavioral endpoint (e.g. spontaneous approach to a human hand) can result in rats will be strongly biased to seek out and stay near to a human handler.5

In traditional animal husbandry, humans were naturally connected with the delivery of resources like food, water, and bedding—but even in the absence of these connection handling itself is rewarding to most rats or can be paired with treats or tickles to ensure this outcome. See people + approach people = get treats and tickles. These programs are also highly rewarding for staff.

Managing Sensory Experiences

Other parts of the environment that are meaningful to rats may be outside our sensory range or more suitable for the senses of humans than of rats. For example rats are more prepared to enjoy activities when they occur during the dark period of the day.

Whatever is routine in a facility will tend to be accepted as normal, however staff provided with ongoing educations about their animals’ sensory abilities6 and natural history, and provided with data about the sensory environment of the facility, will be able to consider and manage their animals experiences in a way that encourages the animals to interact with their environment and anticipate pleasant outcomes.

For example, a slightly cooler environment may encourage activity and reward the building of a fully structure nest. Providing nuts in the shell encourage investigating and manipulating novel objects. And knowledge of ethology allows staff to identify when animals are expressing rich and largely positive interactions with features of their habitat. For example, the way a rat grooms has a distinct grammar and progression. When it becomes disordered and shorter, this indicates anxiety.7

Other informative behaviors may include group huddling, play, nest building, foraging and hoarding, and a readiness to explore and be handled. Disruption to behaviors of this type may represent a problem with a population, or with a specific individual who might–for example–be in an unsuitable social group of exhibiting preclinical signs of illness.

Subjective experience is at the heart of animal welfare, and thought and feeling are inseparable aspects of this experience. How an animal understands and interprets its world is fundamentally connected to how they feel, emotionally, about their situation. If mainly positive events can be predicted and “earned” the animals sees life as generally good.

Understanding Cognition

Not understanding how cognition and emotion blend together can lead to many misunderstandings. For example, we are taught that a maze measures learning, and so we understand that rats raised in more barren environments experience a cognitive deficit. But we have also known for decades that if the rat from the barren environment is made more motivated, their performance rises to the same level as the enriched rats.8 So it may be just as accurate to say mazes measure motivation as to say they measure intelligence.

Conversely, welfare research often overlooks cognitive explanations of behavior. Recent research showed that if you remove rats from a cage, it disturbs the behavior of the remaining animals.9 The authors concluded that either the act of removing the animal or the disruption of social hierarchies causes this stress. But nothing that we know about the rat mind removes another option, that rats worry they will be next. As a preyed-upon species there is every reason to suspect they are biologically programmed to feel anxiety when other rats are vanishing from the environment.

Developing a Cognitive Enrichment Program

Entering into a program of cognitive enrichment requires some skills and training. For example on how to elicit perform “rat tickling.”10, 11 This type of interaction can be invaluable when attempting to transform a procedure that might cause mild pain (such as injection or blood draw) into an interaction the animal with experience and remember as being positive (a minor injury in rough and tumble play being quite natural and not something to resent for long).

Staff also need to understand that in rats as with many other species, positive anticipation is often expressed as agitation.12 We have gone through a long period where most kinds of stress are interpreted as negative. But high energy positive states are enormously beneficial. That include play, exploration, and any anticipatory agitation of a rewarding outcome for their behavior.

Deliberate programs of cognitive enrichment can be created to support, whenever possible, the rats’ active enjoyment of their home environment, many husbandry and experimental procedures, and handling events.13 And as a result they will also develop an overall optimistic or pessimistic outlook which affects how they feel about ambiguous, neutral, or even somewhat aversive events. The goal is competent animals with predominantly positive expectations who cooperate with even novel procedures and situations.

Cognitive enrichment is an approach that brings into focus particular ways we can improve our care of animals, that other paradigms de-emphasise or overlook—helping to make the pursuit of optimal animal welfare an active, explorative, and positive task for animal caretakers.

References:

  1. Clark, F. E. (2011). Great ape cognition and captive care: Can cognitive challenges enhance well-being? Applied Animal Behaviour Science135(1), 1-12.
  2. Panoz-Brown, D., Corbin, H. E., Dalecki, S. J., Gentry, M., Brotheridge, S., Sluka, C. M., … & Crystal, J. D. (2016). Rats remember items in context using episodic memory. Current Biology26(20), 2821-2826.
  3. Pfungst, O. (1911). Clever Hans:(the horse of Mr. Von Osten.) a contribution to experimental animal and human psychology. Holt, Rinehart and Winston.
  4. Rosenthal, R., & Fode, K. (1963). The effect of experimenter bias on performance of the albino rat. Behavioral Science, 8, 183-189.McCall, R. B., Lester, M. L., & Corter, C. M. (1969). Caretaker effect in rats. Developmental Psychology1(6p1), 771.
  5. McCall, R. B., Lester, M. L., & Corter, C. M. (1969). Caretaker effect in rats. Developmental Psychology1(6p1), 771.
  6. Burn, C. C. (2008). What is it like to be a rat? Rat sensory perception and its implications for experimental design and rat welfare. Applied Animal Behaviour Science, 112(1), 1-32.
  7. Kalueff, A. V., & Tuohimaa, P. (2005). The grooming analysis algorithm discriminates between different levels of anxiety in rats: potential utility for neurobehavioural stress research. Journal of neuroscience methods143(2), 169-177.
  8. Woods, P. J., Fiske, A. S., & Ruckelshaus, S. I. (1961). The effects of drives conflicting with exploration on the problem-solving behavior of rats reared in free and restricted environments. Journal of Comparative and Physiological Psychology54(2), 167.
  9. Burman, O., Owen, D., AbouIsmail, U., & Mendl, M. (2008). Removing individual rats affects indicators of welfare in the remaining group members. Physiology & behavior93(1), 89-96.
  10. Panksepp, J., & Burgdorf, J. (2003). “Laughing” rats and the evolutionary antecedents of human joy?. Physiology & behavior79(3), 533-547.
  11. Cloutier, S., Panksepp, J., & Newberry, R. C. (2012). Playful handling by caretakers reduces fear of humans in the laboratory rat. Applied Animal Behaviour Science140(3), 161-171.
  12. Spruijt, B. M., van den Bos, R., & Pijlman, F. T. (2001). A concept of welfare based on reward evaluating mechanisms in the brain: anticipatory behaviour as an indicator for the state of reward systems. Applied Animal Behaviour Science72(2), 145-171.
  13. Burman, O. H., Parker, R., Paul, E. S., & Mendl, M. (2008). A spatial judgement task to determine background emotional state in laboratory rats, Rattus norvegicus. Animal Behaviour76(3), 801-809.

Emily Patterson-Kane, Ph.D. is a New Zealand-born psychologist specializing in animal welfare and the human-animal bond. She is employed as an Animal Welfare Scientist in the Animal Welfare Division of the AVMA. Previously she was employed as an animal behavior researcher at institutions including Purdue University, the University of British Columbia and the Scottish Agricultural College. She is co-author of the book The Sciences of Animal Welfare.

 

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