by Mandy Wintink
Animals, including us human animals, and our sacrificial laboratory rodents, seek novelty quite innately and readily. We use a variety of mazes in the laboratory setting that rely on the a rat’s innate curiosity, which motivates them to explore and then move through its new environment. Without that curiosity it would be hard for us to provoke the rat into moving and then we could not test things like memory, motor skills, sensations, perceptions, fear, or motivation, which means we would not be able to create animal models of disorders like Alzheimer’s disease, amnesia, stroke, Parkinson’s disease, vision, smell, audition, anxiety, or depression.
One example of a test that we use in the lab is called the elevated plus maze. Just as the name indicates, the maze stands elevated above the ground and includes 4 planks extending from a centre space. Two of the arms are enclosed with high arms whereas the other two are opened high above the ground. To start the experiment, a rat is placed in the centre of the plus and experimenters (like I did), watch to see where the animal goes. A typical rat (or mouse) will venture quickly into the closed arms to feel safe and secure. Rodents don’t like to be exposed in the open. It’s not very adaptive in terms of protecting oneself from vultures from above. But a typical rat won’t stay in the closed arm that long. Soon, the fear of being in the open, dwindles and the rat is motivated more strongly by its own curiosity to explore the rest of the maze. After having explored its first arm, a typical rat will make its way back to the open centre, peak around the corners to see the open space below, then quickly run across to the other closed arm and begin its exploration of that relatively safe arm. I use the work “relatively” because there is some inherent fear present as the rat moves about but as it explore over and over again the rat becomes more familiar with its environment and the fear dwindles. This is not that unlike what we do, even unconsciously. Imagine yourself last time you were in a new environment. Perhaps you were at a party with new people. Perhaps you were starting a new job in a new office building. Perhaps you were visiting a new city. Each of these “new” environments come with a bit of fear, or anxiety. But over time, as we become more familiar with the environment, we, including our brain, settle in and fear more at ease. That same thing is going on inside the brain and body of the rat that explores its plus maze.
Eventually, the rat becomes so comfortable in its new environment in the plus maze that it will head back to the center and peak around the corner again and look out to the open arms. These open arms are typically the most fearful of the entire maze. They are high and exposed. But the curiosity typically gets the best of the rat as it eventually makes it way out into the exposed open arm, pausing often to get a sense of its environment. Often times the rat will stand in one spot along the arm and dip its head down to see what is below and to assess how far it is from the ground. It’s the maze is not elevate high enough — or if the rat is particularly curious — it might even jump! Through this observation, the scientist is recording many behaviours to capture this curiosity: 1) Time to venture on to the open arms, 2) peaks around the corner, 3) head dips, 4) number of time it moves all the way to the end of the arm. Collecting these numbers form the basis of comparing curiosity — or rather the degree to which curiosity emerged and fear subsided — among groups of animals. With my own research, we did this for the purpose of testing anti-anxiety treatments, including both pharmaceutical medication and herbs. When a treatment worked, we saw that the rats would more quickly venture out into the open arms, peak around the corners, sit on the open arms and dip its head, and move all the way to the end of the open arms.
This same basic curiosity is actually present in many other tests, for example, a maze in which there is food at the end requires the animal to be curious enough to move from the starting spot, walk into blind alley, walk back out, and then attempt a new alley, eventually happening upon the yummy treat at the end. Several days may go by and then eventually the rat can easily run right from the starting location to the treat if it’s memory is in tact. By then, curiosity is no longer the motivator, the yummy treat is. But, if an animal has memory problems, it won’t be able to remember where to go and instead, might take many wrong turns along the way.
Curiosity is Anxiety-Provoking and Stressful
There are many more examples of how we use curiosity in our laboratory animals to motivate them to move so that we can test other functions of the brain. Ultimately, we are assessing the balance between curiosity and anxiety, because novelty is inherently anxiety-provoking and stressful. As mentioned in the chapter on Stress. I remember this quite poignantly when I think back to my experience having moved from my hometown of Winnipeg to St. Catharines to do my master’s degree. Everything was knew to me. The house I was living in and the street I was living on. My roommates. The route to get home, to the university, and to the grocery story. Walking through the grocery store one day I had a little breakdown. I was trying to find some particular food item and was beside myself trying to figure out which aisle it was in. I couldn’t help but think about my grocery store at home and how there, I would know exactly where to go. But not in this grocery store. This grocery store was unfamiliar to me and as a result, came with a significant amount of novelty stress to compound the pervasive novelty stress that surrounded me each day. Eventually, things did become familiar but it took me a long time to be open to that familiarization process. I yearned so deeply for my life back in Winnipeg that a big part of my brain was resisting letting anything feel or become familiar. That ultimately didn’t fair well for a brain of mine that needed to rest in routine and automaticity.
This balance is important to take into consideration when planning our own curiosity-inspired adventures, whether it is travel, education, or any new activity. For someone who is already at his or her max for novelty stimulation, adding something more might not be advisable. But for someone who is plagued with too much routine and familiar activities, a poke with the curiosity stick might very well prompt exploration into the unknown, or, as Todd Kashdan, Paul Rose, and Frank Fincham, researchers in the Department of Psychology at the State University of New York write, opportunities for personal growth.
Curiosity and the Brain
Most of the neuroscience research on curiosity is studied under terms like “sensation seeking”, “novelty seeking”, or “exploratory behaviour”. In each of these cases there is a fairly good idea of the difference between newness and old and familiar and at the root of this difference typically lies activity within the hippocampus, frontal cortex, and more recently structures of the dopamine-reward system. The hippocampus, as already discussed, and its surrounding structures are highly involved in our ability to create memories and, in particular, memory of our environment. As we walk through an environment we are making use of the hippocampal mapping system of the environment, which includes cells specifically designed to code place cells, boundaries, and form a grid-like map for us. If the environment is new, we begin for code features of our environment in these cells. If our environment is familiar, these cells are activated and give us the sense of familiarity in our environment. Thinking back to my experience in St. Catharines, when I first arrived, I didn’t have any mapping cells created for this new place I was living in. So a lot of energy was being exerted to create this map and make me feel, almost literally “at home”. But, unlike a rat being placed in its elevated plus maze for a short duration of time, it was as if I was placed there in the center without any closed in hallway to ease my anxiety for days on end, trying hard to make something feel comfortable without much success.
We also know that the frontal cortex is involved in newness of experiences. In fact, back when I was living in St. Catharines, I was studying this in humans. What had already been known was that during the early phase of learning a new task, there was a lot of activity in the frontal cortex, but once the task was familiar and lost its novelty appeal, activity in the frontal cortex subsided. What we were studying was the timing of when this changed and we found that for simple tasks, this novelty wears out quite rapidly.
The other important brain element of curiosity has to do with dopamine, the neurotransmitter that is involved in the wanting and reward discussed later on about motivation (see chapter on Goal Setting). Briefly, dopamine is the neurochemical that is targeted by the very powerful stimulatant drugs like cocaine and amphetamine and without adequate dopamine, a person (or animal) can suffer from a lack of motivation. This connection between dopamine and its associated brain structures (e.g., caudate and nucleus accumbens) was described in a study by Kang and colleagues who found that motivation to learn trivia answers was associated with greater activity in this region of the brain. In a 2014 study, researchers Gruber, Gelman, and Ranganath discovered two important findings. First, they found that states of high curiosity enhanced learning and not just learning when the information was interesting but also of incidental information. Second, when they looked at the brains of the individuals in their study, through fMRI (functional magnetic resonance imaging) they found that learning was better when there was corresponding activity of dopaminergic brain circuits, including the hippocampus. These results point to the idea that curiosity not only enhances learning and memory but that it does so through activation of specific dopamine pathways, which likely involve inherent reward inspired by curiosity. For me, this also further supports the idea that curiosity is at least valuable enough that the brain is devoting resources to it and that curiosity has some adaptive value beyond simply letting us being curious for the sake of curiosity.