When I first started teaching rats to drive cars, I never dreamed that those little rodents would steer me toward a surprisingly big discovery, a lesson about the importance of joy in our lives. It turns out that we had a lot to teach each other. But I'm getting ahead of myself. I'm a behavioral neuroscientist. I’m interested in brains, behavior and environment and how they influence one another. For most of my career, I've focused on the negative emotions: fear, stress, anxiety, symptoms of depression, and for good reason. Depression rates remain unacceptably high, and recent reports suggest that deaths of despair, deaths related to suicide and addiction and loneliness, are on the rise in the United States. Even though we've invested a lot of research and resources toward understanding mental illness, it seems that we have a long way to go. Perhaps we need some fresh perspectives in this area. Several years ago, when I was writing my book “Lifting Depression,” I started to investigate the connections between reward and physical effort. I introduced this term "behaviorceuticals," the idea that we can intentionally change our behavior to alter neurochemistry in therapeutic ways. If you have enjoyed knitting or cooking or producing a piece of art, you've experienced your own dose of behaviorceuticals. But that's anecdotal evidence. I needed to take this to the lab and consult with my research colleagues, that's the laboratory rats.

So we trained them to exert physical effort for Froot Loops, and that's the currency of my lab. They love Froot Loops, so they'll work for Froot Loops. So we had about five weeks where the animals had to connect physical effort, digging up those Froot Loops. And at the end of that time, we saw that there was enhanced evidence of emotional resilience, more effective coping strategies and even signs of neuroplasticity, this idea of the brain changing in response to the changing demands of the life of the animal. And that's traditionally thought to be good and healthy for the brain. Now when we compared these animals to the control group, this was a group that received the same number of Froot Loops, but they didn't have to work for it. We called this the Trust Fund Rats group, and we did not see the benefits in these animals. So it seemed to be more than just the reward. It's our relationship with the reward and perhaps the ability to control these rewards. So this was interesting. And we did a good bit of research on what we call “effort-based reward protocol” and found some interesting findings, but I still found myself going back to these negative emotions, especially chronic stress. Investigating all the ways things can go wrong with brains. But it took the rats to point me in the direction of looking at what could go right.

But it took the rats to point me in the direction of looking at what could go right. Let me provide a little context here. So those rats that I talked about, the driving rats, in the beginning of the talk, we originally trained them to drive to understand more about agency and a sense of control and skill acquisition on their brains and behavior. And so we taught them to drive these rodent-operated vehicles, or ROVs, as we call them. And we found some interesting findings, and we published it. But we quickly realized that this program of research had a lot of potential for science outreach. And this is something that we really need today. So we decided to keep a group of rats trained up on driving so that we could continue with this science outreach. And they became little rodent celebrities. They were in documentaries and newscasts and podcasts, and that was all great. But I remember during the pandemic, when all the students were gone, it was very quiet on campus, and a few colleagues and I were taking turns going into the lab to take care of the animals. And I vividly remember this one morning, I walked into the lab, and I saw these rats run up to the front of the cage, and they were reaching their little arms out and jumping up and down. And it looked like they were excited to see me, like little rat joy. And it made me excited that they were excited to see me. And on the heels of all the negative-emotion research that I had conducted through the years, and all the negativity of the pandemic, I decided right then and there that whatever that was I was seeing, I wanted to investigate it. I wanted to know more. But could a neuroscientist study something as complex as joy in a rat? I went to the literature and was encouraged. I even found a definition of joy in non-human animals: “a brief and intense burst of activity associated with a favored event or object.” So when my husband and I would ask our little dog, Brody, if he wanted to go for a walk or just showed him the leash and saw him running around in circles and jumping up and down and yelping endlessly, that seemed to fit the definition of joy. If I could see it in a dog, I was encouraged that we could see it in the rats. But I still needed a plan. I landed on this idea of anticipation, the time before an award, because I knew that we could manipulate that time in the laboratory. So I was encouraged and really fascinated by some research conducted by scientists, where they trained rats to press a bar to have cocaine delivered directly to their brains. And when the cocaine hit the brain, their natural kind of feel-good neurochemical known as dopamine, would rise. But what was even more interesting was when that rat would approach that bar, before the cocaine was there, you'd also see this rise in dopamine. It seemed that the brain was interpreting the reward and the time before the reward in a similar manner. It really makes me wonder what our Founding Fathers knew when they emphasized life, liberty and the pursuit of happiness. It's really interesting. So we had an idea: anticipation. We still needed to translate this into something that we could use in the laboratory. We came up with this protocol that we referred to as “unpredictable positive event responses,” or UPERs, in keeping with this behaviorceutical theme. So this was pretty simple. For about five weeks we introduced the rats to three good things, fun things, every day, in an unpredictable order and time. So they were exposed to a LEGO block, and they had to wait 15 minutes to get that Froot Loop, or a sunflower seed, they had to wait patiently to shell it, or they were placed in a transport cage and wheeled across the hallway into another space in the lab where they got to play around, run around in what we called Rat Park. And they had to wait in that transport cage for three minutes. We were encouraged that we were on to something when we started to observe the rats in that transport cage. And we saw brief bursts of behavior, running around, they seemed so excited. So we were encouraged that indeed, we were influencing something that looked like joy, or at least positive anticipation in these rats.

So what are we finding? The results are still rolling in, but we're starting to see some trends. If we expose these rats to a rat-optimism task, and yes, there is such a thing, we've seen that the males shift from a pessimistic strategy to an optimistic strategy. But we don't see that with the females. They remain more reality-based in both groups. (Laughter) Now I should mention that the control group for this bit of research is a group that receives all the good things at once, so they don’t have that anticipation period there. So we’re not sure if that generalizes to humans, about the females, but we need to pursue that further. But the other results we see both in males and females, and it is important to look at sex differences when we’re doing this research, so both males and females show increased and intense exploration, as if they think they’re going to find something good, when they're exploring a novel environment. So we're very encouraged by these results. And surprisingly, one day, a student ran into my office and said, "Doctor Lambert, why are the UPER-trained rats' tails sticking straight up?" I thought, I've been working with rats for over three decades, and I've never seen this or heard of it. But I went to the literature, and I saw that some researchers would inject an opioid into the animals, and their tails would go up. And I thought, oh my goodness, maybe we're doing something with behaviorceuticals that has been done with pharmaceuticals. So this is something that we need to explore further. This research made me think about some classic research conducted in the 1950s by Curt Richter at Johns Hopkins University. He was interested in swim behavior between lab rats and wild rats, and he had some interesting laboratory conditions for this. But in the swim tank, it was turbulent water, so it was challenging. And he saw that the lab rats could swim for hours or days. They're great swimmers. But the wild rats, when he trapped them, brought them in and put them in the tank, they sank immediately, dying. And he was shocked by this because it's tough living out there in the wild, and he'd thought those wild rats would be more resilient. He said it looked like they were just giving up. But when he thought about the experiences of the lab rats and the wild rats, he realized that those lab rats had been periodically picked up by human hands, and their conditions had changed. So there was some hope that if you didn't like what was going on now, it could change. But the wild rats hadn't had that experience. So he devised this intervention where his assistants would pick up the wild rats from the restraining cage or from the water just once or twice. And he ran the study again. And he found that a majority of those wild rats at that time, they went from dying to surviving. And he said it was the hope of rescue that led them down that path. It makes you think: is this important for humans? There is a good bit of research to suggest that hope and positive attitudes are important for health and longevity. One of my favorite studies was conducted on Israeli children who were very ill, and they were part of the Make-A-Wish Foundation program, and the researchers monitored their general physical health and mental health outcomes from the time they were told specifically what their wish was to the time the wish was granted. And that was about five months, so they could extend that anticipatory time. And they found that these outcomes improved, to suggest that maybe their quality of life during that time was enhanced. And when they compared it to the children who were in the queue to get a wish, but they hadn't been told the specifics, so they really couldn't wish specifically and hope specifically for that to happen. Hopefully, when those children received the details of their wish, they also benefited from this. So there's a lot of research to suggest that, yes, those negative emotions are important to understand, but these positive emotions are as well. And when we step back and look at the brain and everything that's going on during positive anticipation and joy, you can see that there are a lot of different areas of the brain that are on board or activated during this time. Areas involved with processing reward and monitoring internal feelings and planning and movement are all activated during this time of joy and positive anticipation. So with all of this evidence, behavioral, anecdotal, neurological, suggesting that positive emotions are important, this isn't always reflected in our culture. It's really interesting to me that we have a word for anticipating something negative, it’s dread. But to my knowledge, I don't know that we have a word related to anticipating something positive. But in the German language they do. It's "vorfreude." It means joyful anticipation. Perhaps it's time for us to step up and come up with our own word for joyful anticipation. And personally, I find myself going back to this Puritan work ethic too often where we equate busyness and hard work with virtue. And if I find an hour or two to watch Netflix or something I enjoy, I often describe it as a "guilty pleasure." But why does it have to be a guilty pleasure? Far from an indulgence, it's looking like these pleasure and positive events are important and critical for healthy maintenance of our brains. Let me end by going back to those driving rants. A lot of people ask me, "Kelly, do they like to drive? Do they enjoy driving?" And my response has typically been, "I can't give them a questionnaire, I don't really know, I think they do." But we could ask them from a behavioral perspective. And that's what we did recently. We gave them a choice of walking to the Froot Loop tree, that's what they drive to, in a more efficient path, or they could take a detour and backtrack and jump in the car and drive to the rewards. And I couldn't wait to see what they would do. And what we found was a majority of the animals did indeed backtrack, take a tour and jump into the car and drive to their Froot Loop rewards. (Laughter) And if you saw a human, jumping in the background, that was me, jumping for joy seeing rats choose pleasure or fun over efficiency. (Laughter and applause) I taught rats to drive cars, but they taught me to enjoy the ride. Thank you. (Applause)