I Taught Rats to Drive. They Taught Me to Enjoy the Ride | Kelly Lambert | TED

The speaker, a behavioral neuroscientist, began her career focusing on negative emotions like fear, stress, anxiety, and depression, given their high prevalence and the rising deaths of despair in the United States. Despite significant research and resources dedicated to mental illness, progress remains slow, suggesting a need for fresh perspectives. During the writing of her book “Lifting Depression,” the speaker explored the connection between reward and physical effort, coining the term "behaviorceuticals." This concept proposes that intentional behavioral changes can therapeutically alter neurochemistry. She cites examples like knitting, cooking, or creating art as personal experiences of behaviorceuticals. To validate this in the lab, she and her colleagues trained rats to exert physical effort, specifically digging, to obtain Froot Loops. After five weeks, these rats showed enhanced emotional resilience, more effective coping strategies, and signs of neuroplasticity—brain changes in response to life’s demands, which is considered healthy. A control group, the "Trust Fund Rats," received the same number of Froot Loops without effort and did not exhibit these benefits, suggesting that the relationship with and control over the reward, rather than just the reward itself, was crucial. This “effort-based reward protocol” yielded interesting findings, but the speaker still found herself drawn back to investigating negative emotions, particularly chronic stress. However, the rats eventually led her to investigate what could go right with brains. The driving rats, initially trained to understand agency, control, and skill acquisition, were part of a research program that also proved valuable for science outreach. A group of these "rodent celebrities" was maintained for this purpose. During the quiet of the pandemic, while caring for these rats, the speaker observed them running to the front of their cage, reaching out, and jumping, seemingly excited to see her—an apparent display of "little rat joy." This observation, coming after years of negative-emotion research and the pandemic's negativity, prompted her to investigate this phenomenon. She found encouragement in the literature, including a definition of joy in non-human animals as "a brief and intense burst of activity associated with a favored event or object." This resonated with her observations of her dog's excited reaction to the prospect of a walk. To study joy in rats, she focused on anticipation, the period before a reward, as it could be manipulated in the lab. She was inspired by research where rats pressing a bar for cocaine showed a rise in dopamine, not only when the cocaine hit the brain but also as they approached the bar, suggesting the brain interprets both the reward and the anticipation similarly. This led her to reflect on the emphasis on "the pursuit of happiness" by the Founding Fathers. The team developed a protocol called “unpredictable positive event responses,” or UPERs, in line with the behaviorceutical theme. For five weeks, rats were exposed to three positive, fun events daily, in an unpredictable order and time. These included waiting 15 minutes for a Froot Loop after seeing a LEGO block, patiently shelling a sunflower seed, or being transported to "Rat Park" for playtime after a three-minute wait in a transport cage. Observing brief bursts of excited behavior in the transport cage encouraged them that they were indeed influencing something akin to joy or positive anticipation. Preliminary results from this research are promising. In a "rat-optimism task," male UPER-trained rats shifted from a pessimistic to an optimistic strategy, a change not observed in females, who remained more "reality-based." The control group, which received all good things at once without anticipation, lacked these benefits. Both male and female UPER-trained rats showed increased and intense exploration in novel environments, as if expecting to find something good. A surprising observation was that the UPER-trained rats' tails would stick straight up, a phenomenon previously linked to opioid injections, suggesting a potential behaviorceutical effect mirroring pharmaceutical outcomes. This research brought to mind Curt Richter's 1950s study on swim behavior in lab and wild rats. Lab rats, accustomed to human handling and changing conditions, swam for hours, displaying hope that their situation could improve. Wild rats, lacking such experiences, initially sank and died, appearing to give up. However, a brief intervention where assistants picked up the wild rats just once or twice dramatically shifted their survival rates, suggesting "the hope of rescue" was crucial. This raises the question of hope's importance for humans. Research supports the idea that hope and positive attitudes contribute to health and longevity. A study on Israeli children in the Make-A-Wish Foundation program found improved physical and mental health outcomes during the five-month anticipatory period between learning their wish and its granting, compared to children awaiting wish details. This suggests that extending anticipatory time can enhance quality of life. The speaker concludes that while negative emotions are important to understand, positive emotions are equally vital. Brain imaging reveals that during positive anticipation and joy, multiple brain areas—involved in reward processing, internal feeling monitoring, planning, and movement—are activated. Despite this evidence, positive emotions are not always reflected in culture. While there's a word for anticipating something negative ("dread"), there isn't a widely known English word for anticipating something positive, unlike the German "vorfreude" (joyful anticipation). The speaker also challenges the "Puritan work ethic" that equates busyness with virtue and labels enjoyable activities as "guilty pleasures." She argues that these pleasures and positive events are not indulgences but critical for maintaining healthy brains. Finally, returning to the driving rats, the speaker shared a recent experiment where rats were given a choice: walk efficiently to their Froot Loop rewards or take a detour, backtrack, and drive. A majority chose to drive, demonstrating a preference for pleasure and fun over efficiency. The speaker, initially teaching rats to drive, learned from them to "enjoy the ride."