Do you naturally see the best in people, or are you quick to notice signs of frustration or anger? According to new research from the Norwegian University of Science and Technology (NTNU), how you interpret others’ emotions may depend on your age. The study found that older adults tend to view ambiguous facial expressions—those that are neither clearly happy nor clearly angry—as more positive than younger people do. This suggests that as we age, our brains may help us focus more on the good, which, in turn, can improve our sense of well-being.
Researcher Maryam Ziaei at NTNU’s Kavli Institute for Systems Neuroscience led the study, exploring how the brain processes uncertainty in others’ emotions. She focused on a tiny structure called the locus coeruleus, located deep in the brainstem. Despite being only about 1.5 centimetres tall, it plays a significant role in how alert we are and how we respond to stress. This area produces norepinephrine, often called the “fight-or-flight” hormone, which helps us stay awake, attentive, and ready to act in response to danger or sudden change. Too little activity in this region makes us sluggish and tired, but too much can cause stress and distraction.
When we look at someone whose expression is hard to read—perhaps smiling slightly but with furrowed brows—the locus coeruleus helps us stay alert and decide whether the situation is friendly or threatening. As we grow older, our cognitive abilities naturally decline, yet the NTNU researchers discovered that the locus coeruleus seems to adapt to these changes. In their study, 144 participants—half young adults aged 21 to 30, and half older adults aged 67 to 75—were shown a series of facial expressions ranging from happy to angry, including ambiguous ones in between. The older group took slightly longer to decide what they saw, but they were also more likely to interpret the uncertain faces as happy.
Brain scans revealed that older adults showed greater activity in the locus coeruleus when viewing ambiguous faces than younger adults. Moreover, this brain activity was more strongly linked to the frontal lobe, particularly the dorsolateral prefrontal cortex, which is responsible for memory, attention, and self-control. This increased connection supports positive interpretation and emotional regulation. Older participants with stronger links between these two brain areas also reported higher levels of mental well-being and fewer symptoms of anxiety or depression.
These results suggest that as the brain ages, it adjusts by strengthening pathways that help maintain emotional stability and positivity. The locus coeruleus appears to compensate for the mild cognitive decline that typically accompanies ageing, helping older adults remain emotionally balanced. Since the same regions are involved in conditions such as Parkinson’s and Alzheimer’s disease, understanding how these systems change with age could lead to new ways of treating emotional or cognitive difficulties in older people.
Ziaei and her team believe this adaptation has a protective effect. When the locus coeruleus remains responsive, it helps older adults stay alert to essential signals in their surroundings—like noticing a car approaching when distracted—while filtering out unnecessary stress. Future research may explore how stimulation, medication, or even mental exercises could enhance this system. Ultimately, understanding how our brains process social and emotional signals could help people of all ages maintain better mental health and emotional resilience throughout life.
More information: Maryam Ziaei et al, Age-Related Increase in Locus Ceruleus Activity and Connectivity with the Prefrontal Cortex during Ambiguity Processing, JNeurosci. DOI: 10.1523/JNEUROSCI.2059-24.2025
Journal information: JNeurosci Provided by Norwegian University of Science and Technology
