Memory is slippery and mysterious. Some events are indelibly etched into our brains, emerging intact decades later, crucial sensory details flooding our minds unbidden. Other important experiences return to us as atmosphere, the ideas and feelings taking precedence.
Now researchers from the United States and Singapore have shown, across many studies, that certain kinds of motivation can profoundly shape what and how we remember. What you’re motivated to do in the moment changes not only what you remember but the style of memory that gets lodged deep in your psyche. Sometimes you form rich, flexible, web-like memories. Other times, your memories are tightly focused on narrow sets of sensory details.
Building on recent findings in the field of cognitive neuroscience, the scientists propose that two separate chemical broadcast systems drive these different modes of memory. They published their findings in the Annual Review of Psychology.
“Beyond studying whether motivation helps memory, we investigated how it shapes memory,” said the study author Poh Jia-Hou, a researcher at NUS Medicine in Singapore, in a statement. “Our framework explains that curiosity, stress, deadlines, and rewards result in distinct learning outcomes. This is because each factor induces a different motivational ‘mood’ which in turn modulates how information is processed.”
The scientists described the first of those moods as “interrogative.” This mood helps the brain form flexible memories that connect related ideas, support abstract thinking, and build mental maps for use later. It’s supported by dopamine—a neurotransmitter thought to be involved in reward, movement, mood, and focus—and is linked to a few distinct regions of the brain: the ventral tegmental area, which helps signal what’s motivating or rewarding; the hippocampus, which builds and connects memories; and the prefrontal cortex, which uses those signals and memories to plan, decide, and regulate behavior.
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The other mood is “imperative,” which is more urgent and high-stakes, dominated by the desire to act. This mood favors goal-directed behavior in the moment and quick processing of sensory information, and can help us remember details relevant to the goal we have in mind. It’s supported by noradrenaline, a neurotransmitter critical for the body’s fight-or-flight stress response, and is associated with activity in the amygdala, the brain’s emotional processing center, as well as sensory systems and parts of the medial temporal lobe that support item or context representations.
“These neuromodulatory systems, dopamine and noradrenaline, act like switches that tune the entire brain for different kinds of learning,” explained R. Alison Adcock, a study author and director at the Center for Cognitive Neuroscience at Duke University. It alters the operating system, Adcock and his colleague write, changing which networks cooperate, which details get noticed and what kind of memory gets inked into storage.
What they found could help us understand why curiosity can improve learning, helping you to remember unrelated information. Why stress can sharpen memory for a single salient thing but shrink attention to peripheral details. And why rewards don’t always support memory, particularly if they dial up the stress to 11.
The findings could also help educators improve learning environments and help clinicians create better therapies for disorders involving impaired motivation and memory, including depression, schizophrenia, ADHD, dementia, and age-related cognitive decline. “Understanding these switches gives us powerful new levers for designing more effective classrooms and therapies. We hope to help individuals identify these motivational moods and learn to match them to the challenges they face,” said Adcock.
The researchers intend to pursue further experimental work in a few different areas: AI-driven learning technologies that adapt to students’ motivational moods as well as studying how aging affects the relationship between mood and memory. They’re also looking into whether neurofeedback can help tweak the dopamine and noradrenaline systems in ways that might improve memory.
“Our long-term goal is to empower people with the ability to tune their own brains for learning,” said Poh. “By understanding how motivation shapes memory, people can learn to harness urgency to focus learning and support efficient action, or engage their curiosity to prepare for flexibility in an unknown future.” 
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Lead image: Jorm Sangsorn / Shutterstock
