The brain is 'programmed' for learning from people we like

Our brains are "programmed" to learn more from people we like -- and less from those we dislike. This has been shown by researchers in cognitive neuroscience in a series of experiments.

Memory serves a vital function, enabling us to learn from new experiences and update existing knowledge.

We learn both from individual experiences and from connecting them to draw new conclusions about the world.

This way, we can make inferences about things that we don't necessarily have direct experience of. This is called memory integration and makes learning quick and flexible.

Inês Bramão, associate professor of psychology at Lund University, provides an example of memory integration: Say you're walking in a park.

You see a man with a dog. A few hours later, you see the dog in the city with a woman.

Your brain quickly makes the connection that the man and woman are a couple even though you have never seen them together.

"Making such inferences is adaptive and helpful. But of course, there's a risk that our brain draws incorrect conclusions or remembers selectively," says Inês Bramão.

Important who provides the information

To examine what affects our ability to learn and make inferences, Inês Bramão, along with colleagues Marius Boeltzig and Mikael Johansson, set up experiments where participants were tasked with remembering and connecting different objects.

It could be a bowl, ball, spoon, scissors, or other everyday objects.

It turned out that memory integration, i.e., the ability to remember and connect information across learning events, was influenced by who presented it. If it was a person the participant liked, connecting the information was easier compared to when the information came from someone the participant disliked.

The participants provided individual definitions of 'like' and 'dislike' based on aspects such as political views, major, eating habits, favorite sports, hobbies, and music.

Can be translated to politics

The findings can be applied in real life, according to the researchers.

Inês Bramão takes a hypothetical example from politics:

"A political party argues for raising taxes to benefit healthcare. Later, you visit a healthcare center and notice improvements have been made. If you sympathize with the party that wanted to improve healthcare through higher taxes, you're likely to attribute the improvements to the tax increase, even though the improvements might have had a completely different cause."

About fundamental mechanisms

There's already vast research describing that people learn information differently depending on the source and how that characterizes polarization and knowledge resistance.

"What our research shows is how these significant phenomena can partly be traced back to fundamental principles that govern how our memory works," says Mikael Johansson, professor of psychology at Lund University.

We are more inclined to form new connections and update knowledge from information presented by groups we favor.

Innate way of handling information

Understanding the roots of polarization, resistance to new knowledge, and related phenomena from basic brain functions offers a deeper insight into these complex behaviors, the researchers argue.

So, it's not just about filter bubbles on social media but also about an innate way of assimilating information.

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Early life experiences can have long-lasting impact on genes

Early life experiences can impact the activity of our genes much later on and even affect longevity, finds a new study in fruit flies led by UCL researchers.

In the study published in Nature Aging, the scientists report that gene expression 'memory' can persist across the lifespan, and may present a novel target for improving late-life health.

Lead author Dr Nazif Alic (UCL Institute of Healthy Ageing, UCL Biosciences) said: "Health in old age partially depends on what a person experienced in their youth or even in the womb. Here, we have identified one way in which this happens, as changes in gene expression in youth can form a 'memory' that impacts health more than half a lifetime later."

The scientists were building on their previous research in which they found that fruit flies fed a high-sugar diet early in life lived shorter lives, even after their diets were improved in adulthood. Here, they uncover the mechanism likely explaining the finding.

In their previous study, the researchers found that a high-sugar diet inhibited a transcription factor called dFOXO, which is involved in glucose metabolism and is known from multiple studies to affect longevity, so they now sought to enact the opposite effect by directly increasing the activity of dFOXO. Transcription factors are proteins that regulate transcription, or copying, of information from DNA into messenger RNA, which is the first and key step in gene expression. For this study, the researchers activated dFOXO by increasing its levels in female fruit flies during the first three weeks of the fly's adulthood.

They found that these early-life experiences caused changes to chromatin -- a mixture of DNA and proteins that can be seen as the 'packaging' of DNA -- that persisted and resulted in genes being expressed differently late in life. This counteracted some changes that would be expected as part of the normal ageing process, eventually improving health in late life and impacting the fruit flies' lifespan more than a month (half a fruit fly lifetime) later.

The researchers say their findings could lead to ways to impact late-life health in people as well.

Dr Alic said: "What happens early on in an animal or person's life can affect what their genes do late in life, for better or for worse. It may be that a poor diet early in life, for example, could impact our metabolism later in life by tweaking how our genes are expressed, even after substantial dietary changes over the years -- but fortunately, it may well be possible to reverse this.

"Now that we know how gene expression memory can persist across the lifespan to affect gene activity, we may be able to develop ways to counteract these changes later in life to preserve health and enable people to stay healthy for longer."

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New experiences enhance learning by resetting key brain circuit

 A study of spatial learning in mice shows that exposure to new experiences dampens established representations in the brain's hippocampus and prefrontal cortex, allowing the mice to learn new navigation strategies. The study, published in Nature, was supported by the National Institutes of Health.

"The ability to flexibly learn in new situations makes it possible to adapt to an ever-changing world," noted Joshua A. Gordon, M.D., Ph.D., a senior author on the study and director of the National Institute of Mental Health, part of NIH. "Understanding the neural basis of this flexible learning in animals gives us insight into how this type of learning may become disrupted in humans."

Dr. Gordon co-supervised the research project with Joseph A. Gogos, M.D., Ph.D., and Alexander Z. Harris, M.D., Ph.D., both of Columbia University, New York City.

Whenever we encounter new information, that information must be consolidated into a stable, lasting memory for us to recall it later. A key mechanism in this memory consolidation process is long-term potentiation, which is a persistent strengthening of neural connections based on recent patterns of activity. Although this strengthening of neural connections may be persistent, it can't be permanent, or we wouldn't be able to update memory representations to accommodate new information. In other words, our ability to remember new experiences and learn from them depends on information encoding that is both enduring and flexible.

To understand the specific neural mechanisms that make this plasticity possible, the research team, led by Alan J. Park, Ph.D., of Columbia, examined spatial learning in mice.

Spatial learning depends on a key circuit between the ventral hippocampus (a structure located in the middle of the brain) and the medial prefrontal cortex (located just behind the forehead). Connectivity between these brain structures strengthens over the course of spatial learning. If the connectivity remains at maximum strength, however, it impairs later adaptation to new tasks and rules. The researchers hypothesized that exposure to a new experience may serve as an environmental trigger that dampens established hippocampal-prefrontal connectivity, enabling flexible spatial learning.

In the first task, the researchers trained mice to navigate a maze in a certain way to receive a reward. Some of the mice were then allowed to explore a space they hadn't seen before, while others explored a familiar space. The mice then engaged in a second spatial task, which required that they switch to a new navigation strategy to get a reward.

As expected, all of the mice favored their original navigation strategy at first. But the mice that had explored a new space gradually overcame this bias and successfully learned the new navigation strategy about halfway through the 40-trial training session. When the researchers tested a subset of the mice on the first task again, they found that the novelty-exposed mice were able to switch back to the original strategy, indicating that they updated and chose their strategy according to the task demands.

Additional findings showed that the effects of novelty extended beyond new spaces: Encountering new mice before the second task also enhanced learning of the new reward strategy.

Changes in brain activity throughout training revealed the neuronal mechanisms that drive this novelty-enhanced learning. In rodents, there is a well-defined firing pattern in the hippocampus known as the theta wave, which is thought to play a central role in learning and memory. When Park and coauthors examined recordings from the ventral hippocampus, they found that the theta wave became stronger during exploration of the novel arena and the hour that followed; the theta wave decreased as the mice became familiar with the arena over the next two days. The researchers found that novelty exposure also disrupted encoding of the original navigation strategy, reorganizing the firing pattern of individual neurons in the ventral hippocampus to bring them in sync with the theta wave.

At the same time, neurons in the medial prefrontal cortex showed decreased theta wave synchrony, and correlations between hippocampal activity and prefrontal activity weakened. These and other findings suggest that novelty exposure dampened the synaptic connections between the ventral hippocampus and medial prefrontal cortex, resetting the circuit to allow for subsequent strengthening of connectivity associated with learning.

By triggering this reset, novelty appears to facilitate strategy updating in response to the task's specific reward structure. Machine learning analyses indicated that, following novelty exposure, ventral hippocampal neurons switched encoding from a strategy that predicted reward on the first task to one that predicted reward on the second task. The task-specific information was then relayed to the medial prefrontal neurons, which updated encoding accordingly.

On a chemical level, the neurotransmitter dopamine acts as a key mediator of this plasticity. Several experiments showed that activating dopamine D1-receptors in the ventral hippocampus led to novelty-like effects, including dampened hippocampal-prefrontal connectivity and enhanced learning. Blocking D1-receptors prevented these novelty-induced effects.

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Why experiences are better gifts for older children

 What should we get for our kids this holiday? As children get older, giving them something they can experience (live through) instead of material things makes them happier, according to new research led by Lan Nguyen Chaplin, associate professor of marketing at the University of Illinois Chicago.

The research, published in the International Journal of Research in Marketing, compared the level of happiness children derive from material goods with the level of happiness they derive from experiences.

Across four studies with children and adolescents, Chaplin and her collaborators demonstrated that children ages 3-12 derive more happiness from material things than from experiences. However, older children derive more happiness from their experiences than from their possessions.

"What this means is, experiences are highly coveted by adolescents, not just expensive material things, like some might think," Chaplin says.

She goes on to explain, "Don't get me wrong. Young children do love experiences. Entire industries (e.g., theme parks such as Disneyland) are built around this premise. In fact, young children are ecstatic throughout the experience. However, for experiences to provide enduring happiness, children must be able to recall details of the event long after it is over."

Long after they have unwrapped their Legos and stuffed animals, there will still be a physical reminder to give them a "jolt" of happiness. However, young children can't see or touch experiences after they are over, making it harder for them to appreciate experiences long after the event is over. There's an easy and inexpensive fix though, according to Chaplin.

"Take pictures or videos of family walks, playing in the snow, and birthday parties," she said. "Children are likely going to appreciate those experiences more if there is something to remind them of the event. Additionally, they'll be able to learn the social value of shared experiences."

Children will remember and appreciate not only the birthday gifts they received, but also the time spent with family and friends as they relive the experience through concrete reminders such as photos and videos.

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