The human brain is incredibly skilled at solving complicated problems. One reason for this is that humans can break down complex tasks into manageable subtasks that are easy to solve one at a time. This strategy helps us handle obstacles easily, as shown by the example of going out for coffee, where we can revise how we get out of the building without changing the other steps.

While there’s a great deal of behavioral evidence demonstrating humans’ skill at these complicated tasks, it’s been difficult to devise experimental scenarios that allow precise characterization of the computational strategies used to solve problems. A new study by MIT researchers has successfully modeled how people deploy different decision-making strategies to solve a complicated task – in this case, predicting how a ball will travel through a maze when the ball is hidden from view.

The human brain cannot perform this task perfectly because it’s impossible to track all possible trajectories in parallel, but the researchers found that people can perform reasonably well by flexibly adopting two strategies known as hierarchical reasoning and counterfactual reasoning. The researchers were also able to determine the circumstances under which people choose each of those strategies.

“Weak humans are capable of doing is breaking down the maze into subsections, and then solving each step using relatively simple algorithms,” says Mehrdad Jazayeri, a professor of brain and cognitive sciences at MIT. “When we don’t have the means to solve a complex problem, we manage by using simpler heuristics that get the job done.”

The researchers recruited about 150 human volunteers to participate in the study and evaluated how accurately they could estimate timespans of several hundred milliseconds. For each participant, the researchers created computational models that could predict the patterns of errors that would be seen for that participant if they were running parallel simulations, using hierarchical reasoning alone, counterfactual reasoning alone, or combinations of the two reasoning strategies.

The researchers compared the subjects’ performance with the models’ predictions and found that for every subject, their performance was most closely associated with a model that used hierarchical reasoning but sometimes switched to counterfactual reasoning. This suggests that instead of tracking all possible paths that the ball could take, people broke up the task into smaller subtasks, picked the direction in which they thought the ball turned at the first junction, and continued to track the ball as it headed for the next turn.

If the timing of the next sound they heard wasn’t compatible with the path they had chosen, they would go back and revise their first prediction – but only some of the time. Switching back to the other side represents a shift to counterfactual reasoning, which requires people to review their memory of the tones that they heard.

The researchers found that people decided whether to go back or not based on how good they believed their memory to be. “People rely on counterfactuals to the degree that it’s helpful,” Jazayeri says. “People who take a big performance loss when they do counterfactuals avoid doing them. But if you’re someone who’s really good at retrieving information from the recent past, you may go back to the other side.”

The research was funded by various organizations, including the Lisa K. Yang ICoN Fellowship, the Friends of the McGovern Institute Student Fellowship, and the National Science Foundation Graduate Research Fellowship.

By slightly varying the amount of memory impairment programmed into the models, the researchers also saw hints that the switching of strategies appears to happen gradually, rather than at a distinct cut-off point. They are now performing further studies to try to determine what is happening in the brain as these shifts in strategy occur.

As we delve into the fascinating world of marine mammals, a team of scientists from the SETI Institute and the University of California at Davis has made a groundbreaking discovery. For the first time, they’ve documented humpback whales producing large bubble rings, akin to a human smoker blowing smoke rings, during friendly interactions with humans. This previously little-studied behavior may represent play or communication.

Humpback whales are already known for using bubbles to corral prey and creating bubble trails and bursts when competing to escort a female whale. These new observations show humpback whales producing bubble rings during friendly encounters with humans. This finding contributes to the WhaleSETI team’s broader goal of studying non-human intelligence to aid in the search for extraterrestrial intelligence.

The study, published in Marine Mammal Science, analyzed 12 bubble ring-production episodes involving 39 rings made by 11 individual whales. According to Dr. Laurance Doyle, SETI Institute scientist and co-author on the paper, “Because of current limitations on technology, an important assumption of the search for extraterrestrial intelligence is that extraterrestrial intelligence and life will be interested in making contact and so target human receivers.” This assumption is certainly supported by the independent evolution of curious behavior in humpback whales.

Dr. Fred Sharpe, co-lead author and UC Davis Affiliate, notes, “Humpback whales live in complex societies, are acoustically diverse, use bubble tools, and assist other species being harassed by predators. Now, akin to a candidate signal, we show they are blowing bubble rings in our direction in an apparent attempt to playfully interact, observe our response, and/or engage in some form of communication.”

The team’s findings have significant implications for the search for extraterrestrial intelligence. By studying intelligent, non-terrestrial (aquatic), nonhuman communication systems, they aim to develop filters that aid in parsing cosmic signals for signs of extraterrestrial life.

Other team members and coauthors of the paper include Dr. Josephine Hubbard, Doug Perrine, Simon Hilbourne, Dr. Joy Reidenberg, and Dr. Brenda McCowan, with specialties in animal intelligences, photography, behavior of humpback whales, whale anatomy, and the use of AI in parsing animal communication.

An earlier paper by the team was published in PeerJ, entitled “Interactive Bioacoustic Playback as a Tool for Detecting and Exploring Nonhuman Intelligence: ‘Conversing’ with an Alaskan Humpback Whale.” The authors would like to acknowledge the Templeton Foundation Diverse Intelligences Program for financial support of this work.

Starting statin therapy as soon as possible can dramatically reduce the risk of heart attack and stroke for patients with diabetes, according to a new study published in the Journal of the American Heart Association. Despite clinicians’ recommendations, nearly one-fifth of diabetic patients choose to delay taking statins, which is a proven and effective way to lower cholesterol levels.

Researchers from Mass General Brigham conducted an analysis of electronic health records of 7,239 patients with diabetes who started statin therapy over a nearly 20-year period. The study found that those who delayed statin therapy for more than a year were significantly more likely to experience heart attacks or strokes compared to those who started taking the medication right away.

The median age of the patients in the study was 55, and about half of them were women. The researchers used artificial intelligence methods to gather data from the electronic health records and found that nearly one-fifth (17.7%) of the patients declined statin therapy when it was first recommended by their clinicians. However, they later accepted the therapy after a median of 1.5 years.

The study’s findings are clear: starting statin therapy on time can save lives. For diabetic patients who delayed taking the medication, the rate of heart attacks or strokes was 8.5%, compared to just 6.4% for those who started taking statins immediately.

Clinicians should use this information to guide shared decision-making conversations with their patients, said senior author Alexander Turchin, MD, MS. “Time is of the essence for your heart and brain health,” he added.

The researchers’ findings are timely, given that heart attacks and strokes remain the leading causes of complications and mortality for patients with diabetes. Statin therapy has been proven to reduce risk by preventing plaque buildup in blood vessels, which can lead to delivery problems for the heart and brain.

The study’s authors emphasize the importance of early intervention and encourage diabetic patients to discuss their individual risks and treatment options with their clinicians. By starting statin therapy on time, patients with diabetes can significantly reduce their risk of heart attack and stroke, and improve their overall health and well-being.