The Evolving Mind


It’s all in your head

The Evolving Mind

By Amy Patterson Neubert

A senior moment. Teens cramming for tests with flashcards. Putting a name with a familiar face. Many people think of memory as a tape-recorder, simply capturing a moment or thought to recall later, but a Purdue professor is showing that memory is its own functional system. His groundbreaking findings are changing the way people think. Literally.

James S. Nairne, Reece McGee Distinguished Professor of Psychological Sciences, has been a major figure in learning and memory research for more than 30 years, but he recently took a different approach by suggesting that memory evolved to solve problems related to survival and reproduction.

“Let’s say an organism gained the capacity to remember where a predator hid or the location of food,” Nairne says. “It would be more likely to survive, and therefore pass on its genetic material. I asked the question, ‘Maybe our memory systems are there to help us remember things that are relevant to survival and reproduction.’”

His research findings indicate this might be true.

“Evolution sculpted the system, and natural selection determines what is important, particularly things that help people survive long enough to reproduce,” he says.

The norm in psychological sciences was to view memory as structural and not worry too much about its function or why it evolved. Since Nairne’s findings were published just a few years ago, there have been conferences, dozens of research articles, and special journal issues dedicated to the topic. His line of work, and the discovery that is built from his foundation, could help in educational and rehabilitation settings.

“His contributions span decades, but within the last eight years, he has started a new line of research that is really changing the way people are studying memory and thinking about memory,” says Jeffrey Karpicke, an associate professor and James V. Bradley Chair of Psychological Sciences who also focuses on memory and learning. “Jim’s findings are creating a buzz, and it’s what people are talking about in cognitive science.”

Power of mind

Nairne is author of the universally used introductory textbook Psychology: The Adaptive Mind. The book, now in its sixth edition, covers a variety of topics, including consciousness, memory, intelligence, and personality. It opens with, “You can’t truly understand a psychological process unless you first know what it’s for — that is, how it helps you adapt to or solve problems in your environment. Psychology: The Adaptive Mind is based on this idea.”

This functional adaptive problem-solving approach was the foundation for Nairne’s popular teaching style. About eight years ago, he realized he should apply this approach to research questions in his lab.

“That led me to start asking the most fundamental question: ‘If you were designing a memory system from scratch, what would you put in there? Would you leave it a blank slate or build a brain that is ready to recognize and adapt?’” Nairne asks.

He asks his students in “Elementary Psychology” this question each semester: “If you were God, and you were designing a memory system, what would you put in there and why?”

He then points out that structures in the human body are there to solve particular problems. The cardiovascular system pumps blood. The digestive system feeds and nourishes the body. To explain the function of memory, which can be harder to visualize than a system pumping blood, Nairne uses the analogy of the iPhone.

“Think about an iPhone as a system that contains a number of apps and each of those apps are there to do something specific,” he says. “You have a weather app, stock market app, music app, and so on. While these apps are running on the operating system and may interact, they are systems designed to do particular things. That is much more efficient than just having a general-purpose system.”

Nairne likes to think of the human body as an iPhone composed of many apps. The heart app pumps blood, the visual app generates sight, and the lungs app helps the body breathe.

“If you look at sensory systems, like the visual system, it also can be thought of as being composed of many apps. You have a program that solves the problem of transferring light into the language of the brain, and others that detect and define color and motion,” he says. “Like any system in the body, the visual system is there to solve a problem or answer these questions. But, if you turn to the topic of memory, the psychological field has never thought about memory solving particular kinds of problems. So, we don’t have a functional app view of the way memory operates.”

The Evolving Mind

Survival of the fittest

Like any bodily system, memory is there to solve problems, Nairne hypothesizes. And knowing that natural selection designed the human body, that means memory was advanced through natural selection: the survival of the fittest.

“We’ve got two clues: everything in the body is functional and there to solve problems, and second, we know that the criteria to design these programs, apps, and systems are related to survival and reproduction,” he says. “If we follow these clues, it is likely that the function of memory is to enhance our survival and possibly to obtain an appropriate mating partner. No one has framed it quite this way before.”

And no one had tested these hypotheses like Nairne.

For example, in some studies through Purdue’s Adaptive Memory Lab, participants were given different scenarios of being stranded in hot grasslands with no food or water or moving to a new home in a foreign land. At a later time, the participants were asked to remember a variety of words, and the ones that were remembered were ones they linked to concepts of survival, such as water and safety. In fact, thinking about things in terms of how they relate to survival turns out to be one of the best ways to get a person to remember.

Evolutionary psychology has historically been controversial because the research has often not been sound, but Nairne, who is known for bringing laboratory rigor to the field, has published his findings in key academic journals such as Psychological Science and Current Directions and presented at various research meetings. But this doesn’t mean everyone agrees.

“The problem we run into in psychology is that people are not trained in evolutionary theory,” he says. “Most researchers in cognitive psychology don’t have background in biology, and there is a big disconnect between how biologists and psychologists think.”

But even for those who don’t embrace evolution, and the question certainly comes up in his classes, Nairne’s reply is, “Wouldn’t a loving God build a functional memory that can adapt to help one survive?”

Expanding one’s mind

Nairne is certainly known as a leader in his field as a scientist, as he was inducted in the Society of Experimental Psychologists last year. He also has been recognized as one of Purdue’s top instructors. He’s won the university’s top teaching award, the Outstanding Undergraduate Teaching Awards in Memory of Charles B. Murphy, and is listed in Purdue’s Book of Great Teachers.

“He has certainly influenced me as a teacher,” says Karpicke, who also has won a Murphy award and has been recognized for his strengths as an instructor. “One of the first things he told me when I started at Purdue was that students don’t come to class for material. They can get the information from a book, Wikipedia or YouTube. He said, ‘Your goal should not be to present material, but to give students something they can’t get elsewhere,’ and that core belief shaped how I teach.”

Students sitting in any beginning psychology course are going to hear about the infamous classical conditioning experiments by Ivan Pavlov. The Russian physiologist was studying digestion in dogs, and during his experiments he observed that when dogs heard a dinner bell, they began to drool, conditioned to know food was coming.

“Students have no idea why we teach this or any topic, so I’ve taken a very functional approach to teaching,” Nairne says. “If I want students to understand material, it needs to be set up as a problem to solve. And so, I explain, ‘If you are walking on a mountain trail and you hear rattling, you need to know that it could kill you. It’s important to know that other events can signal the occurrence of other events. So, let me tell you about classical conditioning.’”

future brain

Looking ahead

Nairne’s building on his work in functional memory by focusing on memory and animacy. There is a lot of evidence — including the big business of popular children’s television shows and characters that feature objects such as talking cars or tools — that living things are more appealing than nonliving objects. Another example, animal sounds are one of the first things that many children learn across cultures.

“The mind’s distinction between living and nonliving is foundational,” Nairne says. “There is no question of its importance, but no one has investigated whether people remember animate things better than inanimate things.”

Nairne has found they do, and that makes sense in evolutionary psychology as living things, a caring mother or terrifying predator, infer survival. The other related area that he continues to explore is called contamination, and it also relates to survival. For example, people who are repulsed by disease or someone’s behavior will stay away from items they touched because it is believed that some essence of that person is left on the item. It turns out that people will also remember things touched by a sick person better than those touched by a healthy person.

Or as Nairne asks, “If a serial killer wore a sweater, would you wear it?” The topic of contamination also relates to belief in the supernatural, which Nairne is interested in. He leads a group of honor students to Transylvania each spring to explore some of these issues more deeply.

“The idea is that if a person lives in the house that a ghost haunts, some essence of that spirit is transferred,” he says.

It’s also a belief that he says has shaped cultural rituals for dealing with death. Again, demonstrating the mind’s emphasis on survival.

“Our minds are purposive,” Nairne says. “And whether it is memory, perception or reasoning, the mind is trying to solve a problem.”

Amy Patterson Neubert (LA’99, MS LA’08) is a health sciences and news writer for the Office of Marketing and Media. Illustrations by Jon Benson (LA’12).