Paul D. Heideman--Research

Curriculum vita (pdf file)


Copies of Publications (1981-1989)

Materials for Evolutionary Physiology Lab Research Students


Research Topic Outline   

I. Research on Learning and Studying 
II. Research on Neuroendocrine Physiology




What methods help students learn, particularly in mathematics and the sciences?

1.  What are our questions?

   Researchers in neuroscience, cognitive psychology, and education have learned a tremendous amount about how learning works and how learning happens.  That knowledge is changing how teachers teach.  More and more, instructors from the K-12 through college level are trying to apply that knowledge to transform teaching.  It is proving surprisingly difficult – our classes are often not very different from how they were 20 years ago.  One possible problem is that almost all of our attention is focused on changing teachers and teaching, not on changing students and their choices to learn.

    In the newest research area in my lab, we focus on changing students.  Even though researchers have learned a great deal about how to study effectively, we don’t seem to give this information to students.  The most common way that most students study is rereading text or notes, rewatching videos, or visually reviewing images and PowerPoints.  Research tells us that this is a study method of low effectiveness: visual review makes it take longer to master and retain information than some other methods, such as ‘retrieval practice’.  A problem for students, though, is that these other methods take time and coaching to apply.  Once learned, students find these other methods to be faster, easier, and more interesting. Researchers know all of this, but we don’t tell students.  We know all of this, but we don’t teach students how to apply these faster, better methods.

    In my lab, my students and I are testing ways to help students manage their own learning.  We want students to know how to use effective methods for particular tasks.  We are studying how to help students gain accurate information about their own learning, learn how to use new study methods quickly and easily, and in the end, learn more in less time.  This isn’t easy: it takes effort and practice to master better ways to learn.  We’re trying to make that process faster.

2.  Is drawing and imagining valuable?    

    In the sciences, it is essential to be able to perceive structures and events in our imagination.  It doesn’t have to be with our eyes: I argue that it is just as important to be able to imagine those structures and events as if they were floating in front of us.  Every scientist does this, as far as I can see, often without thinking.  If I tell a fellow scientist to close their eyes when describing their research, they first look at me oddly.  As they close their eyes and begin to talk, nearly always their hands begin to move in the air, shaping what they are describing.  When I know their topic, especially in neuroscience, I recognize what they shape: brain areas, cells, or signaling pathways.  It is as if their topic is floating in the air between us.  If I stop them abruptly to ask, “what’s in your mind right now?” they always say “I have an image of X in my head.”  This is clearly a skill that scientists develop.  It seems that all the scientists I know develop it.  There is some research showing that this kind of skill can be critical for success in some fields (engineering, for example).  So why don’t we tell our students about this skill?  Why don’t we teach students how to develop that skill for themselves? 

3.  Teaching students to draw and visualize.

    Both drawing and visualizing seem to be useful.  When I meet former students who have continued their education for advanced degrees (graduate school, medical school, or veterinary school), I ask them how they study, and I ask them if there is anything they learned in college that they still use for studying.  The most common answer is “I still draw”.  (The second most common answer is, “I make concept maps”.)  Often I hear, “I couldn’t learn all this without drawing”.  Students who learn how to draw as part of studying often feel that drawing is essential for their higher-level learning.

   Research shows that drawing improves recall: what we draw we remember better than when we spend the same amount of time in visual review.  That alone is a benefit of spending some of our study time drawing.  But drawing has more uses.  Drawing also helps us explain things to others.  Drawing helps us think through complex problems, in the same way that writing down a math problem on paper helps us solve it.  Complex structures or events have too many pieces to hold in memory.  Drawing them allows us to focus on different parts of the problem and break the problem into steps, just as we do when solving a math problem on paper. Done well, drawing students can master material better and remember it longer.  My lab studies the process of learning to use drawing and visualization to learn.

    Some students draw easily and naturally, but they spend too much time on each drawing, so it takes too long.  Some students make simple drawings, but they don’t yet know how to turn words or a textbook image into a useful drawing.  To use drawing effectively as a study method, students need information and practice.  They need to know why drawing can help.  They need to learn what aspects of drawing are most useful.  They need practice and feedback as they apply drawing to their studying.

    And many students need to be pushed to keep practicing.  I’ve had many students tell me, “I hated it at first, but because you made me keep going, now I see how useful it is, and I’ve kept on drawing ever since.”  Those comments tell me that we need methods that will give students information, practice, and feedback for a long enough time for them to get good enough to draw effectively.  It’s like learning to ride a bike.  It would be easy to quit because, “This is stupid!  I keep falling down and getting hurt.  Look at all my scrapes and bruises!  A bicycle is an idiotic machine.”  That’s true.  Until we’ve practiced enough to discover how fast and far we can go.

4.  Our research.

    We study methods to give students information about learning combined with ways to improve their studying.  Our current focus is on drawing, because that’s where we see the most need and the most benefit.  Our first paper is listed in my publications: “Effectiveness and Adoption of a Drawing-to-Learn Study Tool for Recall and Problem Solving: Minute Sketches with Folded Lists” with my student coauthors K. Adryan Flores, Lu Sevier, and Kelsey Trouton.  You can find it at

   We have new projects to explore ways to assess drawing and help students learn how to use drawing to learn in science and mathematics.  Nearly all of these projects involve student coresearchers.

   Finally, we have been developing projects on a few other aspects of learning.  One current project is designed to help students discover, for themselves, whether it matters for their learning or on exams if they get enough sleep.  Most students are sleep-deprived; most students are hurting their learning more than they realize.



Natural Variation in how the Neuroendocrine System (Brain and Hormones) control the Body

   We are still doing research projects in neuroendocrine physiology, but increasingly my students and I are focusing on learning – on how humans best study and learn to master and retain new information and new skills.  We are starting very few new projects on the topics below.

1.  What are our questions?
   Do human brains function optimally, or are our brains riddled with poorly functioning parts and connections?  No one knows the answer.  This specific question is at the heart of a major question in biology.  To what extent does natural selection optimize complex systems such as brains? 

    The big questions in my research arise from this question on optimality of complex systems.  First, how much variability is there in complex brain pathways, and, second, how do complex brain pathways evolve?  The complex brain pathway we study is the neuroendocrine pathway that uses seasonal changes in photoperiod and other cues to regulate fertility.  We study the nature and amount of variability within species, and try to understand the importance of that variability.  Why does this matter?  This is fundamental basic science research into the aspects of brain function that make individuals physiologically unique.  Understanding this variation is important in  ecology, in evolutionary biology, and in medicine.  (How and why is this important?  Click here.)

2.  What are our study systems, or 'models'?
    My laboratory uses two different study animals (or 'models') in order to get at questions on variability in two different ways. To understand why we need two different models, consider this problem: in natural populations of humans or other mammals, every individual is different both in their genes and in their environment during life.  Thus, when we measure physiological variation in natural populations, it is very hard to determine how much of the difference is due to genes, to environment, and to measurement error.  (This problem is the reason we know so little about the sources of natural physiological variation, despite it's importance.)  Laboratory rats and mice have been inbred to the point that many laboratory strains, such as the Sprague Dawley strain of rat, have relatively low levels of genetic variation when compared to wild populations of mammals.  Biomedical researchers also have created 'inbred' strains in which all individuals are (very nearly) genetically identical by brother-sister mating for at least 25 successive generations.  This makes it possible to study genetically identical individuals within a strain, but these strains no longer contain normal variation!  Even if we compare different inbred strains, we know that none of the strains is quite natural in genetic terms.  For one thing, these inbred strains are homozygous at all loci (which is not normal in itself), and therefore typical inbred rats are homozygous for one or more deleterious recessives that would very rarely be homozygous in a wild population.  In addition, no strain carries alleles that are lethal as homozygotes but have slight effects, potentially even beneficial effects, as heterozygotes.  As a result, we've chosen to study a wild rodent species as a model that contains natural variation, and also a laboratory rat model to let us isolate known genetic differences.  (Click here for more on how we use these two models.)

     Our goal is to use these two species as model systems for natural variability in complex brain pathways.  We would like to be able to predict the kinds of complex brain variation in humans and other mammals, to be able to predict how natural populations of mammals will react to particular kinds of selection pressures (such as climate change), and even to be able to use this information to solve questions in clinical human and veterinary medicine.

What do we do, and what kind of results do we get?
     Our research has included ecological field work, artificial selection, quantitative and classical genetic analyses, photoperiod manipulations to test daily and seasonal rhythms, hormone measurements or hormone manipulation, brain manipulation by such things as neurotransmitter agonists or antagonists to stimulate or inhibit particular neural pathways, and the use of immunocytochemical techniques and autoradiography with computer image analysis systems to identify particular neurons in the brain.  I have three current research areas.  The first project examines variation in the neural pathways that regulate seasonal reproduction in field mice, Peromyscus leucopus (the "white-footed mouse").  We have tested the heritability of seasonal responses (and continue to study their genetics), and have been examining variation in the neuroendocrine components of this brain pathway. We have found variation in daily rhythms (the biological clock), variation in the abundance of melatonin receptors, in the number and location of immunoreactive GnRH neurons, in food intake, and in the way some individuals respond to food (but not leptin, the 'fat' hormone discovered recently).  The second project is a similar series of studies on several strains of laboratory rats, most of which are seasonal, and one is not.  Some of our results here have implications for studies on aging as well as on reproduction.  Finally, a third research area involves mathematical analysis and modeling of populations that contain genetic variation in winter reproduction and in neuroendocrine physiology.  The latter project is conducted with collaborators in biological mathematics.

What do students do?
    Almost all of my research involves undergraduates and masters students.  Many, perhaps most, of these are true collaborations in which students develop ideas, do experiments, and write manuscripts.  In all cases, students work on at least one of these elements, though not everyone actually contributes something we can report as new findings.  At any given time there are 8-15 undergraduates and 0-2 master's students in the lab, some just beginning and others finishing up their experiments, working in my laboratory.  Usually we have a research technician who assists with some student projects and also carries out her/his own projects with me.  We  have had several postdoctoral fellows (recent Ph.D.'s) who helps me run the laboratory and also teaches in one semester, though we do not have a postdoc as I am revising this section in  2012.  I like to stay in touch with former students, and I love updates, but I'm not very good at posting updates to the web!  [A badly out-of-date file(Click here for a list of students and where they are now--updates or corrections will be appreciated!)]

Finally, what can we say about our big questions to date?  
    First, there are high levels of selectable variation in the photoperiod pathway in this single population of mice.  There is variation in so many traits that I infer the variation exists in multiple genes, and probably many genes.  There are hints that variation in one trait may not always match variation in another.  For example, at least occasionally it appears that mice with no sperm in the winter may, nevertheless, attempt to mate, suggesting that they shut down spermatogenesis without shutting down the behaviorally expensive and risky behaviors associated with mating.  In addition, it appears that maintaining the ability to breed in the winter may require higher food intake (a 'cost of reproduction'), but mice with that ability eat more even in summer photoperiods!  That high food intake in summer suggests that the potential for winter mating also carries with it a higher cost of reproduction in the summer.  We have also found a large amount of genetic variation in the number of GnRH neurons we can detect with labeling, and significant heritability for number of GnRH neurons; recent unpublished data indicates heritable variation in other types of neurons as well.  The story isn't complete yet.  However, putting this all together suggests that this pathway is not 'optimized'.  Rather, the population carries variation at multiple alleles.  Different combinations of those alleles are probably successful at some times and in some microenvironements, but not others.  However, because the environment is highly variable from year to year, and from place to place, selection never consistently favors any single combination of alleles.  The result appears to be a highly variable population, some of which have combinations of alleles that may be badly matched to where they happen to be born, and others have combinations of alleles that just happen to be well matched to where they happen to be born.  Probably few or none of these variable alleles are strictly deleterious--they're just different, and good or bad for an individual depending upon individual context and environment.

How might this apply to humans?  
    If human populations are similar, then we might expect high variability in the details of how our brains regulate such things as reproduction, feeding, stress, behavior, and biological rhythms.  Further, we might expect specific combinations of alleles for these neurophysiological control mechanisms to be effective in some situations, but not others.  Humans may have combinations of alleles that may be badly or well matched to where and how we live.  Probably few or none of these variable alleles are strictly deleterious--they're just different, and good or bad for an individual depending upon individual context and environment.  


68  research and review papers

     Publications: 1990 & after

     Publications: 1981-1989

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Last updated  6/1/17
College of William and Mary, Department of Biology