We know that bipolar and other mental illnesses affect behavior, but what precisely is behavior? Rather than go for a definition, maybe it’s best to look at a select sampling of classic experiments and observations representing wildly disparate fields. Let’s get started:
Conditioned Reflex - Ivan Pavlov’s celebrated experiments into conditioned reflex on dogs set the scene for research into human behavior. What you may not have known was that this research grew out of Pavlov’s studies into the digestive systems of dogs, which was his primary focus. Pavlov received the Nobel in Physiology and Medicine in 1904.
Memory and Learning - Intending to become a Freudian psychiatrist, Eric Kandel got sidetracked by neuropsychiatry, which led to decades of research using the humble California sea snail as his unlikely model for the human brain. In the lab, Dr Kandel investigated how the brain laid down memory and learned new tricks. This led to breakthrough findings into neural signaling pathways. Thanks to Dr Kandel, we know that the strength or weakness of neural circuits looms large in human behavior. Dr Kandel shared the Nobel in Physiology and Medicine in 2000.
Genes and Environment - Rather than hunt for a “depression” gene or a “bipolar” gene, psychologists Terrie Moffit and Avshalom Caspi investigated how stress affects certain gene variations, which may in turn influence behavior. Their 2002 and 2003 studies on a New Zealand birth cohort totally changed the discussion from one of “genes OR environment” to “genes AND environment.” One of the studies found that those with a certain gene variation experienced far greater rates of depression when faced with stress while those with a different variation of the same gene proved far more resilient. Take home message: Watch your environment, manage your stress - your brain will thank you for it.
Selfish vs Altruistic - Working at RAND in the 1950s, mathematicians Merrill Flood and Melvin Dresher came up with the “prisoner’s dilemma,” the best known of all game theories. For example, two prisoners are taken to separate rooms for questioning. If neither one snitches, they both get off. If one snitches, he will be charged with a lesser crime while his partner gets charged with a major crime. What would you do in the situation? Self-interest vs cooperation - the two co-exist in a knife-edge tension.
Love and Lust - What happens in the brain when we fall in love? Thanks to brain scans, we have a pretty good idea. In a 2005 paper, anthropologist Helen Fisher reported that three separate but interrelated brain systems are activated for sex, falling in love, and long-term relationships, respectively. Love may still be an affair of the heart, but like all human emotion it is mediated in the brain. In all fields of human behavior, brain scans are telling a very interesting story.
Healthy Responses - Back in the 1967, Freudian psychiatrist George Vaillant took over a study involving tracking one cohort of Harvard men and another of inner city men that began in the 1930s. He kept it going for another 42 years. Amongst other things, Dr Vaillant discovered that those who aged in healthy ways had adopted successful defense mechanisms to the trials life throws our ways. In other words, responding to a challenging situation with say humor has long-term mental health pay-offs.
Child-Rearing - No survey of this type is complete without at least one rat study. During the 2000s, biological psychiatrist Michael Meany has observed what happens to rat pups when raised in poor maternal environments. Predictably, these rats grew up far more stressed. From there, Dr Meany dug deeper into neuroendocrine system pathways and into how stress may switch on or off certain genes (which embraces the fairly new field of epigenetics). Take home message: Yes, your childhood matters.
Life in the Jungle - Likewise, no survey of this type would be complete without at least one wild animal study. Robert Sapolsky is a card-carrying neuroendocrinologist and is celebrated for his lab work, but he is also a bona fide primatologist who has been studying baboons in the wild for more than a quarter-century. Alpha males may make life miserable for betas, but they don’t last long at the top, which makes their lives as stressful as those they bully. It’s a jungle out there.
As you can see, human behavior covers an immensely wide range of disciplines, each making a major contribution to the field but neither telling the whole story. Neurons and circuitry, for instance, may tell us what went on in our brains a half a second before that behavior occurred, but then, according to Dr Sapolskly in the first of a fascinating 25-part lecture series on human behavior:
Just as we are about to get happily settled into that bucket, we push back a bit and say what smell, what sound, what sensory stimulation in the environment caused those neurons to get activated and produce that behavior?
Then we push it back further to hormone levels in the blood in the last few hours that changed how sensitive you are to those sounds and smells. Then we work our way even further back through early development, fetal life, the genetic make-up of an individual, the genetic makeup of an entire population species.
I’ve been writing on mental illness since 1999. I’ve attended lectures delivered by Drs Kandel, Fisher, Sapolsky, and Meany. I reported on the significance of the Moffit-Caspi studies very soon after they appeared. One thing I learned: Prepare to be surprised. For instance, just when we thought the field had grown far too sophisticated for the likes of Freud, the stress-trauma connection got validated across a wide range of fields, from genes to rats to primatology, and suddenly Freud (as illustrated by the Vaillant study) is back in play.
We haven’t even gotten started. I hope this little sample, though, gives you an appreciation.