Most animals have a particular and limited set of behaviors that are fairly easy to identify and codify. If we see a cat attacking a mouse, we know the behavior is normal for cats—whether or not we condone it. But is there really a set of “normal” behaviors for human beings?

We know that many human behaviors derive from social norms and early training. For example, as modern Americans we are taught that certain clothes and behaviors are appropriate at certain ages and for certain occasions. We wouldn’t typically wear a bathing suit to a funeral or a dark suit to a pool party—and while we may tolerate temper tantrums from young children, we know they’re inappropriate for adults. All of these behaviors, however, are taught – and vary widely from culture to culture and from one historical period to another.

We know that there are human instincts that, at least in theory, are baked into our physical selves. Sex, for example, is instinctual. Yet, in almost every culture over time, celibacy has been not only accepted but (in some cases) celebrated.

Most people are, by nature, more likely to seek pleasure than pain—and this seems like a normal behavior. Yet there are millions who actively seek pain through “bootcamp” athletic challenges and other extreme sports.  And ascetism – self denial for spiritual or other purposes – has been part of human culture for thousands of years. So far, the desire to participate in these painful activities has not been described as “abnormal.”  In fact, in many cases, the choice to choose pain as a form of self-discipline is applauded.

To distinguish between “normal” and “abnormal” behaviors, psychologists have created a regularly updated publication called the Diagnostic and Statistical Manual of Mental Disorders (aka the DSM). This book lists the criteria for every currently diagnosable developmental disorder and mental illness. What makes the book so interesting (at least to me!) is that, each time it is updated, disorders are changed, added, or removed. As a result, the “official” definition of “normal” changes regularly. For example:

• Homosexuality, long included in the DSM as a mental illness, was removed in 1973. In a single day, being homosexual ceased to be a mental disorder – and being gay was normalized.
• In 1994, a disorder called Asperger Syndrome was added to the DSM as part of an autism spectrum.  Until that time, “autism” was a profound disorder; people with autism were general unable to care for themselves or even communicate effectively. Overnight, people with a wide range of relatively mild differences “became” autistic – an “abnormal” group of humans.
• In 2013, “hoarding” was added to the DSM.  What had, the day before, been a harmless eccentricity was suddenly a diagnosable disorder.

Given the extremely flexible nature of human behavior and thought—and the impossibility of creating a permanent and universal set of mental disorders—is there a “normal” at all?  What’s your take on this question? Add your thoughts to the Forum!