The Power of Rebound Dreaming

The Power of Rebound Dreaming by Kelly BulkeleyThere is a surprisingly easy way to stimulate an intense phase of dreaming, if you’re willing to take advantage of the “rebound effect” of sleep deprivation.  The rebound effect is a term for when a person sleeps longer than usual after a period of sleeping shorter than usual.  The magnitude of the rebound depends on 1) the severity of the sleep deprivation and 2) the freedom to sleep without awakening after the deprivation.

I just had a personal experience of this process, although I didn’t exactly plan for it.  My wife and I had seen a play the night before (the excellent “Astoria, Part 2” at Portland Center Stage), and I didn’t get to sleep until much later than I usually do.  I had to get up early the next morning, so my overall sleep that night was less than 2/3 of my usual sleep.  Not drastic sleep deprivation at all, but enough to set the rebound effect in motion.

The next night I went to bed at my usual time, but I made the mistake of not bringing my phone with me, which has the clock I use at night.  I woke up after being asleep for a long time, and figuring it was morning I got out of bed, left the bedroom, went to the kitchen—and saw from a thermostat clock that it was 3:30 am.  I didn’t want to disrupt my wife, so I went to another bedroom and buried my head under the pillows, hoping I’d fall asleep again.

I did, for another four hours without interruption, during which time I had a phase of unusually intense and dynamic dreaming.  Most of my dreams are in the range of 70-80 words per report; this dream was more than 400 words in length.  It had instances of all five major emotions (fear, anger, sadness, happiness, wonder/confusion), characters from three different ethnicities, a wild golden lion, and a fast-moving skunk.  Suffice it to say, it was quite a memorable dream.

This is exactly what the science of sleep and dreaming would predict: after a period of diminished sleep, the brain responds with a period of enhanced sleep, which naturally includes more energetic and extensive dreaming.

You can benefit from this process in your own life, the next time you have a night or two of shortened sleep then get to sleep without interruption.  The key is allowing your dreaming imagination as much freedom as possible on the “rebound” night, especially at the end of the sleep cycle, when the brain is most active and dreams are most likely to occur.  If you can let yourself sleep until you naturally awaken the next morning, you will very likely be rewarded with a stellar creative effort by the inner artist who creates your dreams.


Note: this post first appeared in Psychology Today.

The Science of Dreaming: 9 Key Points

The Science of Dreaming: 9 Key Points by Kelly BulkeleyThe most important findings of scientific dream research can be summarized in nine key points.  Many important questions about dreaming remain unanswered, but these nine findings have solid empirical evidence to support them. 

  1. Rapid eye movement (REM) sleep is a trigger for dreaming, but is not identical with dreaming. All mammals have sleep cycles in which their brains pass through various stages of REM and non-REM sleep.  Dreaming seems to occur most often, and most intensely, in REM sleep, a time when many of the brain’s neuro-electrical systems have risen to peak levels of activation, as high as levels found in waking consciousness.  However, dreaming occurs outside of REM sleep, too, so the two are not identical; REM sleep is neither necessary nor sufficient for dreaming.
  2. REM helps the brain grow. The fact that REM sleep ratios are at their highest early in childhood (newborns spend up to 80% of their sleep in REM, whereas adults usually have 20-25% of their sleep in REM) suggests that REM, and perhaps dreaming, have a role in neural maturation and psychological development.
  3. Dreaming also occurs during hypnogogic, hypnopompic, and non-REM stage 2 phases of sleep. In the transitional times when a person is falling asleep (hypnogogic) or waking up (hypnopompic), various kinds of dream experiences can occur.  The same is true during the end of a normal night’s sleep cycle, when a person’s brain is alternating exclusively between REM and non-REM stage 2 phases of sleep, with a relatively high degree of brain activation throughout.  Dreams from REM and non-REM stage 2 are difficult to distinguish at these times.
  4. The neuro-anatomical profile of REM sleep supports the experience of intense visionary imagery in dreaming. During REM sleep, when most but not all dreaming occurs, the human brain shifts into a different mode of regional activation.  Areas of the prefrontal cortex involved in focused attention and rational thought become less active, while areas in the limbic system (involved in emotional processing, memory, and instinctive responses) and the occipital lobe (involved in visual imagination) become much more active.  This suggests that the human brain is not only capable of generating intense visionary experiences in dreaming, it has been primed to do so on a regular basis.
  5. The recurrent patterns of dream content are often continuous with people’s concerns, activities, and beliefs in waking life. This is known as the “continuity” hypothesis, and it highlights the deep consistency of waking and dreaming modes of thought.  People’s dreams tend to reflect the people and things they most care about in the waking world.  A great deal of dream content involves familiar people, places, and activities in the individual’s waking life.  The dreaming imagination is fully capable of portraying normal, realistic scenarios. This means dreaming is clearly not a process characterized by total incoherence, irrationality, or bizarreness.
  6. The discontinuities of dreaming, when things happen that do not correspond to a normal waking life concern, can signal the emergence of metaphorical insights. Research on the improbable, unreal, and extraordinary elements of dream content has shown that, on closer analysis, this material often has a figurative or metaphorical relationship to the dreamer’s waking life.  Metaphorical themes and images in dreams have a long history in the realm of art and creativity, and current scientific research highlights the dynamic, unpredictable nature of dreaming as an endless generator of conceptual novelty and innovation.
  7. Dream recall is variable. Most people remember one to two dreams per week, although the memories often fade quickly if the dreams are not recorded in a journal.  On average, younger people tend to remember more dreams than older people, and women more than men.  Even people who rarely remember their dreams can often recall one or two unusual dreams from their lives, dreams with so much intensity and vividness they cannot be forgotten.  Dream recall tends to respond to waking interest.  The more people pay attention to their dreams, the more dreams they are likely to remember.
  8. Dreaming helps the mind to process information from waking life, especially experiences with a strong emotional charge. From a cognitive psychological perspective, dreaming functions to help the mind adapt to the external environment by evaluating perceptions, regulating emotional arousal, and rehearsing behavioral responses.  Dreaming is like a psychological thermostat, pre-set to keep us healthy, balanced, and ready to react to both threats and opportunities in the waking world. Post-traumatic nightmares show what happens when an experience is too intense and painful to process in a normal way, knocking the whole system out of balance.
  9. The mind is capable of metacognition in dreaming, including lucid self-awareness. During sleep and dreaming the mind engages in many of the activities most associated with waking consciousness: reasoning, comparing, remembering, deciding, and monitoring one’s own thoughts and feelings. Lucid dreaming is one clear example of this, and so are dreams of watching oneself from an outside perspective.  These kinds of metacognitive (thinking about thinking) functions were once thought to be impossible in dreaming, but current research has proven otherwise.  Dreaming has available the full range of the mind’s metacognitive powers, although in different combinations from those typically active in ordinary waking consciousness.

The Science of Dreaming: 9 Key Points by Kelly Bulkeley

For further reading:

Barrett, Deirdre and Patrick McNamara, ed.s.  The New Science of Dreaming.  Westport: ABC-Clio, 2007.

Bulkeley, Kelly.  Big Dreams: The Science of Dreaming and the Origins of Religion.  New York: Oxford University Press, 2016.

Domhoff, G. William.  Finding Meaning in Dreams: A Quantitative Approach.  New York: Plenum, 1996.

Hurd, Ryan and Kelly Bulkeley, ed.s.  Lucid Dreaming: New Perspectives on Consciousness in Sleep.  Westport: ABC-Clio, 2014.

Kryger, Meir H., Thomas Roth, and William C. Dement, ed.s. Principles and Practice of Sleep Medicine.  Fourth Edition.  Philadelphia: Elsevier Saunders, 2005.

Maquet, Pierre, Carlyle Smith, and Robert Stickgold, ed.s.  Sleep and Brain Plasticity. New York: Oxford University Press, 2003.

Pace-Schott, Edward, Mark Solms, Mark Blagrove, and Stevan Harnad, ed.s.  Sleep and Dreaming: Scientific Advances and Reconsiderations. Cambridge University Press, 2003.

Pagel, James.  The Limits of Dream: A Scientific Exploration of the Mind/Brain Interface. New York: Academic Press, 2010.

Solms, Mark.  The Neuropsychology of Dreams: A Clinico-Anatomical Study.  Mahway: Lawrence Erlbaum, 1997.



What the 2017 Nobel Prize in Medicine Means for Dream Research

This year’s Nobel Prize in Physiology or Medicine has an indirect but significant connection to dream research. For those of us who believe the scientific study of dreaming needs to be grounded in the evolutionary biology of sleep, the news of the 2017 Nobel should be a cause for celebration.

The prize was awarded to three Americans—Michael W. Young, Michael Rosbash, and Jeffrey C. Hall—in recognition of “their discoveries of molecular mechanisms controlling the circadian rhythm” (quoted from the Nobel committee’s public statement).  The key point, from a dream research perspective, is that these three investigators have shown we have a genetically hard-wired need to sleep.

What the 2017 Nobel Prize in Medicine Means for Dream Research by Kelly BulkeleyAll life on earth is fundamentally oriented toward the cyclical presence and absence of the sun. Every kind of living being has evolved internal clocks of approximately 24 hours in length that guide and regulate their biological processes and behaviors. These internal clocks are known as circadian rhythms, and they have long been observed as powerful factors in plant and animal life.  But only recently have the details of how these clocks work become known, thanks to the work of this year’s trio of prize winners.  Their studies, going back to the 1980’s, explain how circadian rhythms are programmed into the genetic activities of each cell at the molecular level.

The researchers focused on the circadian rhythms of the fruit fly (Drosophila melanogaster), as a model for understanding similar rhythms in the cells of other organisms.  They identified a specific gene in each cell whose activities oscillated in a 24-hour rhythm.  During the night, this gene encodes a specific kind of protein that accumulates in the cell.  It reaches a high point at the beginning of day, after which the gene shuts itself off and the protein slowly dissolves, reaching a low point at the beginning of night when the process repeats itself.  According to this year’s prize winners, the feedback loop involving this specific gene is a key part of the self-sustaining internal chronometer that shapes the functioning of all biological organisms, from flies to humans.

The committee that decides each year’s award made it clear in its statement that the work of Hall, Rosbash, and Young has important relevance for medical practice and social welfare:

“Our wellbeing is affected when there is a temporary mismatch between our external environment and this internal biological clock, for example when we travel across several time zones and experience ‘jet lag.’ There are also indications that chronic misalignment between our lifestyle and the rhythm dictated by our inner timekeeper is associated with increased risk for various diseases.”

Most commentators on the 2017 prize have highlighted this last point, about the diagnosis and treatment of illness.  Circadian rhythms influence the human body in numerous ways: via hormone levels, metabolism, temperature, and of course the sleep/wake cycle. Disruptions to the biological clock, whether through behavior (e.g., traveling across several time zones) or internal malfunctioning (e.g., a genetic mutation), can lead to a variety of serious health problems, including diabetes, obesity, cancer, cardiovascular disease, depression, bipolar disorder, memory defects, Alzheimers, and attention-deficit disorders.

The hope is that the more we learn about the elemental mechanisms of circadian rhythms, the better we can treat these problems, and prevent them from occurring in the first place.  Further research in chronobiology may show us there are better and worse times of the day for undergoing surgery, taking a medication, or participating in a psychotherapy session.

What the 2017 Nobel Prize in Medicine Means for Dream Research by Kelly BulkeleyIt may also give us new insights into the rhythms, cycles, and recurrent patterns in human dreaming.  Anything that gives a new understanding of sleep has the potential to provide a new understanding of dreams, since dreaming naturally emerges out of the state of sleep.  The ubiquity of dreaming in human experience throughout recorded history, in cultures all over the world, strongly suggests it is a phenomenon deeply rooted in our evolutionary heritage.  It strengthens the argument in favor of this idea to show, as this year’s Nobel winners have done, that the circadian rhythms guiding our waking and sleeping behaviors are encoded in every cell in our bodies.   There can no longer be any question that sleep is an absolutely vital feature of healthy human life.  The study of dreams can build on this solid foundation in evolutionary biology to explore in more detail what exactly is happening in the mind and body during sleep that contributes so powerfully to human health.

Note: this was originally published in Psychology Today on October 23, 2017.

How the Enlightenment Went Astray on Dreaming

 Enlightenment philosophers helped to spark the scientific revolution, but they were not always accurate or justified in their assumptions about dreaming.

How the Enlightenment Went Astray on Dreaming by Kelly BulkeleyThe English philosopher John Locke (1632-1704) played a vital role in promoting the ideals of the Enlightenment throughout Europe in the seventeenth and eighteenth centuries.  These ideals included a trust in human reason, a corresponding distrust in authority and received opinion, and a demand that people who make theoretical claims about nature, society, the mind, etc., must offer empirical evidence to back up their assertions.

These powerful principles of the Enlightenment set the stage for the scientific and technological revolutions that have changed the world over the past few hundred years.  The digital technologies we use and enjoy today have emerged directly out of this cultural lineage reaching back to Locke and his contemporaries.  Unfortunately, many Enlightenment philosophers made false and misguided claims about dreaming that have also shaped the lineage of our digital world.  If we want to create a healthy ecosystem for technologically enhanced dream exploration, we have to make sure we accept and trust the philosophical assumptions built into that ecosystem.

In his greatest work, An Essay Concerning Human Understanding (first published in 1690), Locke explains how the mind works and the process by which humans gain true knowledge about the world and themselves. Early in the book he delves into the topic of sleep and dreaming, because he recognizes that the functioning of the mind while awake is quite different from the functioning of the mind while asleep.  Locke is here confronting a key question that many philosophers before and after him have tried to answer: how does mental activity during sleep relate to mental activity while awake?

Unfortunately, Locke makes two false assumptions about human dreaming experience right at the outset, false in Locke’s own sense of being contradicted by empirical evidence.  These assumptions allow Locke to make several other claims that do not square with actual scientific research on sleep and dreaming.  I will address those further claims in a later post; here, I want to focus on the first two missteps, to see as clearly as possible where Locke initially goes astray.

The first comes in Book II, chapter 1, section 14, when Locke is discussing the nature of ideas and the issue of whether people can dream without remembering it.  In this section he asserts, “Most men, I think, pass a great part of their sleep without dreaming.” He then mentions a scholarly friend who never dreamed until he was in his mid-twenties, after a fever.  Locke goes on to say, “I suppose the world affords more such instances: at least everyone’s acquaintance will furnish him with examples enough of such, as pass most of their nights without dreaming.”

The empirical reality is more complex than Locke suggests.  Modern sleep laboratory research flatly contradicts his claim.  If someone sleeping in a laboratory is awakened at certain points in the sleep cycle, the chances are extremely high that the person will recall some kind of dreaming content.  Research on “non-dreamers” by James Pagel has shown the proportion of such people appears to be very unusual in the general population.  Dozens of studies have shown high levels of regular dream recall people from all demographic groups, all across the social and cultural spectrum.

Locke is right that many people rarely remember their dreams. But he is wrong to suggest that such people are somehow typical or normal, and he makes a major mistake in dismissing from his philosophical theory the mental activities of other people who do remember their dreams frequently.

It might seem unfair to judge Locke’s 17th century claims using 20th and 21st century research.  But he did mention, as evidence for his claim, the experience of one of his friends, which means he did at least this much investigation on his own.  Did he ever talk with anyone else about their sleep and dream experiences?  Did his circle of acquaintances include anyone who was a vivid dreamer? Apparently not, because Locke offered no other empirical support for his assertion than this one friend.  That strikes me as a weak foundation for building a larger argument about the nature of the mind.

The second assumption comes in section 16 of the same chapter, in which Locke describes the rational workings of the soul, which he insists occur only in the waking state:

“‘Tis true, we have sometimes instances of perception, whilst we are asleep, and retain the memory of those thoughts; but how extravagant and incoherent for the most part they are; how little conformable to the perfection and order of a rational being, those who are acquainted with dreams, need not be told.”

Locke offers nothing to support this claim; he suggests it is self-evidently true to anyone who is “acquainted” with dreams.  The assumption that dreams are characterized by rampant bizarreness continues into the present day, despite there now being several decades of solid empirical research showing that most dreams are, in fact, rather mundane and non-bizarre.  Most dreams, it turns out, revolve around familiar people, familiar places, and familiar activities.  Many dreams are indistinguishable from people’s descriptions of ordinary events in waking life. Of course there are strange and outlandish things happening in dreams, too, but research on dream content shows that such bizarre elements are not a pervasive and overwhelming quality of dreaming as such.

Again, Locke could have gained this insight if he had taken the time to talk with a few different people about their actual dream experiences.  It would not have been difficult for him to reach the empirical conclusion that dreaming includes a mix of both bizarre and non-bizarre elements. But Locke evidently felt his philosophical ideas required him to mute or eliminate entirely the possibility of significant mental activity in sleep, and so he did his best to discourage any further attention to this realm of the mind.

The irony is that this topic of bizarreness is actually an excellent example of where dream researchers have put Locke’s principles into practice, to wonderfully liberating effect.  Empirical studies of thousands of dream reports, using careful and systematic methods of analysis, have produced results that have overturned an authoritative but irrational assumption, transforming a false opinion into true knowledge.  Locke’s powerful method is an excellent means of refuting Locke’s weak assumptions.


Note: all the references to research findings are cited in Big Dreams: The Science of Dreaming and the Origins of Religion (Oxford University Press, 2016).

Keeping a Dream Journal

Keeping a Dream Journal by Kelly BulkeleyFor anyone interested in learning more about dreaming, I have a simple piece of advice: keep a dream journal.  Record your dreams on a regular basis, track their themes and patterns over time, and you will discover through your own experience many of the key psychological principles that shape the general process of dreaming.  

Beyond that, you may find your journal becomes a unique personal treasure—an invaluable source of insight into your most important concerns, activities, and relationships in the waking world.

You can start a journal at any time by making some retroactive entries.  For example, write out the earliest dream you ever remember, even if it was just a tiny fragment or wispy image.  There it is, the beginning of a dream journal!

Keeping a Dream Journal by Kelly BulkeleyHave you ever had a dream of flying, or being chased, or having an intense sexual experience, or seeing someone who is dead appear as if they were alive again?  Write those out, too.  Do you remember any recurrent dreams?  That’s very important to note, because recurrent dreams provide one of the best points of entry for a study of the long-term themes and patterns in your dreaming.

Recording especially memorable dreams from the past can be a good way of initiating a dream journaling practice going forward into the future.  Regular journal-keepers typically place a pad of paper and a pen next to their bedside, and when they wake up with a dream in mind they immediately write it down.  Because these bedside notes are often scrawled in semi-legible form, people will usually transcribe their dreams later in the day, into either better handwriting or a computer word processing system.

People today may want to use voice-to-text programs on their cell phones, which can be just as effective for those who know how to manage the technology.  Whatever method is used, the main goal is to set up a smooth, friction-free process to record as much of the dream as can be remembered, as soon upon awakening as possible.

Keeping a Dream Journal by Kelly BulkeleyIt is worthwhile to include information about one’s sleep patterns in the journal, since the conditions of sleep often make a significant impact on the dreaming process.  Ideally, each entry has the date, the location where you are sleeping, the time you go to sleep, the time you wake up, and a subjective assessment of the quality of your sleep (e.g., good, fair, poor).  If you do not remember any dreams for that night, at least you have gathered some useful information about your sleep.

If you do remember a dream, the key is to record it in as much detail as you can manage, including aspects of your internal experience (e.g., what you were thinking or feeling during the dream).  When people narrate their dreams they typically leave out numerous details that seem too trivial or obvious to mention.  Yet it is precisely these seemingly worthless details that often become highly significant in later explorations.

Take your time when initially recording a dream, and don’t worry if some aspects of the dream are vague, fragmentary, or impossible to describe.  Just write them out as best as you can.  All of these fragments can be sources of unexpected significance when you look at the dreams over time.

Keeping a Dream Journal by Kelly BulkeleyAlong with the dream report, a journal will typically include thoughts, memories, and associations that come to mind in relation to the dream.  These comments can be brief or very extensive, depending on your time and inclination.

I find it helpful to give each dream a title, as if it were a poem or short story.  It’s a way of crystallizing in a phrase or image something important about the dream.  The titles also make it easier to refer back to the dreams and sift through the series for recurrent threads of meaning.

One of the greatest values of a dream journal is the way it grows in power and depth over time.  The ever-expanding pool of dreaming experience creates an evolving network of meaningful connections.

Keeping a Dream Journal by Kelly BulkeleyCarl Jung, one of the pioneers of Western dream psychology, proposed back in the 1930’s that a series of dreams can provide an extremely useful means of exploring an individual’s life.  In his essay titled “Individual Dream Symbolism in Relation to Alchemy,” he presented his analysis of “over a thousand dreams and visual impressions coming from a young man of excellent scientific education.” (116) Jung described his method in these terms:

“[H]ere we are not dealing with isolated dreams; they form a coherent series in the course of which the meaning gradually unfolds more or less of its own accord.  The series is the context which the dreamer himself supplies. It is as if not one text but many lay before us, throwing light from all sides on the unknown terms, so that a reading of all the texts is sufficient to elucidate the difficult passages in each individual one… Of course the interpretation of each individual passage is bound to be largely conjecture, but the series as a whole gives us all the clues we need to correct any possible errors in the preceding passages.” (119-120, italics in original)

Jung’s insight has been actively explored by many people who study dream series over time, and in a future post I will say more about their findings.

For now, I will leave you with this thought: keeping a dream journal is a priceless gift to your future self.



C.G. Jung, Dreams (trans. R.F.C. Hull), Princeton University Press, 1974.

This post first appeared in Psychology Today, May 27, 2017.

The Study of a 32-Year Long Dream Journal

The Study of a 32-Year Long Dream Journal by Kelly BulkeleyThe latest series to be uploaded into the Sleep and Dream Database (SDDb) is the biggest yet: the “Brianna Journal 1984-2016,” 2,448 dream reports from a woman who kept a journal fairly consistently for 32 years.  This series offers an amazing opportunity to observe in unusually close detail the emotional contours of an individual’s life as she makes her way through a challenging and often dangerous world.

Brianna (not her real name) shared these dreams with me and Deirdre Barrett last year, which we initially studied for a presentation at the 2016 conference of the International Association for the Study of Dreams.  Using the word search functions of the SDDb, I performed a “blind analysis” on three subsets of Brianna’s dream journals, meaning I 1) tabulated the frequencies of word usage for several categories of dream content, 2) compared her frequencies with baseline averages for each category, and 3) made inferences, based on nothing other than her dream patterns, about her concerns and activities in waking life.  For instance, I inferred that Brianna is closer to her mother than her father, is interested in books and writing, is not interested in sports, and has significant involvement with issues of death and dying.  Brianna herself, who attended the conference presentation, confirmed these and other inferences, which helped demonstrate the general idea that patterns in dreaming can accurately reflect people’s waking life concerns.

Now I have finally uploaded the complete collection of dreams Brianna shared with me, which provides a broader overview of her dreaming experiences over the span of more than three decades.  I will share more details from my analysis at the upcoming 2017 IASD conference (held in Anaheim, California, June 16-20).  For now, here are some of the initial findings of my study of this remarkable series.

Length: This is a long series in at least three ways: total number of dreams (2,448), time span covered by the journals (32 years), and average number of words per report (292).  The median word length is 168 words, meaning half the reports are shorter than that, and half the reports are longer.  Looking at the distribution of word lengths in the series as a whole, 851 of the dreams have between 1 and 99 words, 794 of the dreams have between 100 and 299 words, and 803 of the dreams have 300 or more words.  A series with this many dreams at both the short and long ends of the spectrum poses special challenges for analysis.  For now, I will study the series as a whole, but at some point I will look at subsets of varying lengths (e.g., the dreams of 50-300 words in length, of which there are 1,192).

Cognition: The series as a whole has a remarkably high frequency of dreams with at least one word relating to thinking (71%), speaking (56%), and reading/writing (19%).  The dreams have lots of strange, irrational material, too, but much of the content is oriented around normal cognitive activities that are also important in her waking life (Brianna is, in fact, a literate, well-educated, and sociable person).  The high proportion of cognition references could be a result of the unusual length of her dreams, and/or it could be an accurate reflection of her waking personality.  Either way, this is a topic worth further investigation.

Death: One out of every seven (15%) of Brianna’s dreams has a reference to death.  That is quite high compared to other dream series I have studied, and it strongly suggests that death and dying are major concerns in Brianna’s waking life.  I know enough about her to confirm the general accuracy of this inference, and now I am curious to look more closely at how this theme weaves its way through her series as a whole.

Religion: The frequency of references to religion is also unusually high in this series, and the list of specific words used in the dreams makes it fairly easy to accurately infer that Brianna is Jewish.  In previous studies I have found that patterns in dreaming offer good clues to a person’s beliefs and attitudes towards religion.  The Brianna series seems to be another illustration of that premise, and through deeper analysis I hope to understand better how religious and spiritual themes in the dreams track with Brianna’s waking life interests, concerns, and experiences.

Note: this post was originally published in Psychology Today, March 10, 2017.