Carl Jung, the Swiss founder of depth psychology and early proponent of dream analysis, was the first to seriously study what he called "big dreams" -- vivid and memorable dream experiences that occur rarely, but when they do, can have a lasting impact on an individual's life.

Jung noted that while most dreams are fuzzy in our memory and quickly forgotten, others remain imprinted in our minds for months or even years. So why do we intensely remember a few striking, symbolic dreams?

In his new book "Big Dreams: The Science of Dreaming and the Origins of Religion," dream researcher and theologian Dr. Kelly Bulkeley picks up this inquiry where Jung left off. Bulkeley scientifically explores these types of vivid, imaginative dreams as a "primal wellspring of religious experience," and argues that they play a universal role in the evolution of spirituality and religion across cultural contexts.

Dreams represent a “neurologically hard-wired capacity” for greater self-awareness, creativity and insight into the spiritual dimensions of life, according to Bulkeley. By integrating the scientific and spiritual aspects of dreaming, therefore, we might be able to learn more about why we dream and what our dreams tell us about the imaginative powers of the mind.

HuffPost Science caught up with Bulkeley to learn more about the science of "big dreams," the role they've played in the evolution of religion and spirituality, and how anyone can prime the mind for these kinds of dream experiences.

Why do a few vivid dreams sometimes have a profound impact on us, while the rest quickly slip away?

The basic idea is that most of our dreams seem to be relatively everyday, mundane kinds of things that don't last in our memory long, if at all. Whereas a few dreams -- maybe only one or two in a lifetime -- have a much greater combination of intensity, emotion, imagery and waking-life impact. Carl Jung felt that it was important to acknowledge that as a different kind of phenomenon in the dream world, so he coined this term "big dreams." So that's been my research: What are these big dreams? How do we operationalize that insight of Jung's?

Because dream studies tend to focus on the dreams that people happen to have while in a sleep lab, we don't really look at "big dreams." What do we miss by only looking at more mundane dreams?

Most modes of dream research have tended to be conducted in a sleep laboratory, asking college students to write down their most recent dreams. That's great data and there's nothing wrong with that, but it's looking at what Jung called "little dreams."

By focusing on everyday dreams over big dreams, researchers miss the opportunity to learn about how the dreaming mind operates at maximal intensity and creativity. To use a weather analogy, it's great to know average temperature and rainfall, but to really understand the weather one needs to look at the extremes, too -- big storms, droughts, blizzards, heat waves, etc. There's a practical value here, too, for therapists in particular: Everyday dreams can reveal everyday concerns, but big dreams tend to address deeper life issues with powerful emotions attached, which makes them directly relevant to therapists and counselors.

You're looking at both the scientific and the spiritual aspects of dreams. What are the unique benefits and challenges of this kind of integrated approach?

One of the things that appealed to me about dreams is that they're this amazing amalgam of physiological brain-based processes as well as psychological and even spiritual processes. They're kind of a nexus of the mind and the body and the spirit. To understand what's going on in terms that we can gain more insight from, my approach is trying to bring together insights from all those different disciplines. There are challenges ... everyone's coming at it from a different angle but they're pointing to similar conclusions.

How have dreams played a role in the origins of various world religions?

Dreams -- and big dreams in particular, which tend to be the most celebrated in spiritual and religious contexts -- seem to connect the dreamer with something greater than him or herself, something more powerful and wiser. They generate a sense of awe and wonder, which is a classic quality of mystical experiences.

Dreams ... seem to connect the dreamer with something greater than him or herself, something more powerful and wiser." Dr. Kelly Bulkeley

Big dreams tend to involve visitations from people who have died, which naturally lend themselves to thinking about the afterlife, the soul, heaven and hell -- lots of deep existential questions arise from these dreams. Then there are mystical dreams of flying, traveling to otherworldly realms, visiting places of astonishing beauty or symmetry. These are themes that lend themselves to religious and spiritual kinds of interpretations and uses.

Dreaming naturally generates those kinds of experiences -- and how can religions help [but] draw upon those experiences and weave them into their beliefs and practices?

What does the universality of these experiences tell us about the workings of the human mind?

What I've tried to do here is try to link big dreams to aspects of our evolutionary psychology as humans. Dreaming at one level is a powerful expression of the deep evolutionary imperatives of our species -- reproduce, survive, adapt, spread -- and the deeper scientific argument of the book is that these dreams aren't just silly nonsense. They're actually grappling with the great issues and challenges each member of the species faces, in my view, in beneficial ways.

Like any evolutionary argument, if you see something throughout a species in all settings and contexts, it makes you think, that seems to be a feature -- not just a random bug in the system. It's something integral to how that species thrives and prospers.

Are there methods that anyone can use to increase their likelihood of having big dreams?

One thing would be to thing back through your life and ask if you'd had a big dream before. If so, it's worth writing that down in a journal. Some sort of reflection on an earlier big dream opens the door to [a] new one -- it's like the idea of 'Build it and they will come.' You open your awareness. There's a fair amount of research that shows that simple methods of paying attention to dreams increase dream recall.

If you want to remember more dreams, pay attention to your dreams and more will come. A pad and paper next to your bedside is a good way to go.

Can dreams enhance our thinking and creativity?

Dreaming in some ways is what helps humans be humans, in terms of being creative, flexible, adaptive problem-solvers. We're not the fastest runners and we don't have the sharpest claws, but we're smart and we're adaptive.

My short definition of dreaming is imaginative play in sleep. In dreaming, we let the imagination run wild and play. We explore possibilities -- things that worry us and things that intrigue us -- and it's part of the 24-hour mind. It's not like the mind only works part of the day. In my view, part of the role of dreaming is to keep things loose and flexible and alert, so that we're ready when we wake up for whatever happens.

This interview has been lightly edited for length and clarity.