I’ve heard that actors, when required to cry during a scene, often call upon the memory of a pet’s death to open the waterworks. Not only is the pain of this loss acute and deep, it retains an immediacy and power for many of us. Like in the Mr. Bo Jangles song (“The dog up and died, he up and died . . . after 20 years he still grieved”), the emotions aroused by losing a beloved pet have a curious tenacity.

Without fail, every time I hear that song, I do cry. The reason is twofold: I am feeling the loss of my own pets anew, but I am also identifying with Bo Jangles, whose heart, I imagine is broken. The love we feel for pets is pure and uncomplicated, and it directly touches our universal longing for unconditional love.

We begin life with the innate need to merge with our caretakers. The first three months of life, sometimes referred to as “the fourth trimester,” are marked by a symbiotic bond between mother and child, one in which the infant has no sense of being a separate person. The process of psychological development depends on that merger, and the subsequent separation and individuation that occur. This was termed by researcher Margaret Mahler and her colleagues, as “the psychological birth of the human infant,” in their eponymous 1975 landmark book. Relative health and/or pathology both depend on the successful navigation of this process.

And the process is lifelong. At each juncture of our lives, the separation “crisis” is re-negotiated and refined. For example, even a secure toddler will have separation anxiety when she starts school, and echoes of this process reoccur throughout the life cycle: going to camp, college, even getting married can reawaken the primary anxiety of separation from that initial symbiotic bliss.

Small children often use teddy bears, blankets, etc. as “transitional objects” as a way to soothe themselves during separation. The object comes to symbolize the mother’s soothing function, and helps calm the child’s fears as she learns to internalize it and learn to calm herself even when the mother is absent. A key aspect of this process is the projection of our fantasies onto the object. Its power is endowed by our own wishes to see it as we wish to see it.

Pets are like living transitional objects. We are able to project our fantasies onto them, and as they are unable to contradict us, they can attain enormous emotional force in our lives. One family I knew had a guinea pig whose feelings were interpreted differently by each person in the family. One child felt the animal was always hungry; another thought he was nervous; the mother imagined he was lonely; and the father felt sure the guinea pig felt trapped. All were clearly projections of their own issues onto the pet.

Of course, dogs and cats are less inscrutable than rodents, often displaying their own distinct personalities. Yet they still leave lots of room for projection and anthropomorphizing. Listening to the way an owner talks to their pet can reveal a great deal about their internal life. Even the choice of pet, and the breed itself, reflects our self-image. The choice of small dogs, big dogs, elegant ones, classics, comical dogs, even mangy ones reflect something we see in ourselves.