Young zebra finches learn what songs to sing from their parents and siblings. For these birds, native to Australia, producing songs is not innate; the notes are rehearsed over and over when the birds are awake and also in their sleep. As David Peña-Guzmán explains in When Animals Dream: The Hidden World of Animal Consciousness,Footnote 1 “The pattern elicited by the act of singing while awake was an exact structural replica of the pattern elicited during the period of sleep marked by sudden bursts of high-level neural activity.”
What fascinates Peña-Guzmán about this study is not only the finding about finch song rehearsal itself but also the interpretation put forth by researchers Amish Dave and Daniel MargoliashFootnote 2 to explain it: The replay of the rehearsal during sleep occurs without the finches being aware of it. The birds are, these researchers claim, analogous to laptops; just as laptops are oblivious to the fact that Microsoft Word or some other program is running, so the finches are oblivious to activity in their brains during sleep.
In direct contrast to that computationalist interpretation, Peña-Guzmán offers a brilliant account of the zebra finches, indeed of all animal dreamers, as conscious, creative beings. It is an account that doubles as an urgent call to recognize and reverse our society’s failed animal ethics. As an anthropologist and animal activist already convinced of the richness of animals’ interior lives, I thrillingly discovered new worlds of meaning and motivation in Peña-Guzmán’s insistence that dreams are not only “mental works of art that the mind creates for itself” but also a “hitherto unrecognized moral force” that should shape how we see and treat animals.
No one who has watched a cat or dog who, in sleep, vocalizes with a whine or growl even as their eyelids, whiskers, or paws twitch could conclude that dreaming is unique to humans. Coming to the book, I knew, as well, that baby elephants who have witnessed their closest family members slaughtered by poachers sometimes have bad dreams. Yet still I wondered, might a firm rejection of human exceptionalism be compatible with the possibility that highly imaginative, narrative-based dreaming is unique to humans?
Consider some of the dreams I experience repeatedly and remember (no points here for originality; these themes are classic). In one scenario, I am scheduled to give a scholarly talk at a conference. Entering a room packed with people, I realize that I am completely unprepared because I have no notes, PowerPoint slides, or any notion of what to say. Or sometimes I find myself standing in a classroom in front of students, with no notion of how to go about teaching a coherent class. Perhaps worst of all is the dream in which I am riding in a car that is moving backward at a fast speed, on ice. The vehicle is out of control, and as the certainty of coming spectacular crash washes over me, I can do nothing to stop it. These dreams become for me deep wells of dread and anxiety.
As it turns out, dreaming rats punched a hole right through any notion that animals’ dreams do not match up to humans’ dreams. I was stunned to learn from Peña-Guzmán the ability of electroencephalography (EEG), functional magnetic resonance imaging (fMRI), and positron emission tomography (PET) scans to isolate neural circuits involved in dreaming and to compare individual animals’ neural dream signatures with those from daytime activity. Researcher Freyja ÓlafsdóttirFootnote 3 and colleagues tasked rats to run a maze with access to food treats blocked off, at which, in Peña-Guzmán’s words, they “stared longingly.” Next, the rats napped. Finally, they ran the maze again with the blocked area opened, but—alas—the food treats were removed.
I want to quote at some length Peña-Guzmán’s explanation of what the researchers found:
“As the rats shuttled up and down the previously cued arm, the researchers recorded hippocampal spike events and found that the pattern associated with physical exploration of this specific part of the maze was identical to the one they recorded while the rats were napping. The same hippocampal cells fired – and fired in the same order – when the rats slept after seeing but not physically exploring the cued arm as when they explored this arm after their nap. This established beyond doubt that the hippocampus was doing the same thing at only two moments: when the rats slept after having seen the reward, and when they explored the space that, much to their disappointment, no longer contained it. The rats, in other words, remembered aspects of their physical environment that piqued their emotional interest and actively imagined a ‘future experience’ in which their desires were fulfilled. This act of imagination took place while they were fast asleep.”
This finding blows me away. This rich internally generated narrative arc effectively contests any reductionist view of rats’ lives as driven by rewards and punishments.
Seeing rats’ cognitive and emotional complexity in this way only makes it harder to read about experiments led by researcher Bin YuFootnote 4 in which rats are made to participate in painful experiments to startle awake from nightmares. Peña-Guzmán minces no words in describing this research. He refers, correctly, to one group of rats “physically tortured” by electric shocks of increasing intensity applied to their sensitive feet and a second group “psychologically tortured” by being forced to observe the sufferings of the first group. Individuals in this second group “watched helplessly as their friends jumped, struggled, screamed, and eventually uncontrollably urinated and defecated from the pain.”
Three weeks later, the rats were brought back to the location of the earlier experiment. They simply would not or could not move; they froze in place. Later, after the rats fell asleep, they woke up in a panic. EEG data “in the moments leading up to startled awakening demonstrated that the rats were experiencing nightmares triggered by traumatic memories.” Their amygdalae had become disinhibited and, stuck in a hyperfunctional state, caused the rats to feel relentless fear.
This example of rat torture haunts me. It profoundly supports Peña-Guzmán’s argument that it is past time to reform how mainstream science experiments (deemed acceptable by committees charged with welfare oversight) cause animals to suffer.
As its subtitle indicates, the book explores animal consciousness in some depth. Peña-Guzmán offers an innovative tripartite model that rejects any monolithic consideration of consciousness in favor of a focus on subjective, affective, and metacognitive types of consciousness. Dreaming animals show subjective consciousness because an individual’s body occupies “a specific spatiotemporal location” as they dream. Affective consciousness, which many but not all dreaming animals have, reflects the fact that, as we have just seen, dreams are not always emotionally neutral. It is far more challenging to evaluate the presence or absence of metacognitive consciousness, such as seen in lucid dreaming, in animals. Might some animals experience perceptual incongruity, an awareness of a gap between what happens in their everyday lives and in their dreams? Peña-Guzmán thinks perhaps so, though he admits this is speculation. I am not sufficiently conversant with neuroscience to evaluate the details of this model, but do applaud the fact that emergent from it is the clarity that a dreaming individual, no matter the species, is an individual with consciousness.
Not all examples offered by Peña-Guzmán are equally effective. He opens the volume with a focus on the day octopus Heidi, who, thanks to the television show Nature, “became a viral sensation overnight.” Her explosive color changes during sleep—“from a smooth and consistent alabaster white to a flashing yellow with blotches of mandarin orange,” for instance—track color changes she experiences during waking-hours foraging. I do not doubt that Heidi dreams. But in calling for a revolution in our understanding and treatment of animals, it is not enough to describe Heidi as “living with” biologist David Scheel at his private residence. It misses the mark to describe an octopus confined to a small tank, deprived of bodily autonomy or any significant degree of choice, as “a charming mix of roommate, companion animal, and research assistant.”
Peña-Guzmán accepts at face value published accounts of the western lowland gorilla Michael’s use of signs in American Sign Language to report (“Bad people kill gorillas”) the content of his nightmares, which apparently stem from witnessing poachers kill his mother. However, journalists’ accounts of conditions experienced by gorillas like Michael held in captivity at Penny Patterson’s Gorilla Foundation have raised serious questions of linguistic interpretation and basic ethics.Footnote 5 , Footnote 6
Humanity’s treatment of animals must not be entirely dependent on their ability to dream. In their article “Regularly occurring bouts of retinal movements suggest an REM sleep–like state in jumping spiders,” researchers led by Daniela Rößler report:Footnote 7 “Eye movement patterns during REM sleep have been hypothesized to be directly linked to the visual scene experienced while dreaming—begging the deeper question of whether jumping spiders may be experiencing visual dreams.” How tantalizing! I am confident that more and more animal dreamers will be revealed in future years. Nonetheless, the strong probability remains that not all animals dream, and yet almost all deserve our protection and kindness. I hedge here with that “almost all” because ticks, fleas, and mosquitoes are animals too; a consideration of what protection and kindness for them would look like is outside the scope of my writing here.
My take-home message about When Animals Dream is, however, offered without qualification: This book is brilliantly conceived and argued. Ground-breaking in its conclusions, it deserves to be read across disciplines in the humanities, social sciences, and sciences, most urgently of all by biomedical researchers and anyone else who dismisses or ignores the moral meaning of complex animal interiority.Footnote 8 As Peña-Guzmán puts it, the time is now to recognize “the extraordinary world-building power of animals” and, especially for animals seen as food, clothing, tools for biomedical science, or sources of entertainment, act accordingly.
