By the time they reach puberty, 75 percent of children who have questioned their gender will identify as the gender assigned at birth. However, those who identify as transgender in adolescence almost always do so permanently. Some people question the idea of providing puberty-blocking drugs when their side effects are not well understood. Yet denying transgender adolescents the ability to transition by withholding the drugs is unethical, say many people who are involved in this area of treatment. Failing to treat adolescents is not simply being neutral, they point out; it means exposing them to harm.
The Endocrine Society is working to update its guidelines for treating transgender youth. Stephen Rosenthal, a pediatric endocrinologist at the University of California, San Francisco, and a leader of the effort, expects that the guidelines, which now advise clinicians to withhold cross-sex hormone therapy until age sixteen, will allow greater flexibility, since many children enter puberty before age sixteen. Another change in guidelines may encourage children to live as the gender they identify with before puberty. This is an increasingly popular choice, says Diane Ehrensaft, a psychologist at the University of California, San Francisco, but it is controversial.11 Many psychologists discourage such social transitioning until the teenage years.
No matter what the approach to children’s gender identity, says bioethicist Simona Giordano of the University of Manchester, clinicians and families should help children to understand what they are experiencing. “Going through the social and physical transition is a long journey.”12
LOOKING AHEAD
Sexual differentiation of the brain is a rich and important field of study that is beginning to uncover the neural circuits governing gender-specific behavior, including cognitive aspects of behavior such as gender identity. We now realize, for example, that gender identity has a biological basis and that it can diverge from anatomical sex during prenatal development. Moreover, as Swaab and Garcia-Falgueras note, “There is no proof that social environment after birth has an effect on gender identity or sexual orientation.”13
A sharper focus on the biology of gender identity will give us a much clearer picture of the range of human sexuality and thus make us more understanding and accepting of transgender men and women. It will enable us to understand what a child means when he or she declares, “I am in the wrong body.” And it will enable us to help that child transition into adulthood.
11
CONSCIOUSNESS: THE GREAT REMAINING MYSTERY OF THE BRAIN
Francis Crick, the most important biologist of our time, devoted the last thirty years of his life to studying how consciousness arises from the workings of the brain. “[Y]our joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules,” Crick wrote in his 1994 book The Astonishing Hypothesis: The Scientific Search for the Soul.
Crick made relatively little progress in figuring out the mechanisms of consciousness, however, and today the unity of consciousness—our awareness of self—remains the greatest mystery of the brain. As a philosophical concept, consciousness continues to defy consensus, but most people who study it, and who have examined disorders of consciousness, think of it not as a unitary function of mind but as different states in different contexts.
One of the most surprising insights to emerge from the modern study of states of consciousness is that Sigmund Freud was right: we cannot understand consciousness without understanding that complex, unconscious mental processes pervade conscious thought. All conscious perception depends on unconscious processes. So as we delve into the mystery of consciousness, let us remember what our exploration of brain disorders has taught us about mental processing. We know that the brain uses unconscious and conscious processes to construct an internal representation of the outside world that guides our behavior and our thoughts. If the neural circuits of our brain are disordered, we experience the world differently in both degree and kind than other people do, on both conscious and unconscious levels.
The new biology of mind—the marriage of modern cognitive psychology and neuroscience—has created a new understanding of consciousness. As we shall see in this chapter, scientists have used brain imaging to explore different states of consciousness, revealing some basic ways in which our brain gives rise to our mind. Next, we revisit decision making, this time not from the perspective of faulty moral decision making, but from the broader perspective of how this critical skill makes use of both unconscious and conscious processing. Along the way, we learn what the unlikely collaboration of economics and cell biology has revealed about the rules that govern decision making.Finally, we consider the contributions of psychoanalysis to our understanding of mental processes, and how this mode of treatment can derive renewed power and purpose by engaging with the new biology of mind.
FREUD’S VIEW OF THE MIND
Freud divided our mind into conscious and unconscious components. The conscious mind, the ego, is in direct contact with the outside world through our sensory systems for vision, hearing, touch, taste, and smell. The ego is guided by reality, what Freud called the reality principle, and is concerned with perception, reasoning, the planning of actions, and the experiencing of pleasure and pain, qualities that enable us to defer gratification. Freud later realized that the ego also has an unconscious component, as we shall see.
The unconscious mind, the id, is not governed by logic or reality but by the pleasure principle—that is, by seeking pleasure and avoiding pain. Freud initially defined the unconscious as a single entity consisting largely of instincts that lie outside our awareness yet influence our behavior and our experience. He considered instincts to be the principal motivating forces in all mental functions. While Freud held that an infinite number of such instincts exist, he reduced them to a basic few, which he divided into two broad groups. Eros, the life instinct, covers all self-preservation and erotic instincts; Thanatos, the death instinct, covers all aggressive, self-destructive, and cruel instincts. Thus it is incorrect to think of Freud as asserting that all human actions spring from sexual motivation. Those that spring from Thanatos are not sexually motivated; moreover, as we shall see, the life and death instincts can be fused.
Freud later expanded his idea of the unconscious mind beyond the id, or instinctual unconscious. He added a second component, the superego. The superego is the ethical component of mind that forms our conscience. Freud completed his structural model of the mind by adding a third component, the preconscious unconscious, which is now called the adaptive unconscious. This third unconscious component is part of the ego; it processes the information necessary for consciousness without our being aware of it (fig. 11.1). Thus, Freud appreciated that a great deal of our higher cognitive processing occurs unconsciously, without awareness and without the capacity to reflect. We will return to the adaptive unconscious and its role in decision making later in this chapter.
Figure 11.1. Freud’s structural model of the mind
Much of Freud’s work was devoted to the id, our unconscious storehouse of socially unacceptable desires, traumatic memories, and painful emotions, and to the study of repression, the defensive mechanism that keeps these emotions from entering our conscious thought. Brain scientists are now beginning to examine the biological basis of some of our instincts, the powerful subterranean forces that shape our motivations, behavior, and decision making.
In studies of the neurobiology of emotional behavior, David Anderson of the California Institute of Technology, whom we first encountered in chapter 10, has found some of the biological underpinnings of two of the instincts that Freud observed—eroticism and aggression—as well as the fusion of those instincts.1
We have known for some time that the amygdala orchestrates emotion and that it communicates with the hypothalamus, the region that controls instinctive behavior such as parenting, feeding, mating, fear, and fighting (fig. 11.2). Anderson has found a nucleus, or clust
er of neurons, within the hypothalamus that contains two distinct populations of neurons: one that regulates aggression and one that regulates sex and mating. About 20 percent of the neurons located on the border between the two populations can be active during either mating or aggression. This suggests that the brain circuits regulating these two behaviors are intimately linked.
Figure 11.2. The two groups of neurons in the hypothalamus that regulate mating and fighting are closely linked.
How can two mutually exclusive behaviors—mating and fighting—be mediated by the same population of neurons? Anderson found that the difference hinges on the intensity of the stimulus applied to those neurons. Weak sensory stimulation, such as foreplay, activates mating, whereas stronger stimulation, such as danger, activates fighting.
The proximity of the regions concerned with sexuality and aggression, and the zone of overlap, help explain why these two instinctual drives can be so readily fused, as they are, for example, in sexual rage, the extra pleasure some couples derive from sexual experiences that follow an argument.
THE COGNITIVE PSYCHOLOGICAL VIEW OF CONSCIOUSNESS
Modern cognitive psychology has taken an approach to mind that differs from Freud’s. Rather than focusing on our instincts, it has focused on how our unconscious mind makes possible a variety of cognitive processes without our being aware of them. But before examining unconscious cognition, let us first consider how modern cognitive psychologists view consciousness.
When cognitive psychologists refer to consciousness, they are talking about different states in different contexts: awakening from sleep, being aware of an oncoming person, sensory perception, and the planning and execution of voluntary action. To understand these different states, we must analyze our conscious experience from two independent but overlapping perspectives.
The first perspective is the overall arousal state of the brain—for example, being awake versus being in deep sleep. From this perspective, level of consciousness refers to different states of arousal and vigilance, from awakening from sleep to alertness to normal conscious thought, whereas lack of consciousness refers to conditions such as sleep, coma, and general anesthesia.
The second perspective is the content of processing in the aroused state of the brain—for example, feeling hungry, seeing a dog, or smelling cinnamon. From the perspective of content, we need to determine what aspects of sensory information are processed consciously and what aspects are processed unconsciously, as well as the advantages of each type of processing.
These two perspectives are obviously related: unless we are in an appropriate state of wakefulness, we cannot process sensory stimuli, consciously or unconsciously. So we begin by considering the biology of wakefulness.
Until recently, wakefulness—arousal and vigilance—was considered a result of sensory input to the cerebral cortex: when sensory input is turned off, we fall asleep. In 1918 Constantin von Economo, an Austrian psychiatrist and neurologist who was studying the flu pandemic, had several patients who were in a coma before they died. When he carried out autopsies on their bodies, he found that their sensory systems were largely intact, but a region of the upper brain stem was damaged. He called this region the wakefulness center.
Von Economo’s finding was tested empirically in 1949 by Giuseppe Moruzzi, an Italian scientist of great renown, and Horace Magoun, a major American physiologist. In experiments on animals, they found that severing the neural circuits that run from the sensory systems to the brain—specifically, the circuits that mediate touch and sense of position—in no way interferes with consciousness, the wakeful state. However, damaging a region of the upper brain stem—von Economo’s wakefulness center—produces coma. Moreover, stimulating that region would awaken an animal from sleep.
Moruzzi and Magoun realized that the brain contains a system—which they called the reticular activating system—that extends from the brain stem and midbrain to the thalamus, and from the thalamus to the cortex. This system carries the sensory information from the various sensory systems necessary for the conscious state, and distributes it diffusely to the cerebral cortex (fig. 11.3). But while the reticular activating system is necessary for wakefulness, it is not concerned with the content of conscious processing, that is, with the content of awareness.
Figure 11.3. The reticular activating system distributes sensory information necessary for the conscious state from the brain stem to the cerebral cortex.
The content of awareness, our conscious state, is mediated by the cerebral cortex. John Searle, a professor emeritus of philosophy at the University of California, Berkeley, argues that although people sometimes say consciousness is hard to define, the commonsense definition is not so difficult. Consciousness is the state of awareness, or sentience. It begins in the morning when we wake up, and it continues all day until we go to sleep again at night, or otherwise become unconscious.
Consciousness has three remarkable features. The first is qualitative feeling: listening to music is different from smelling a lemon. The second is subjectivity: awareness is going on in me. I am pretty sure that something similar is going on in you, but my relation to my own consciousness is not like my relation to anybody else’s. I know you are feeling pain when you burn your hand, but that’s because I am observing your behavior, not because I am experiencing—actually feeling—your pain. Only when I burn myself do I feel pain. The third feature is unity of experience: I experience the feeling of my shirt against my neck and the sound of my voice and the sight of all the other people sitting around the table as part of a single, unified consciousness—my experience—not a jumble of discrete sensory stimuli.
Searle goes on to say that there is an easy problem of consciousness and a hard problem. The easy problem is figuring out what biological processes in the brain correlate with our conscious state. At present, scientists such as Bernard Baars and Stanislas Dehaene are beginning to look for such neural correlates of consciousness using brain imaging and a variety of other modern techniques. We shall return to their work later.
The hard problem, according to Searle, is figuring out how these neural correlates of our conscious state relate to conscious experience. We know that every experience we have—the smell of a rose, the sound of a Beethoven piano sonata, the angst of postindustrial man under late capitalism, everything—is produced by variable rates of firing of the neurons in our brain. But do these neural processes, these correlates of consciousness, actually cause consciousness? If so, how? And why does conscious experience require these biological processes?
In theory, we should be able to determine whether neural correlates cause consciousness by the usual methods: see if consciousness can be turned on by turning on the neural correlates of consciousness, and see if consciousness can be turned off by turning off the neural correlates of consciousness. We’re not quite able to do that yet.
THE BIOLOGY OF CONSCIOUSNESS
The nineteenth-century physiologist and psychologist Hermann von Helmholtz was probably the first person to realize that the brain assembles basic bits of information from our sensory systems and unconsciously draws inferences from them. In fact, the brain can make complex inferences from very scanty information. When you look at a series of black lines, for instance, the lines don’t mean anything; but if the lines begin to move—and particularly if they move forward—your brain instantly recognizes them as a person walking.
Helmholtz also realized that unconscious processing of information isn’t just reflexive or instinctive, it’s adaptive—it helps us to survive in the world. Moreover, our unconscious is creative. It integrates a range of information and delivers it to consciousness, using both information that is stored in memory and information that is currently being perceived. The brain takes this partial information, compares it to previous experience, and makes a more learned, rational judgment.
This was an amazing insight, and Freud picked up on it. He was interested in a group of diseases called the aphasias, various defects in the
capacity to speak, and he made a remarkable observation: we don’t consciously pick the words we’re going to use. We don’t consciously form grammatical structure. It’s all done unconsciously—we just speak. In fact, when we speak, we know the gist of what we’re going to say, even though we don’t know precisely what we’re going to say until we say it.
Similarly, when we look at a face, we don’t consciously see two eyes and two eyebrows and two ears and a mouth and say, “Ah, yes, that’s so-and-so.” Recognition just comes to us. Such high-level, adaptive thinking takes place in Freud’s preconscious unconscious. Thus, Freud’s question might really be, “What is the nature of all that integration that allows us to recognize something complex?”
To answer this question, look at figure 11.4. The left side seems to show a white square lying on top of four black disks; the right side seems to show four black disks, each with a piece taken out of it. Your brain, which is accustomed to making sense out of its perceptual experience, tells you that you are looking on the left at a white square lying on top of four black disks. But in fact that white square isn’t there. Your brain has created it. When you look at the four black disks on the right, you realize this. Moreover, your brain even creates a difference between the whiteness of the square lying on the disks and the whiteness of the background, a difference that also doesn’t exist.
Figure 11.4. The Kanizsa Square: conscious thought creates implied lines (left) where actual lines do not exist.
The cognitive psychologist Bernard Baars thought that the brain’s integration of conscious and unconscious mental processes—our mind’s interpretation of what we see—could probably be explored empirically if it could somehow be linked to developments in neuroscience. He therefore set out to do that.
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