A Sustainable Point of View

Depression, Part II: A Brain For Faith And Hope

Depression, Part II: A Brain For Faith And Hope

Human beings were the first organism to stop reacting to their circumstances, and start directing their own futures.1 But with possibility came risk. The gift of self-determination was bestowed with a brain that creates motivation by expecting good things just over the horizon. This is a brain that invented two unique things in the animal kingdom: a need for faith and hope; and a vulnerability to losing both.

 

What if depression was normal? This is a reasonable question if we A) question some of our assumptions about how and why the brain functions, and B) consider some more recent insights about the brain’s functions.

In our last post, we looked at how the brain was likely not a module for general intelligence; the brain just isn’t optimized to help people solve problems reasonably and rationally. Such a theory supposes that the brain sees the world as it is and responds accordingly. Instead, the brain that emerges in research is one that has to construct the world, representing the environment in the mind’s eye. It takes snapshots of everything it sees and stores them for two purposes: to A) predict the future based on the past; and B) to imagine what might lie beyond what can be seen and heard directly. These functions make the mind goal-directed: we deploy our representational imagination to picture rewards across space and time, and those mental pictures spur action designed to make those mental pictures come true. We know this in part because our motivational systems are tied directly to the reward value of those pictures, how many obstacles there are to realizing them, how close they are to becoming true and so on. And this means two significant implications for our well-being:

  • The need to anticipate future rewards—faith and hope—is key to the release of motivating neurochemistry in the brain
  • The real world can throw up numerous and nested obstacles to our dreams, thereby affects normal neurotransmitter release

A lot of people can intuit that the further away a positive future feels, the more depressed we feel. I think there is a lot of evidence that this is exactly right.

A Brain With One Foot In The Future

The subconscious brain makes constant predictions from memory, embedding mind and brain in a flow of a perceived time and narrative.2 In that context, we can understand why the neurotransmitter dopamine has come to be seen as a chemical of anticipation.3 Dopamine not only feeds off our perceptions of world, but perceptions of events that haven’t yet happened. Contrary to popular belief, dopamine is not controlled by some isolated physiology (in the sense that depression isn’t caused by some genetically-caused “chemical imbalance,” the evidence for which we can’t seem to pin down)4; rather, dopamine is controlled by our brain’s predictions about the future. It is controlled by the mind.

Robert Sapolsky has looked at the chemical and shown that it does not do what we think it does.

 

 

Dopamine does not compel us hedonistically toward “frivolous rewards.” Rather, a prediction of something rewarding in our future—anything from food to sex, social contact to stimulating experiences, new ideas to creative expression, a political utopia or a religious afterlife—releases dopamine in our synapses to motivate or “energize” behavior in pursuit of that thing. From a hierarchy of needs perspective, we might say we need rewards and we need the dopamine they provide, because the anticipation of the reward is necessary to activate the basic motor controls of our bodies. Expectation is necessary for physical movement. Knock out the dopamine receptors in a rat, for instance, and it will die of starvation next to a heaping bowl of delicious rat food.5

Most of us have probably never starved to death next to our food (a pretty decent analogy to depression, actually), but many will recognize the power of anticipation more generally over our sense of willpower. Consider a phenomena called “ratio strain.” The D1 dopamine receptor circuit in the brain has a job: to try to predict how much work will be required to attain some future reward in order to decide if the reward is “worth it.”6 When the ratio of work to reward is too high, the body simply doesn’t release the motivating neurotransmitter, and it becomes nigh impossible to, say, get out of bed while imagining another day at a thankless job. The name ratio strain comes from how the original behaviorists brought it about, by straining the ratio of work-to-rewards in rats (in this case the amount of lever-presses the rat had to crank out for food pellets).7 Invariably researchers would reach a point where the rat would throw up its tiny arms and stop working, because the rat subconsciously calculated that the predicted reward wasn’t worth the predicted amount of work. Essentially, willpower has a breaking point that exists entirely in our subconscious predictions.

The need to perceive something good down the road to motivate ourselves in the here-and-now, is the neural substrate of what we call hope and faith. On a grand scale, Robert Sapolsky argues that this mechanism has driven human beings to conjure visions of overstuffed afterlives full of hedonistic rewards to keep pulling us forward in the present. On a smaller scale, this is why people obsess over the new thing they’re going to buy, or the cigarette they’re going to huff down on break, or life with the girl they don’t actually stand a chance with: their fantasies “energize” their willpower and mobilize their agency. This need can run deep, leading people to sustain motivation with an air of desperation when things look bleak—shopping therapy while broke; reaching for another Twinkie; buying an expensive pack or bottle of vice. That’s because the most intelligent, far-seeing people aren’t trying to sustain willpower through one day of school, work or family, but the thousands of days that make up our bigger goals and paths, each with its own recurrent forms of ratio strain pushing back.

All this is to say that hope and faith aren’t lost in the mind, but to the body too. If we keep holding out for a reward that never comes, if we keep working toward a motivator and don’t get it, it can lead to what behaviorists call extinction.8 When a conditioned behavior goes unrewarded for long enough, our brains simply stop producing dopamine in response to the stimulus, and that conditioned behavior stops being produced; the rewarding rush of anticipation stops being felt. A related concept is learned helplessness: struggling hard for a reward that proves elusive again and again, essentially teaches our brain that the dopamine rush doesn’t predict the arrival of a reward, and we lose a sense of control over that goal.9 Eventually, feeling “helpless” means that no matter what we do, we can’t feel optimistic about attaining the reward and we stop feeling the sense of positive anticipation for it. These are entirely plausible mechanisms whereby someone might reach for a reassuring idea, only to find that they don’t feel the reassurance; the idea rings hollow and unmotivating.

When we try to extrapolate how these mechanisms add up to affect someone’s mental health, the key element that requires somewhat more empathy is to imagine the overall balance of a person’s rewards and motivators. Experiencing ratio strain is manageable, but what if someone experiences multiple, nested forms of ratio strain? In other words, what if they need money to get the car to get to the job to get the education to get the career that will allow them to stop working three jobs paycheck to paycheck? Or what if someone is hopeless about more things than they are hopeful? What if being stuck in their small rustbelt town limits so much possibility, waiting for the next football game just doesn’t cut it anymore?

It is when lots of small deficits add up to make for an overall sense that the world has little to anticipate just over the horizon (say, in conditions of youth, poverty, or something as mundane as being new in a town, etc), that spells significantly less dopamine in the present, and can make for anhedonia (the diminishing of pleasure), avolition (the inability to motivate), and apathy (the inability to care).10 Now their imagination projects forward in time and comes up empty; they can no longer imagine a meaningful interaction with the world in the foreseeable future. This translates to even less motivation, pleasure and engagement, which can feed back on itself, making our future predictions even more dim. This sounds an awful lot like the feedback loop pop-culture has called the downward spiral, and that metaphor fits—a downward trajectory that begets itself, biologically, psychologically and socially.

All this may sound familiar to people who work three jobs just to stay afloat, without time to date and find romance, haunted by debt they can’t dream of paying down, or otherwise lay behind patterned barriers of finances, education, time and circumstance. We’re talking about people whose environments are stacked against them. Of course, not all people we know in these circumstances will become depressed. The common refrain is that this is a difference of genetics, a tempting explanation that puts the onus of suffering on the sufferer. But before we get to genetics, we should consider a few other variables in which the world can sow the seeds of depression. That will be the topic of the next post.

  1. Depression, Pt I: A Brain For All Occasions, by MA Kinney
  2. On Intelligence, by Jeff Hawkins
  3. Dopamine Enhances Expectations of Pleasure in Humans, by Sharot, et al.
  4. Is Depression Just Bad Chemistry, by Hal Arkowitz
  5. A Molecule of Motivation, Dopamine Excels At Its Task, by Natalie Angier
  6. Dopamine D1 receptors in the anterior cingulate cortex regulate effort-based decision making
  7. ScienceOfBehavior.com: Ratio Strain
  8. Wikipedia: Extinction (Psychology)
  9. Wikipedia: Learned Helplessness
  10. The Dopamine Side(s) of Depression, by Scicurious

 

Pt III of Several, Coming Soon