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Sensing and Perceiving
the Physical World

December 27, 2023 by Joycelyn Campbell Leave a Comment

Sensation is the information the brain receives; perception is the result of the brain selecting, organizing, and interpreting this information. We don’t experience the sensory data directly; we experience the result of the brain’s processing of it.

As an aside, some people consider sensation to be a physical process, while perception is a psychological process. We may talk about and think about the physical and the psychological as being two distinct domains, but the brain that receives sensory data also does the interpreting that gives rise to perception. It doesn’t make a distinction between the physiological and the psychological in this or in any other regard.

An example of the difference between sensation and perception is prosopagnocia, a neurological disorder experienced by about one in 50 people, including neuroscientist Oliver Sacks. More commonly known as face blindness, it’s the inability to recognize faces, including one’s own in a mirror. Prosopagnocia is not a result of memory dysfunction or loss, impaired vision, or learning disabilities. The sensory data is input, so to speak, but the brain can’t interpret it so there is no perception.

While an interpretation—anyone’s, of anything—can be more or less accurate, it is always approximate. As Daniel Gilbert said, there isn’t a view from nowhere. All interpretations are based in a point of view from a particular brain at a particular point in time, so interpretations are inherently limited and slanted—and they vary both from individual to individual and within individuals at different times and under different circumstances.

“Normal” vs “Abnormal”

We tend to think that there is always a correct interpretation (perception) of an object or an event—that objects and events and their properties exist in an immutable state independent of us. And if we apply the appropriate lens, we believe we can achieve complete, or nearly complete, accuracy in our perception. At the same time, we tend to assume (operate as if) we are perceiving correctly.

So it’s tempting, not to mention less troublesome, to view others’ experiences or perceptions—especially when they don’t match ours—as missing the mark somehow. There’s an error in their, or their brain’s, calculations. One example is color blindness (also called color deficiency—see what I mean?), which has a genetic basis. Another example is tone deafness. There are many more, including:

Aphantasia: the inability to create a visual mental image of something that isn’t present.
Synesthesia: a sort of mixing up of sensory pathways in the brain (experiencing letters of the alphabet as having colors or associating a smell with a word).
Misophonia (aka soft sound sensitivity): a disorder in which certain repetitive sounds like gum chewing or paper crinkling automatically trigger powerful negative emotional responses.

And don’t forget prosopagnocia.

Clearly color blindness, aphantasia, synesthesia, misophonia, and other such conditions provide individuals with different experiences of reality than we might consider the norm. But does it make sense to say it’s wrong to experience the letter “M” as orange or the color green as smelling like cilantro? Richard Feynman had synesthesia and saw his equations in colors. Far from being wrong, this sounds pretty great to me, although that’s coming from a point of view of not having the experience.

Is there something wrong with that fellow over there who can’t mentally visualize a field of poppies or fluorescent purple mushrooms or a galloping horse? Aphantasia, unlike synesthesia, seems tragic to me; I can’t imagine I would be the same person if I didn’t have the vivid visual imagination I have. But how could one miss it if they never had it to begin with?

Is it wrong that the crinkling of paper or chewing of gum elicits a fight or flight response in that woman seated the next row over on the plane? She just seems to be overreacting and behaving rudely. Misophonia doesn’t seem desirable to me in any way. Of the few conditions I’ve included here, it’s the one that people who have it are perhaps most likely to view as being abnormal. That’s because it can cause problems beyond the purely sensory. It can create a lot of stress in personal relationships or interactions and in social settings. Many sufferers and the people they interact with tend to think it’s a psychological problem, meaning they could control their response if they tried harder. Or they need therapy. Nevertheless, it is an example of the brain sensing and perceiving (interpreting) sensory data and providing a resulting experience. It’s no different from any other instance of sensory processing.

External vs. Internal

The conditions described above all relate to the processing, interpretation, and experiencing of external sensory data. Enough research has been done on how the brain processes external sensory data to allow scientists to map the parts of the brain associated with them.

But there’s still much to learn about how the brain processes internal sensory information. How does it sense and organize feedback from internal organs to regulate hunger, satiation, thirst, nausea, pain, breathing, heart rate, blood pressure, etc.?

Scientists think that internal sensing may be more complicated than external sensing because, according to cell biologist Chen Ran:

[I]nternal organs convey information through mechanical forces, hormones, nutrients, toxins, temperature, and more—each of which can act on multiple organs and translate into multiple physiological responses. Mechanical stretch, for example, signals the need to urinate when it occurs in the bladder, but translates into satiation when it happens in the stomach and triggers a reflex to stop inhalation in the lungs.

How does the brain determine (interpret) sensory data so that we have an accurate enough experience to allow us to respond appropriately? Researchers do have some leads they’re following as they attempt to get a handle on the coding of internal senses throughout the brain. One motivation for this area of study concerns treatment for diseases that arise from internal sensory system malfunctions—i.e. abnormal feedback.

Of course this is a bit oversimplified since this so-called feedback involves sensation, perception, and interpretation. Feedback might relate to external or internal sensory data or what we think of physiological or psychological sensory data. No matter what it relates to, however, there’s feedback that occurs at the unconscious level and feedback that we are aware of at the conscious level. Most feedback occurs at the unconscious level and doesn’t make it into conscious awareness.

What We’re Aware of

When feedback does make it into conscious awareness, we have thoughts about it (our interpretation, usually in the form of an explanation).

We also experience an emotion, which neuroscientist Antonio Damasio would refer to as a homeostatic indicator. Emotions constitute a sort of personalized, constantly updated, running report to consciousness, indicating the status quo of the organism—as the brain sees it—both internally and externally. This is pretty damn amazing, when you think about it.

If the interpreter (see last post) is like a play-by-play announcer calling a game (your life) over the radio, emotion is your response to what you perceive to be happening both on the field (externally) and internally. There’s lots of information available to you. Are you tuned in?

Making Sense of
Sensory Information

December 21, 2023 by Joycelyn Campbell Leave a Comment

On a continuous basis, our brain receives multiple streams of exteroceptive sensory data about the physical world and other people. At the same time it receives a steady stream of interoceptive data about us: our physical, mental, and emotional states.

We don’t have the necessary machinery, and we wouldn’t even want it, to process carefully all of the amount of information that we’re constantly bombarded with. —Susana Martinez-Conde, neuroscientist

We have to filter it, sort it, and make sense of it. The lenses or filters through which our brain views and processes the streams of information include:

Our mental model, which consists of our personality (much of which is genetically determined), our beliefs, and our experiences.
Our current situation or circumstances.
What we know or don’t know that’s relevant in the moment.

All of this data processing takes place in an environment in which everything everywhere is in motion all the time, everything is a process, and everything is an interpretation.

Perception vs. Reality

However, the previous statement, while true, does not reflect our experience. Our experience is that the world is full of relatively stable things that are inherently meaningful (that is, we’re not interpreting them; they simply are as we perceive them to be).

My brain manages to create for me the experience of a constant, unchanging world through which I move. —Chris Frith, neuropsychologist

Our brain creates this illusion and many, many more, all of which we take for granted. But in fact, nothing is static, fixed, or permanent; nothing is unchanging.

Because nothing is fixed or unchanging, there are no things—tangible or intangible—there are only processes. Each of us is a process composed of multiple processes: purely physical processes (blood flow, digestion) as well as personal identity, emotions, memories, thoughts, and relationships. Processes, both physiological and psychological, are a result of the multiple interactions (motion) of complex adaptive systems. Each of us is continuously in the making, becoming, being constituted.

Identity as a programmatic—but not deterministic—process welcomes innovation through small, recurring changes. Under these metaphysical assumptions, a meaningful life is less about finding your ‘real’ self than expanding its boundaries. —Celso Vieira, philosopher

The solar system, climate, ecosystems, life cycles, plants, and also the device you’re reading this on, your vehicle, and the mug you drink coffee or tea from are processes, too. Some of them just happen to be much longer processes than the process of you or the process of me.

The Interpreter Explains Everything

As previously stated, in order to make sense of what is happening externally and internally the brain has to interpret the data it’s exposed to.

[Your brain is] locked inside a bony skull, trying to figure what’s out there in the world. There’s no lights inside the skull. There’s no sound either. All you’ve got to go on is streams of electrical impulses which are only indirectly related to things in the world, whatever they may be. So perception—figuring out what’s there—has to be a process of informed guesswork in which the brain combines these sensory signals with its prior expectations or beliefs about the way the world is to form its best guess of what caused those signals. The brain doesn’t hear sound or see light. What we perceive is its best guess of what’s out there in the world. —Anil Seth, Professor of Cognitive and Computational Neuroscience, University of Sussex

Since the conscious brain only processes about 40 bits of information at a time, it has no idea of what the unconscious is dealing with. Thousands (perhaps millions) of brain activities go on relatively independently of one another and all outside the realm of conscious experience. Once these brain activities are expressed [action, thought, emotion], the expressions become events that the conscious system takes note of and that must be explained.

That is the job of an interpreter, so-called, in the left hemisphere of the brain that essentially explains us to ourselves. The interpreter constructs theories about why we act and behave the way we do based on the limited and fragmentary data available to it. (It’s a little bit like listening to a play-by-play announcer calling a game over the radio.)

Our conscious life is essentially an “afterthought” constructed by the interpreter.

In truth, when we set out to explain our actions, they are all post hoc explanations using post hoc observations with no access to nonconscious processing. Not only that, our left brain fudges things a bit to fit into a makes-sense story. Explanations are all based on what makes it into our consciousness, but actions and the feelings happen before we are consciously aware of them—and most of them are the results of nonconscious processes, which will never make it into the explanations. The reality is, listening to people’s explanations of their actions is interesting—and in the case of politicians, entertaining—but often a waste of time. (Michael Gazzaniga)

If you recall from the last article, our brain is more concerned with utility than with accuracy. As a result, the most satisfying explanations are the ones that are simple, straightforward, and unambiguous. If we find a satisfying explanation, we accept it as true and move on. Consider the implications.

Our Brain Creates Our Experience

December 12, 2023 by Joycelyn Campbell Leave a Comment

As Rodney King famously asked in 1992:

Can we all get along?

While we may accept the notion that people disagree with each other all the time, we tend to believe and operate as if we’re right and the people with whom we disagree are wrong. We also tend to believe and operate as if we all have access to the same information and the same thinking processes, and if we just tried hard enough, applied ourselves correctly, we could get on the theoretical same page. We think the truth is out there, and we could all see it if we wanted to.

That’s very kumbaya, but since it’s not in fact the case, believing in and operating from that perspective is detrimental to our collective wellbeing and possibly to the survival of the planet.

We are wired not to experience the world as it is, but rather to apprehend it just accurately enough to function effectively in it. And contrary to the perception of many, including David Williams, as expressed in The Trickster Brain, this isn’t a design flaw.

Instead of being elegantly designed—the most efficient and marvelous epitome of creation—the brain is in many ways a botched construction job leading to endless contradictory impulses as the new and old parts of the brain attempt to work together.

Williams goes on to quote neuroscientist David J. Linden of John Hopkins as declaring the brain to be:

… a cobbled together mess…quirky, inefficient, and bizarre…not an optimized, generic problem-solving machine, but rather a weird agglomeration of ad hoc solutions that accumulated throughout millions of years of evolutionary history.

If you’ve tried to get your brain to do one thing, but it keeps on doing something you don’t want it to do, you might be tempted to agree with these assessments. Or if you’ve realized your memory of something is oddly distorted, missing altogether, or missing significant details. Or if you’ve been absolutely certain about something that proved not to be the case.

The Brain According to Linden?

Linden published a book in 2008 titled The Accidental Mind. I haven’t read it but part of his agenda appears to be a refutation of the idea that the brain was designed—something I’m totally in agreement with. I would probably enjoy the book: he has an engaging writing style and he covers topics of interest to me. But—and it’s a big but—you can’t describe the brain the way he’s described it (inefficient, not optimized, bizarre, etc.) unless you have in mind some other way you believe the brain should be.

I think that’s not an uncommon belief. It doesn’t, however, add anything useful to the conversation. We weren’t present throughout the course of the brain’s evolution. So how it developed, or how it should have developed not only can’t be known by us, it’s also essentially irrelevant. All we can do right now is acknowledge that this is the brain we have and put neuroscientists to the tasks of identifying how it work. Then once we figure out what we want, we can use the brain effectively to get more of that (individually and collectively) and less of what we don’t want.

We Perceive both Less than Is There, and More than Is There

It turns out that it’s actually more functional to have a brain that screens out from our awareness most of the sensory data it encounters and streams a stripped-down version into our conscious awareness. Our brain is more concerned with utility than with accuracy, which is why our experience is not an accurate reflection of reality.

Our experience of the world and our experiences of self within the world are forms of perception, a form of hallucination that’s incredibly useful in staying alive. We perceive both less than is there, and more than is there. —Anil Seth, neuroscientist

Consider the way the brain processes external visual stimuli and turns them into what we see. We have no conscious awareness of the brain’s complex visual processing operations that involve multiple pathways and the coordination of many different parts of the cerebral cortex; all we are aware of is the result, which seems much more straightforward than it actually is. We’re also not aware of our visual blind spot (everyone has one) because our brain does such a good job of filling it in with what we expect to see in that location.

You’re not perceiving what’s out there. You’re perceiving whatever your brain tells you. —David Eagleman, Incognito

The result is that in terms of what we see, both figuratively and literally, we miss quite a lot of detail, are easily fooled by visual and other illusions, fail to notice significant changes, and may not observe something that’s directly in front of us. This is somewhat shocking, really, given that over 10 million of the 11 million bits of information our brain processes moment-to-moment are devoted to visual perception.