Saskia de Vries is a neuroscientist at the Allen Institute in Seattle Washington. Raised in California, she bounced back and forth between the west and east coast for her training, moving to Seattle in 2012 when she joined the Allen Institute. Her research has focused primarily on visual physiology, how the cells and circuits in our eyes and brain transform the visual world into perception. She is also very active in Open Science, creating tools and infrastructure to make scientific data and knowledge more transparent and accessible. She’s a Ruling Elder in the Presbyterian Church (USA) and is active in her community at Northminster Presbyterian Church. She regularly preaches on the intersection of science and faith. She lives in Seattle with her partner, Colleen, and their very needy dog, Hobbes.
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Background music by Lexin_Music: Inspiring East.
Saskia de Vries
[00:00:00] Intro: Welcome to the Holden Village Podcast. Holden is a community of education, programming, and worship located in the remote wilderness of the Cascade Mountains. These snapshots provide a glimpse into the learnings taking place in our community. Let's tune in to this week's highlight.
[00:00:22] Dev: Welcome to another episode of the Holden Village Podcast. We are in week five of the 2023 summer program and I'm with the wonderful Saskia de Vries. How would you like to introduce yourself?
[00:00:36] Saskia: I guess I'm a neuroscientist. I've spent the last 25 years studying visual physiology of how the neurons in our eyes and our brains receive light and construct our perceptions of the world and shape our behaviors.
[00:00:57] Dev: Why sight...out of all the senses? Why did you focus on that?
[00:01:24] Saskia: I mean sight kind of grabbed me. I guess I'd say I really just fell in love with visual processing when I was a college student...and I talked about this in my first session about when I was an undergraduate, I was studying molecular biochemistry. So, you talk a lot about different molecules and how they're structured and their shapes an, taking organic chemistry and talking about all these bonds and electrons and things like that. And really the questions that drew me in were questions about behavior and questions about how the outside world gets in.
And so when I learned about photo transduction, which is when light gets absorbed by a molecule and it breaks just this one bond and flips the configuration of that one bond...and it causes this cascade of molecular events that then create an electrical signal that then creates our perception of the world.
It literally just blew my mind in that moment. And I told them, I was like, I learned this on October 26th, 1996...it was a singular moment of awe and fascination. And the thing is there are those moments in other sensory modalities as well...in hearing we've got these really cool (they're called hair cells)...it's a mechanical process that kind of triggers channels to open and creates electrical currents.
But at the same time...we're very visual animals and our visual experience is a lot easier for us to articulate, than say, our olfactory experience. Auditory, we can articulate it pretty well, but there's a lot of things about it that are kind of hard to unpack and unravel. And so it really kind of captures the imagination and we feel a lot...it feels very accessible.
The reality is we don't actually have access to a lot of it and there's a lot more construction going on with our perceptions of the world...and it's not just this literal transformation of light into image. And so that's maybe a little misleading, but it makes it feel very accessible.
[00:03:29] Dev: Absolutely. I love that you brought in the auditory component as well because part of my passion is acoustics. I'm curious with vision...so you mentioned the mechanical translation that happens in sound. It goes through like three other translations as well. So, no one actually knows what we're hearing with that raw acoustic data. Is that the same with visual as well? Does it go through that many translations before it becomes an electrical signal?
[00:04:02] Saskia: So it's a pretty fast from a photon of light to an electrical signal. But that electrical signal gets changed so much in both the retina and then also in the brain. But there's less. So with hearing, there's like a bunch of bones that are actually moving and then it's vibrating against a membrane. Right? There's a lot of mechanics involved, whereas with light it's pretty direct.
[00:04:26] Dev: So do you believe the reasons we were designed this way, however you want to frame that...is for stability purposes...is for an ability to be able to function?
[00:04:38] Saskia: Absolutely. I think that the purpose of our visual system...it's easy and nice to kind of talk about our perceptual experience, but the purpose of our visual system is to allow us to survive. And it's to help us, you know, navigate our environment to locate food...to avoid predators...to avoid our obstacles and danger. And some of those processes are conscious and some of them are not conscious. And there's aspects of our visual experience that don't enter into that perceptual awareness.
For part of my training, I worked with fruit flies and they have really cool visual behaviors. They're easy to study...they're also really small so sometimes they're hard to study...but there's a lot of tools working with them genetically that are really useful for kind of dissecting how these circuits work. But the thing with fruit flies is when we're studying their visual system, we never talk about what the fly sees or what the fly thinks. It's not like the fly decided to turn right. It's just we showed the fly a bar that moved right and the fly turned right.
And we don't really use that language of the fly thinking. I have no idea what the conscious experience of a fly is, right? But when we talk about mammals, we talk about them seeing things...thinking things...deciding things...and so I think for me...that experience working with flies...where it was less about what is their conscious experience...what is their perceptual experience...and simply how do these different visual stimuli shape their behavior?
When I came back to working with mammals, I brought a bit of that with me and so I can still ask questions about their perception, but I can't actually ask a mouse what it's seeing. I can really only access its behavior and I can make assumptions about what it's seeing, but I really don't know.
And it helped me kind of disassociate the two a little bit more. There are, you know, a lot of fascinating questions about how our perception is created, but there's other questions about vision in terms of how does it guide and shape our behavior...allow us to find our ways of interacting with the world that are beneficial and help us survive.
[00:06:46] Dev: If you're looking at something...let's say like you look at a tree...you have all these mental associations with that tree...almost to the point where you're not even seeing the tree. Like we often like go through the world not even perceiving things correctly just because we have all these mental blocks that go along the way.
[00:07:06] Saskia: Yeah, we have a lot of strong...what we call priors...and we use those often to our advantage in order to be able to use small snippets of sensory information to be able to figure out where we are or what things are around us.
But they can also get in the way. One place where I see this actually...so my partner who's here with me...she's an artist and a long time ago she was teaching me how to draw. The thing about it that really struck me...and it's not like I'm great at it...but what I learned kind of in that process was when you're looking at an object that you're trying to draw...it's not about seeing that this is a vase and then thinking...okay, this is what a vase looks like and how do I represent that?
But it's really looking at that object in front of you and kind of forgetting that it's a vase, but noticing the actual angle of the edges and how the shadow is falling here and how the interaction of the light on that object in that moment. And you almost have to like...I think sometimes you can kind of like physically just block part of it so you're not thinking about the whole in order to really get the details of the actual thing you're looking at.
And so that was really revelatory for me is to see that when you kind of step back and try to conceptualize this is what I'm trying to draw...it gets in the way. Whereas if it's what is the actual perception in that moment? How is the light exactly hitting that surface and reflecting off that surface? And how do I represent that? And if I put it all together now it looks like the vase that I'm sitting in front of.
[00:08:42] Dev: That's a wonderful and delightful example of that. Thank you. Our summer theme is Eden is calling. What does that mean to you in the context of your work?
[00:08:54] Saskia: So actually tomorrow's session, I'm going to talk about twilight...there's an important thing about it. So in the creation myth in Genesis one...the six days of creation...on the first day, God creates light and dark and separates light and dark.
And then there's evening and morning and evening and morning...twilight is when light and dark come back together. So it was really striking to me in that passage of this first act of separating and then immediately bringing them back together. Visually, that time of twilight is actually kind of really fascinating because there's a lot of changes in the light that happened during twilight.
And there's a lot of animals who are active during twilight, right? So we're diurnal animals...we're active during day. Bats are nocturnal. They're active at night, right? And then there's crepuscular animals who are active during dusk and dawn...and so the mice that I study are crepuscular...the fruit flies that I studied are crepuscular and a lot of birds are crepuscular.
There's actually just a ton of activity and life at that phase of our day...and it's a pretty substantial part of the day, right? It's not a fast transition and so the types of things that happen during twilight...the one that we kind of think of most is just that light gets dimmer. Say if we talk about twilight at sunset, the reverse happens at sunrise. But you know, like as the sun is setting, we have less light and things get darker and there's changes in how our visual system processes information...when there's bright lights and when there's dim lights.
But we're seeing this substantial change in the luminance, but there's other changes that happen too. And so one of the big changes that is that the color of the light that we see in our environment shifts really down to the blue and then to the ultraviolet range of the spectrum. And this is because the sun is below as it sets...it's below the horizon. So you're not getting the direct ray and it's reflecting off the atmosphere. And when it reflects, it reflects from in that bluer end of the spectrum. We can see blue. We can't see ultraviolet. Most crepuscular animals have photoreceptors that are sensitive to ultraviolet light.
[00:11:11] Dev: Lucky!
[00:11:12] Saskia: Yeah! I don't know if you've ever seen images where people have taken pictures of flowers with a camera with a lens for ultraviolet light? They're really cool patterns that are reflecting ultraviolet light that we can't see, but the bees...the birds...they're able to see.
And so a lot of times it's like landing strips that are like...this is where the nectar is. It's like right here in the middle, but we don't have access to that. We don't see that, but all these crepuscular animals...particularly during twilight...when there's a lot more ultraviolet light in the atmosphere...are able to see different patterns in petals and flowers.
There's different animals that reflect their skin or their shells for insects...their exoskeleton reflect ultraviolet in different ways. And so that makes like forging for fruits or for insects a different type of...basically just adding a different color that is more detectable. We don't have access to that, but there's animals who are really well adapted for that.
There's another change in light during twilight, which is in the polarization of light. We aren't able to detect changes in polarization, but there are animals whose photoreceptors will respond when light is polarized. And so polarization is...light is a wav...and that wave can be kind of aligned to a plane. That's when it's polarized...or it can kind of like spin around and not be aligned to a single plane in space...and then it's uncollared. So we will see polarized/unpolarized light as the same, but there are animals whose photoreceptors will be able to discriminate the angle of the polarization of the light or know if it's unpolarized.
So for instance, water reflects light at a particular polarization. And so when there's a lot of strong polarization in the light...which happens again during twilight...it's easier for animals who could have polarized vision to see water...whether it's a drop on a leaf or like a lake of water. And you see that water is a really important resource for every living being...to be able to find and access water...and so that really helps them to detect that.
Again, different berries and insects reflect polarized light in different way...like if you look at the back of a beetle through a polarized filter...you'll see really kind of cool and radiance patterns...and so if beetles are the food that you're looking for...it's easier to see them when the light is polarized in the sky, which happens during twilight. There's this really rich visual experience that happens during twilight...that isn't for us.
[00:14:00] Dev: Why? I want it!
[00:14:01] Saskia: Yeah. I mean, it's a bit of a bummer. There's plenty of visual experience that works just fine for us. We've got plenty of daylight hours and colors that we're able to perceive, but there's also this time of day that isn't for us...it's for someone else...and this notion of being in between...of not fitting into clean definitions...this is actually like a very kind of queer space.
And the thing that really resonates for me is that what this tells me is that from the very first day of creation, there has always been queer space in our world. And this isn't a new thing...we're not making exceptions...we're not changing the rules. The world was created with and for queer people...with beings that don't fit into any category. And it can be all sorts of categories. It can be categories of ability. It can be categories of ethnicity or race or the things that bring you joy that nobody quite understands...that don't fit into any label.
There's always been a space in our world for everybody, no matter what label or lack of label we can find. And so for me, that is the thing about twilight that's so great. It's not really for us as humans, but it's like this important space that we need to kind of hold and maintain and celebrate because it makes space for beings that we don't understand. We can't see that polarized light and yet it's there. Right?
[00:15:33] Dev: I love when people can merge science with social justice as well. I feel like people can access it a little easier. Is that a part of your world as well?
[00:15:45] Saskia: It does then start to touch on social justice. Because social justice is a crucial part of my faith tradition. It kind of is a lens of opening it up and changing that conversation about what is this story telling us? Why is this an important myth that we continue to tell? We often talk about myths being like falsehoods and fabrications that we're kind of using to hide the truth.
And that's not what myths are. Myths are stories that we tell that contain some truth that is important that we want to continue telling. And for me, that important thing is that from the very first day...there's always been an in-between space. There's always been an evening and morning of every single day of creation.
They keep saying and wanting to be able to take this passage...a lot of people want to ignore and discard, but it's telling us something important about our lives...and about how we can better recognize and see one another. that makes me excited.
And I don't know per se if I've have been pushing it in a social justice way. I have a very dear friend from college who is a biracial trans-man...and that really resonated with him and he's doing a lot of work in his community in Missouri. And that metaphor has really kind of transformed a lot of his activism. And that has meant a lot to me to be able to be like...all right...yes...this is helping.
[00:17:09] Dev: What is your connection to Holden?
[00:17:11] Saskia: So I have a friend who's been coming here for a few years. I think like six or seven times, so not one of these people who's like...I started coming in the seventies. He and his family have been coming for I think six or seven years...and he was on teaching faculty a couple of seasons...and he told me about it a while ago. Then this past year, he kind of reminded me about it and I think also reached out to Emer Kate and suggested that she connect with me.
So that was what got me up here and it's really delightful. I mean, I think there's something really powerful about the invitation of friends and there was a moment kind of when we were kind of coming up here where I'm like...I have no idea what we're stepping into...what this is going to be like. And it's been absolutely delightful. It's been just a really beautiful week...an exciting week. And so I'm really grateful to kind of be let in on this little secret of the world.
[00:18:09] Dev: Would you ever live in an intentional community like this?
[00:18:13] Saskia: The idea of intentional community is exciting to me. I kind of feel like this phase of my life, it might be harder. I could have very much have imagined myself as a 20-year-old being really excited to live in this type of community for a longer period of time. There's also intentional community and remote intentional community and that that remote part might be a little harder.
One of the things I love...like I'm a pretty urban person. I mean, I love being out in nature, but I grew up in cities. I live in cities. I really like how cities are, but one of the things I'm really fascinated by is that it actually kind of shows you how cities work by being in this remote village because everything has to be done by the people who are here.
And so it makes you very aware of what it means to deal with your garbage and what it means to be able to have power and all of these things...and the work that goes into maintaining and doing all that. So I love hearing stories from some of the more long-term Holden people...the people who've been coming year after year. And they'll talk about the things that have changed and how they needed to fix this and that...decided they wanted to bring in something new and what it took to be able to do that. And that is kind of exciting to me to kind of see all those pieces working.
[00:19:26] Dev: Yeah, I totally agree. Slightly off the cuff question, but something I ask everyone...what makes you laugh? A lot of the people that come here do such amazing work...that can sometimes get very serious. So I'm curious how people balance out and bring levity into their lives. Because that's also another part of the Holden experience is...Holden hilarity is what we call it.
[00:19:49] Saskia: I like a good dad joke.
[00:19:50] Dev: A good dad joke. Excellent. That's fantastic.
[00:19:54] Saskia: But also sometimes they're just awful. Right? I mean, humor is great. And humor I think is a really important part of how we work and how we relate with people. And I'd like to be able to find those moments of levity...I think it's a really crucial way of connecting with people. When jokes work between people, it's because you have some shared understanding and some shared ideas about things...and so the things that make me laugh...our godson is nine years old and like...he's kind of in those peak kind of dad joke stages.
[00:20:36] Dev: That's why we have children, you know, it's for the dad jokes.
[00:20:38] Saskia: Except there's a phase where children have terrible jokes, right? Like, they don't understand the structure...they don't actually understand the humor. They know there's a cadence, but they don't know what the actual funny thing is.
[00:20:52] Dev: Any final words that you'd like to say?
[00:20:55] Saskia: I would conclude with it's great to continue to be able to be curious and to explore...and I think that's one of the joys of being here is that there's just this freedom to let go of everything going on outside in the world. I have no idea what's happening in news this week.
[00:21:14] Dev: Congratulations.
[00:21:15] Saskia: I'm really grateful. I'm a little nervous to go home and like open up the news.
[00:21:20] Dev: Down Lake is on fire.
[00:21:23] Saskia: But it gives you a bit of a freedom to kind of ask questions...and think...and have curiosity...and let that guide when there's opportunities to see the world through somebody else's lens. To kind of take that and embrace it and run with it...and see what you can learn...and then to start thinking about what the lenses that you see the world through. So sometimes understanding your own lens helps to understand what might I be missing...or why am I noticing that particular detail? It's nice to be in a place where you can take a little moment to think about that.
[00:21:58] Outro: Thanks for joining us. Be sure to view the links in the description for more information or visit our website to find out more about the village. We hope you will make a pilgrimage to Holden. Blessings and peace to you.