6 ms·

Hits the nail on the head. Our brains are back propagating, recursive neural networks that are consistently making predictions about the next input in the strea

by ghthor 9y ago

Hits the nail on the head. Our brains are back propagating, recursive neural networks that are consistently making predictions about the next input in the stream of input signals as it changes over time. When the prediction results are correct we save a fuzzy recording of the higher-order-pattern that resulted in our correct prediction. Each time our predictions are correct that "memory" is reinforced so we're able to make faster predictions, at earlier points in the pattern. I hypothesize that the source of most anxiety or nervousness stems from our brains making no correct predictions in that moment. This is supported anecdotally by my patterns for overcoming social interactions that used to make me anxious that I've now become comfortable with. My brain now makes enough correct predictions that I don't feel the need to leave the situation. I hypothesize that part of why I started acting on my transgender feelings was because I'd become so uncomfortable in my own body that my brain wasn't able to make accurate predictions about the sensations coming from my within. This is supported anecdotally by the following. I started 2 activities when I accepted my desire to transition to female. Both were touted at reducing the feelings of un-comfortableness in my own body. Female to Male hormone therapy and taijiquan. Both produced lots of new feelings for my brain. Both gave me a sense of agency over my own body, the understanding that I have the ability to shape my body into what I want. In the end I stopped transitioning because taking the hormones(mostly the T blocker) isn't known to be healthy for the body(Liver/Kidneys). Taijiquan is almost unanimously a positive source of change in ones health for the rest of their lives therefore I choose taijiquan and a long healthy life over my desires to have female genitals. Practicing Taijiquan makes me feel better, and in regards to my gender dysphoria taijiquan has cured it; I am very comfortable with my male genitals now that I'm able to make enough consistent predictions during sex to remain engaged with the situation and remain turned on. Edit Addition: I'd like to state that I still identify as a cross dresser and I'm comfortable saying that love certain parts/styles of womens fashion and accessories. Example, I love long flowing skirts. As a society I feel we should reassess men wearing skirts as it is much healthier for our genitals.

johndotsun 9y ago
>Hits the nail on the head. Our brains are back propagating, recursive neural networks that are consistently making predictions about the next input in the stream of input signals as it changes over time. When the prediction results are correct we save a fuzzy recording of the higher-order-pattern that resulted in our correct prediction. Each time our predictions are correct that "memory" is reinforced so we're able to make faster predictions, at earlier points in the pattern. I'm not sure that I could ever be so confident in anything as you are to be stating so unequivocally how the brain works given the track record of previous attempts to model brain function and the current state of neuroscience.
- ghthor 9y ago
  When I get feelings for and idea I let my mind thoroughly explore its possibilities. The work of Jeff Hawkins has heavily influenced how I meditate and observe my brain leading to consistently better mental health management. While I say this with such certainty, I know it is a hypothesis that's unproven by studies. But it just feels satisfyingly right from my observations of myself and the world around me. My model of the world is always changing and I'm open to being disproved and accepting new ideas, and ultimately, reality as we understand it.
  - johndotsun 9y ago
    I'm personally very conscientious in avoiding forming models of the world around me by incorporating what my brain decides "feels satisfyingly right" based on my own anecdotal observations. Humans have been operating as you describe for thousands of years but it was only when some of us began replacing pure cognition, feelings, and intuitive satisfaction with systematic empiricism that we began to make significant headway in understanding the world.
    - ghthor 9y ago
      I personally view the feeling of satisfyingly right as the touch point begin empirical analysis. Given the amount of effort required to conduct a study, I wouldn't personally put forth the effort for anything that didn't feel satisfying right, as I'm sure most of our famous scientists of the past guided there own interests and motivations. You shouldn't be afraid of feeling ways about ideas, you should be afraid of becoming attached to a hypothesis, but you could still use an unproven hypothesis to guide your own life.
      - johndotsun 9y ago
        I agree that the intuitive feelings can be a good starting point for better analysis, but I don't then incorporate those ideas into my model of the world without verifying them to a sufficient degree of rigor. If the subject is something like, "what food is in this unlabeled tin can" then sufficient rigor is opening the can and then I can reasonably assume that the rest of the identical unmarked cans in the box it came from are probably more of the same. If the subject is, "how does the human brain work" I'm going to require a hell of a lot more investigation and evidence before I can say that a theory that I've come up with is correct. Extremely intelligent people have been working on this problem for many decades and while we've learned some things we're not yet anywhere close to understanding how the brain works in even animals with much simpler brains. Because of this, I am very skeptical of any theory I as a laymen could come up with regardless of how much research I read from scientists working in the field, and I certainly wouldn't consider a "feeling of satisfyingly right" as being meaningful at all in my consideration of what model is correct and which is not correct. I'm also not "afraid of feeling ways about ideas", I just don't built my models of the world based on feelings unless I'm building a model of my feelings.
dboreham 9y ago
Isn't this called "Cognitive Dissonance" ?
- ghthor 9y ago
  I would say no. Cognitive Dissonance is more about someone saying they believe something but then their actions don't reflect that belief. An area of Cognitive Dissonance that I have, I know that I need to take more consistent breaks from computer work more often to prevent pain from repetitive stress injuries, But I don't.
  - Bakary 9y ago
    Akrasia is a good word for this concept.
  - matt4077 9y ago
    The term itself is concerned more with a person's own experience of the world. What you're describing, i. e. his actions/words as observable by others, is probably closer to 'hypocrisy'. "Cognitive dissonance' is far less judgemental–its considered to be an essential mechanism of learning.
  - islanderfun 9y ago
    aka "Practice what you preach?"
  - Digit-Al 9y ago
    Your description is not quite right: https://en.wikipedia.org/wiki/Cognitive_dissonance https://en.wikipedia.org/wiki/Cognitive_dissonance Your example is not cognitive dissonance. To be that, not taking the breaks would have to go against a deeply held belief, and make you feel uncomfortable.
erikpukinskis 9y ago
I really hope we can break down the rules tying gendered expressions to sex. I can see the power in the archetypes, but assigning them at birth is really cruelty. It's a shitty time. I don't know how old you are, but I really hope 30 years from now I meet you somewhere and we can look back and see that the world has moved on. I'm trying to keep a promise to myself that I'll keep trying. Sometimes I think we're closer to that future than we think.
- ghthor 9y ago
  We're so close. ^_^ We need to make sure the internet and this magical way of archiving and sharing information can't be taken from away from us unless the whole civilization is crippled or destroyed.
  - erikpukinskis 9y ago
    Well, I don't share your fear because I think the whole of mandatory centralized civilization should and will be destroyed, and replaced with equivalent voluntary microcivilizations. I also think anyone trying to control the flow of information is fighting a losing battle, so I don't lose sleep over that one either. Censoring the internet is already difficult and economically costly. Once we have Ethereum on a mesh network of $5 handheld computers, the difficulty goes up probably two orders of magnitude. And we're what, 10 years away from that? I also think corporations are trying to lure you into thinking they control things, when in fact they don't have any real power any more, we (people with a little credit and a computer) have it all. We are just brainwashed into thinking we need them, so we're not exercising most of our power. What if Comcast et al stopped offering you service entirely? Would you be lost? Would you be able to find the internet again?
    - ghthor 9y ago
      That's actually a scary scenario. I'd be stuck relying on my neighbors for "pirate" wifi which would be unreliable unless I was able to run some QoS and setup their router. If that failed I'd be SoL because I don't know how use HAM radio and access the packet network. What other options or ideas am I missing? Excluding the cell carrier network.
searealist 9y ago
I'm just trying to help: https://en.wikipedia.org/wiki/Schizotypal_personality_disorder https://en.wikipedia.org/wiki/Schizotypal_personality_disord...
- ghthor 9y ago
  That's actually pretty interesting. I'd say that I hit a lot of those checkmarks, but I've never had problems making friends and developing deeper relantionships. On the other hand, I've had incredible difficulties developing my software engineering career because of my difficulties is trusting my employer and co-workers. I'd say I struggle to build relationships in competitive environments.
  - beaconstudios 9y ago
    I think that's quite a common experience - I tend to find that I develop small pockets of mutual trust (usually <5 people) in highly political and competitive companies. I think aggressively metricised environments are very hard to feel comfortable in because you don't feel like you have a stable footing.
_98fj 9y ago
> I hypothesize that the source of most anxiety or nervousness stems from our brains making no correct predictions in that moment. Since fight/flight behaviour is regulated by the amygdala and basal ganglia, you can say: Anxiety stems from our amygdalae getting started up, because they sense a threat where none is, and effecting inappropriate behaviour thereafter. Actually, the threat is often correctly sensed, it's just the behaviour (running away, attacking, feigning death/freezing) that's not useful in the modern world. The therapeutically interesting question is how to change that. Compared to the rational parts, those emotional mechanisms are much deeper and better wired to the rest of the brain. At the same time they aren't very sophisticated. Some people refer to them as "reptilian complex". We can't adjust emotions directly and in general we have to wait much more time (think: weeks, sometimes months) to let new ideas like not being afraid of something sink into the subconscious. But knowing and accepting that makes it possible to grow.
- smallnamespace 9y ago
  > it's just the behaviour (running away, attacking, feigning death/freezing) that's not useful in the modern world. The therapeutically interesting question is how to change that. Finding ways to channel your 'negative' energies into positive, constructive action is basically the foundation to every self-help book ever written. I'd wager that the first, and often most difficult step is to identify a path that will lead to eventual success (eliminating the threat). Unfortunately, sometimes that's simply not possible. Like, if you don't have a degree, have a family to support, and the factory you work at is closing down soon, your brain is going to 1) correctly identify a major threat and 2) try to spur you into action. But what if there's no clear path open that will avert the disaster? I'd wager at least some of this is responsible for the rising rates of chronic illness, drug abuse, and suicide in many parts of the US. Modern life often constantly exposes us to and reminds us about threats that we can personally do little about.
  - coldtea 9y ago
    >Finding ways to channel your 'negative' energies into positive, constructive action is basically the foundation to every self-help book ever written. That, soppy quotes and a desire for a quick buck.
marmaduke 9y ago
There're real neuroscience studies that could accompany the theories here. It's a shame none of them have come up in this discussion.
rootlocus 9y ago
> Our brains are back propagating, recursive neural networks that are consistently making predictions about the next input in the stream of input signals as it changes over time. Neural networks are a simplistic model of how our brain works, not the other way around.
agumonkey 9y ago
Your first sentence reminds me of the bliss of music. Music is a subtle and sophisticated "plane" say, and predicting where you can walk while keeping some harmonic relationships and sensing it at the same time makes me think that it's a bit like aligning prediction, models and sensation into one.
andrepd 9y ago
> Our brains are back propagating, recursive neural networks (...) Why so you say that? Or knowledge of the brain is still very very dim and rudimentary, and ANNs are simple mathematical models (inspired by brain neural networks, to be sure) to fit parameters to data. It's a bit naive, in my view, to assert such a simplistic answer to a very hard question without conclusive evidence for anything.
- matt4077 9y ago
  There's a saying in neurophysiology that predates neural nets: "Neurons that fire together, wire together". It's not exactly the same as back-propagation, but it's quite close.
  - Balgair 9y ago
    In fact, it's the exact opposite of back propagation. Long/Short Term Potentiation is all about the synaptic buton of the firing cell, not the receiving cell (or that mess of the astrocytes). https://en.wikipedia.org/wiki/Long-term_potentiation https://en.wikipedia.org/wiki/Long-term_potentiation
andrepd 9y ago
> Our brains are back propagating, recursive neural networks (...) Why so you say that? Or knowledge of the brain is still very very dim and rudimentary, and ANNs are simple mathematical models (inspired by brain neural networks, to be sure) to fit parameters to data. It's a bit naive, in my view, to assert such a simplistic answer to a very hard question without conclusive evidence for anything.
imranq 9y ago
When the steam engine was invented, we thought of the brain as a series of pressures. When we discovered electricity, we thought of the brain as wires. When we got the internet, we thought of the brain as a network. Now sure neural networks have the word "neuron" in them, but they are far far away from the wetware that produced this conversation.
- peter303 9y ago
  Also clockworks, when they became sophisticated
- deleted 9y ago
  [deleted]
- Bulkington 9y ago
  Tangential, but worth sharing for HN crowd, I think. Psychologist Jung and physicist Pauli worked very closely together to explore the unity of mind and matter. Some of their theories are, frankly, difficult to grasp and so intuitively unfathomable they're easy (for me) to just dismiss. But when you consider that Pauli could conceive the idea of the neutrino, impress Einstein with a critique of general relativity, etc., then maybe he's just onto something. The collection of letters referenced below is really wonderful. https://www.brainpickings.org/2017/03/09/atom-and-archetype-pauli-jung/ https://www.brainpickings.org/2017/03/09/atom-and-archetype-...
mrkgnao 9y ago
For others who don't know: taijiquan is more usually called tai chi.
nojvek 9y ago
Thanks for sharing your story. That's awesome. Tell us more about tajiquan? Is it like tai chi? How long have you been doing it and what were the major effects ? While I can't imagine what you've been through I have spent a lot of time pondering over what it'd be like to be a woman.
magic_beans 9y ago
Do you think if you had been born into a society where male and female roles weren't so binary, and you as a man were allowed to, for example, wear long flowing skirts and other "female" clothes, that you would have felt such a strong need to transition to female? I sometimes think our culture's binary approach to gender creates a sense of imbalance and alienation for those people who do not fit into the binary. It saddens me that these people see no other choice but to loathe their sex, and make such drastic and medically questionable efforts to transition to the binary other. I think there must be a way for people to learn to love how their bodies are, even if that sex does not necessarily match the cultural mandate of the "corresponding" gender. It's a hard fight, but it's a fairer fight to fight the culture, rather than one's own body.

by ghthor 9y ago

johndotsun 9y ago

>Hits the nail on the head. Our brains are back propagating, recursive neural networks that are consistently making predictions about the next input in the stream of input signals as it changes over time. When the prediction results are correct we save a fuzzy recording of the higher-order-pattern that resulted in our correct prediction. Each time our predictions are correct that "memory" is reinforced so we're able to make faster predictions, at earlier points in the pattern. I'm not sure that I could ever be so confident in anything as you are to be stating so unequivocally how the brain works given the track record of previous attempts to model brain function and the current state of neuroscience.

ghthor 9y ago
When I get feelings for and idea I let my mind thoroughly explore its possibilities. The work of Jeff Hawkins has heavily influenced how I meditate and observe my brain leading to consistently better mental health management. While I say this with such certainty, I know it is a hypothesis that's unproven by studies. But it just feels satisfyingly right from my observations of myself and the world around me. My model of the world is always changing and I'm open to being disproved and accepting new ideas, and ultimately, reality as we understand it.
- johndotsun 9y ago
  I'm personally very conscientious in avoiding forming models of the world around me by incorporating what my brain decides "feels satisfyingly right" based on my own anecdotal observations. Humans have been operating as you describe for thousands of years but it was only when some of us began replacing pure cognition, feelings, and intuitive satisfaction with systematic empiricism that we began to make significant headway in understanding the world.
  - ghthor 9y ago
    I personally view the feeling of satisfyingly right as the touch point begin empirical analysis. Given the amount of effort required to conduct a study, I wouldn't personally put forth the effort for anything that didn't feel satisfying right, as I'm sure most of our famous scientists of the past guided there own interests and motivations. You shouldn't be afraid of feeling ways about ideas, you should be afraid of becoming attached to a hypothesis, but you could still use an unproven hypothesis to guide your own life.
    - johndotsun 9y ago
      I agree that the intuitive feelings can be a good starting point for better analysis, but I don't then incorporate those ideas into my model of the world without verifying them to a sufficient degree of rigor. If the subject is something like, "what food is in this unlabeled tin can" then sufficient rigor is opening the can and then I can reasonably assume that the rest of the identical unmarked cans in the box it came from are probably more of the same. If the subject is, "how does the human brain work" I'm going to require a hell of a lot more investigation and evidence before I can say that a theory that I've come up with is correct. Extremely intelligent people have been working on this problem for many decades and while we've learned some things we're not yet anywhere close to understanding how the brain works in even animals with much simpler brains. Because of this, I am very skeptical of any theory I as a laymen could come up with regardless of how much research I read from scientists working in the field, and I certainly wouldn't consider a "feeling of satisfyingly right" as being meaningful at all in my consideration of what model is correct and which is not correct. I'm also not "afraid of feeling ways about ideas", I just don't built my models of the world based on feelings unless I'm building a model of my feelings.

dboreham 9y ago

Isn't this called "Cognitive Dissonance" ?

ghthor 9y ago
I would say no. Cognitive Dissonance is more about someone saying they believe something but then their actions don't reflect that belief. An area of Cognitive Dissonance that I have, I know that I need to take more consistent breaks from computer work more often to prevent pain from repetitive stress injuries, But I don't.
- Bakary 9y ago
  Akrasia is a good word for this concept.
- matt4077 9y ago
  The term itself is concerned more with a person's own experience of the world. What you're describing, i. e. his actions/words as observable by others, is probably closer to 'hypocrisy'. "Cognitive dissonance' is far less judgemental–its considered to be an essential mechanism of learning.
- islanderfun 9y ago
  aka "Practice what you preach?"
- Digit-Al 9y ago
  Your description is not quite right: https://en.wikipedia.org/wiki/Cognitive_dissonance https://en.wikipedia.org/wiki/Cognitive_dissonance Your example is not cognitive dissonance. To be that, not taking the breaks would have to go against a deeply held belief, and make you feel uncomfortable.

erikpukinskis 9y ago

I really hope we can break down the rules tying gendered expressions to sex. I can see the power in the archetypes, but assigning them at birth is really cruelty. It's a shitty time. I don't know how old you are, but I really hope 30 years from now I meet you somewhere and we can look back and see that the world has moved on. I'm trying to keep a promise to myself that I'll keep trying. Sometimes I think we're closer to that future than we think.

ghthor 9y ago
We're so close. ^_^ We need to make sure the internet and this magical way of archiving and sharing information can't be taken from away from us unless the whole civilization is crippled or destroyed.
- erikpukinskis 9y ago
  Well, I don't share your fear because I think the whole of mandatory centralized civilization should and will be destroyed, and replaced with equivalent voluntary microcivilizations. I also think anyone trying to control the flow of information is fighting a losing battle, so I don't lose sleep over that one either. Censoring the internet is already difficult and economically costly. Once we have Ethereum on a mesh network of $5 handheld computers, the difficulty goes up probably two orders of magnitude. And we're what, 10 years away from that? I also think corporations are trying to lure you into thinking they control things, when in fact they don't have any real power any more, we (people with a little credit and a computer) have it all. We are just brainwashed into thinking we need them, so we're not exercising most of our power. What if Comcast et al stopped offering you service entirely? Would you be lost? Would you be able to find the internet again?
  - ghthor 9y ago
    That's actually a scary scenario. I'd be stuck relying on my neighbors for "pirate" wifi which would be unreliable unless I was able to run some QoS and setup their router. If that failed I'd be SoL because I don't know how use HAM radio and access the packet network. What other options or ideas am I missing? Excluding the cell carrier network.

searealist 9y ago

I'm just trying to help: https://en.wikipedia.org/wiki/Schizotypal_personality_disorder https://en.wikipedia.org/wiki/Schizotypal_personality_disord...

ghthor 9y ago
That's actually pretty interesting. I'd say that I hit a lot of those checkmarks, but I've never had problems making friends and developing deeper relantionships. On the other hand, I've had incredible difficulties developing my software engineering career because of my difficulties is trusting my employer and co-workers. I'd say I struggle to build relationships in competitive environments.
- beaconstudios 9y ago
  I think that's quite a common experience - I tend to find that I develop small pockets of mutual trust (usually <5 people) in highly political and competitive companies. I think aggressively metricised environments are very hard to feel comfortable in because you don't feel like you have a stable footing.

_98fj 9y ago

> I hypothesize that the source of most anxiety or nervousness stems from our brains making no correct predictions in that moment. Since fight/flight behaviour is regulated by the amygdala and basal ganglia, you can say: Anxiety stems from our amygdalae getting started up, because they sense a threat where none is, and effecting inappropriate behaviour thereafter. Actually, the threat is often correctly sensed, it's just the behaviour (running away, attacking, feigning death/freezing) that's not useful in the modern world. The therapeutically interesting question is how to change that. Compared to the rational parts, those emotional mechanisms are much deeper and better wired to the rest of the brain. At the same time they aren't very sophisticated. Some people refer to them as "reptilian complex". We can't adjust emotions directly and in general we have to wait much more time (think: weeks, sometimes months) to let new ideas like not being afraid of something sink into the subconscious. But knowing and accepting that makes it possible to grow.

smallnamespace 9y ago
> it's just the behaviour (running away, attacking, feigning death/freezing) that's not useful in the modern world. The therapeutically interesting question is how to change that. Finding ways to channel your 'negative' energies into positive, constructive action is basically the foundation to every self-help book ever written. I'd wager that the first, and often most difficult step is to identify a path that will lead to eventual success (eliminating the threat). Unfortunately, sometimes that's simply not possible. Like, if you don't have a degree, have a family to support, and the factory you work at is closing down soon, your brain is going to 1) correctly identify a major threat and 2) try to spur you into action. But what if there's no clear path open that will avert the disaster? I'd wager at least some of this is responsible for the rising rates of chronic illness, drug abuse, and suicide in many parts of the US. Modern life often constantly exposes us to and reminds us about threats that we can personally do little about.
- coldtea 9y ago
  >Finding ways to channel your 'negative' energies into positive, constructive action is basically the foundation to every self-help book ever written. That, soppy quotes and a desire for a quick buck.

marmaduke 9y ago

There're real neuroscience studies that could accompany the theories here. It's a shame none of them have come up in this discussion.

rootlocus 9y ago

> Our brains are back propagating, recursive neural networks that are consistently making predictions about the next input in the stream of input signals as it changes over time. Neural networks are a simplistic model of how our brain works, not the other way around.

agumonkey 9y ago

Your first sentence reminds me of the bliss of music. Music is a subtle and sophisticated "plane" say, and predicting where you can walk while keeping some harmonic relationships and sensing it at the same time makes me think that it's a bit like aligning prediction, models and sensation into one.

andrepd 9y ago

> Our brains are back propagating, recursive neural networks (...) Why so you say that? Or knowledge of the brain is still very very dim and rudimentary, and ANNs are simple mathematical models (inspired by brain neural networks, to be sure) to fit parameters to data. It's a bit naive, in my view, to assert such a simplistic answer to a very hard question without conclusive evidence for anything.

matt4077 9y ago
There's a saying in neurophysiology that predates neural nets: "Neurons that fire together, wire together". It's not exactly the same as back-propagation, but it's quite close.
- Balgair 9y ago
  In fact, it's the exact opposite of back propagation. Long/Short Term Potentiation is all about the synaptic buton of the firing cell, not the receiving cell (or that mess of the astrocytes). https://en.wikipedia.org/wiki/Long-term_potentiation https://en.wikipedia.org/wiki/Long-term_potentiation

andrepd 9y ago

imranq 9y ago

When the steam engine was invented, we thought of the brain as a series of pressures. When we discovered electricity, we thought of the brain as wires. When we got the internet, we thought of the brain as a network. Now sure neural networks have the word "neuron" in them, but they are far far away from the wetware that produced this conversation.

peter303 9y ago
Also clockworks, when they became sophisticated
deleted 9y ago
[deleted]
Bulkington 9y ago
Tangential, but worth sharing for HN crowd, I think. Psychologist Jung and physicist Pauli worked very closely together to explore the unity of mind and matter. Some of their theories are, frankly, difficult to grasp and so intuitively unfathomable they're easy (for me) to just dismiss. But when you consider that Pauli could conceive the idea of the neutrino, impress Einstein with a critique of general relativity, etc., then maybe he's just onto something. The collection of letters referenced below is really wonderful. https://www.brainpickings.org/2017/03/09/atom-and-archetype-pauli-jung/ https://www.brainpickings.org/2017/03/09/atom-and-archetype-...

mrkgnao 9y ago

For others who don't know: taijiquan is more usually called tai chi.

nojvek 9y ago

Thanks for sharing your story. That's awesome. Tell us more about tajiquan? Is it like tai chi? How long have you been doing it and what were the major effects ? While I can't imagine what you've been through I have spent a lot of time pondering over what it'd be like to be a woman.

magic_beans 9y ago

Do you think if you had been born into a society where male and female roles weren't so binary, and you as a man were allowed to, for example, wear long flowing skirts and other "female" clothes, that you would have felt such a strong need to transition to female? I sometimes think our culture's binary approach to gender creates a sense of imbalance and alienation for those people who do not fit into the binary. It saddens me that these people see no other choice but to loathe their sex, and make such drastic and medically questionable efforts to transition to the binary other. I think there must be a way for people to learn to love how their bodies are, even if that sex does not necessarily match the cultural mandate of the "corresponding" gender. It's a hard fight, but it's a fairer fight to fight the culture, rather than one's own body.