Here is the question: How is the flicker fusion rate interpreted as an on-off rate?

After 2 close-votes were in I edited it to stress it is all about flicker fusion. In my area of research a commonly encountered parameter. As background - retinal implants operate at certain frame rates and when those frame rates are too slow, folks perceive flickering or shimmering images (they indeed often report so).

Anyway - the question itself is about the frequency of light pulses and what the unit Hz means in this regard.

Yes that's Physics, but so are questions on colors and wavelengths in the VIS frequency range of light, e.g. see the 4-answer and 8-upvoted question Is human vision sensitive to frequency or wavelength?.

There is an interesting discussion going on under the question - here is it [partially anonymized] quoted below:

Besides the fly, I don't think the main question has anything to do with biology. I'm voting to close as off topic [TFE]

@TFE - I think questions like this are not Bio per se, but frequencies and cycle times are so fundamentally important in the visual and acoustical sciences that I strongly argue to keep this post alive. Biologists often don't receive training in signal processing, although it's an essential part of some pretty big disciplines. I have attempted to make the question biologically more interesting too, adding the key term 'flicker fusion' in there + a link – AliceD

@AliceD I agree that they are important, and I can see why the OP asked this question here. However, unless the OP edits in a way to make the question more biologically relevant, {edit from AliceD - I did!!} I think it's off topic. This is more for their sake b/c they could likely get good answers if asked elsewhere. However, I just saw that you provided a perfectly viable and useful answer (+1), so that seems moot at this point :p. But even your answer does not mention anything biological. This whole Q&A would still probably be more appropriate on Physics.SE in my opinion. [TFE]

If questions about chromatography get closed, I can't imagine how this one would be on-topic. –[C]

@[C] I think everyone here is biased toward their own interests. The question here is so fundamentally linked to my areas of research I find it on topic. Others outside this field think differently. That's OK. – AliceD 1 hour ago

@AliceD I disagree, it's not okay. If this or any other question is about biology then it shouldn't be closed because some people don't realize the connection. I'm not sure what can be done about this, though. – [C]

@[C] - it's not that black and white I'm afraid. I've added substantial biological context in the question when 2 votes were in, and despite these efforts it still got closed. – AliceD

@AliceD That suggests to me that we have a problem with the way we close questions. I would re-iterate my point that if a question is about biology it should be on-topic on this site. [C]

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    $\begingroup$ I agree that the question should not have been closed. I would also argue that it isn't much about physics, the OP was really asking about a stimulus paradigm, not a physical phenomenon. Likely a physicist or someone who does any sort of signal processing would give the same answer, but it isn't a question about the physics, moreso the terminology in the context of a flicker-fusion experiment. $\endgroup$
    – Bryan Krause Mod
    Commented Mar 7, 2017 at 18:00
  • $\begingroup$ @BryanKrause if you agree with my question, please upvote. Here in meta it's not about rep mining, but it indicates if you agree (+1) or not (-1). $\endgroup$
    – AliceD Mod
    Commented Mar 7, 2017 at 18:07
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    $\begingroup$ Thanks, I am aware of the meta meta, it was an oversight. One thing to note, although it was fairly clear to infer from your text and the quoted comments what your opinion is, I'd like to point out that you never actually state it explicitly in your post. Might be nice to do that so it is clear what we are +1/-1ing for. $\endgroup$
    – Bryan Krause Mod
    Commented Mar 7, 2017 at 18:12
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    $\begingroup$ I upvoted here because I think this discussion is very important. I'm glad you escalated this conversation to Meta. See my discussion below... $\endgroup$ Commented Mar 7, 2017 at 20:45
  • $\begingroup$ Can I re-re-iterate my point? $\endgroup$
    – canadianer
    Commented Mar 8, 2017 at 7:17

1 Answer 1


Instead of filling in a bunch of comments, I'm just going to write my many comment points as an answer (though it's still very much just discussion).

  1. I definitely agree that we have a problem w/ the way we close questions. Well, perhaps not a problem, but inconsistency based on lack of community agreement/discussion. Also, I would say overall, we've become very trigger-happy with question closing (likely because question quality has noticeably dropped). I think many of us read questions at face value. The question really should be, should we instead put ourselves in the OP's shoes and consider their reasoning for assuming biological relevance? If so, though, I would assume further editing would still usually be needed.

  2. I think this discussion is very important here -- these types of questions lay on the fringe of what would be on-topic or not, so it'll be good to have multiple folks discuss it.

  3. I think in the context of the community discussing such pseudo-mostly-off-topic questions (PMOTQ's) in this Meta post, that C's argument about another question being closed is irrelevant and should not weigh the decision in this case. We need to come to a new agreement about how to handle such PMOTQ instances and only use previous instances as a point of reference for discussion (not decision making per se).

  4. I (the one and only TFE :p) saw that you (AliceD) updated the question, but here was my reasoning: your updates may provide further "weight" to the biological reason for the OP to ask the question (which is great), but your edits do not add further biological focus to the main question itself. In other words, if we removed the entire 1st paragraph, then the question has nothing to do with biology. In fact, the question "how long is each light pulse?" has inherently nothing to do with biology. Further, your answer (though it answered the question superbly) does not discuss any strictly biological principles or information.

    • I'll also just note that the "Is human vision sensitive to frequency or wavelength?" question you link to explicitly asks the main question within a biological context. However, the post under question (even after your edits) has a brief intro providing biological context, but the main question lacks any explicit biological focus. As a result, I think these 2 questions represent different degrees of on-topicness within the PMOTQ spectrum.
  5. I still feel that the question and answer appear to be off topic based on both the focus of the question and the entire answer having little inherent relevance to biology without providing further context. However, as you mention, this information can be hugely relevant to certain subfields of biology. And as I noted, you provided a reasonable and useful answer to the question. So in that regard, the Q&A seem to fit ok on Bio.SE.

  6. So this leaves the question: how to determine if these PMOTQ's are on topic (or relevant) enough to not be closed?

    • Should a seemingly off-topic question (as voted by 4 other users) be closed even if it receives a very good and useful answer? (assuming some argument can be made for biological relevance).

    • Conversely, If a reputable Bio.SE user answers the question and acknowledges biological relevance, should it be left open?

    • Should that answerer be responsible for editing the question to make it seem more biologically relevant?

    • Should that answerer also be responsible for trying to explicitly mention the biological relevance of the topic / their answer if the question does not explicitly do so?

    • Overall, does biological relevance have to be implicit or explicit??

I guess overall I have not thought up or included any major answers here, but I wanted to discuss my original thinking in this specific case as well as acknowledge the importance of having this discussion.

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    $\begingroup$ The reason I think that post should be allowed is because of this item in the on-topic list in the help: "questions about techniques in a biological or biochemical laboratory". Although the answer to the question wasn't really about biology, when defining "flicker fusion rate" which is purely a biological concept, OP wanted to know whether the rate is referring to the ON-OFF cycles or the number of times the image changes (i.e. is a cycle a full period or half period). $\endgroup$
    – Bryan Krause Mod
    Commented Mar 7, 2017 at 20:58
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    $\begingroup$ Note also that, unlike in some of the other questions we have had about wavelengths etc, there is really zero interesting physics in this question. The OP was clear on understanding the physics, they were only asking about the definition in a biological sense. (note the original title was terrible, but that's another issue that an edit addressed) If I was a Physics.SE regular, I would have to answer the question with "I have no clue how those crazy biologists define things, go ask them!" $\endgroup$
    – Bryan Krause Mod
    Commented Mar 7, 2017 at 21:01
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    $\begingroup$ Lastly, and sorry for the vomit of comments, I think maybe it would make sense to open this as a meta topic the way our resident arboreal ecologist has laid things out, discussing how we want to handle the "PoMOTaQs" - that sounds like a delicious cocktail. I like the discussion @AliceD has started here but I think the discussion will end up too focused on this one example, and what we really need is a more broadly applicable ruling. $\endgroup$
    – Bryan Krause Mod
    Commented Mar 7, 2017 at 21:13
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    $\begingroup$ @BryanKrause I agree, good idea. I'll copy the last paragraph from my response and create a new question based around those points. $\endgroup$ Commented Mar 7, 2017 at 21:27
  • $\begingroup$ Good work guys thanks $\endgroup$
    – AliceD Mod
    Commented Mar 7, 2017 at 21:31
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    $\begingroup$ The new question now exists: meta.biology.stackexchange.com/questions/3567/… $\endgroup$ Commented Mar 7, 2017 at 21:43
  • $\begingroup$ My comment about another question (which is still closed, by the way) was tongue in cheek. As I (hopefully) made clear in subsequent comments, I think any question that is related to biology should be allowed here. I voted to close because, to me, it wasn't evidently related. As AliceD made clear, I was wrong. $\endgroup$
    – canadianer
    Commented Mar 8, 2017 at 7:11

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