Sunday, June 14, 2015

Islands are not parametric

Every now and then the world works exactly the way our best reasoning (and theory) says it is supposed to work. Pauli (whose proposal was en-theoried by Fermi) postulates the neutrino to save the laws of conservation and momentum in the face of troubling data from beta decay (see here) and 20 years later the little rascalino is detected and 40 years later Nobel prizes are collected. Ditto for the Higgs field, but this time the lag was over 40 years from theory to detection, and again a Nobel for the effort. These are considered some of the great moments in science for they are times when theory insisted that the world was a certain way despite apparent counter-evidence, and patience plus experimental ingenuity proved theory right. In other words, we love these cases for they comes as close as we can hope to get to having proof that we understand something about the world.

Now linguistics (I am almost embarrassed to say this, but I really don’t want to be painted as hyperbolic) is not quantum mechanics. It’s not even Newtonian mechanics (if only!). But every now and then we can snag a glimpse of FL by considering how its theories, and the logic that allows us to develop these, yield unexpected validation of its core tenets. The logic I refer to in this case is the PoS. Many denigrate its value. Many are suspicious of its claims and dispirited by its crude reasoning. They are wrong. Today I want to point to one of its big success stories.  And I want to luxuriate in the details so that the wonders of PoS thinking shine clearly through.

The Athens participants, to a person, touted islands effects as one of GG’s great discoveries. It is such for several reasons.

First, they are non-obvious in the simple sense that the fact that islands exist is not cullable from inspection of live text. Listen all you want to the speech around you and you will nary spot an island. It is the classic example of a dog that doesn’t bark. It is only when you ask informants about extractions that the distinctive properties of structures as islands shines through.

Second, it takes quite a bit of technical apparatus to even describe an island. No conception of phrasal structure, no islands. No understanding of movement as a transformation of a certain sort, no islands. So, the very fact that islands are linguistic objects with their own distinctive properties only becomes evident when the methods and tools of GG become available.

Third, and IMO the most important point, islands are perfect probes into the structure of FL and were among the first linguistic objects to tell us anything about its structure. Why are they perfect probes? Because if islands exist (and they do, they do) then their existence must be grounded in the structure of FL. Let me say this very important point another way: the fact that there are islands cannot be something that is learned (in the simple sense learning as induction from the ambient linguistic data). That islands exist and constrain movement operations cannot possibly be learned because there is no data to learn this from in the PLD. Indeed, absent inquiries by pesky linguists interested in islands, there would be virtually no data at all concerning their islandish properties, neither in the PLD nor the positive LD.  Island data must be manufactured by hard working linguists to be seeable at all. Thus, island phenomena are the quintessential examples of linguists acting like real scientists: they are unobvious, based on factitious data, only describable against a pretty sophisticated technical background and pregnant with implication for the fine structure of the principle object of inquiry, FL.  Wow!! So islands are a really, really, really big deal.

And this sets up why this poster by Dave Kush, Terje Lohndal and Jon Sprouse (KLS) is so exciting. As the third point above notes, what makes islands so exciting is that they are the perfect probes into the structure of FL precisely because whatever properties they have cannot possibly be learned and so must reflect the native structure of FL. To repeat, there exists no data relevant to identifying islands and their properties in either the PLD or the positive LD. But this absence of data implies that island effects should not vary across Gs. Why? Because variation is a function of FL’s response to differential data input and if there is no plausible data input relevant to islands then there cannot be variation. However, for many years now, it has been argued that different Gs invidiously distinguish among the islands. In particular, since the early 1980s several have argued that the Scandinavian languages don’t have islands. KLS shows that this is simply incorrect. Here’s how it shows this.

The argument that Scandinavian Gs are not subject to islands rests on the claim that they do not display island effects. What are island effects? These are the native speaker judgments which categorize extractions out of islands as unacceptable. Thus, a native speaker of English will typically judge (1) as garbage, this being typically annotated with a “*”.

(1)  *What did the nominee hear the rumor that Jon got

In contrast to this judgment concerning (1) in English, the claim has been that speakers of Swedish and Norwegian accept such sentences and do not give them *s. Maybe they give them at most a ?, but never a *. So the basis for the claim that Scandinavian Gs are exempt from islands is that native speakers do not find them unacceptable. The conclusion that has been drawn is that Gs vary wrt to islands. But this is impossible given PoS reasoning that implies that Gs could never so vary, ever. As you can see, there is an impasse here: theory says no variation, empirics say there is. Not surprisingly, given the low value much of the field assigns to PoS style theoretical “speculation” (aka logic), much of the field has concluded that there is something deeply wrong about our theory of islands. [1]  

Now for a long time this is how things sat. The obvious answer to this empirical challenge is to deny that Scandinavian acceptability judgments are good indicators of grammaticality wrt Scandinavian islands. In other words, the fact that Scandinavian speakers accept movement out of Scandinavian islands does not imply that the structures so derived are grammatical. More pithily, in this particular case (un)acceptability poorly tracks (un)grammaticality.

Let me quickly say two things about this general point before proceeding lest too big a moral gets drawn. First, it is important to remember that within GG, conceptually speaking, “ungrammatical” is not a synonym for “unacceptable,” despite the practice within linguistics of confusing them (especially terminologically).  “Acceptable” is a descriptive predicate of data points, a report of speaker judgments. “Grammatical” is a theoretical predicate applied to G constructs. GGers have been lucky in that over a large domain of data the two notions coincide. In other words, often, (un)acceptability is a good indicator of (un)grammaticality. However, one obvious way of dissolving the Scandinavian counter-examples above is to suggest that the link between the two is looser in this particular case. In other words, that the English data is more revealing of the underlying G facts than is the Scandinavian data in this case.

Second, the fact that this may be so in this case does NOT mean that acceptability is always or generally or usually a bad indicator of grammaticality. It isn’t. First, as Sprouse and Almeida and Schutze have demonstrated in their various papers, over a large and impressive range of data, the quick and dirty acceptability judgment data is a very stable and reliable kind of data.[2] Second, cross-linguistic research over the last 60 years has shown that the MLGs discovered in one language using acceptability data in that language generally map quite well onto the acceptability data gathered in other languages for the same constructions. In fact, what made the Scandinavian data intriguing is that it was somewhat of an outlier. Many many languages (most?) exhibit English style island effects. So, even if the assumption that acceptability tracks grammaticality might not be perfectly correct, it is roughly so and thus it is prima facie reasonable to take it to be a faithful indicator of grammaticality ceteris paribus.[3]

Ok, back to KLS. How does it redeem the PoS view of islands? Well, it provides a method for detecting island effects independently of binary (i.e. ok vs *) acceptability judgments. The probe comes from a battery of relative acceptability data gathered using the now well-known techniques of Experimental Syntax (ES). ES does acceptability judgment gathering more carefully than we tend to do. Factors are separated out (distance vs island) and their interaction (more) carefully compared. Using this technique one can gather relative acceptability data even among sentences all of which are judged quite acceptable. Using this method, the empirical signature of ungrammaticality is a super additivity (SA) profile apparent when you cross distance and structure.[4]

With this machinery in place, we are ready for KLS’s big find. KLS applies this SA probe to English and Scandinavian and shows that both languages display a SA profile for sentences involving extraction from islands.[5] Where the languages differ then is not in being responsive to islands but in how speakers map an island violation into a binary good/bad judgment. English speakers judge island violations as bad and Scandinavian speakers often judge them as ok.[6]

Conclusion: Scandinavian obeys islands restrictions and this is visible when we use a more sensitive measure of G structure than ok vs *. In other words we clearly see the effects of islands in Scandinavian when we look at their SA profiles. 

We should all rejoice here. This is great. The PoS reasoning we outlined above is vindicated. Gs do not differ wrt their obeisance to island restrictions and these are still excellent probes into the structure of FL. I, of course, am not at all surprised. The logic behind the PoS is impeccable. I have the irrational belief that if something is logically impossible then it is also metaphysically impossible. Thus, if some G difference cannot be  learned due to an absence of any possibly relevant data, all Gs must be the same. This is as close to apodictic reasoning as we are likely to find in the non-mathematical sciences, so I have always assumed that the KLS results (or some other indication that Scandinavian obeys islands) must exist. That said, who can’t delight when logic proves efficacious? I know I can’t!

However, KLS is actually even more interesting than this. It not only vindicates the logic of the GG program against a long-standing apparent problem, but it also reshapes the domain of inquiry. How? Well, note that English and Scandinavian still differ despite the fact that both show island effects. After all, the former assign *s to sentences that the latter assign at most ?s to. Why? What’s going on? KLS offers some speculations worth investigating regarding how non-syntactic conditions might affect overall (i.e. binary) acceptability judgments.[7] I personally suspect that this overall measure is affected by many different factors including intonation (and hence old/new info structure) lexical differentiation and a host of other things that I really can’t imagine. Sorting this out will be hard if for no other reason that we have not really concentrated much on how these myriad effects interact to provide an overall judgment. What KLS shows is that if we are interested in how speakers construct an overall judgment (and, off hand, it is not clear to me that we should be interested in this but I am happy to hear arguments for why we would be), then this is where you need to look for “variation.” Why? Because they have provided very good evidence that islands are NOT parameterized, which is the conclusion that elementary PoS reasoning leads to.

Diogo Almeida, has a nice paper (here, and here)[8] that does similar things along these ES lines for extraction out of Wh-islands in Brazilian Portuguese (BP). The paper uses ES methods to probe not only sensitivity to islands but also to compare how sensitive  different constructions are to island restrictions. The paper compares Topicalization and Left Dislocation showing that both induce island effects (as On WH Movement would lead us to expect). It also shows that BP here differs in part from English, raising further interesting research issues. I for one would love to see ES applied in comparing Topicalization, Left Dislocation and Hanging Topics in languages where one finds case connectivity effects. How do these do wrt islands? I can imagine a simple predication wherein case connectivity being a diagnostic of movement implies that Hanging Topics do not exhibit SA effects in island contexts. Is this so? I have no idea.

Diogo’s paper provides one further service. It provides a nice name for SA-without-unacceptability effects. Diogo dubs them “subliminal islands.” Diogo argues that the simple existence of subliminal effects has interesting implications for how we understand SA effects. He argues, convincingly IMO, that we expect subliminal effects if grammaticality is one component of acceptability, not so much if we take a performance view of islands. The paper also has a nice discussion of the conceptual relation between acceptability and grammaticality that I recommend highly.

Ok, time to end. I have two concluding points.

First, IMO, this kind of work demonstrates that ES can tell us something that we didn’t know before. Heretofore, ES work has aimed to either re-establish prior results (Jon’s work was aimed at showing that island effects are real) or to defend the homeland against the barbarians (Jon & Co arguing that informal methods are more than good enough much of the time). Here, KLS and Diogo’s paper show that we can resolve old problems and learn new things using these methods. In particular, these papers show that ES methods can open up new questions even in well-understood domains. In particular, I believe that both papers show that ES has the potential to reinvigorate research into the grammatical structure of islands. I mention this because many syntacticians have been wary of ES, thinking that it would just make everyone’s cushy life harder. And though I generally agree, that ES methods do not displace the more informal ones we use, these papers demonstrate that they can have real value and we should not be afraid (or reluctant) of using them.

Second, go out and celebrate. Tell friends about this stuff. It’s science at its best. Yipee!

[1] The impression I have (even after Athens) is that such speculation is considered to be just this side of BS.  At the very least it really plays (and can play) no serious role in our practice. I may be a tad over-sensitive here.
[2] The fact that such a crude method of data collection has proven to be so reliable and useful raises an interesting question IMO: why? Why should such a dumb method of gathering data work so well? I believe that this is a function of the modularity of FL and the fact that Gs play a prominent role in all aspects of linguistic performance. More exactly, how Gs are used affects performance but performance does not affect how Gs are structured. Thus Gs make an invariant and important contribution to each performance. This is why their effects can be so easily detected, even using crude methods. At any rate, whether this diagnosis is correct, the fact that such a crude probe has been so successful is worth trying to understand.
[3] Note that this implies that the challenges to the universality of islands based on Scandinavian data were reasonable, even if ultimately wrong.
[4] See Jon’s thesis here, or many of his other writings for a simple explanation of these effects.
[5] KLS discusses Wh islands, Noun complement islands, subject islands and adjunct islands. It does not address relative clauses. However, Dave Kush has told me that they have looked at these too and the results are as expected: Scandinavian shows the same SA profile for RCs as for all the others.
[6] There is a kind of judgment one often hears from linguists which this methodology questions. It’s “the sentence is not perfect but it is grammatical.” The ES methodology suggests that one treat this kind of judgment very gingerly for it might indicate the underlying effects of the relevant G distinction, not its absence, as is typically concluded. Note that the quoted judgment above runs together “acceptable” and “grammatical” in a not wholly coherent way. It relies on the assumption that informal judgments concerning degree of unacceptability is a reliable probe of the binary grammatical/ungrammatical distinction. In other words, it assumes that grammaticality is binary (which it may be, but who knows) and that the severity of an acceptability judgment can reliably indicate the grammatical status of a structure. This assumption is challenged in the KLS paper.
[7] Sprouse’s thesis already demonstrated how e.g. D-linking could affect overall acceptability (i.e. the binary judgment) without inducing an SA signature.
[8] Same paper but for formatting. Latter is published version for citation purposes.


  1. That is an interesting result, but I actually find it worrying rather than relieving. One (okay, let's be honest here, my) story for certain island effects, including extraction from relative clauses, is that they follow from the Optionality Theorem: every grammar is provably incapable of extracting anything out of an optional constituent if extraction is required to satisfy a dependency at the target site. This cannot be squared with KLS's interpretation of the experimental findings, which relies on the grammar still generating sentences with island violations but marking them as degraded.

    Now admittedly the Optionality Theorem is also too strong in other cases, e.g. Truswell sentences, but for those I can think of a way to weaken it accordingly by refining the notion of optionality to take semantics into account. But for KLS's story to work optionality would have to be weakened to such a degree that it is completely stripped of any power and the theorem falls apart.

    So on the one hand I'm relieved that the problem of Scandinavian RCs is solved as I didn't have a story for that, on the other hand it's a Pyrrhic victory unless there is a different interpretation of the findings (which in turn probably wouldn't solve the issue of Scandinavian RCs).

    One follow-up question: Repair of island violations via resumptive pronouns poses the very same problem for the optionality story. Any idea whether there are similar experimental findings for those sentences?

    1. There is currently work being done on RPs. My understanding is that they also license SA effects, suggesting movement here too.

      As for the Pyrrhic nature of the victory, it depends what one is aiming for. What the papers show is that there is little variation in island effects wrt sensitivity to such structure. It leaves open what the correct analysis of these island effects is. It also notes that there is a second global effect that varies between Gs. I ma not yet convinced that this fact reflect properties of FL so much as the interaction of FL effects with others. If this is so, then, given that my job is not to explain acceptability but to investigate the structure of FL it is not clear why I should care about the latter. Maybe I should, but I want an argument to that effect.

      At any rate, if KLS is right (and it is) then there is no variation wrt island sensitivity in all Gs. All Gs obey them and all show the same signature property of Islands. There is another difference it appears, but we don't really know what goes into making an overall judgment. KLS have some speculations, as I noted, but if this is what you are interested in, I suspect you will need to look outside the purview of FL and Gs per se and towards interactions with other systems. Good luck.

    2. @Thomas: The picture from Resumptive Pronouns is, as far as I can tell, quite complex. At least for Modern Standard Arabic, resumption by itself does not seem to do much island repairing, but when it interacts with D-Linking, then it does seem to improve acceptability quite a bit (at least for whether- and adjunct-islands). However, even in the d-linked cases, one still finds the super-additive signature of island effects, and the interaction plots look very similar to the ones in KLS2015 for Norwegian and Swedish and Almeida2014 for Brazilian Portuguese (meaning the island-violating case is relatively acceptable, but it is still much worse than what would have been predicted by the linear addition of the effects of structure and distance of dependency). Matt Tucker, Ali Idrissi, Jon Sprouse and I just presented a poster about this at the CUNY Conference, back in March. The poster can be found at:

    3. Thanks for the link, that's great stuff. It is really interesting that all of this fits exactly with the predictions of the Optionality Theorem, except that it is unclear what the linking hypothesis between grammar and acceptability judgments would have to look like to yield the observed difference between "not generated and not acceptable" and "not generated but acceptable".

    4. There's also Dora Alexopoulou's older work showing little ameliorating effects of resumptives. Various papers on her cambridge website.

  2. Thanks for discussing this interesting study. You write:

    That islands exist and constrain movement operations cannot possibly be learned because there is no data to learn this from in the PLD.

    The existence of islands shouldn't be controversial, at least at the level of grammaticaly judgments for sentences like *what did the nominee hear the rumor that Jon got. I'm not sure the POS argument is particularly strong here, though. My reading of Lisa Pearl and Jon Sprouse's modeling paper was that the fact that movement only happens in a circumscribed set of structural configurations in the PLD provides substantial indirect negative evidence for the ungrammaticality of islands. Of course, their argument presupposes that the learner represents the PLD using a phrase structure grammar rather than as just sequences of words, but I got the impression that the POS argument you were making was quite a bit more specific.

    1. I have no fish to fry as to how strong a conclusion to draw wrt islands and the PoS. All I know is that it cannot be parametric.You noted Jon's and Lisa's paper. I found it interesting, personally, but not compelling. As you note, they rely on a pretty strong set of assumptions concerning what to count (embeddings) and even how finely to divide up labels (not just Cps but +WH etc). Moreover, some of the decisive data is very very poorly represented (e.g. one example in about 10,000) and this suggests to me that their approach, though possible is probably not right. I think that Colin's discussion of their paper in the volume I edited with Jon has it more or less right. Also, it is critical that they count trios in a specific way, and there are many others that are imaginable. That said, the PoS does not say what is innate. It's not that magical. But what it delivers is very good, and here is makes an important contribution.

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    3. Interesting, is the chapter by Colin you're referring to available online?

    4. There is a version on his website. #78 is downloadable.

  3. I would like to press a little harder on the claim that the sheer logic of the Poverty of Stimulus argument forces one into the conclusion that islands are universal, or rather that what counts as an island in each language is universal. I don't think it goes through. Here's the hypothetical situation I am thinking of. Suppose there is a clutch of very abstract universal things, like hierarchical structure, the very fact of Chunking (perhaps for third factor reasons such as memory in computation), and the existence of dependencies between different parts of the representation/computation. Suppose a learner grows a grammar with these properties. But in addition, in interaction with the particular language being acquired, learns what the chunks are based on very simple sentences and straightforward input (like maybe on the basis of prosody, or lexicalization). And suppose these chunks are subtly and learnably different from language to language. Then, when you get a complicated sentence that requires you to deal with the dependency, plus the chunks you know you have, plus the rule you have to relate chunks to each other. Its no problem. You have a robust judgement of course that something goes wrong with the dependency formation. Because we all believe that people are growing a G, and not a list of constructions. I also agree in a PoS way, that people's behaviour and judgements on complicated constructions they could not have literally heard in the input is the best evidence for that.

    Having said that, we are dealing with an MLG here, not a universal. It could be these more abstract things that are universal, and the fact that there will be islands at all (a non trivial discovery). It is logically possible that languages could decide what chunks are encapsulated in this way, and that this could be learnable on the basis of evidence that does not come from actual island constructions.
    Now, this latest research seems to indicate that the islands in Scandinavian probably ARE the same as the ones in English, and if that stands up, then that is an empirical result that to my mind could have been otherwise. I would like to understand better though, the factors (necessarily language specific) that fill in the space between grammaticality and the psycholinguistic behaviour which we call an Acceptability Judgement.
    Bottom line is that while I believe in universals, I suspect that Islands are MLGs, and that the universals that underpin them are way more general and abstract than that. If that is the case, then the ACTUAL things that come out as islands could `by logic' vary from one language to the other. If they do not vary, then there must be universal or third factor pressures that make them be what they are.
    Islands are not at the same level as neutrinos.

    1. I agree almost completely. Islands themselves are not primitives of FL. Since Chomsky's subjacency theory I think that this has been the standard position. Islands are derived generalizations (MLGs) and what occupies FL is some version of bounding theory. Now, even this, I believe is still deservedly controversial as a basic theory as we don't yet have a great idea about how to integrate bounding effects (including, IMO, the adj/arg asymmetries of the ECP) into a theory of islands with the right set of minimalist virtues, but, that said, Islands are not primitives. However, a standard view has been that the correct MLG sees the products of the fundamental theory to vary across Gs. In other words, e.g. islands hold in English but not Scandinavian. KLS has put paid to this view. Moreover, and this is what I wanted to stress, the idea that islands could so differ made no sense on PoS grounds. Note, PoS does NOT say which more basic theory is correct. I cannot do this. It can be used to argue for some theory over another (e.g. see the post I had discussing the work of Chacon et al on this wrt the fixed subject effects) but it alone does not provide a fundamental theory. It is a technique of investigation, a logical tool that when successfully deployed provides boundary conditions on any adequate fundamental theory. In this case, it argued that island effects (the explanada of a fundamental theory) could not vary across Gs. There was just no PLD (or positive LD for that matter) that was available to fix the differences. So whatever the fundamental theory is, it should not allow for parametric islands.

      I think that you agree with all of this and so I just say it again to encourage the spirit of agreement. I love agreeing with others, though it appears that I don't generally get the opportunity. So thx.

  4. Incidentally, the lack of relative clause test cases in KLS is a little disappointing, since the most spectacular cases of apparent grammaticality in Swedish come from relative clause examples like the classic `De blommorna känner jag en man som säljer´ (Those flowers I know a man that sells). So I really would have liked to see the super-additivity effect demonstrated there. The fact that Swedish Niceness seems to lump together wh-islands and relative clause extractions should be used as a clue for figuring out what is going on here.

    1. See note 5 above. It's been done and same results. They are putting this together now I was told.

    2. Yeah, I saw the note. I just don't believe it until I see it. I think the SA effect will be much less striking here. I only say so because I am stubborn. That and the fact that my five year old does these rel clause extractions ( though not in English).

    3. Quite right to be skeptical. But that's what Dave Kush told me about the results. I too cannot wait to see it. But given my faith in PoS I know what the answer must be. BTW, there still remains the interesting question of whether in languages that accept these are ok this has an effect on use. It seems you are saying that it does, though the evidence is, well, anecdotal?

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    5. Oh yes, you hear these all the time -- just yesterday I heard, 'Den [kjolen] protesterer ho villt når æ skal ta på ho': literally, "That [dress] protests she wildly when I should put on her," i.e. She [a child] protests wildly when I am trying to put that dress on her, with topicalization from the object of put in the when-adjunct. They don't elicit so much as a raised eyebrow here. [edited to regularize the nonstandard orthographic rendition of the dialectal Norwegian]

    6. And 'protestere' is not transitive, in this sense, so this is not a parasitic gap; you can't protest a dress, in Norwegian.

    7. Yep. The relative clause ones seem to be very natural, idiomatic speech and pretty commonly heard. And the so-called island violations are interestingly restricted: they are usually `topicalizations' rather than wh-extractions; the relative clause for many speakers needs to be sentence final (Taraldsen 1980); there are restrictions on the matrix verb that goes into the V2 position; the results are usually presentational or clefts and there is some kind of connectivity at stake. You can see Engdahl 1997 for a description of the data. I don't think you can wave a `this is all down to pragmatics and acceptability' wand at this and make them go away. I am pretty sure they are grammatical, in the sense of grammatical-grammatical. That's a hunch. I am sure we risk missing something important here if we just make them go away.

    8. Perhaps. That's exactly what we want tof find out. If KLS is right then subliminal islands are precisely the domain where acceptability has to handled gingerly. We shall see.

  5. "To repeat, there exists no data relevant to identifying islands and their properties in either the PLD or the positive LD." I don't think we really know this. Allen (1980) (LI 11.2) managed to find at least two examples of extraction from doubly embedded tensed clauses in the OE corpus, but none from Wh or CNPC islands, except for one with a resumptive pronoun, and while the OE corpus is large by philological standards, and the 'list of works consulted' impressively long, the amount of material she looked at was surely small relative to the entire linguistic experience of a college student in their first syntax class (the first testing ground for the classic generative claims, I think).

    A possible project for people who can read Swedish would be to see how many island violations come up in those Scando thrillers and murder mysteries that are so popular these days, and then see how they are handled when they are translated into English.

    1. Avery, we can do better now. Thanks to the work of Lisa Pearl & Jon Sprouse, who parsed a big pile of child-directed and adult-directed speech. Their corpus includes upward of 20,000 wh-questions, and allows reasonably good estimate of the distribution of different extraction types in the PLD. The clearest conclusion from their work is that complex questions are extremely rare. That means that we can focus on the question of what children might learn from the breadcrumbs that are present in the input. Pearl & Sprouse (2013) argue that you can get a lot from that. I argue in this paper that you probably can't. But whoever is right, they have done the field a great service by allowing us to stop speculating about what learners might encounter.

      I agree that knowing more about Scandinavian PLD would be valuable.

    2. I thought Norbert's argument here --"To repeat, there exists no data relevant to identifying islands and their properties in either the PLD or the positive LD"
      is that you can't learn about islands because these are things that don't happen and so there cannot be in principle any way of learning about them from things that do happen (positive LD) even if you have access to a larger amount of data than children have.

    3. What is the difference between PLD and positive LD?

    4. PLD is what the child uses. LD is the sider data available to the linguist. LD contains both acceptable and unacceptable examples. Positive LD is the data the linguist uses minus the unacceptable stuff.

    5. The Pearl and Sprouse work is excellent, but:

      a) the data is still small relative to the PLD for college students venturing their first judgments of island violations in syntax classes

      b) it is furthermore restricted to language produced and more or less directed at preschoolers, whereas Gathercole 2002 finds indications that school is relevant for acquiistion of that-trace; I don't know what kind of followup there has been of that, but my friendly local psycholinguist things that school is probably important and we don't know much about its effects

      c) it's not Swedish

      d) getting to the point of being able to produce a big, relevant, treebank for Swedish would take a lot of time and money

      e) Just reading the detective stories is something that people who could already read Swedish could start doing this evening, and might well be able to find something out within a year (for example, if island violations were frequent in the texts).

      So I don't think it is necessarily a hopeless idea, if one really wants to know about island effects in the PLD.

    6. 'preview' was swallowing the text, so sorry about the typos, and, is it known when kids become able to produce island judgements? (should have gone under a or b above).

    7. Avery has a good point. Looking at Childes is appropriate for those syntactic properties that are robustly acquired in childhood; but if we are talking about the syntactic abilities of adults -- particularly if measured on WEIRD (white educated industrialized rich democratic) undergraduates, then they typically have been exposed to a large amount of written academic texts with long sentences, so the PLD is vastly larger.

  6. BTW, I am running a similar experiment in Turkish. Since Turkish is wh-in-situ, I am looking at scrambling.