45-Gaskell-Chap45 3/10/07 8:15 PM Page 739 CHAPTER 45 Relating structure and time in linguistics and psycholinguistics Colin Phillips and Matthew Wagers 45.1 Linguistics and questions, and vice versa. This is an area where a rich linguistic literature and a sizeable body of psycholinguistics psycholinguistic research address closely related The field of psycholinguistics advertises its men- phenomena. The most widely discussed form of talistic commitments in its name. The field of unbounded dependency occurs when a noun linguistics does not. Psycholinguistic research fre- phrase (NP) such as which voters in (1) appears in quently involves ingenious experimental designs, a position that is structurally distant from the fancy lab equipment such as eye-trackers or elec- verb that it is an argument of (e.g. bribe in (1)). troencephalograms (EEGs), large groups of exper- Following standard practice, we mark the canon- imental subjects, and detailed statistical analyses. ical position of the direct object of bribe with an Linguistic research typically requires no special- underline or gap in (1), but it is a matter of great ized equipment, no statistical analyses, and controversy whether such gap positions are a part somewhere between zero and a handful of coop- of the mental representation of sentences like (1). erative informants. Psycholinguistic research is After reviewing some of the competing linguistic most commonly conducted in a Department of analyses of unbounded dependency construc- Psychology. Linguistic research is not. Some of tions in section 45.2, we discuss in section 45.3 these differences may contribute to the wide- the contributions of psycholinguistics to the ques- spread perception, well-represented among lin- tion of how these dependencies are represented. guists and psychologists alike, that the concerns (1) Which voters did the prosecutor suspect of psycholinguistics are somehow more psycho- that the candidate wanted his operatives to logical than those of linguistics, and that psy- bribe ___ before the election? cholinguistics can be looked to for psychological validation of the constructs proposed by linguists. The status of constraints on long-distance Although this view of the relation between the dependencies, such as the ban on dependencies two fields gives the impression of a neat division that span relative clause boundaries, as illustrated of labor, we find it misleading, and suspect that in (2), is a major topic of linguistic research. it may have led to unrealistic expectations, and In section 45.4 we discuss the effects of such consequently to disappointments and mutual constraints on language processing and their frustration. implications for the relation between linguistic In this commentary we focus on issues in the and psycholinguistic models. representation of unbounded syntactic depend- (2) *Which voters did the prosecutor ask [NP encies, as a case study of what psycholinguistic the operative [RC that bribed ___]] to testify methods can and cannot tell us about linguistic against his boss? 45-Gaskell-Chap45 3/10/07 8:15 PM Page 740 740 · CHAPTER 45 Relating Structure and Time in Linguistics and Psycholinguistics As far as we can tell, there is no principled dif- tasks such as speaking and understanding. In ference between the psychological relevance of contrast, questions about realtime processes have psycholinguistic and linguistic research. Most been central in adult psycholinguistics, whereas modern linguists have serious mentalistic com- less attention has been given to the question of mitments (and those that do not are of little con- why certain expressions are possible and others cern to us here).1 The data that linguists and are impossible. This focus of adult psycholin- psycholinguists collect and the theories that they guistics upon mechanisms that are closely tied develop based on those data are all “psychologi- to speaking and understanding is sometimes jus- cal,” in the sense that they aim to explain some tified by the notion that these are more directly aspect of human cognitive abilities. There are cer- related to common behaviors, or by the assump- tainly differences in the issues and methods that tion that the goal of psycholinguistics is to pro- the two fields tend to pay closest attention to; but vide “processing models.” However, a look at we are unaware of reasons to think that either psycholinguistic work with children casts doubt discipline has more direct access to psychological upon this rationale. Developmental psycholin- evidence, and we would include in this those guistics has devoted much attention to the ques- strains of psycholinguistics that draw on cogni- tion of what children can and cannot represent tive neuroscience methods, as we do in our own at different ages. Studies of childrens realtime work. Since this is not a standard position, we will processing and detailed studies of learning have briefly attempt to substantiate this claim. become more prominent only recently. Much There is broad agreement that mastery of a lan- work in developmental psycholinguistics asks the guage involves at least an (unconscious) under- same questions about children that linguists ask standing of the range of possible expressions that about adults. Therefore, the question of what a can be represented in the language, and also an speaker can and cannot represent, and the ques- ability to identify those expressions that cannot be tion of how the representations are constructed represented in the language. It is also agreed that in time, are presumably both psychologically since the expressive power of human languages is respectable concerns. We suspect that the discipli- too large for any individual to simply memorize nary divisions have more to do with the method- the possible representations of his language, a ological biases of the respective fields. speaker must have the ability to generate, recog- There are obvious differences between the data nize, and interpret novel expressions of the lan- collection methods most commonly used in lin- guage relatively quickly in order to speak and guistics and psycholinguistics. The primary data understand. Since humans are able to learn any of theoretical linguistics comes from native speak- language for which they receive adequate expo- ers’ intuitive judgements about the acceptability sure from an early age, it is also agreed that the of sentences or the availability of specific inter- ability to learn language is a key component of the pretations. Such data are relatively easy to come human capacity for language. Understanding by, making it possible to establish a large number each of these abilities is an important part of the of facts about many different languages in rela- task of explaining how human language works, tively little time. Psycholinguistic data, on the and it is perhaps an accident of history or method- other hand, typically require a good deal more ology that different sub-fields have emerged that effort. In order to establish reliable generalizations focus on each of these problems. about reaction times, focal brain activity, or any of Linguistic theory typically focuses on charac- a number of other common dependent measures, terizing the representations that a speaker of a one needs to use specialized equipment, test large language can entertain, often allied with the ques- numbers of experimental items on large num- tion of what is a “possible human language.” bers of participants, devise ingenious ways to hide Theoretical linguists have generally paid less atten- one’s goals from the participants, and use com- tion to questions about how these representa- plex statistical analyses to interpret the results. tions might be retrieved or constructed in realtime It can take a lot of work to establish just one fact, and it can be difficult to conduct experiments on a number of different languages. 1 We should emphasize that we are concerned in this com- The different data collection practices of lin- mentary with what we take to be the “best practices” in either guistics and psycholinguistics have a clear impact field. It is not difficult to find instances of careless misrep- upon the fields. First, they affect the empirical resentation of linguistic data, uninterpretable experimental designs, unwarranted inferences from brain activation scope of the fields. Thanks to its low-tech meth- patterns, etc., of which neither field would be proud. Our ods, linguistics has amassed a large body of find- interest here is more in what can be learned from carefully ings from a very diverse set of languages, including conducted work in either field. languages for which only a small number of 45-Gaskell-Chap45 3/10/07 8:15 PM Page 741 Linguistics and psycholinguistics · 741 speakers remain. In contrast, most psycholin- among half a dozen friends will do (e.g. two-tailed guistic research has been confined to a handful sign test). One can often do without the half dozen of closely related western European languages. friends, too, if one is sufficiently confident about Second, differences in data collection methods the judgement. There are, of course, examples of affect what linguists and psycholinguists spend errors and disagreements, and notorious cases their time on, shape what is valued in the two of judgements that are subtle at best, but these fields, and also affect the safeguards that the two are the exception rather than the rule. In our fields place on data reliability. In psycholinguis- own work we often run large acceptability rating tics data collection is sufficiently difficult that studies as controls for our on-line studies. These great value is placed on elegant experimental studies cost little effort, since the materials are designs that make it possible to establish a single independently needed for the on-line studies, fact, and many procedural safeguards are put in but the results are almost never surprising, and place in order to ensure that results are reliable. are generally so robust statistically as to indicate In linguistics, on the other hand, data collection that we tested more subjects than needed.