The past tense inflection project (PTIP): speeded past tense inflections, imageability ratings, and past tense consistency measures for 2,200 verbs

The processes involved in past tense verb generation have been central to models of inflectional morphology. However, the empirical support for such models has often been based on studies of accuracy in past tense verb formation on a relatively small set of items. We present the first large-scale study of past tense inflection (the Past Tense Inflection Project, or PTIP) that affords response time, accuracy, and error analyses in the generation of the past tense form from the present tense form for over 2,000 verbs. In addition to standard lexical variables (such as word frequency, length, and orthographic and phonological neighborhood), we have also developed new measures of past tense neighborhood consistency and verb imageability for these stimuli, and via regression analyses we demonstrate the utility of these new measures in predicting past tense verb generation. The PTIP can be used to further evaluate existing models, to provide well controlled stimuli for new studies, and to uncover novel theoretical principles in past tense morphology.     

The past and future of the past tense

What is the interaction between storage and computation in language processing? What is the psychological status of grammatical rules? What are the relative strengths of connectionist and symbolic models of cognition? How are the components of language implemented in the brain? The English past tense has served as an arena for debates on these issues. We defend the theory that irregular past-tense forms are stored in the lexicon, a division of declarative memory, whereas regular forms can be computed by a concatenation rule, which requires the procedural system. Irregulars have the psychological, linguistic and neuropsychological signatures of lexical memory, whereas regulars often have the signatures of grammatical processing. Furthermore, because regular inflection is rule-driven, speakers can apply it whenever memory fails.     

Sex differences in past tense overregularization

Hartshorne and Ullman (2006 ) presented naturalistic language data from 25 children (15 boys, 10 girls) and showed that girls produced more past tense overregularization errors than did boys. In particular, girls were more likely to overregularize irregular verbs whose stems share phonological similarities with regular verbs. It was argued that the result supported the Declarative/Procedural model of language, a neuropsychological analogue of the dual‐route approach to language. In the current study we present experimental data that are inconsistent with these naturalistic data. Eighty children (40 males, 40 females) aged 5;0–6;9 completed a past tense elicitation task, a test of declarative memory, and a test of non‐verbal intelligence. The results revealed no sex differences on any of the measures. Instead, the best predictors of overregularization rates were item‐level features of the test verbs. We discuss the results within the context of dual versus single route debate on past tense acquisition.     

Productive use of the English past tense in children with focal brain injury and specific language impairment

In this study, 22 children with early left hemisphere (LHD) or right hemisphere (RHD) focal brain lesions (FL, n=14 LHD, n=8 RHD) were administered an English past tense elicitation test (M=6.5 years). Proportion correct and frequency of over-regularization and zero-marking errors were compared to age-matched samples of children with specific language impairment (SLI, n=27) and with typical language development (TD, n=27). Similar rates of correct production and error patterns were observed for the children with TD and FL; whereas, children with SLI produced more zero-marking errors than either their FL or TD peers. Performance was predicted by vocabulary level (PPVT-R) for children in all groups, and errors did not differ as a function of lesion side (LHD vs. RHD). Findings are discussed in terms of the nature of brain-language relations and how those relationships develop over the course of language learning.     

Brain potentials during language production in children and adults: An ERP study of the English past tense

The current study examines the neural correlates of 8-to-12-year-old children and adults producing inflected word forms, specifically regular vs. irregular past-tense forms in English, using a silent production paradigm. ERPs were time-locked to a visual cue for silent production of either a regular or irregular past-tense form or a 3rd person singular present tense form of a given verb (e.g., walked/sang vs. walks/sings). Subsequently, another visual stimulus cued participants for an overt vocalization of their response. ERP results for the adult group revealed a negativity 300–450 ms after the silent-production cue for regular compared to irregular past-tense forms. There was no difference in the present form condition. Children’s brain potentials revealed developmental changes, with the older children demonstrating more adult-like ERP responses than the younger ones. We interpret the observed ERP responses as reflecting combinatorial processing involved in regular (but not irregular) past-tense formation.     

A neuroconstructivist model of past tense development and processing

We present a neural network model of learning and processing the English past tense that is based on the notion that experience-dependent cortical development is a core aspect of cognitive development. During learning the model adds and removes units and connections to develop a task-specific final architecture. The model provides an integrated account of characteristic errors during learning the past tense, adult generalization to pseudoverbs, and dissociations between verbs observed after brain damage in aphasic patients. We put forward a theory of verb inflection in which a functional processing architecture develops through interactions between experience-dependent brain development and the structure of the environment, in this case, the statistical properties of verbs in the language. The outcome of this process is a structured processing system giving rise to graded dissociations between verbs that are easy and verbs that are hard to learn and process. In contrast to dual-mechanism accounts of inflection, we argue that describing dissociations as a dichotomy between regular and irregular verbs is a post hoc abstraction and is not linked to underlying processing mechanisms. We extend current single-mechanism accounts of inflection by highlighting the role of structural adaptation in development and in the formation of the adult processing system. In contrast to some single-mechanism accounts, we argue that the link between irregular inflection and verb semantics is not causal and that existing data can be explained on the basis of phonological representations alone. This work highlights the benefit of taking brain development seriously in theories of cognitive development.     

Rules vs. analogy in English past tenses: a computational/experimental study

Are morphological patterns learned in the form of rules? Some models deny this, attributing all morphology to analogical mechanisms. The dual mechanism model (Pinker, S., & Prince, A. (1998). On language and connectionism: analysis of a parallel distributed processing model of language acquisition. Cognition, 28, 73-193) posits that speakers do internalize rules, but that these rules are few and cover only regular processes; the remaining patterns are attributed to analogy. This article advocates a third approach, which uses multiple stochastic rules and no analogy. We propose a model that employs inductive learning to discover multiple rules, and assigns them confidence scores based on their performance in the lexicon. Our model is supported over the two alternatives by new "wug test" data on English past tenses, which show that participant ratings of novel pasts depend on the phonological shape of the stem, both for irregulars and, surprisingly, also for regulars. The latter observation cannot be explained under the dual mechanism approach, which derives all regulars with a single rule. To evaluate the alternative hypothesis that all morphology is analogical, we implemented a purely analogical model, which evaluates novel pasts based solely on their similarity to existing verbs. Tested against experimental data, this analogical model also failed in key respects: it could not locate patterns that require abstract structural characterizations, and it favored implausible responses based on single, highly similar exemplars. We conclude that speakers extend morphological patterns based on abstract structural properties, of a kind appropriately described with rules.     

The role of type and token frequency in using past tense morphemes correctly

Type and token frequency have been thought to be important in the acquisition of past tense morphology, particularly in differentiating regular and irregular forms. In this study we tested the role of frequency in two ways: (1) in bilingual children, who typically use and hear either language less often than monolingual children and (2) cross-linguistically: French and English have different patterns of frequency of regular/irregular verbs. Ten French-English bilingual children, 10 French monolingual and 10 English monolingual children between 4 and 6 years watched a cartoon and re-told the story. The results demonstrated that the bilingual children were less accurate than the monolingual children. Their accuracy in both French and English regular and irregular verbs corresponded to frequency in the input language. These results are consistent with the hypothesis that children learn past tense morphemes by analogy with other words in their vocabularies. We propose a developmental sequence based on conservative generalization across a growing set of verbs.     

Time,tense and aspect

The present paper investigates the use of French verbal forms by children between the ages of 2,11 and 8,7. An experiment is presented demonstrating that these Ss do not only use tenses to indicate the relationship of posteriority, anteriority or simultaneity between the events described and the moment of enunciation, but that aspectual factors intervene. Seventy-four subjects were asked to describe eleven actions performed by the experimenter with toys; these actions differed in: Type of result, frequence and duration. For all subjects the type of result influences the choice of the verb forms. More objective features (frequence and duration) exert an influence between the ages of 3 and 6; after that age, the use of tenses begins to resemble adult usage in which the different verb forms are mainly employed to express temporal relationships. Other aspectual and temporal markers show a similar development with age.     

Time, tense, truth

A theory of time is a theory of the nature of temporal reality, and temporal reality determines the truth-value of temporal sentences. Therefore it is reasonable to ask how a theory of time can account for the way the truth of temporal sentences is determined. This poses certain challenges for both the A theory and the B theory of time. In this paper, I outline an account of temporal sentences. The key feature of the account is that the primary bearers of truth-values are not utterances, but sentences evaluated with respect to a time. I argue that unlike other views, the present proposal can meet the challenges faced both by the A and the B theory.     

A challenge to current models of past tense inflection: the impact of phonotactics

Is past tense production better modelled by a Single Mechanism or a Words and Rules model? We present data concerning a phenomenon that has not been considered by either model-regular past tense verbs with contrasting phonotactics. One set of verbs contains clusters at the inflected verb end that also occur in monomorphemic words ('monomorphemically legal clusters', MLC) whereas the other has clusters that can only occur in inflected forms ('monomorphemically illegal clusters', MIC). We argue that if children apply a morphological rule, phonotactics will not affect performance. Conversely, if children store past tense forms, they will perform better on verbs with MLCs because these clusters are more frequent. We investigated three populations--typically developing children, Grammatical-SLI (G-SLI) and Williams Syndrome (WS)--using past tense elicitation tasks. In Experiment 1 we reanalyse data from van der Lely and Ullman [van der Lely, H. K. J. & Ullman, M. (2001). Past tense morphology in specifically language impaired and normally developing children. Language and Cognitive Processes, 16: 177-217] and show that G-SLI children perform better on MLC verbs, whereas for typically developing children phonotactics do not affect performance. In Experiment 2 we replicate these findings in new groups of G-SLI and typically developing children. In Experiment 3 we reanalyse data from Thomas et al. [Thomas, M. S. C., Grant, J., Barham, Z., Gsodl, M., Laing, E., Lakusta, L., Tyler, L.K., Grice, S., Paterson, S. & Karmiloff-Smith, A. (2001) Past tense formation in Williams Syndrome. Language and Cognitive Processes, 16: 143-176] and show that phonotactics do not affect performance in individuals with WS. We argue that the results elucidate the underlying nature of morphology in these populations, and are better accommodated within a Words and Rules model of past tense acquisition.     

Time,quantum mechanics,and tense

The relational approach to tense holds that “the now”, “passage”, and “becoming” are to be understood in terms of relations between events. The debate over the adequacy of this framework is illustrated by a comparative study of the sense in which physical theories, (in)deterministic and (non)relativistic, can lend expression to the metaphysics at issue. The objective is not to settle the matter, but to clarify the nature of this metaphysics and to establish that the same issues are at stake in the relational approach to value-definiteness and probability in quantum mechanics. They concern the existence of a unique present, respectively actuality, and a notion of identity over time that cannot be paraphrased in terms of relations.     

Time,tense and special relativity

In this essay I address the issue of whether Einstein's Special Theory of Relativity counts against a tensed or “A-series” understanding of time. Though this debate is an old one, it continues to be lively with many prominent authors recently arguing that a genuine A-series is compatible with a relativistic world view. My aim in what follows is to outline why Special Relativity is thought to count against a tensed understanding of time and then to address the philosophical attempts to reconcile the two theories. I conclude that while modern physics on its own does not rule out the possibility of a real A-series, the combination of Einstein's theory and the philosophical arguments against tense is decisive. The upshot is that the tenseless or “B-series” view of time is the best one.     

The role of meaning in inflection: why the past tense does not require a rule

How do we produce the past tenses of verbs? For the last 20 years this question has been the focal domain for conflicting theories of language, knowledge representation, and cognitive processing. On one side of the debate have been similarity-based or single-route approaches that propose that all past tenses are formed simply through phonological analogies to existing past tenses stored in memory. On the other side of the debate are rule-based or dual-route approaches which agree that phonological analogy is important for producing irregular past tenses (e.g., think-->thought), but argue that regular past tenses (e.g., walk-->walked) are generated via a +ed rule and that a principled account of regular inflection can only be given by recourse to explicit rules. This debate has become a crucial battleground for arguments concerning the necessity and importance of abstract mental rules, embracing not only language processing, but also the of nature cognition itself. However, in centering on the roles of phonological similarity and rules, the past tense debate has largely ignored the possible role of semantics in determining inflection. This paper presents five studies that demonstrate a striking and decisive role of semantic similarity in inflection. In fact, semantic factors appear to be more important in inflection than the grammatical considerations put forward by the dual-route account. Further, these new findings provide a new way of discriminating between the claims of single-route (similarity-based) and dual-route (rule-based) approaches. It appears that inflection is carried out through analogical reminding based on semantic and phonological similarity and that a rule-based route is not necessary to account for past tense inflection.     

Branching time, indeterminism and tense logic

This paper deals with the historical and philosophical background of the introduction of the notion of branching time in philosophical logic as it is revealed in the hitherto unpublished mail-correspondence between Saul Kripke and A.N. Prior in the late 1950s. The paper reveals that the idea was first suggested by Saul Kripke in a letter to A.N. Prior, dated September 3, 1958, and it is shown how the elaboration of the idea in the course of the correspondence was intimately intervowen with considerations of how to represent indeterminism and of the adequacy of tensed logic in light of special relativity. The correspondence underpins the point that Prior??s later development of branching time may be understood as a crucial part of his attempt at the formulating a conceptual framework integrating basic human notions of time and free choice.