The role of metalinguistic ability in L2 development is seriously underestimated. It may be seen both (1) as a means of initiating or boosting the flow of primary linguistic data and (2) as a generator of substitute knowledge (derived, but epistemologically distinct from domain-specific knowledge) that may compete with or compensate for perceived gaps in the learners current underlying competence. It cannot serve as a simple means of distinguishing the rival theoretical positions.

Barresi & Moore provide an impressive account of how the coordination of first and third person information about the self and other could produce an account of intentional relations. They are less explicit as to how the child comes to understand the basic epistemic relation between experience and knowledge, that is, how informational access causes belief. We suggest one route.

This response agrees with Stanovich's emphasis on the need for decentering, and, in response to Beyth-Marom, attempts to clarify the normative-prescriptive-descriptive distinction and point in the direction of prescriptive models. It takes issue with Cabanac and with Lindsay & Gorayska.

Epstein et al.'s “full access to Universal Grammar” position is conceptually and empirically problematic. Its shortcomings are illustrated through a brief discussion of the following issues: (1) initial versus final states of grammatical knowledge in a second language, (2) knowledge of gradience of grainmaticality, (3) optionality and retention in non-native grammars, and (4) the empirical measurement of syntactic knowledge.

Although Barresi & Moore could have grounded their framework more explicitly in existing models, they offer a provocative testbed for the assumptions of symbolic interactionism and further thinking about self-regulation, especially in autistics.

I argue that SHRUTl's ontology is heavily committed to a representational view of mind. This is best seen when one thinks of how SHRUTI could be developed to account for psychological data on deductive reasoning.

Barresi & Moore assume an equivalence between ontogenetic and evolutionaiy transformations of social understanding. The mechanisms of evolution allow for novel structures to arise, both through terminal addition and through the onset of novel pathways at time points that precede the end points of ancestral pathways. Terminal addition may not be the appropriate model for the evolution of human object-directed imitation, intermodal equivalence, or joint attention.

The most compelling evidence for Epstein et al.'s central thesis that adult second language acquisition is constrained by the innate cognitive structures that constrain native language acquisition would be evidence of poverty of the stimulus. Although there are studies that point to such evidence, Epstein et al.'s primary form of argumentation, targetlike performance by second-language acquiring adults, is much less convincing.

Shastri & Ajjanagadde (1993) (S&A) argue convincingly that both structured connectionist networks and parallel dynamic inferencing are necessary for reflexive reasoning - a kind of inferencing and reasoning that occurs rapidly, spontaneously, and without conscious effort, and which seems necessary for everyday tasks such as natural language understanding. As S&A describe, reflexive reasoning requires a solution to the dynamic binding problem, that is, how to encode systematic and abstract knowledge and instantiate it in specific situations to draw appropriate inferences. Although symbolic artificial intelligence systems trivially solve the dynamic binding problem using computers' registers and pointers, it has remained a difficult problem for connectionist systems (see Fodor & Pylyshyn 1988). S&A's temporal synchrony solution to the dynamic binding problem using synchronous firing of argument units and the entities that are bound to them illustrates one way in which connectionist networks can do thisusing a constrained but important class of long-term knowledge rules. Their structured connectionist solution allows dynamic inferencing to proceed in parallel and therefore has a number of advantages for reflexive reasoning over most other connectionist and symbolic systems.

This commentary addresses two pervasive misconceptions which emerge in Epstein et al.'s target article: (1) that study of second language acquisition (SLA) began in the mid-twentieth century; (2) that SLA has only recently become able to contribute to linguistic theory. There is abundant historical counterevidence; I argue that (1) and (2) obscure the legitimacy of Epstein et al.'s “full access” hypothesis.

Barresi & Moore's “intentional schema” will not do the work of “theory of mind.” Their model will account neither for fundamental facts of social competence, such as the social attributions of the 10-month-old infant, nor the possibility that, though having a theory of mind, the chimpanzee's theory is “weaker” than the human's.

Lange & Dyer misunderstand what is meant by an “entity” and confuse a medium of representation (synchrony) with the content being represented. This leads them to the erroneous conclusion that SHRUTI will run out of phases and that its representation of bindings lacks semantic content. It is argued that (1) the limit on the number of phases suffices, and (2) SHRUTI can be interpreted as using “dynamic signatures” that offer significant advantages over fixed preexisting signatures. Bonatti refers to three levels of commitment to a representational theory of the mind (RTM) and states that SHRUTI is committed to RTM at levels 1 and 2. He acknowledges that SHRUTI is not committed at level 3, but argues that an extended SHRUTI would have to make such a commitment. We agree that SHRUTI is committed to RTM at level 1 and, in a sense, also at level 2. SHRUTI, however, is not committed to RTM at level 3 and, even though it has been extended in several ways, it has retained its original representational character.

This target article is mostly a presentation of experimental research devoted to the larger issue of the role of Universal Grammar in second language learning. Deliberately excluding the aspects of human cognition that makes second language (L2) so variant, Epstein et al. focus on what the learners may know and how they come to know it. This is the aspect of Epstein et al.'s work which is more limiting, and potentially more interesting.

Barresi & Moore do not consider information about intentional relations available within emotional engagement with others and do not see that others are perceived in the second as well as the third person. Recognising second person information forces recognition of similarities and connections not otherwise available. A developmental framework built on the assumption of the complete separateness of self and other is inevitably flawed.

Barresi & Moore's account predicts that infants deprived of visual input will be delayed in achieving social understanding, a hypothesis that receives some support from studies of language use. by blind children. It is proposed that recently developed false belief and appearance/reality tasks be used to explore this issue further. Three possibly distracting conceptual issues are also discussed.

Our results support the idea that adults have access to the principles and parameters of Universal Grammar (UG), contrary to Epstein et al.'s misrepresentation of our work as involving partial access to UG. For both LI and L2 acquisition, functional projections appear to develop in a gradual fashion, but in L2 acquisition there is partial transfer in that the lowest projection (VP) is transferred from the speaker's LI.