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Input Processing

SLAMethodologyIPinput processing

Input Processing (IP) is a theory developed by Bill VanPatten (1993, 1996, 2004) that explains how second language learners derive intake from input. While Krashen's Input Hypothesis claims that comprehensible input drives acquisition, it says nothing about how learners actually process that input. VanPatten's theory fills that gap by identifying the specific psycholinguistic strategies learners use when they encounter L2 data in real time — and, crucially, where those strategies go wrong.

Two Core Processes

VanPatten (2004) proposed that input processing involves two sub-processes:

  1. Making form-meaning connections — mapping a grammatical form to the meaning or function it encodes
  2. Parsing — assigning syntactic structure (e.g., determining who did what to whom)

Each process is governed by principles that describe default learner behaviour — defaults that are often non-optimal and lead to failed or delayed acquisition.

Key Principles

Principle 1: The Primacy of Meaning

Learners process input for meaning before form. This overarching principle breaks down into several sub-principles:

  • Lexical Preference: If a lexical item conveys the same meaning as a grammatical form, learners rely on the lexical item and skip the grammar. (e.g., "yesterday" makes past tense morphology redundant — learners process "yesterday" and ignore "-ed")
  • Preference for Non-Redundancy: Learners are more likely to process forms that carry unique semantic information than forms that are redundant with other cues in the sentence.
  • Meaning Before Non-Meaning: Learners process meaningful morphemes before non-meaningful ones (e.g., content morphology before agreement markers).
  • Availability of Resources: Processing form for meaning requires attentional resources. Only when meaning is relatively secure do learners have spare capacity to attend to form.
  • Sentence Location: Items in initial and final position are more likely to be processed than items in medial position.

Principle 2: The First Noun Principle

Learners tend to process the first noun or pronoun in a sentence as the agent/subject. This causes systematic misinterpretation of non-SVO structures — for example, parsing "The boy was kicked by the girl" as "the boy kicked the girl." Sub-principles modulate this default:

  • Lexical Semantics: Animacy and plausibility override word order (learners won't parse "The ball kicked the boy" with "ball" as agent).
  • Event Probabilities: Real-world likelihood constrains parsing.
  • Contextual Constraint: Preceding discourse can override the First Noun default.

Processing Instruction (PI)

Processing Instruction is the pedagogical application of IP theory. Unlike traditional grammar instruction, PI does not teach rules and then practise output. Instead, it restructures the input learners receive to push them away from non-optimal processing strategies. PI has three components:

  1. Explicit information about the target form and the processing problem (e.g., "English uses word order to show meaning, but in passive sentences the first noun is NOT the agent")
  2. Referential activities — structured input activities where learners must process the target form correctly to get the right meaning (no output required)
  3. Affective activities — structured input where learners process the form while responding to content that is personally relevant

Decades of research show robust effects: PI consistently outperforms traditional instruction on interpretation tasks and performs comparably on production tasks — despite never requiring learners to produce the form during instruction.

Significance

IP theory matters because it specifies why certain forms are difficult to acquire (learners' default processing strategies bypass them) and what to do about it (restructure the input, not drill the output). It connects directly to the Noticing Hypothesis — if learners never process a form in the input, they never notice it, and acquisition cannot begin.

Key References

  • VanPatten, B. (1996). Input Processing and Grammar Instruction in Second Language Acquisition. Ablex.
  • VanPatten, B. (2004). Input processing in SLA. In B. VanPatten (Ed.), Processing Instruction: Theory, Research, and Commentary. Routledge.
  • VanPatten, B. & Cadierno, T. (1993). Explicit instruction and input processing. Studies in Second Language Acquisition, 15(2), 225-243.

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