Krashen’s Monitor Model: Five Hypotheses of Second Language Acquisition
Recent Psychological Theories of SLA (1)
Krashen’s Monitor Model
This is an innatist theory of SLA, greatly influencing SL teaching practice. Krashen’s theory (1982) was originally called ‘the Monitor Model,’ constituted by five hypotheses:
- Acquisition-Learning Hypothesis
- Monitor Hypothesis
- Natural Order Hypothesis
- Input Hypothesis
- Affective Hypothesis
1. The Acquisition-Learning Hypothesis
According to Krashen, adult L2 learners develop knowledge of an L2 via: (a) acquisition and (b) learning.
(a) Acquisition: We acquire language by exposure to understandable L2 input, similar to how children acquire their L1, without conscious attention to language form.
We learn via a conscious process of study and attention to form and rule learning.
For Krashen, acquisition is paramount: Only acquired language is readily available for fluent communication, and learning cannot become acquisition.
Evidence:
- Many speakers are fluent without learning rules.
- Some speakers know rules but fail to apply them when focusing on what to say rather than how.
2. The Monitor Hypothesis
An ‘acquired’ system initiates utterances, representing the learner’s competence in phonology, grammar, and semantics.
A ‘learned’ system acts as an editor or monitor, making minor changes to what the acquired system produced.
Learners use the monitor when focused on speaking correctly, having time to recall rules (if known). Writing facilitates monitor use due to more time for form attention.
Language teaching should focus on creating conditions for ‘acquisition’ rather than ‘learning.’
Argument against:
- It’s difficult to prove ‘monitor use’ in utterances.
- Krashen’s definition of acquired language (produced quickly and spontaneously) is somewhat circular.
3. The Natural Order Hypothesis
L2 learners acquire language features in predictable sequences, like L1 learners.
Grammatical rules that are easy to state are not necessarily acquired first. Example: adding -s to 3rd person singular present tense verbs.
The natural order is independent of the order rules are learned in class. Evidence came from ‘morpheme studies,’ though criticized, later research confirmed learners pass through developmental stages.
4. The Input Hypothesis
Language is acquired through exposure to comprehensible input.
If the input contains forms and structures just beyond the learner’s current level (I + 1), comprehension and acquisition occur.
Argument against:
- Krashen’s evidence is intuitive, lacking empirical substantiation.
Undirected pleasure reading is a valuable source of comprehensible input. While not all exposed achieve high proficiency, input is the source of acquisition.
5. The Affective Filter Hypothesis
This hypothesis explains the lack of success when comprehensible input is available.
The affective filter is an imaginary barrier preventing acquisition, influenced by psychological states (motives, attitudes, emotions).
A tense, angry, anxious, or bored learner may ‘filter out’ input.
The filter is ‘up’ (blocking input) when stressed, self-conscious, or unmotivated, and ‘down’ when relaxed and motivated.
This has implications for classroom practice, explaining why some learners succeed while others don’t, and appeals to those who struggled learning an L2 under stress.
Problems:
- It’s difficult to prove affective factors cause differences in SLA.
- Success in acquisition may contribute to positive motivation or a ‘lowered affective filter.’