Stephen Krashen proposed the existence of which construct that controls the amount and quality of input learners receive?

• A. Affective filter
• B. Input control
• C. Output loop
• D. Processing gate

Answer: (A)

Affective filter is the construct at play here. In Krashen’s theory, emotional and attitudinal factors such as motivation, self-confidence, and anxiety shape how much input a learner actually notices and processes. When the affective filter is high—say a learner feels anxious, discouraged, or tense—much of the incoming language is blocked from being processed, so the amount and quality of input that can be acquired are limited. When the filter is low—learners feel relaxed, confident, and interested—the input slips through more readily, allowing more accurate and richer language to be absorbed.

This idea ties directly to the notion of comprehensible input, which is input just beyond current ability that learners can understand with support. The affective filter modulates whether that input becomes intake. In practice, creating a low-anxiety, supportive, meaningful learning environment helps learners engage with more input and improve more effectively.

The other terms don’t capture this psychological gatekeeping role in Krashen’s model. They aren’t the constructs Krashen proposed for controlling how input is received, so they don’t explain why some input is taken in while other input is not.