Inferences in Language Comprehension

Levels of Language Representation

Understanders mentally represent language messages at multiple levels. First, messages convey idea units, called propositions: One idea unit of the Alice sentence is that Alice sat by her sister. Understanders integrate message propositions into a network. Second, people construct mental representations of the situations communicated by a message. Consider the sequence, The Queen outweighed Alice. Alice outweighed the Hatter. A postreading judgment that the Queen outweighs the Hatter must refer to a situation model, because the message did not directly compare those two characters.

Understanders also encode the precise, verbatim form of messages but those representations fade much faster than proposition networks and situation models unless they are of special interest or relevance to the understander. Language inferences are viewed as predominantly encoded in situation models although possibly in proposition networks as well.

Bridging Inferences

The sequence, The tooth was pulled painlessly. The dentist was pleased, is sensible. However, the phrase the dentist suggests prior knowledge about a particular dentist; but the first sentence has not mentioned one. The peculiarity of the alternative continuation, The architect was pleased, highlights this comprehension puzzle.

Understanding the tooth sequence requires an inference that bridges the two sentences: The proposition that the tooth was pulled might be inferentially augmented with the role, DENTIST. The suitability of this inference is confirmed by our ordinary knowledge about dental health. Without bridging inferences, message coherence would be disrupted.

The encoding of bridging inferences is reflected by judgments, during and after comprehension, that are frequently as accurate and fast for stimuli that capture bridging inferences as for ones that repeat explicit message ideas. That includes tasks such as (a) judging the truth of a dentist pulled the tooth, and (b) naming (reading aloud) a bridging inference concept such as BROKE after reading The delicate vase fell. Its replacement cost $100.