How come that someone understands an utterance only after a few moments?

Question

I have seen and experienced the following phenomena. It often happen in a work environment but can happen anytime and anywhere:

1) Person A is doing something that requires full concentration (like reading or thinking deeply).

2) Person B suddenly ask/say something to Person A

3) Person A replied with "What do you say?" or "Pardon please" (or something similar, as if he/she doesn't hear what person B said) after some brief pause/delay.

4) Person B didn't answer back (optional)

5) Person A answers/responses (before Person B repeats what he/she said) to Person B (as if he/she heard it fully)

Is there a psychological term that describes/explain it? How it is happening? What is its effect with the brain of Person A if there is?

P.S. I don't know what is the right tag for it.

Answer 1

I think what you describe can be explained by echoic memory and working memory.

Echoic memory is one of the sensory memory registers; a component of sensory memory (SM) that is specific to retaining auditory information. The sensory memory for sounds that people have just perceived is the form of echoic memory. ... This particular sensory store is capable of storing large amounts of auditory information that is only retained for a short period of time (3–4 seconds). This echoic sound resonates in the mind and is replayed for this brief amount of time shortly after the presentation of auditory stimuli.

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Working memory, a core executive function, is a cognitive memory buffer with a limited capacity that is responsible for the transient holding, processing, and manipulation of information. Working memory is an important process for reasoning and the guidance of decision making and behavior.

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Person A is fully concentrated and his working memory capacity is full, so he does not pay attention to what the other person is saying. But when person A asks "What do you say?", working memory resources are released and attention is diverted to the echoic memory which replays what person B said.

Answer 2

Probably, everyone has experienced such situation, although only a few people pay attention to this.

It is a usual human behaviour. People do ask about your question to get some time for thinking what to answer. Furthermore, this behaviour is very common among journalists, because this may be a way to avoid answering the question.

In addition, there is another reason. A person who is asking feels more confidence. Thus, people may ask again to bring the situation under their own control.