Some linguists (Jackson H and Stockwell P) single out relevance as of greater importance than Grice recognised. Assuming that the cooperative principle is at work in most conversations, we can see how hearers will try to find meaning in utterances that seem meaningless or irrelevant. We assume that there must be a reason for these. Jackson and Stockwell cite a conversation between a shopkeeper and a 16-year old customer:
Customer: Just these, please.
Shopkeeper: Are you eighteen?
Customer: Oh, I'm from Middlesbrough.
Shopkeeper: (after a brief pause) OK (serves beer to him).
 Jackson and Stockwell suggest that “there is no explanation for [the customer's] bizarre reply”. Perhaps this should be qualified: we cannot be sure what the explanation is, but we can find some plausible answer. Possible explanations might include these:
  • The young man thought his being from Middlesbrough might explain whatever it was about him that had made the shopkeeper suspicious about his youth.
  • The young man thought the shopkeeper's question was provoked by his unfamiliar manner of speaking, so he wanted to explain this.
  • The young man was genuinely flustered and said the first thing he could think of, while trying to think of a better reason for his looking under-age.
  • The young man thought that the shopkeeper might treat someone from Middlesbrough in a more indulgent manner than people from elsewhere.
Jackson and Stockwell suggest further that the shopkeeper “derived some inference or other” from the teenager's reply, since she served him the beer. It might of course be that she had raised the question (how old is this customer?) once, but when he appeared to have misunderstood it, was not ready to ask it again or clarify it - perhaps because this seemed too much like hard work, and as a stranger, the teenager would be unlikely to attract attention (from the police or trading standards officers) as a regular under-age purchaser of beer.