Present perfect question and past simple question

Question

Look at these two questions:

Has your brother graduated from college?

Did your brother graduate from college?

Now, both of these questions seem fine to me, but I obviously know they are a little different. However, I can’t seem to explain what the slight difference is between these grammatical sentences.

I know that when I use the present perfect, I am expecting an answer of “yes, he has” or “no he hasn’t “ with no specific details of exactly when in the past. But with the simple past, usually there is a specific time in the past and it conveys finality and that it is completely finished at a specific point that the speaker knows the time reference when he/she asks that question. Is there anything else I am missing?

Edit: Both are acceptable to my ear but what would people assume differently if they hear one or the other? Or is it the same?

Edit: Are both acceptable to use depending on the circumstances?

Answer 1

I will answer for US English (not sure if this will hold in UK English).

If I don't have any prior knowledge about the brother, I'd ask, "Did your brother go to college?" (Depending on where the conversation went from there, I might ask, "Did he get his degree?".)

I would probably only ask, "Has your brother graduated from college?" if I happen to know that the brother has some college studies under his belt. Otherwise, I'd ask, "Does your brother have a college degree?" or "Did your brother go to college?" or possibly "Did your brother graduate from college?". The latter form doesn't sound very conversational, though.

If you want to get more authentic you'll want to take into account that nowadays the person might stop after a two-year degree (Associates) -- it's complicated!

If that doesn't address your question, please clarify.

Answer 2

I will mostly focus on American English, since the expression graduated from college is not used in the same sense in the UK.

I doubt there are any contexts where, in American English, one of the sentences

[1]  i  Has your brother graduated from college?
      ii  Did your brother graduate from college?

would be acceptable but the other would not. Having said that, one or the other may be preferred.

In brief, the simple preterite [1ii] is used in practice much more frequently. Having said that, there may be some circumstances, namely those where 'the focus is on the present' (in an appropriate sense), where the present perfect is more likely than in other circumstances. This is discussed in the section 'A general consideration', below.

Evidence from various corpora

Evidence from the Google Books Ngram Viewer and COCA

Interestingly, if you search Hoogle Ngram Viewer, you will find that [1i] has no hits at all. Similarly, on the Corpus of Contemporary American English (COCA) there are zero hits for 'have you graduated', but 8 hits for 'did you graduate', including entries such as

Have you ever had a job? Did you graduate from high school?
Did you graduate from Paseo, Miss Bloom?
"So did you graduate?" I ask.

Evidence from Google Books

If one searches google books, one does find a number of hits for both 'have you graduated from' and 'did you graduate from', though the latter are more numerous.

Apart from the overall higher number of hits for the simple preterite 'did you graduate from', there is one other tendency that seem to be discernable.: if a specific institution is named (as in, Did you graduate from Gibbs High School?), then the simple preterite is strongly preferred. (Obviously, if a specific time is indicted or asked for, then the simple preterite is basically obligatory, as in What year did you graduate from college?)

A general consideration

It is not easy, when searching on Google Books, to precisely specify the context for an expression, and so I will add something that comes close to being a mere opinion. However, this opinion is at least consistent with the general analysis from CGEL reproduced below.

The general observation is that the present perfect (as in [1i]) is used when 'the focus is on the present'. This focusing may take several forms. Perhaps we are focusing on the fact that the graduation is recent; one way to emphasize that focus even more would be to add yet (Has your brother graduated from college yet?).¹ . Or, perhaps we are focusing on the fact that the graduation had a specific result—your brother becoming a college graduate—which persists through and is relevant now.

^{1In some varieties of American English, even the presence of yet wouldn't exclude the use of the preterite:
%Did your brother graduate from college yet?
(Here ' % ' in front of a sentence signifies that what follows is grammatical only in some dialects.)}

On the other hand, if the focus is on the past, then the simple preterite is more likely. This helps explain the observation, noted above, that the simple preterite is preferred when a particular institution is specified. Note that if the institution is famous, so that becoming a graduate of that particular institution is itself a well-recognized change in status, then the present perfect becomes more acceptable. For example, it is easier to imagine contexts where Have you graduated from Harvard? is acceptable² than it is to imagine contexts where Have you graduated from Lincoln High School?³ is acceptable.

^{2One example would be the contexts where what you're really asking is Have you graduated from an elite university?
3Lincoln is one of the more frequent names of high schools.}

So suppose the institution itself is not famous, and the graduation did not happen recently. Then the fact that one graduated from a specific high school or college is not connected to the present in a way that would warrant the present perfect. This is arguably so even when the identity of the institution is actually relevant to the present situation in some other way. An example: You seem very familiar. Did you attend Lincoln High School? Here it does matter right now whether the person attended that specific high school. But since the relevance concerns neither recency nor change in status, we are more likely to stick with the simple preterite. (The present perfect is also possible, but is less likely.)

General analysis from CGEL

For completeness, it will be helpful to recall the main uses of the present perfect. This discussion follows (and quotes) that in CGEL, pp. 143–146.

In the first place, there is a reasonably sharp distinction between continuative and non-continuative uses. A useful criterion is whether the expression in question is compatible with ever since: if it is, the use is continuative; otherwise, it is non-continuative. In your example, we clearly couldn't add ever since (as in ^*Has your brother graduated from college ever since?, where the ' ^* ' in front of a sentence signifies that what follows is not acceptable English). Thus your sentence is an example of non-continuative use. Further, within the category of non-continuative use, traditionally there are three further subdivisions: the experiential (or 'existential') perfect, the resultative perfect, and the perfect of recent past. These three are not as sharply delineated, and many examples of use belong to more than one subdivision. Nevertheless, grammarians consider the distinctions useful. Let's consider how they might apply to [1i].

The experiential perfect

This subdivision has to do with 'the occurrence of situations within the time-span up to now'. CGEL gives three types of use that belong to this subdivision, of which the most relevant for us is exemplified by

[11]  iii  His sister has been up Mont Blanc twice.

The connection with now is less direct in [11iii]: the ascents could be quite a long time in the past. The focus, however, is not on their occurrence at some particular time in the past but on the existence of the situation within the time-span. The connection with now is the potential for occurrence, or recurrence, of the situation at any time within the time-span up to now. Thus [iii] implicates that his sister is still alive, while I haven't been to the market yet implicates that the possibility of my going to the market still exists (it hasn't closed down).³⁷

^{37The implicature may be weaker: that the same kind of situation is still possible. Nixon has been impeached, for example, can still be acceptable even though Nixon has since died, given a context where the issue is the occurrence within the time-span of situations of the kind 'impeachment of a president'.}

Given that one graduation from college is usually a one-time thing, this subdivision seems to not fit very well with [1i]. I'm not saying it's impossible to interpret [1i] as an experiential/existential perfect, but only that it is less likely than the alternatives.

The experiential/existential perfect vs. the simple preterite

The experiential/existential perfect can be usefully contrasted with the simple preterite in the following situations (and unlike some other cases, this contrast is present in all varieties of English). This will be useful to review, despite the fact that we decided that [1i] is less likely to be interpreted as experiential/existential perfect.

[12]  i  a.  It is better than it has ever been.       b.  It's better than it was.
        ii  a.  Have you seen Jim?                              b.  Did you see Jim?

In [ia] the comparison is between its quality now and its quality at any time within the time-span – clearly the potential for it to be of such and such a quality still exists. In [ib] the comparison is between now and then; the past is contrasted with the present, the 'then' situation is over and excludes now.

Example [i2iia] brings out the point that there may be limits to the time-span beyond those inherent in the situation itself. The inherent limit is that Jim (and you) must be alive, but in the salient interpretation I will have in mind a much shorter span than this: the time of his current visit to our vicinity, today, the period since we were last together, or whatever it might be. It would not be acceptable for you to answer yes on the strength of having seen him before this time-span. Whatever the limits on its beginning, however, the time-span stretches up to now. But [iib] is very different. Assuming again that you know Jim and have seen him perhaps many times, you need to determine more specifically what I am asking. This time, however, it is not a matter of placing limits on the start of the time-span up to now, but of finding which particular, definite past time I am asking about - your visit to Jim's sister last month, or whatever it might be, but a time that is over, exclusive of now.

The resultative perfect

CGEL again lists three types of use that belong to this subdivision. The most relevant for us seems this one:

[14]  i  She has broken her leg.    He has closed the door.    They've gone away.

The clearest cases of the resultative perfect are illustrated in [i], where the situation is one that inherently involves a specific change of state: breaking a leg yields a resultant state where the leg is broken, closing the door leads to the door's being closed, going away (from place x) results in a state where one is no longer at place x, and so on. The connection with the present in this resultative use is that the resultant state still obtains now. She has broken her leg does not mean "Her leg is broken", but this is the likely implicature unless the context selects an experiential interpretation. Cases like [i] are known more specifically as the perfect of continuing result: the resultant state begins at the time of occurrence of the past situation itself and continues through into the present.

This fits quite well with [1i]: the resultant state is 'being a college graduate' (or 'having a college degree'), which begins at the time of occurrence of the past situation itself (at the time of graduation) and continues through into the present.

The perfect of recent past

[15]  i  It has been a bad start to the year with two fatal road accidents overnight.
         ii  I've discovered how to mend the fuse.
        iii  She has recently/just been to Paris.

One respect in which a past situation may be connected with now is that it is close in time to now. It is clear from examples like [11iii] (His sister has been up Mont Blanc twice) that it does not have to be recent, but there is nevertheless a significant correlation between the present perfect and recency, whereas the simple preterite is quite indifferent as to the distance between T_r and T_o. [Here T_r is the 'time referred-to', the time when the action is taking place, e.g. the time of graduation in [1i]. T_o is the 'time of orientation', the time relative to which we are positioning T_r as being before, simultaneous, or after it; in [1i], T_o is the time of utterance, 'now'.] The present perfect is therefore the one most frequently used in news announcements, as in the radio bulletin example [15i]. It is arguable that the experiential and resultative categories are broad enough to cover all non-continuative uses, but recency adds an important component to the account. For example, [15ii] has a continuing result interpretation: the discovery resulted in my knowing how to mend the fuse and this knowledge persists. Such knowledge can persist for a long time, so there is nothing in the idea of continuing result itself to exclude my having made the discovery years ago. But in fact the normal interpretation involves a recent discovery. We have noted that experiential perfects like [i2iia] (Have you seen Jim?) impose limitations on the time-span up to now beyond those inherent to the situation, and these additional limitations also involve recency.

Thus, [1i] is likely to be interpreted as asking whether the brother has graduated from college recently. The addition of yet would further emphasize this connotation.

Answer 3

The past tense is used to report past events or states and is preferred in any context that does not call for a "present perfect". The present tense of the Perfect construction (aka "the present perfect tense") is formed by the present tense of have, followed by the past participle of the main verb. McCawley distinguishes four such contexts, which occur with different kinds of predicates:

(a) The Universal sense of the Perfect, used to indicate that a state of affairs prevailed throughout some interval stretching from the past into the present

• I've known Max since 1960.

Universal perfects require stative or continuous predicates. Anything else will be interpreted as generic if it's possible.

• I've eaten here/walked a bit/*hit Max/*graduated from college since 1960.

but graduating from college is something you only do once, so you need a different type of Perfect

(b) The Existential sense of the Perfect, used to indicate the existence of past events

• I have read Bridge of Birds five times.

Existential Perfects work with punctual predicates like graduate from college. The Perfect and the past tense both can describe the same event or state, but with the Perfect the emphasis is on the fact that it happened, whereas in the past it's just ordinary past notation. The next question to ask, of course, is why the speaker was concerned with its occurrence.