It may seem that getting instant results would enhance learning, but various studies indicate a benefit to feedback that is delayed. Test takers are more likely to retain the correct answer if they receive it several seconds after providing their answers rather than immediately.
To understand why delayed answers improve learning, researchers at Iowa State University asked college students to give their best guess to trivia questions such as “Who coined the word ‘nerd’?” and “What color is a grasshopper's blood?” and to rate how curious they were about each answer. For half of the items, participants learned the correct answer immediately after responding to the question. For the remaining items, the answers either followed a four-second delay or an unpredictable interval of two, four or eight seconds. The students were then tested on the questions after engaging in unrelated distracting tasks.
The results, which were published in the November 2014 issue of Memory & Cognition, confirm the benefit of delayed feedback and show that it hinges on curiosity: in follow-up tests, participants answered more accurately when feedback arrived later but only for items that piqued their interest. The researchers suggest that delayed feedback encourages learners to anticipate the answer, which may increase their level of attention to it when they receive it. The effect was strongest when feedback was presented at unpredictable intervals, which is in line with previous studies showing that attention is enhanced when an upcoming event's timing is uncertain. So if you are studying with a buddy, ask that person to give you the answers after an unpredictable delay of a few seconds. If you are working alone, resist the urge to Google or look up an answer immediately and take a guess first.
By the way, Dr. Seuss coined the word “nerd,” and a grasshopper's blood is white. If you were wondering about these answers, that delay may have just sealed them in your memory forever.