When should one use the simple past or the present perfect in summaries?

Present perfect tense is the less specific of the two: "I have eaten horse meat" informs the listener that the speaker has, at some point in his past, eaten a kind of meat that most people avoid. Simple past tense is a lot more specific: "I ate horse meat yesterday." The listener knows not only that the speaker has eaten it in the past, but specifically when.

Suppose you were applying for a job at...

Present perfect tense is the less specific of the two: "I have eaten horse meat" informs the listener that the speaker has, at some point in his past, eaten a kind of meat that most people avoid. Simple past tense is a lot more specific: "I ate horse meat yesterday." The listener knows not only that the speaker has eaten it in the past, but specifically when.

Suppose you were applying for a job at a very specialized restaurant. They have horse meat on the menu and want to know if you are squeamish about eating, preparing or recommending this delicacy to their clientele. their first question might be "Have you eaten horse meat?" The present perfect is the right way to answer: "Yes, I have eaten horse meat." In your resume of life experiences, eating this is on the list. But eating horse flesh is suddenly popular, because a famous rock star just announced he loves eating it. So now the restauranteur wants to know: "Is this something you did a long time ago as a child, or if it's something you've done recently, so the details are vivid?" And you want to give a detailed, specific answer: "Why yes, I ate horse meat last night. It was delicious!"