Few subjects cause as many headaches for language learners as new verb tenses, and for students of English, the present perfect tense is a frequent source of exasperation. Because it's used to express actions in the past that are still relevant to the present, we use it often in scientific discourse to discuss past research or hypotheses. Indeed, it's used abundantly in the Introduction and Discussion sections of scientific papers when authors describe how past work is relevant to their own. However, when describing anything that has already taken place, the simple past tense also plays an important role. If you're feeling a bit unsure about when to use each tense, and how to use them together, here are some simple guidelines to help you:
1. Use the simple past for actions that occurred one or several times in the past, but do not continue to occur today.
Examples:
"This technique was used until the 1980s, when technological improvements rendered it obsolete."
"The data supported our hypothesis."
2. Use the present perfect when describing an action or body of research that took place in the past, but pertains to your research today.
Examples:
"This technique has been used since the 1980s, and has been shown to be highly efficacious (Smith, 1984; Jones, 1995; Zhang et al., 2002)."
Here, it is implied through the use of the present perfect that this technique was used in the past, continues to be used today, and during that entire time has been highly efficacious.
"Until now, most published data have been consistent with this hypothesis."
Instead of referring to a single set of data that tested one hypothesis at a specific moment in time, as in #1, here we're referring to data collected over a period of time that have continually supported the hypothesis until the present day.
3. If you are referring to a single study, you may use the simple past, but if you refer to multiple studies or an on-going body of work, the present perfect is better.
Example:
Simple past: "In their 2010 paper, Kapolsky and Slater highlighted the need for more precise methods."
Present perfect: "The research of Kapolsky and Slater (2010; 2011) has highlighted the need for more precise methods."
"Research" is an somewhat abstract term, encompassing various experiments that Kapolsky and Slater have performed (and, implicitly, continue to perform) that are relevant to the subject topic.
4. Use the two tenses together when you're expressing past actions that occurred over a period of time and that are still relevant today (present perfect), punctuated by a single, completed event (simple past).
Example:
"Ever since she introduced her famous hypothesis in a 2000 Nature paper, Jenson's work has been highly regarded."
"She introduced" is in the simple past because it happened once, and the action was completed. The present perfect is used in the second clause because the hypothesis has been highly regarded in the past and continues to be highly regarded today.
Wondering about examples from your own work? Post them in the comments and we can help!
1. Use the simple past for actions that occurred one or several times in the past, but do not continue to occur today.
Examples:
"This technique was used until the 1980s, when technological improvements rendered it obsolete."
"The data supported our hypothesis."
2. Use the present perfect when describing an action or body of research that took place in the past, but pertains to your research today.
Examples:
"This technique has been used since the 1980s, and has been shown to be highly efficacious (Smith, 1984; Jones, 1995; Zhang et al., 2002)."
Here, it is implied through the use of the present perfect that this technique was used in the past, continues to be used today, and during that entire time has been highly efficacious.
"Until now, most published data have been consistent with this hypothesis."
Instead of referring to a single set of data that tested one hypothesis at a specific moment in time, as in #1, here we're referring to data collected over a period of time that have continually supported the hypothesis until the present day.
3. If you are referring to a single study, you may use the simple past, but if you refer to multiple studies or an on-going body of work, the present perfect is better.
Example:
Simple past: "In their 2010 paper, Kapolsky and Slater highlighted the need for more precise methods."
Present perfect: "The research of Kapolsky and Slater (2010; 2011) has highlighted the need for more precise methods."
"Research" is an somewhat abstract term, encompassing various experiments that Kapolsky and Slater have performed (and, implicitly, continue to perform) that are relevant to the subject topic.
4. Use the two tenses together when you're expressing past actions that occurred over a period of time and that are still relevant today (present perfect), punctuated by a single, completed event (simple past).
Example:
"Ever since she introduced her famous hypothesis in a 2000 Nature paper, Jenson's work has been highly regarded."
"She introduced" is in the simple past because it happened once, and the action was completed. The present perfect is used in the second clause because the hypothesis has been highly regarded in the past and continues to be highly regarded today.
Wondering about examples from your own work? Post them in the comments and we can help!
RSS Feed
