More than anything, your abstract should be perfect, because it is all most people will read. It shouldn’t tease, or hint, but should be the whole paper, writ small. This is not so easy to do, but is worth the effort. I find it useful to have models, not just lists of instructions, so here is what I think is a great model, by Lindsey Walters of Northern Kentucky University, presented last week at the Animal Behavior Society. OK, maybe the title isn’t perfect.I like to always know which way the influence goes. But here is the abstract with commentary:
Title: Egg color influences the nestling provisioning rate of male house wrens. I think a better title would be: Male house wrens increase provisioning of babies from eggs that indicate more female investment, as indicated by egg color. Well, I like my title better because it tells which way the influence goes, and that is important, but it is clunky, so maybe leaving that vague in the title is ok.
Then Lindsey says in Sentence 1: Recent research suggests that female birds could use eggshell color as a signal to advertise their quality or investment in order to secure more parental care from their mates. This sentence very clearly tells what the paper is going to be about. It is about variation in egg color in the nest, and a potential adaptive explanation for it. There is a lot packed in there, and she may not really address it all. Here’s a list. 1. Eggshell color varies with the quality of contents. 2. Females have evolved to use this to advertise high quality. 3. Males detect the variation. 4. Males have evolved to invest more in higher quality babies. 4. Males use this signal to do this investing. You could imagine that males would invest less in higher quality babies, assuming mom could pick up the slack. You could also imagine that males pick up on the difference, but it is just an incidental effect to laying good eggs, not a strategy by the females. But, hey, we are only one sentence along!
Sentence 2. Previous studies have found support for this hypothesis in bird species that lay blue eggs, but it has not been thoroughly tested in species that lay brown eggs. I love this sentence. In one fell swoop, Lindsey tells us what has gone before, and what she will do to add to it. So many abstracts sound like their study was the first ever on the planet. Tell us what went before, and how your work will extend the previous work. In this case, Lindsey is lucky because this is particularly clear.
Sentence 3. In house wrens (Troglodytes aedon), browner eggs are associated with lower female investment. With this sentence, Lindsey gives us the background information we need. We know we need it, and are reassured. Don’t give us information on your system until you have told us why we need it. Then, only tell us what we need to know. I know you love your species, and there are lots of cool and irrelevant details, but this is not the time to share them. (Have you ever heard a house wren sing? Lovely.)
Sentence 4. I present results from a study testing whether males respond to this potential cue. This sentence uses active voice, and says what Lindsey does. She softens the first sentence of the abstract by calling the egg color a “potential cue.” It sets us up to be ready to hear how she did this, and what she found, and Lindsey does not disappoint.
Sentence 5. I experimentally manipulated egg color by randomly adding either a brown or white plastic egg to each nest during incubation. OK, this is what she did. It is an experiment, and it is clear.
Sentence 6. Male house wrens whose nests had received a white egg provisioned their nestlings at significantly higher rates than males whose nests had received a brown egg. Here are the results, with directionality clear. Now I’m expecting to hear what she thinks this means for this study, and then what it means generally, and again, Lindsey delivers.
Sentence 7. These results suggest that male house wrens pay attention to female investment when deciding how much energy they should spend on nestling provisioning. This is her interpretation of her results, and how they address the hypothesis in the second sentence.
Sentence 8. This study supports the generality of the hypothesis of egg color as a sexually selected signal by demonstrating for the first time that males of a species with brown eggs also respond to egg color. This sentence ties her study to the most general first sentence. I’m not a fan of claiming first for anything, so I would change that. In fact, the Proceedings of the National Academy of Sciences forbids any mention of first. You can’t even say things like novel for their high-profile journal.
There, that’s it. Eight clear sentences. You may disagree with the conclusions, the methods, whatever, but what Lindsey has done and what she thinks about it is clear. By the way, she was one of the 4 winners of the Founders’ Award, and not just because of the abstract – there were 8 other judges who decided this. (And yes, she did give me permission to reprint her abstract, though she had no idea how I would deconstruct it.)