Writing logical paragraphs starts with putting things in context

We need context to understand essentially everything, at every scale. At the level of the whole paper, we need to understand the question before being able to understand the answer; we need to understand an author’s conclusion before we can decide whether their evidence for it is sufficient. We also need the context first at the level of the paragraph and the sentence. If new information appears first, we will struggle to understand what we’re reading. After hearing the context afterward, we’ll then have to go back and read the first part again to really get it. Constantly going back and forth to re-read sentences and paragraphs is what makes a text hard to follow.

Readers expect the first part of a sentence or paragraph to represent the topic, contextual or familiar information. So what represents context in scientific texts? Context is what readers already know, or need to know to understand what comes next. The context is often a description of the main topic, a system, a biological context, or an experimental design, and is typically information that applies to the entire sentence.

Conversely, readers expect the last part of a sentence to contain the new, interesting, or important information. We naturally stress what comes at the end of sentences (and paragraphs), and if it’s not really the most interesting point, we are easily lost. Moving the new and interesting to the ends of your sentences therefore not only makes for easier reading, it gives the content more impact. What is new or interesting information? Often a phenotype, result, or assertion based on evidence.

Consider this example:

Only 1% of BC-derived DRG neurons express the proprioceptive afferent marker parvalbumin, as compared to 10−15% of the total DRG neuron population.

The topic of this sentence is the expression of the marker in different cell populations, and the interesting part is that a subpopulation of neurons doesn’t express this marker as frequently (the whole point of this paper is that the subpopulation is unique). If we shift the contextual and interesting information to their rightful places in the sentence, we get this version:

The proprioceptive afferent marker parvalbumin is expressed in 10-15% of the total DRG neuron population, but in only 1% of DRG neurons derived from BC cells.

Because we mentally emphasize what comes at the end of a sentence, putting the most important point there makes the sentence seem stronger and more convincing.

Here’s another example:

The mGluR5 antagonist MPEP (2-methyl-6-(phenylethynyl)pyridine) can rescue altered dendritic spine morphology as well as behavioral and cognitive deficits in different models of fragile X syndrome.

The context of this sentence is the disease, fragile X syndrome. The interesting and important part is that a particular protein can rescue certain phenotypes. If we rearrange the contextual and interesting information, we get this easier-to-follow version:

In different models of fragile X syndrome, the mGluR5 antagonist MPEP (2-methyl-6-(phenylethynyl)pyridine) can rescue altered dendritic spine morphology as well as behavioral and cognitive deficits.

The ordering of contextual and new information makes an enormous difference in the readability of a paragraph. Here is the above sentence in its original context in a paragraph. This section of the paper discusses different strategies to rescue the phenotypes seen in different disease models:

The second strategy is repression of mRNA translation by inhibiting the action of the group 1 metabotropic glutamate receptors mGluR1 and mGluR5. A 50% reduction in mGluR5 expression decreased excess translation and improved behavior in the fragile X mouse model. The mGluR5 antagonist MPEP (2-methyl-6-(phenylethynyl)pyridine) can rescue altered dendritic spine morphology as well as behavioral and cognitive deficits in different models of fragile X syndrome. Chronic treatments with CTEP, a high affinity, long-acting and orally bioavailable mGluR inhibitor, restored cognitive functions, ameliorated auditory hypersensitivity, aberrant dendritic spine density and overactive extracellular signal–regulated kinase (ERK) and mTOR signaling, and partially corrected the macroorchidism observed in male mouse models of fragile X syndrome.

If we revise each sentence to place context first and new information second, the data become much clearer:

The second strategy is repression of mRNA translation by inhibiting the action of the group 1 metabotropic glutamate receptors mGluR1 and mGluR5. In the fragile X mouse model, a 50% reduction in mGluR5 expression decreased excess translation and improved behavior. In different models of fragile X syndrome, the mGluR5 antagonist MPEP (2-methyl-6-(phenylethynyl)pyridine) can rescue altered dendritic spine morphology as well as behavioral and cognitive deficits. In male mouse models of fragile X syndrome, chronic treatments with a high-affinity, long-acting and orally bioavailable mGluR inhibitor, CTEP, restored cognitive functions, ameliorated auditory hypersensitivity, aberrant dendritic spine density and overactive extracellular signal–regulated kinase (ERK) and mTOR signaling, and partially corrected their macroorchidism.

Instead of stressing the different mouse models, this revised versions stresses the rescued phenotypes. We could continue to revise this paragraph for concision and coherence (and will in an upcoming post!), but already it’s easier to follow.

Take a look at a few of your own sentences, and underline the contextual and new or important information. Does the context or topic come first? Does the most important point arrive at the end of the sentence?

Patricia Gongal works with researchers to improve the structure, clarity, flow, and style of their scientific writing, and has lots of opinions about science and academia.

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