6.1 Stereotypes concerning explicitness in academic research writing

Researchers have often claimed that academic writing is explicit in meaning, especially in contrast to the vague and implicit expression of meaning in conversation. That is, while speech is dependent on a shared situational context, academic writing is claimed to be ‘decontextualized’, ‘autonomous’, and ‘explicit’ (see, e.g., DeVito Reference DeVito1966; Olson Reference Olson1977; Kay Reference Kay, Blount and Sanches1977; Johns Reference Johns1997: 58–64). This ideal is also commonly advocated by writing instructors, who urge students to overtly encode all assumptions and logical relations in the written text. There is little possibility of direct interaction between the writer and a reader of an academic written text, and thus essentially no possibility for clarification if the meaning is not clear and explicit from the text itself. As a result, academic writing is purported to be maximally explicit in the expression of meaning.

In Chapter 1 (see Section 1.2.2), we documented the dominant and pervasive view that academic writing can be characterized as employing an elaborated and explicit discourse style. These characterizations rely on terms such as complexity, elaboration, specificity, and clarity both to describe published academic writing and to identify desired characteristics in student academic writing. It would be nearly impossible to read current writing research and not come away with a general belief that academic writing is ‘complex’, ‘elaborated’, and ‘explicit’.

Functional linguists have made related claims regarding the use of more or less explicit grammatical variants. In particular, Rohdenburg (Reference Rohdenburg1996: 151) argues that linguistic variation is constrained by the ‘complexity principle’: ‘in the case of more or less explicit grammatical variants, the more explicit ones tend to be preferred in cognitively more complex environments’. The more explicit variants are more elaborated structurally, with additional grammatical function words or morphemes. For example, the to-infinitive is regarded as more explicit than the bare infinitive; complement clauses with the complementizer that are more explicit than complement clauses with a ‘zero’ complementizer; and finite complement clauses are regarded as more explicit than non-finite complement clauses.

Rohdenburg approaches cognitive complexity from the perspective of syntactic environment. For example, occurrence in a passive voice construction would be regarded as more cognitively complex than occurrence in an active voice construction. The central claim underlying the ‘complexity principle’ is that increased cognitive complexity of the syntactic environment encourages the use of more explicit grammatical variants.

However, by extension it might be expected that the increased cognitive complexity associated with the informational focus of written academic texts would also result in the use of more explicit grammatical variants. And this is exactly the relationship claimed in many previous descriptions of academic writing (see discussion in Section 1.2.2).

In the preceding chapters, we have presented strong evidence to challenge the stereotype that academic research writing is structurally elaborated. In fact, just the opposite is the case: academic prose – especially science research writing – relies heavily on extremely compressed grammatical structures, and it has evolved steadily over the last century to favor compressed structures over more elaborated alternatives.

It turns out that there has been a concomitant historical shift towards increasingly inexplicit expression of meaning, further contradicting preconceived stereotypes. That is, in direct contradiction to the proscriptions of writing instructors and the expectations of writing researchers, the preferred grammatical structures of academic research writing are much less explicit in meaning than alternative, more elaborated structures. There can be no doubt that written academic texts are more cognitively demanding and complex than most conversational or popular written texts. However, despite this increased cognitive load, written academic texts systematically prefer compressed structural variants, resulting in a dense use of grammatical structures that are inexplicit in meaning on a scale that has not been generally appreciated. We explore these meaning relationships in detail in the following sections.

6.2 Explicitness of reference in conversation versus academic writing

It is uncontroversial that spoken conversation is often inexplicit, with conversational participants frequently employing expressions with vague and/or implicit references. Conversational participants share the same physical place and time, they often share extensive personal knowledge about each other, and they have the opportunity to interact and thus clarify any misunderstandings. As a result, spoken discourse relies heavily on pronouns, adverbs, definite noun phrases, ellipsis, and deictic expressions that refer directly to the situational context (or to the participants themselves). The meaning of these forms is not explicit, because the words have no referential meaning outside of a particular situational context. Consider the following example (pronouns are underlined; situated place adverbials in bold):

Even full noun phrases are often situation-dependent in conversation. Thus, based only on the written transcript, we are not able to identify the specific reference of ‘the house,’ ‘that envelope,’ ‘the camera,’ and ‘the camera shop’. However, these noun phrases all have specific references that were easily understood by these conversational participants, who shared the same physical situation and background information.

Situated reference of this type is virtually non-existent in professional academic writing. The reader almost never shares time and place with the author of a written academic text. However, other types of situated reference are present in academic writing. Deictic pronouns can be used to refer to the academic text itself, or to the propositions put forward in the text. Thus, consider:

In this example, the text itself provides a context, and so pronouns can be used to refer directly to a part of that text.

However, imagine the difficulties for reader comprehension if an author referred directly to the actual time and place where he/she was writing. So, for example, imagine that one of us pointed to a graph in a book that was sitting on the desk, and we wrote This shows that pronouns are more common in conversation than in writing. Unless we had previously referred to ‘the graph’ in the text itself, readers would have no clue what this referred to. This characteristic holds generally for referring expressions in written texts: if the author fails to use explicit referring expressions, readers will have no chance of identifying the intended reference of those expressions. From that perspective, academic writing is much more explicit in meaning than conversation.

However, an additional consideration is the way in which meaning relations are expressed among grammatical constituents, and in this respect, academic writing is anything but explicit. In fact, it has changed historically to strongly prefer grammatical styles that are dramatically less explicit than in earlier periods.

For example, nominalizations and passives entail reduced explicitness because they omit certain structural elements (see Halliday Reference Halliday and Page1979; Halliday and Martin Reference Halliday and Martin1993). Thus, compare:

1. a) The Department of Water and Power manages hazardous waste >>

   1. b) hazardous waste is managed >>

      1. c) hazardous waste management

In the passive construction (b), we no longer know who the ‘agent’ is. In the nominalized construction (c), it is not even explicitly stated that an activity is occurring. Nominalizations are also inexplicit about the time reference of activities. The clausal constructions in (a) and (b) are marked for tense (compare someone manages hazardous waste and hazardous waste is managed), and they have the potential to be marked for aspect (compare someone has managed hazardous waste and hazardous waste had been managed). However, there is no possibility of expressing tense and aspect in the nominalized version (c); the time reference is implicit and must be inferred by the reader.

The loss of explicit meaning associated with nominalizations and passives has been discussed in previous studies by Halliday (see, e.g., Halliday Reference Halliday and Page1979; Halliday and Martin Reference Halliday and Martin1993). However, what has been less noticed is that there is a large set of compressed structural devices that behave in similar ways: they are all prevalent in academic writing, and they all result in less explicit meanings. Nominalizations and passives are part of this overall pattern, but there are numerous other grammatical devices that are even more common and similarly inexplicit. In particular, the many forms of phrasal (as opposed to clausal) modification described in the preceding chapters all result in a loss of explicitness. In the following sections, we describe the lack of explicitness associated with the most important of those features.

6.3 Inexplicit meaning relationships associated with phrasal pre-modifiers in noun phrases

From a quantitative perspective, many of the most dramatic historical changes documented in the preceding chapters involve the increased use of phrasal NP pre-modifiers in academic writing (see, e.g., Figure 4.5). Nouns as pre-modifiers of a head noun are the most common of these features. Such structures are ubiquitous in present-day informational prose, and as a result, it is easy to gloss over the inexplicit meaning relationships among the elements of these constructions. However, it turns out that these phrasal pre-modifiers represent an extremely wide range of meaning relationships to the head noun, with no overt grammatical marker as to which relationship applies to a particular noun–noun combination. As a result, we could almost characterize these structures as being maximally inexplicit in meaning: exactly the opposite of the stereotypes concerning what we would expect in academic writing.

For example, consider the meaning relationship between a head noun and a pre-modifying noun, as in the noun phrase heart disease. There are no grammatical clues to help the reader know what the meaning relation is between the two nouns. The surprising fact is that there is an extremely wide range of meanings possible between the two nouns, and thus there is no automatic way to determine the relationship between the two nouns. Rather, the reader must rely on background knowledge (often expert knowledge associated with specific specializations) to infer the relationship between the two nouns. Thus consider:

heart disease

a disease located in the heart

prison officials

officials who work in a prison

union assets

assets that belong to a union

age group

a group of people who are the same age

casualty department

the department that deals with casualties

emergency powers

powers that are in force during times of emergency

income tax

a tax based on your income

monopoly act

an act to prevent monopolies

peace conference

a conference that attempts to establish peace

press conference

an interview (or conference) of a celebrity or spokesperson with newspaper reporters

price commission

the commission that regulates prices

sector strike

a strike involving a particular sector of the economy

sex differences

differences between the two sexes

television interview

an interview that is broadcast on television

time interval

the interval, measured in time, between two events

computation time

the time required to compute something

pressure hose

a hose able to withstand pressure

pressure ratio

a ratio that measures pressure

wage increases

something increases wages

weight loss

something or someone loses weight

the population decrease

the population decreases; that is, something causes the population to become smaller

teacher training

someone trains teachers

population averaging

someone averages the population statistics

concentration adjustment

someone adjusts the concentration

fault displacement

something displaces the fault

alcohol consumption

someone consumes alcohol

the 3He absorption

something absorbs the 3He

parameter calculations

someone calculates the parameters

drug resistance

someone/thing resists drugs

a government offer

the government offers something

a Treasury decision

the Department of Treasury decides something

the spring decrease

the decrease that occurs in spring

preshift training

training that occurred during the preshift period

short-term training

training that occurs for a short term

downslope movement

something moves down slope

the chamber concentration

the concentration of something in the chamber

unit variance

something varies with a unit of one

the Dred Scott decision

the courts decided something in the case involving Dred Scott

a two-stage decision

someone decided something, and the process required two stages

heat treatment

someone treated something, and heat was the instrument

climate information

someone informed someone about climate

hand calculations

someone calculated something, using ‘by hand’ methods

human-environment interaction

humans interact with the environment

Monte Carlo variance

something varies in a certain way determined through Monte Carlo methods of analysis

In most cases, the individual nouns used as NP pre-modifiers are not rare or technical words (e.g., nouns like hand, heat, climate, two-stage, unit, spring, government, drug, and teacher in the aforementioned examples). However, because the meaning relationship between the modifying noun and head noun can be so varied, with no explicit indication of the relationship, these combinations can be extremely difficult to comprehend, especially for non-expert readers.

For example, the following sentence, taken from a psychology research article, contains three noun phrases with a noun pre-modifier:

The last noun phrase with a noun pre-modifier, which actually utilizes the most technical vocabulary, is probably the easiest to understand: ‘anxiety’ is the semantic patient of ‘reduction’ (i.e., something reduces anxiety). However, the other two cases are much more difficult to understand, even though the pre-modifying noun is not especially technical. A careful reading of this article shows that punishment training refers to a kind of training where subjects are punished for incorrect behavior. Thus, ‘punishment’ is neither the agent nor patient of ‘training’; it rather has a kind of specialized instrumental semantic relationship to ‘training’. The interpretation of sign function is even more problematic: this combination occurred only once in this research article, and the term ‘sign’ was also not used again in the article. We thus have no idea what the intended meaning is for this combination. Such combinations are not at all uncommon in specialist academic prose; the individual words are usually easy to understand, but without specialist background knowledge, it is not possible to determine the exact intended meaning relationship between the modifier and the head noun.

We have discussed nouns as noun pre-modifiers in detail because they are the most frequent compressed structural device. However, all phrasal forms of modification preferred in academic writing are inexplicit in similar ways. For example, nouns are often compounded with adjectives, which are in turn used to pre-modify a head noun. These structures incorporate multiple complex but inexplicit meaning relations, as in:

• aspirin-resistant patients

  • [compare: patients who resist aspirin]

• an ATP-dependent conformational change

  • [compare: a change that is conformational and that depends on ATP]

Noun–participle compounds functioning as NP pre-modifiers are similarly inexplicit. The use of these structures enables an extremely dense packaging of information, as in:

• This study considers the role of the cytoplasmic segments of Sed61a in the ribosome-binding and translocation-promoting activities of the Sec61 complex.

• actinomycin-treated, RNA-depleted cells effectively support the growth of Mengovirus meanings

Although there are no overt grammatical signals, the grammatical meaning relations underlying ‘N1-ing-participle N2’ constructions are relatively easy to process, because they always express a single meaning: the pre-modifying noun (N1) is the semantic patient of the -ing verb, and the head noun (N2) is the effective agent of the -ing verb. Thus, compare:

• reef-building corals

  • [compare: the corals build the reefs]

• electron-scattering material

  • [compare: the material scatters the electrons]

• ribosome-binding and translocation-promoting activities of the Sec61 complex

  • [compare: the activities of the Sec61 complex bind ribosome and they promote translocation]

In contrast, ‘N1-ed-participle N2’ constructions can represent a range of different meaning relations. Some of these constructions can be directly paraphrased as a non-finite passive voice post-modifying clause, as in:

• a neutron-activated specimen

  • [compare: a specimen activated by a neutron]

• a lead-shielded crystal

  • [compare: a crystal shielded by lead]

• wind-baked ruffians

  • [compare: ruffians baked by the wind]

• a Puritan-ruled state

  • [compare: a state ruled by Puritans]

• teacher-requested prosocial behavior

  • [compare: prosocial behavior requested by the teacher]

But in many other cases, the compounded -ed participle needs to be expressed as a prepositional verb when the structure is rephrased. The specific preposition has been omitted in the compounded pre-modifying structure, but it is required in the clausal construction. For example:

• research-based instructional improvement

  • [compare: instructional improvement based on research]

• sex-related differences

  • [compare: differences related to sex]

• actin-linked mechanisms

  • [compare: mechanisms linked to actin]

• goal-directed play

  • [compare: play directed towards a goal]

• infusion-treated patients

  • [compare: patients treated with an infusion]

In some cases, the omission of the required preposition in the pre-modifying compound can actually lead to uncertainty regarding the intended meaning. For example, consider the following example, containing two ‘N1-ed-participle N2’ modifiers:

• The granules are best seen in sections of OSO₄-fixed, plastic-embedded tissue.

These pre-modifying compounds might be paraphrased with different prepositions:

And this choice of preposition can result in fundamentally different meanings; for example:

• tissue embedded in plastic [compare: the tissue is embedded in the plastic]

•      versus

• tissue embedded with plastic [compare: the plastic is embedded in the tissue]

Thus, for the non-specialist reader, the inexplicit meaning relationships inherent with many attested examples of these ‘N1-ed-participle N2’ constructions may lead to lack of comprehension, ambiguity of meaning, or even incorrect interpretations of the relationship between N1 and N2.

More detailed consideration of ‘N1-ed-participle N2’ constructions shows that they are inexplicit at an even more fundamental level, relating to the semantic relationship between the two nouns and the participle. In cases where the participle can be paraphrased as a simple verb, the pre-modifying noun (N1) is the semantic agent of the -ed verb, and the head noun (N2) is the patient of the -ed verb. For example:

• a neutron-activated specimen

  • [compare: a specimen activated by a neutron >> a neutron activates the specimen]

• a lead-shielded crystal

  • [compare: a crystal shielded by lead >> lead shields the crystal]

• wind-baked ruffians

  • [compare: ruffians baked by the wind >> wind baked the ruffians]

• a Puritan-ruled state

  • [compare: a state ruled by Puritans >> Puritans ruled the state]

• teacher-requested prosocial behavior

  • [compare: prosocial behavior requested by the teacher >> the teacher requested the prosocial behavior]

However, cases where the participle would be paraphrased as a prepositional verb represent a completely different semantic relationship: both nouns are complements of the verb, and the agent is unspecified. For example:

• research-based instructional improvement

  • [compare: instructional improvement based on research >> someone based instructional improvements on their research]

• sex-related differences

  • [compare: differences related to sex >> someone related those differences to sex]

• actin-linked mechanisms

  • [compare: mechanisms linked to actin >> someone linked related those mechanisms to actin]

• goal-directed play

  • [compare: play directed towards a goal >> some group of children directed their play towards a goal]

• infusion-treated patients

  • [compare: patients treated with an infusion >> some medical professional treated patients with an infusion]

The inexplicitness of these constructions is even more complicated when there is another pre-modifying noun, resulting in the ‘N1-ed-participle N2 N3’ pattern. In some cases, it is relatively easy to infer that the N1-ed-participle compound modifies N2, but in other cases, we can infer that the N1-ed compound modifies N3. Thus contrast:

1. a) Accountability-based school reform is not without paradox.

   • versus

2. b) This organization is completely student run and operates as a collective of five student-initiated recruitment centers.

In (a), it is relatively easy to infer that the ‘reforms’ (N3) are based on ‘accountability’ (N1); it would not make sense for the ‘schools’ (N2) to be based on ‘accountability’ (N1). However, in (b), the opposite situation holds, where we can infer that the ‘recruitment’ (N2) is initiated by ‘students’ (N1); in this case, it makes little sense for the ‘centers’ (N3) to be initiated by ‘students’ (N1).

In some cases, inferences like these are facilitated by the core meanings of the nouns (N2 and N3). However, in many other cases, the N1-ed-participle compound could easily modify either noun, and expert background knowledge is required to determine the intended meaning. This is the case even when the specific nouns are non-technical and familiar to the reader. For example, contrast the following:

• The present study was based on […] a decade of accountability-focused reform efforts.

  • [compare: the reforms (N2) are focused on accountability

    versus

    the efforts (N3) are focused on accountability]

• A range of other legislative and court-based change efforts had been attempted.

  • [compare: the change (N2) is based on courts

    versus

    the efforts (N3) are based on courts]

• NCES-constructed student-level panel weights […] can be used to generate national population estimates.

  • [compare: the panels (N2) are constructed by the NCES

    versus

    the weights (N3) are constructed by the NCES]

• The prevalence of airway obstruction and self-reported disease status were calculated…

  • [compare: the disease (N2) was reported by self

    versus

    the status (N3) of the disease was reported by self ]

Of course, the inexplicitness of intended meaning becomes even more problematic with longer structures or with structures that employ technical vocabulary. Thus, consider the following examples:

• Moreover, yeast centromeres cluster near the membrane-embedded spindle pole body.

• With the combination of test-generated error variance and between-cohort variance, it was inevitable that schools would produce a certain amount of ‘noise’.

• … on the mechanisms of ATP-induced shape changes in human erythrocyte membranes.

• … predicting the impacts of harvesting using stage-structured population models

• An ARU:550 indicates the absence of aspirin-induced platelet dysfunction.

• … the multiple actions of GLP-1 on the process of glucose-stimulated insulin secretion.

In all the aforementioned examples, the compound is hyphenated (e.g., accountability-focused, self-reported). In this case, the hyphen provides an overt signal that the participle should be interpreted as the modifier of the preceding noun (rather than as a modifier of the following noun). However, it has recently become common in science writing for these structures to occur without the hyphen – a shift towards an even less explicit representation of the meaning relationship among elements. It turns out that these sequences can in fact be used to express different meaning relations. In some cases, these sequences function as if there were a hyphen, so that the -ing participle modifies N1, and the entire N1 + -ing participle compound modifies the head noun (N2). In these structures, N1 functions as the semantic patient of the -ing participle. For example:

• PLK1 treatment partly inhibited the filament forming ability of vimentin

  • [compare: the ability to form filament, but NOT abilities for forming and abilities for filaments]

• … each experiment was initiated with 1.1 × 106 colony forming units

  • [compare: units that form colonies, but NOT units that form, and units for colonies]

However, there are other structurally-similar examples where both N1 and the -ing participle directly modify the head noun (N2); for example:

• weapons training program

  • [compare: a program that trains people in the use of weapons;

  • that is, a program for training, which is also a program for weapons, but NOT a program that trains weapons]

• high resolution imaging techniques

  • [compare: techniques for imaging, which are also techniques that produce high resolution, but NOT techniques for imaging high resolution]

The aforementioned examples are difficult to comprehend, even when they employ non-technical vocabulary. Longer sequences become even more difficult to process. Thus, consider:

• item difficulty rating screens

  • [compare: screens where participants can rate the difficulty of items]

• item difficulty rating accuracy

  • [compare: the accuracy with which participants have rated the difficulty of items]

• ground truth data sets

  • [compare: sets of data that represent truthful information as it is observed on the ground]

Furthermore, as technical vocabulary is utilized, the inexplicitness resulting from these compressed phrasal constructions becomes even more apparent to the non-specialist reader. In such cases, a non-specialist reader may have little knowledge of the possible meaning relationships between the head nouns and their modifiers. The lack of knowledge about the content meanings of the individual words makes it even more difficult to form hypotheses about the intended meaning of the construction;Footnote ¹ for example:

• mRNA decapping trigger apoptosis in yeast

• GPI-mediated PRP membrane attachment

• a high-accuracy human primary T cell signaling causality map

6.4 Inexplicit meaning relationships associated with phrasal post-modifiers in noun phrases

Most NP post-modifiers have an overt grammatical signal that marks the existence of an embedded structure, providing an indication of the meaning relationship between the head noun and modifier. Finite relative clauses provide the most grammatical information: a full verb phrase that expresses tense, aspect voice, and modality, together with the main verb itself, which expresses a specific meaning relationship between the head noun and the other constituents of the relative clause. Non-finite relative clauses omit the expression of tense/modality, but they are otherwise as explicit as finite relatives. Prepositional phrases as noun modifiers are considerably less explicit, because the preposition is the only indication of the meaning relationship between the head noun and modifying noun phrase (see the following discussion). However, at the opposite extreme from finite relative clauses, appositive noun phrases are similar to NP pre-modifiers in that they have no overt grammatical signals to indicate the intended meaning relation to the head noun.

As described in earlier chapters, appositive structures comprise two noun phrases that occur in sequence, separated by a comma or parentheses. Traditionally, the meaning relationship is straightforward, and thus there was really no need for overt grammatical signals: the two noun phrases are simply co-referential, with each one providing different descriptive information. The typical use in newspaper writing is even more constrained, where the first noun phrase is often a proper noun, and the second noun phrase clarifies the identity or provides descriptive information that would help to specify the reference. The examples follow this pattern, with NP1 (bolded) as a proper noun and the appositive NP2 (underlined) clarifying the identity of that proper noun:

• And so in the middle of Chuseok, the Korean Thanksgiving, Ban was on the phone to his counterparts in Moscow.

• “This will be the first time he’s ever been his own boss,” says Peter Beck, the Seoul-based director of the International Crisis Group’s Northeast Asia project.

In such cases, the meaning relationship is not problematic, because it is almost always a simple identity; for example, Chuseok is the Korean Thanksgiving, and Peter Beck is the Seoul-based director.

In some cases, multiple appositive noun phrases can be embedded, with each one providing additional information about the referent. For example, the following sentence contains two appositive noun phrases, with the second appositive modifying a head noun within the first appositive:

• [The military has made] six daily runs to deliver supplies to some of Indonesia’s most remote villages – all part of Operation Unified Assistance, the largest U.S. military operation in Asia since Vietnam and the backbone of the global campaign to fend off hunger.

In this case, the first NP ‘six daily runs…’ is a part of Operation Unified Assistance, and that noun phrase is the largest U.S. military operation…

However, the use of appositive noun phrases is often less predictable, and therefore less explicit, in academic writing. In some cases, appositive noun phrases are used generally with identity meaning relationships, but even these represent many different specific functions. For example, in humanities academic writing, appositives are often used to identify a person, in a similar way to newspaper writing:

• More fundamentally, what role had Montagu Norman, the Bank’s governor, and Sir Otto Niemeyer, the director in charge of its overseas and foreign department, played…

• The Nazis attempted to secure this gold by threatening Malik and Peroutka, the relevant NBC directors.

More often, though, appositives in academic writing are used to modify an indefinite head noun phrase. In these cases, knowing the specific identity of the head noun is not crucial for the main argument, but providing the specific identity adds credibility. This use is common in both humanities and science writing; for example:

• Plots against Queen Elizabeth revealed that the first allegiance of Catholics was to a foreign prince (the pope).

• Two authors (CD, KS) independently abstracted data from all studies using standardized forms.

• Disagreements between the primary abstracters were resolved by a third author (SS).

• Two Stuart monarchs (Charles I and Charles II) were strongly suspected of Romish sympathies

• Early-onset pneumonia is usually caused by microaspiration of bacteria colonizing the oropharynx (gram-positive cocci and Haemophilus influenza)

• In a field study, we examined a guild of six large-bodied, lotic insects (Plecoptera and Trichoptera)

In other cases, the appositive provides a definition for a technical term, or vice versa:

• These are the three faculties of the soul that, according to the rhetorical tradition, make eloquence possible and need to be developed through exercise: memoria (the ability to remember one’s speech as well as the opponent’s arguments), ingenium (natural intelligence and imagination), and judicium (good sense and good taste).

• In matters of literary exegesis (enarratio poetarum) considering decorum means interpreting a text with regard to its historical context.

• A case study of wild Atlantic salmon parr (salmo salar) showed…

A related function is to provide an acronym for a technical phrase, as in:

• The risk of this complication in the intensive care unit (ICU) ranges from 8% to 25%.

• Length at first capture (LFC) adjusts for a spurious effect resulting from a data bias.

• Pulmonary involvement was defined as bibasilar pulmonary fibrosis as defined above; or crackles (“velcro” rales) plus forced vital capacity (FVC)…

Although these specialized functions differ from the typical uses in newspaper writing, they can all be regarded as sub-types of the same general function of expressing an identity relationship between two noun phrases.

However, it turns out that these are only a small subset of the full range of meanings expressed by appositives in academic research writing. For example, in humanities prose, appositives can be used to provide background commentary about an event or concept referred to by the head noun:

• The civil war ended with the triumph of the Bolshevik regime in Russia, a development that had been increasingly obvious for some months prior to late 1920.

• Blackstone often explained away apparent absurdities and contradictions in his beloved common law, the source and guarantee of English liberty, as vestiges of “the blind days of popery.”

In science research writing, appositives are often used to provide methodological details, describing the way in which a construct was measured or operationally defined in a study. In some cases, appositives identify the role of a variable in the research design, as in:

• Studies were included if mechanically ventilated patients were prospectively assigned randomly to some form of subglottic secretion drainage versus no drainage (control).

• Rehearsal technique (the independent variable) had five levels.

In other cases, appositives simply identify the technical procedures used for a measurement, as in:

• In this study we use measurements of body size (fork-length and wet-weight) to derive empirical models.

This latter function is quite common in science and medical research writing, where it is important to specify how variables were measured for the purposes of the study. Appositives are commonly used to provide these methodological details in a structurally compressed manner; for example:

• Initial scleroderma-related changes included proximal scleroderma; sclerodactyly; puffy hands (sausage-like edema lasting > 6 months)…

• We also applied the American Society of Echocardiography recommendations, in which the diagnosis of pseudonormal filling pattern (early/late diastolic flow: 1.0 to 2.0) and restrictive filling pattern (early/late diastolic flow > 2) requires evidence of structural heart disease (left atrial enlargement, left ventricular enlargement or hypertrophy).

• Trace quantities of algae or detritus (the amount that might be found in gut contents of their prey) were assigned a nominal value of 0·1.

• Hunters registered a total number of 305 roaring males during 4161 observation hours (observation time × number of observers).

• Applying the scale in a nonblinded fashion to the studies in our meta-analysis reveals that they are all of moderate quality (scores of 2 to 4 on a scale of 0 to 5).

In addition, appositives are commonly used to present research findings, such as the frequency for an observed pattern, or the specific results of a statistical analysis:

• Causes of death were renal failure (n = 30), cardiac failure (n = 42), pulmonary involvement (n = 35), and pulmonary arterial hypertension (n = 41).

• Involvement during follow-up was also related to the presence of anti-topoisomerase I antibodies (r = 0.20; P < 0.001).

• Secretion drainage shortened the duration of mechanical ventilation by 2 days (95% CI: 1.7 to 2.3 days) and the length of stay in the intensive care unit by 3 days (95% CI: 2.1 to 3.9 days), and delayed the onset of pneumonia by 6.8 days (95% CI: 5.5 to 8.1 days).

Similarly, appositives are commonly used to identify a table or figure that presents the specific results corresponding to a generalized pattern described by the head noun phrase:

• All cohorts showed significantly increased standardized mortality ratios (Figure 1).

• This study demonstrates large uncertainties in predicting the future growth of an introduced small population of muskox in Central Norway, owing mainly to the effects of environmental stochasticity (Fig. 1).

• The Medline search retrieved 110 citations, of which five met our inclusion criteria (Table 1).

In many cases, scientific prose employs an extremely high density of appositives, even with embedded appositives, each representing a different specific meaning relationship to its head noun. Thus, consider the following examples:

• The individual cohorts comprising the database differed significantly (P < 0.01 for all) in mean age at enrollment (range, 43.7 [Keio] to 55.4 [Mayo] years); proportion of men (5% [Mayo] to 39% [Nijmegen]); and diffuse cutaneous involvement at enrollment (8% [Mayo] to 51% [Pittsburgh]).

• The use of subglottic secretion drainage reduced the risk of ventilator-associated pneumonia by about half (summary risk ratio [RR] = 0.51; 95% confidence interval [CI]: 0.37 to 0.71). There was a similar reduction in the incidence of ventilator-associated pneumonia (summary rate ratio = 0.57; 95% CI: 0.33 to 0.97). […] The effects of subglottic secretion drainage on several outcomes were significantly different among the studies summarized, specifically for the duration of mechanical ventilation (heterogeneity P = 0.004), length of ICU stay (heterogeneity P <0.001), and time to onset of pneumonia (heterogeneity P <0.001) (Figures 2 and 3).

• We compared breeding phenology, i.e. the timing and synchrony of rutting (roaring, sexual aggregation) and calving of red deer (Cervus elaphus L.) in France (latitude: 49°N) and Norway (latitude: 63°N).

In summary, appositive noun phrases can be used to represent an extremely wide range of meanings in relation to the head noun. Like many other phrasal devices used to modify head nouns in modern academic writing, there are no overt grammatical signals of those meaning relationships in the appositive structure. As a result, these features provide yet another important example of the inexplicit packaging of information in academic research writing.

Prepositional phrases as NP post-modifiers differ from other phrasal noun-modifying devices in that they have a grammatical signal of the meaning relationship between the modifier and the head noun: the preposition (e.g., in, on, for, with). On first consideration, it might appear that these prepositions provide a clear, unambiguous expression of the meaning relationship. For example, in means inside; on means a position on top of something; beside means next to something; and so on. In academic writing, though, these prepositions rarely express such explicit locative (or concrete) meanings. Rather, the same preposition can be used to express a wide range of different, and often abstract, meaning relationships.

For example, consider the three prepositional phrases beginning with for in the following sentence:

• Another reason to use Ohio as a surrogate [for the country as a whole] is that the data base [for hazardous waste generation and flow] [for the State] is fairly good.

In their grammatical form, these three phrases are identical. Yet, they express three different meaning relationships. We can see those differences by considering a clausal paraphrase, which would make the meaning relationships explicit:

• a surrogate [for the country as a whole] >>

  • a surrogate that represents the country as a whole

• the data base [for hazardous waste generation] >>

  • the data base that documents hazardous waste generation

• the data base … [for the State] >>

  • the data base that the State uses

Other meaning interpretations could have been possible here, at least for the non-expert reader. For example, the data base for hazardous waste generation could mean ‘the data base used to generate hazardous waste’. Similarly, hazardous waste generation and flow for the State could mean ‘the hazardous waste that is generated and flows in the State’ or ‘the hazardous waste generation and flow that is produced for the purposes of the State’. Thus, although the preposition for restricts the range of possible meanings, it provides no explicit expression of the specific intended meaning. Rather, meaning is implicit and must be inferred by the reader.

Prepositional phrases with other prepositions are similarly inexplicit. For example, consider the wide range of meaning relationships associated with prepositional phrases beginning with in and on:

• farms in Malaysia

  • [compare: farms that are located in Malaysia]

• experiments in India

  • [compare: experiments that were conducted in India]

• experiments in agricultural chemistry

  • [compare: experiments that focused on the study of agricultural chemistry]

• a decrease in oil prices

  • [compare: oil prices decreased]

• the roots on the surface

  • [compare: roots which are on top of the surface]

• restrictions on underground injection of chemicals

  • [compare: rules that restrict the underground injection of chemicals]

• writers on style

  • [compare: writers who discuss style]

The loss of meaning associated with noun-modifying prepositional phrases becomes especially apparent when we attempt to read technical prose about specialized topics. For example, consider the phrase reflection of Alfven waves in the following sentence:

• Interest is now developing in a theoretical approach involving reflection [of Alfven waves.]

For the non-expert reader, two meanings are possible:

Similar potential for misunderstanding by novice readers arises when there are multiple prepositional phrases in sequence. In this case, readers must determine which head noun is being modified by each prepositional phrase, in addition to determining the intended meaning relationship represented by the preposition. For example, consider the following sentences from an ecology article about food web structure:

• Therefore, in our case it was possible to find an association between the number of trophic connections and productivity for individual predator species.

  • [compare: ‘an association that holds for (= in the case of ) individual predator species’ or ‘productivity for (= associated with) individual predator species’]

• Time lags suggest the involvement of population processes in determining observed patterns.

  • [compare: ‘involvement in determining’ or ‘processes in determining’]

• Among predator populations, changes in abundance often imply variation in the proportions of species with different feeding strategies.

  • [compare: ‘the proportions with different feeding strategies’ or ‘species with different feeding strategies’]

6.5 Inexplicit expression associated with compressed clausal connectors in academic writing

All of the grammatical devices discussed in the previous sections are phrasal modifiers of head nouns. They are inexplicit in that they omit grammatical markers that could specify the meaning relationship between the head noun and the modifier. However, there is also evidence that this style of discourse is spreading to a less explicit marking of meaning relations generally in academic texts. One reflection of this general trend is a shift in the way that authors mark the meaning relationships among independent clauses. Traditionally, authors employed linking adverbials for this purpose. These are clause connectors like however, therefore, thus, for example, furthermore, and in addition. Linking adverbials have a peripheral syntactic role in their matrix clause; their primary function is to specify the logical relationship of a clause to other clauses in the discourse. Thus, consider the role of linking adverbials (bold underlined) in the following passage from an education research article:

From a syntactic perspective, linking adverbials like however and thus are optional: the grammatical structure of the matrix clause is not affected by the presence or absence of a linking adverbial. However, these clause connectors serve an important discourse function in explicitly identifying the logical relations among independent clauses. Thus, in the aforementioned example, the use of however tells the reader that the following independent clause will contradict the assumption of ‘no direct bearing’ expressed in the preceding clause. And the use of thus in the final clause signals that the following information will explicate the statement made in the preceding clause.

Linking adverbials – similar to finite dependent clauses – are most common in humanities and social sciences academic prose, but considerably less common in specialist science research articles. In fact, Table 6.1 shows that there are only about half as many linking adverbials in specialist science articles as in the other academic sub-registers.

Table 6.1 also presents the results for colons across academic sub-registers. Although colons have no semantic content, they can be regarded as an alternative device used to connect independent clauses.Footnote ² As Table 6.1 shows, colons have a quite different distribution across disciplines from linking adverbials: they are common in social science and specialist science research writing, but much less common in humanities and popular science writing.

Similar to the other grammatical devices that are especially characteristic of present-day science writing, there has been major historical change in the use of these clause-connecting devices. Figure 6.1 shows that linking adverbials were quite common in academic writing in the eighteenth and nineteenth centuries, but they have decreased rapidly in use in the twentieth century. Linking adverbials that overtly express meanings of logical consequence or contrast (therefore, thus, and however) are less than half as frequent in present-day research writing as they were in 1800. In contrast, colons have rapidly increased in use, especially during the twentieth century.

Figure 6.1 Historical change in the use of linking adverbials versus colons as clause connectors in academic prose

Here again we see the general historical trend (especially in science research writing) away from the explicit marking of meaning relations towards a discourse style that is more compressed structurally, and as a consequence, less explicit in meaning. That is, similar to the other grammatical devices discussed earlier, the meaning relation signaled by a colon is entirely implicit.

In academic writing, there are several different meaning relations that can be signaled by a colon. In some cases, a colon is used as an alternative to a comma to connect two appositive noun phrases, as in:

• No understanding of slavery can avoid these themes: violence, power, and the usurpation of labor for the purpose of aggrandizing a small minority.

The colon is also often used to connect appositive noun phrases at a distance. For example:

• One possible pathogenetic mechanism can be excluded with certainty in man: a physiological decrease of intestinal lactase activity with advancing age.

In addition, the colon can be used for clausal rephrasing, with the second clause elaborating or explaining the content of the first clause:

• This is indicated in Figure 2b by the difference in slopes of the mean correct-response curves: The higher 8-minute recovery curve rises more steeply than the 1-minute curve.

However, clauses connected by a colon can also have an explanatory or causative relationship. Thus, the following sentence could be paraphrased with a reason clause:

• If replication of the viral nucleic acid is dependent, there is no need for special enzymes in order to carry it out: the normal cellular enzymes should be sufficient.

  • [compare: there is no need … because the normal cellular enzymes should be sufficient]

In all of these cases, there is no overt grammatical device to specify the meaning relationships. The colon signals only that some meaning relationship exists between the following phrase/clause, and some preceding phrase/clause. Thus, similar to phrasal noun-modifiers, colons are structurally compressed, resulting in more compact discourse, which in turn results in less explicit signaling of the meaning relationships in specialist academic discourse.

In this chapter, we have highlighted many of the ways in which the compressed, phrasal discourse style of academic writing results in inexplicit meaning relationships. These inexplicit meanings are in fact contrary to the often-held perceptions of academic writing as explicitly encoding logical relationships. In Chapter 7, we turn to a discussion of the implications of this compressed, inexplicit discourse style.