Reader SN writes:
One of my students has just received extensive comments on a MS. Some were extremely helpful, others less so. Two in the latter category were:
The plural of behaviour is not necessary.
The term ‘variation’ subsumes the plural. Eliminate the ‘s’ here and throughout.
“Behaviours” troubled me the first few times I came across it, but I am now happy that there is a difference between saying an animal shows a range of behaviour and saying it has a range of behaviours. I had never come across this attitude to variation though. Do you think Elgar was aware of his solecism when he named his "Variations on an Original Theme for Orchestra ("Enigma”)",?
Without seeing the original contexts of use, it's hard to tell how far out of line the editorial comments were. But whether or not "the plural of behaviour is necessary", it's certainly hallowed by centuries of usage. Having glossed the singular of behaviour as "Manner of conducting oneself in the external relations of life; demeanour, deportment, bearing, manners", the OED takes the trouble to note that it occurs "Also in pl.", with these citations:
a1563 J. Bale Brefe Comedy Iohan Baptystes in Harleian Misc. (1744) I. 109 Your fastynges, longe prayers, with other holy behauers.
a1616 Shakespeare Julius Caesar (1623) i. ii. 44 Which giue some soyle (perhaps) to my Behauiours.
1678 R. Cudworth tr. Plautus in True Intellect. Syst. Universe i. iv. 366 To observe the Actions, Manners and Behaviours of men.
a1763 ‘G. Psalmanazar’ Mem. (1764) 186, I could see..thro' all his artifices and different behaviours.
1959 Cambr. Rev. 7 Mar. 405/1 We must surely accept that the pattern of associated behaviours first noticed by Weber was one of the most brilliantly successful suggestions in the whole history of intellectual endeavour.
This usage remains common in scientific writing:
Communication behaviours in a hospital setting: an observational study [BMJ 1998]
Sexual behaviour in Britain: partnerships, practices, and HIV risk behaviours [The Lancet 2001]
Regulation of parkinsonian motor behaviours by optogenetic control of basal ganglia circuitry [Nature 2010]
Illuminating the Neural Circuitry of Compulsive Behaviors [Science 2013]
The count-noun version of behavio(u)r also occurs in the singular:
The act of writing is a familiar example of a behavior that is continuously self-regulated through evaluative self-reactions. [American Psychologist 1978]
The alternative, inclusive fitness models 10 –12 , achieves simplicity and clarity by attributing all fitness effects of a behaviour to an expanded fitness of the actor. [Nature 1985]
However, the basking shark spends long periods feeding at the waters' surface, a behaviour that allows study of this shark by tracking, observation of active feeding, and sampling of zooplankton prey. [Nature 1998]
Whereas the high-energy dispersion varies with doping, the dispersion converges within about 50 meV of the Fermi energy, revealing a behaviour that is independent of doping. [Nature 2003]
A whale whacks the water surface with its tail, a behavior that may increase the effectiveness of feeding on schools of small fish. [Science 2013]
The same pattern applies in the case of variations, even outside the musical "theme and variations" usage, which has been around at least since the 18th century. John Donne used the plural in a non-musical context in 1631:
Though thy heart have some variations, some deviations, some aberrations from that direct point, upon which it should be bent.
The calculus of variations has been around since the early 18th century; and various uses of count-noun varieties of variation continue to be widespread in scientific writing to this day:
Variations in the Earth's Orbit: Pacemaker of the Ice Ages [Science 1976]
Copy number variations and clinical cytogenetic diagnosis of constitutional disorders [Nature Genetics 2007]
Large Variations in Southern Hemisphere Biomass Burning During the Last 650 Years [Science 2010]
Prediction of seasonal climate-induced variations in global food production [Nature Climate Change 2013]
Pulsar Test of a Variation of the Speed of Light with Frequency [Science 1969]
Site-specific DNA binding using a variation of the double stranded RNA binding motif [Nature Structural Biology 1998]
… a negative value represents a variation that is opposite in phase, i.e., peaking in summer rather than winter [Science 2004]
Type-shifting between mass noun and count noun is commonplace in English, and indeed this process is regular enough that it applies instantly to many newly-coined words: No sooner is there email than we have "an email" and "37 separate emails".
Is this kind of category-shifting strictly necessary? Well, you could always say "piece of email" or "pieces of email" instead, just as you could say "type(s) of wine" instead of "wines". But why forbid a useful, generally-accepted morphological process? And especially, why intervene in specific cases where elite writers from Shakespeare and Donne to the present day are thereby put in the wrong?
Perhaps there is some misguided guidance on this topic in someone's usage guide. Or perhaps the guilty copy-editor or referee just formed this idiosyncratic non-rule by mis-applying some long-ago lesson about mass and count nouns. The details would give us another case study in the psychopathology of peeving…