We left off at the crucial moment when a pair of sticklebacks fall in love. In the nest he has prepared, she lays her eggs and then waves goodbye; he fertilizes them and hangs around for a week or two until the fry are able to fend for themselves.
However… One thing that could happen is that the female just might check back to see if any eggs were snuck into the nest by some hussy, because she is not prepared to tolerate that, and will eat them. Or an entire roving gang of female sticklebacks might attack the nest and eat the babies, just because they are feeling ornery.
Under this threat, the male is apt to heroically and creatively try to distract the attackers with some kind of fake news. Professor of Biology Susan A. Foster wrote,
[T]hese conspicuous displays appear to include elements of behavior co-opted from other contexts, and subsequently ritualized or made more conspicuous in the new context of the diversionary display.
Typically, human researchers insist on defining displacement activity as wrong, inappropriate, irrelevant, etc. Sure, it may be “behavior co-opted from other contexts,” but why is that framed as an indictment? It is a positive defense that protects the young from cannibalistic wild women — yet humans insist on denigrating it as “displacement.”
In all fairness, it seems like the determination to save babies should be called a basic drive. And what could be more in-context than a diversionary tactic — especially if it succeeds? What could possibly be more appropriate than a clever life hack that works?
And yet so many humans, like salmon expert Thomas Kline, are adamant: “Essentially a displacement activity is doing the wrong thing.” Another explainer says,
Certain species of fish, such as the stickleback, also exhibit such out-of-context displacement activity. When at the boundary between its own territory and that of another stickleback, where both attack and escape behaviors are elicited, inappropriate nest-building behavior is often displayed.
Early behaviorists N. Tinbergen and J. J. A. Van Iersel wrote in 1946,
[S]uch irrelevant movements occur when the animal is under the influence of a powerful urge, but at the same time is in some way prevented from expressing this urge in the appropriate way. The animal, under such conditions, does not suspend action, but vents its urge in movements belonging to another drive. The behavior “sparks over” from one drive to another.
Okay, combat is a drive, and escape is a drive, but what if sliding out of the situation peacefully is also an equally strong and valid drive? Surely, diversionary tactics are successful at least some of the time. And when that happens, why is the action deemed a mere substitute caused by frustration engendered by the inability to fulfill another drive?
Why isn’t the avoidance of violence (or the avoidance of disgraceful flight) seen as the fulfillment of a legitimate drive, in and of itself? If a diversionary tactic produces a peaceful outcome, why is that judged as inappropriate, irrelevant, out-of-context, and wrong?
Your responses and feedback are welcome!
Source: “Evolutionary and Natural History of the Threespine Stickleback,” ScienceDirect.com, undated
Source: “Salmon displacement activity,” Salmonography.com, undated
Source: “English Dream,” Naver.com, 08/27/2020
Source: “’Displacement Reactions’ in the Three-Spined Stickleback,” Jstor.org, undated
Image by Biodiversity Heritage Library/Public Domain
FAQs and Media Requests: 
