Editing Animal cognition (section)

== Biological constraints ==
[[Instinctive drift]] can influence the interpretation of cognitive research.  Instinctive drift is the tendency of an animal to revert to [[instinctive behavior]]s that can interfere with learned responses. The concept originated with [[Keller Breland|Keller]] and [[Marian Breland|Marian]] Breland when they taught a [[raccoon]] to put coins into a box. The raccoon drifted to its instinctive behavior of rubbing the coins with its paws, as it would do when foraging for food.<ref>{{cite journal | vauthors = Breland K, Breland M | s2cid = 51818837 | year = 1961 | title = The misbehavior of organisms | journal = American Psychologist | volume = 16 | issue = 11| pages = 681–684 | doi=10.1037/h0040090}}</ref>

Animal ability to process and respond to stimuli is correlated with brain size. Small-brain animals tend to show simple behaviors that are less dependent on learning than those of large-brained animals. Vertebrates, particularly mammals, have larger brains and complex behavior that changes with experience. A formula called the [[encephalization quotient]] (EQ) expresses a relationship between brain and body size; it was developed by H.J. Jerison in the late 1960s.<ref>{{cite book |editor1-last=Brett-Surman |editor1-first=Michael K. |editor2-first=Thomas R. |editor2-last=Holtz |editor3-first=James O. |editor3-last=Farlow | name-list-style = vanc|others=Illustrated by Bob Walters |title=The complete dinosaur |publisher=Indiana University Press |location=Bloomington, Ind. |isbn=978-0-253-00849-7 |pages=191–208 |edition=2nd|date=2012-06-27}}</ref> When the encephalization quotient is plotted as a curve, an animal with an EQ above the curve is expected to show more cognitive ability than the average animal of its size, whereas an animal with an EQ below the curve is expected to have less. Various formulas been suggested, but the equation  '''''Ew(brain) = 0.12w(body)<sup>2/3</sup>'''''  has been found to fit data from a sample of mammals.<ref>{{cite web | vauthors = Moore J | date = 1999 | url = http://weber.ucsd.edu/~jmoore/courses/allometry/allometry.html | title = Allometry | publisher = [[University of California]] San Diego | access-date = 2014-08-18 | archive-date = 2013-08-07 | archive-url = https://web.archive.org/web/20130807045627/http://weber.ucsd.edu/~jmoore/courses/allometry/allometry.html | url-status = dead}}</ref> The formula is suggestive at best, and should only be applied to non-mammals with extreme caution. For some of the other [[vertebrate]] classes, the power of 3/4 rather than 2/3 is sometimes used, and for many groups of [[invertebrates]], the formula may not give meaningful results.