Editing Morris water navigation task (section)

== History ==
The Morris water navigation task was conceived by [[Richard G. Morris]] (then at the [[University of St Andrews]]) in 1981 as an alternative to the radial maze.<ref>{{cite book |last=Wenk |first=GL |title=Assessment of Spatial Memory Using the Radial Arm Maze and Morris Water Maze |journal=Current Protocols in Neuroscience |date=May 2004 |volume=Chapter 8 |pages=8.5A.1–8.5A.12 |pmid=18428607 |doi=10.1002/0471142301.ns0805as26 |isbn=978-0471142300 |s2cid=205151857 |editor=Jacqueline N. Crawley |editor-link=Jacqueline Crawley |display-editors=etal}}</ref> The test was developed to study spatial learning and how it differed from other forms of [[associative learning]].<ref name="Morris1984">{{cite journal |last=Morris |first=R |title=Developments of a water-maze procedure for studying spatial learning in the rat |journal=Journal of Neuroscience Methods |date=May 1984 |volume=11 |issue=1 |pages=47–60 |pmid=6471907 |doi=10.1016/0165-0270(84)90007-4|s2cid=8292701 }}</ref> Originally rats, now more commonly mice, were placed in an open pool and the latency to escape was measured for up to six trials a day for 2–14 days.<ref name="Morgan2009">{{cite journal |last=Morgan |first=D |author2=Buccafusco, JJ |title=Water Maze Tasks in Mice: Special Reference to Alzheimer's Transgenic Mice |year=2009 |pmid=21204327}}</ref> Several variables are used to evaluate an animal's performance. For example, a "probe trial" measures how long the test subject spends in the "target quadrant" (the quadrant with the hidden platform).<ref name="Morgan2009" /> More elaborate trials alter the location of the hidden platform, or measure distance spent swimming in the pool before reaching the platform.<ref name="Morgan2009" /> Over the years, many different versions of this test have been performed with a large amount of variables. For example, neuroscientists examine the effect of differences of sex, weight, strength, stress levels, age, and strain of species. The results vary dramatically, so researchers cannot draw conclusions unless these variables are kept constant.<ref name="Hooge2001" /> Many different size pools have been used throughout the history of this task, but it has been shown that this does not have a significant impact on the results of the test.<ref>{{cite journal |last=Van Dam |first=D |author2=Lenders, G|author3=De Deyn, PP |title=Effect of Morris water maze diameter on visual-spatial learning in different mouse strains |journal=[[Neurobiology of Learning and Memory]] |date=March 2006 |volume=85 |issue=2 |pages=164–72 |pmid=16290194 |doi=10.1016/j.nlm.2005.09.006|s2cid=19824659 }}</ref> In early versions of the task, researchers only timed latency to escape, however video tracking devices are now routinely used to measure the path to escape, time spent in each quadrant, and distance traveled in the pool.<ref name="Terry2009">{{cite journal |last=Terry AV |first=Jr |author2=Buccafusco, JJ |title=Spatial Navigation (Water Maze) Tasks |year=2009 |pmid=21204326}}</ref>

=== Original experiment ===
In Morris' first experiment, the apparatus was a large circular pool, 1.30 m across and 0.60 m high. The purpose of the original experiment was to show that spatial learning does not require the presence of local cues, meaning that rats can learn to locate an object without any auditory, visual, or olfactory cues.<ref>{{cite journal |journal=[[Learning and Motivation]] |author=Morris, R.G.M. |title=Spatial localization does not require the presence of local cues |volume=12 |issue=2 |pages=239–260 |date=May 1981 |doi=10.1016/0023-9690(81)90020-5 }}</ref>