Question: Which documentary was produced first, The Trials of Life or Restrepo?
Context: Spaced retrieval, also known as expanded retrieval or uniform retrieval, is a learning technique, which requires users to rehearse information to be learned at different and increasing spaced intervals of time or a set uniform amount of time.  In testing this type of learning, people are instructed to rehearse a given set of information at a certain time, and each new rehearsal is expected to have a longer period of time between itself and the previous rehearsal or an equal amount of time between rehearsals.  At the end of every trial period there is a test phase.  Landauer and Bjork first studied this technique of learning in 1978.  The study required participants to learn names from flash cards.  Prior to learning participants were placed into five different rehearsal types: uniform short, uniform moderate, uniform long, expanding, and contracting.  These all indicate the amount and spacing of trials between each test.  Uniform trials involve a number of trials between each test stage, but the trial numbers are fixed (e.g. 2-test-2-test-2-test).  Contracting rehearsals involve larger intervals of time between the first few trials and the test phase, but eventually the trials decrease in number.  Expanding involves starting with trials and tests close together, and as they progress the person would have more time between each trial and test (e.g. 1-test-2-test-3-test).  The effectiveness of the rehearsal types was measured by seeing how accurately participants responded during a test phase.  Expanding was proven to be the most important because it produced the highest amount of recall during the test period. Shigofumi: Letters from the Departed, titled Shigofumi: Stories of Last Letter (シゴフミ ～Stories of Last Letter～ ) in Japan, or simply Shigofumi, is a Japanese anime television series created by Tomorō Yuzawa and produced by Bandai Visual and Genco, which aired in Japan on Chiba TV and other networks between January 6 and March 22, 2008 and contains twelve episodes.  An original video animation episodes was included with the final anime DVD volume released on September 26, 2008.  A light novel series was originally adapted from the anime's premise set by Tomorō Yuzawa, featuring story composition and illustrations by Ryō Amamiya and Poko, respectively.  Four novels were published by MediaWorks under their "Dengeki Bunko" imprint between October 2006 and March 2008.  Despite the novels being produced first, the anime is considered the original work, as stated by Yuzawa.  The anime has been acquired by Bandai Visual for English language localization.  The title "Shigofumi" comes from the combination of the Japanese words for "after death" (死後 , shigo ) , and "letter" (文 , fumi ) , which literally translates to an "after death letter". Nell Gwynne is a three-act comic opera composed by Robert Planquette, with a libretto by H. B. Farnie.  The libretto is based on the play "Rochester" by William Thomas Moncrieff.  The piece was a rare instance of an opera by a French composer being produced first in London.  Farnie had written an earlier libretto on the same subject, with the same name, for composer Alfred Cellier, which was produced at the Prince's Theatre in Manchester in 1876. Hank Parker's Outdoor Magazine is an American half-hour outdoor fishing television series hosted by Hank Parker The show made its debut in syndication on January 8, 1985, and was originally called "Outdoor Magazine".  The show was created by Hank Parker and Michael Runnels.  In 1986, the show was picked up by TNN, and was retitled "Hank Parker's Outdoor Magazine".  The show was picked up by the Outdoor Life Network in 2003, and ran until 2004.  In 2004, the show was picked up by The Outdoor Channel.  The show was produced first by Parker/Runnels Productions, and then, by Hank Parker Productions. Child's Play 3 is a 1991 American supernatural slasher film.  It is the third installment in the "Child's Play" series.  The film is written by Don Mancini, and directed by Jack Bender, with Brad Dourif returning as the voice of Chucky.  Although released only one year later, the story takes place eight years following the events of 1990's "Child's Play 2".  It was executive produced by David Kirschner who produced first two "Child's Play" films. Roundaboutness, or roundabout methods of production, is the process whereby capital goods are produced first and then, with the help of the capital goods, the desired consumer goods are produced. Power Rangers is an American entertainment and merchandising franchise built around a live action superhero television series.  Produced first by Saban Entertainment, later by BVS Entertainment, and today by SCG Power Rangers, the television series takes much of its footage from the Japanese tokusatsu "Super Sentai", produced by Toei Company.  The first "Power Rangers" entry, "Mighty Morphin Power Rangers", debuted on August 28, 1993, and helped launch the Fox Kids programming block of the 1990s, during which it catapulted into popular culture along with a line of action figures and other toys by Bandai.  s of 2001 , the media franchise has generated over $6 billion in retail sales worldwide. The New Adventures of Black Beauty was a television drama series produced in the early 1990s.  The show was produced first in New Zealand, then in Australia.  The two different productions had different characters and plotlines, un-related except through the horse, Black Beauty. The Trials of Life: A Natural History of Behaviour is a BBC nature documentary series written and presented by David Attenborough, first transmitted in the United Kingdom from 3 October 1990. Restrepo is a 2010 American documentary film about the Afghanistan war, directed by American journalist Sebastian Junger and British photojournalist Tim Hetherington.
Answer: The Trials of Life