Editing Perceptron (section)

=== Mark I Perceptron machine ===
{{Main article|Mark I Perceptron}}
[[File:Organization_of_a_biological_brain_and_a_perceptron.png|thumb|281x281px|Organization of a biological brain and a perceptron.]]
The perceptron was intended to be a machine, rather than a program, and while its first implementation was in software for the [[IBM 704]], it was subsequently implemented in custom-built hardware as the [[Mark I Perceptron]] with the project name "Project PARA",<ref name=":6" /> designed for [[image recognition]]. The machine is currently in [[National Museum of American History|Smithsonian National Museum of American History]].<ref>{{Cite web |title=Perceptron, Mark I |url=https://americanhistory.si.edu/collections/search/object/nmah_334414 |access-date=2023-10-30 |website=National Museum of American History |language=en}}</ref>

The Mark I Perceptron had three layers. One version was implemented as follows:

* An array of 400 [[photocell]]s arranged in a 20x20 grid, named "sensory units" (S-units), or "input retina". Each S-unit can connect to up to 40 A-units.
* A hidden layer of 512 perceptrons, named "association units" (A-units).
* An output layer of eight perceptrons, named "response units" (R-units).
Rosenblatt called this three-layered perceptron network the ''alpha-perceptron'', to distinguish it from other perceptron models he experimented with.<ref name=":0">{{Cite book |last=Nilsson |first=Nils J. |url=https://www.cambridge.org/core/books/quest-for-artificial-intelligence/32C727961B24223BBB1B3511F44F343E |title=The Quest for Artificial Intelligence |date=2009 |publisher=Cambridge University Press |isbn=978-0-521-11639-8 |location=Cambridge |chapter=4.2.1. Perceptrons}}</ref>

The S-units are connected to the A-units randomly (according to a table of random numbers) via a plugboard (see photo), to "eliminate any particular intentional bias in the perceptron". The connection weights are fixed, not learned. Rosenblatt was adamant about the random connections, as he believed the retina was randomly connected to the visual cortex, and he wanted his perceptron machine to resemble human visual perception.<ref>{{Cite book |url=https://direct.mit.edu/books/book/4886/Talking-NetsAn-Oral-History-of-Neural-Networks |title=Talking Nets: An Oral History of Neural Networks |date=2000 |publisher=The MIT Press |isbn=978-0-262-26715-1 |editor-last=Anderson |editor-first=James A. |language=en |doi=10.7551/mitpress/6626.003.0004 |editor-last2=Rosenfeld |editor-first2=Edward}}</ref>

The A-units are connected to the R-units, with adjustable weights encoded in [[potentiometer]]s, and weight updates during learning were performed by electric motors.<ref name="bishop">{{cite book |last=Bishop |first=Christopher M. |title=Pattern Recognition and Machine Learning |publisher=Springer |year=2006 |isbn=0-387-31073-8}}</ref>{{rp|193}}The hardware details are in an operators' manual.<ref name=":6">{{Cite book |last=Hay |first=John Cameron |url=https://apps.dtic.mil/sti/tr/pdf/AD0236965.pdf |title=Mark I perceptron operators' manual (Project PARA) / |date=1960 |publisher=Cornell Aeronautical Laboratory |location=Buffalo |archive-url=https://web.archive.org/web/20231027213510/https://apps.dtic.mil/sti/tr/pdf/AD0236965.pdf |archive-date=2023-10-27 }}</ref>
[[File:Mark I Perceptron, Figure 2 of operator's manual.png|thumb|Components of the Mark I Perceptron. From the operator's manual.<ref name=":6" />]]

In a 1958 press conference organized by the US Navy, Rosenblatt made statements about the perceptron that caused a heated controversy among the fledgling [[Artificial intelligence|AI]] community; based on Rosenblatt's statements, ''[[The New York Times]]'' reported the perceptron to be "the embryo of an electronic computer that [the Navy] expects will be able to walk, talk, see, write, reproduce itself and be conscious of its existence."<ref name="Olazaran">{{cite journal |last=Olazaran |first=Mikel |year=1996 |title=A Sociological Study of the Official History of the Perceptrons Controversy |journal=Social Studies of Science |volume=26 |issue=3 |pages=611–659 |doi=10.1177/030631296026003005 |jstor=285702 |s2cid=16786738}}</ref>

The Photo Division of [[Central Intelligence Agency]], from 1960 to 1964, studied the use of Mark I Perceptron machine for recognizing militarily interesting silhouetted targets (such as planes and ships) in [[Aerial photography|aerial photos]].<ref>{{Cite web |title=Perception Concepts to Photo-Interpretation |url=https://www.cia.gov/readingroom/document/cia-rdp78b04770a002300030027-6 |access-date=2024-11-14 |website=www.cia.gov}}</ref><ref>{{Cite journal |last=Irwin |first=Julia A. |date=2024-09-11 |title=Artificial Worlds and Perceptronic Objects: The CIA's Mid-century Automatic Target Recognition |url=https://direct.mit.edu/grey/article/doi/10.1162/grey_a_00415/124337/Artificial-Worlds-and-Perceptronic-Objects-The-CIA |journal=Grey Room |language=en |issue=97 |pages=6–35 |doi=10.1162/grey_a_00415 |issn=1526-3819|url-access=subscription }}</ref>