Navigation Links
Decoding the dictionary: Study suggests lexicon evolved to fit in the brain

Troy, N.Y. The latest edition of the Oxford English Dictionary boasts 22,000 pages of definitions. While that may seem far from succinct, new research suggests the reference manual is meticulously organized to be as concise as possible a format that mirrors the way our brains make sense of and categorize the countless words in our vast vocabulary.

Dictionaries have often been thought of as a frustratingly tangled web of words where the definition of word A refers users to word B, which is defined using word C, which ends up referring users back to word A, said Mark Changizi, assistant professor of cognitive science at Rensselaer Polytechnic Institute. But this research suggests that all words are grounded in a small set of atomic words and its likely that the dictionarys large-scale organization has been driven over time by the way humans mentally systematize words and their meanings.

Dictionaries are built like an inverted pyramid. The most complex words (e.g., albacore and antelope) sit at the top and are defined by words that are more basic, and thus lower on the pyramid. Eventually all words are linked to a small number of words called atomic words, (such as act and group) that are so fundamental they cannot be defined by simpler terms. The number of levels of definition it takes to get from a word to an atomic word is called the hierarchical level of the word.

Changizis research, which was published online this week and will appear in the June print edition of the Journal of Cognitive Systems Research, indicates that the dictionaries we use every day utilize approximately the optimal number of hierarchical levels and provide a visual roadmap of how the lexicon itself has culturally evolved over tens of thousands of years to help lower the overall brain space required to encode it, according to Changizi.

Many other human inventions such as writing and other human visual signs have been designed either explicitly or via cultural selection over time so as to minimize their demands on the brain, Changizi said.

By conducting a series of calculations based on the estimation that the most complex words in the dictionary total around 100,000 different terms, and that the number of atomic words range from 10 to 60, Changizi was able to devise three signature features present in the most efficient dictionaries as well as in their human counterpart, the brain.

Most importantly, he discovered that the total number of words across all the definitions in the dictionary (and thus the size of the dictionary) changes in relation to the total number of hierarchical levels present. Optimal dictionaries should have approximately seven hierarchical levels, according to Changizi.

The presence of around seven levels of definition will reduce the overall size of the dictionary, so that it is about 30 percent of the size it would be if there were only two hierarchical levels, Changizi said.

Additionally, users will find that there are progressively more words at each successive hierarchical level, and that each hierarchical level contributes mostly to the definitions of the words just one level above their own, according to Changizi, who put his three predictions to the test by studying actual dictionaries.

The Oxford English Dictionary and WordNet a large, online lexical database of English, developed at Princeton University were found to possess all three signatures of an economically organized dictionary, and thus were organized in such a way as to economize the amount of dictionary space required to define the lexicon, according to Changizi.

Somehow, over centuries, these revered reference books have achieved near-optimal organization, Changizi said. That optimality can likely be attributed to the fact that cultural selection pressures over time have shaped the organization of our lexicon so as to require as little mental space and energy as possible.

Changizi believes his research has potential applications in the study of childhood learning, where scientists could analyze how students learn vocabulary words and possibly develop ways to optimize that learning process.


Contact: Amber Cleveland
Rensselaer Polytechnic Institute

Related biology news :

1. Decoding effects of toxins on embryo development
2. Childhood obesity indicates greater risk of school absenteeism, Penn study reveals
3. A study by the MUHC and McGill University opens a new door to understanding cancer
4. Study begins to reveal clues to the cause and progression of sepsis
5. Clones on task serve greater good, evolutionary study shows
6. New study warns limited carbon market puts 20 percent of tropical forest at risk
7. New study examines how rearing environment can alter navigation
8. Study links cat disease to flame retardants in furniture and to pet food
9. New continent and species discovered in Atlantic study
10. Study shows link between alcohol consumption and hiv disease progression
11. Feeling hot, hot, hot: New study suggests ways to control fever-induced seizures
Post Your Comments:
(Date:11/11/2015)... MedNet Solutions , an innovative SaaS-based eClinical technology company that ... announce that it will be a Sponsor of the ... held November 17-19 in Hamburg , Germany.  ... iMedNet , MedNet,s easy-to-use, proven and affordable eClinical ... able to deliver time and cost savings of up to ...
(Date:11/10/2015)... , Nov. 10, 2015 ... biometrics that helps to identify and verify the ... is considered as the secure and accurate method ... of a particular individual because each individual,s signature ... results especially when dynamic signature of an individual ...
(Date:11/9/2015)... , Nov. 9, 2015  Synaptics Inc. (NASDAQ: ... today announced broader entry into the automotive market with ... match the pace of consumer electronics human interface innovation. ... are ideal for the automotive industry and will be ... Europe , Japan ...
Breaking Biology News(10 mins):
(Date:12/1/2015)... , Dec. 1, 2015  Symic, a clinical-stage ... the extracellular matrix (ECM), today announced that it has ... advance the company,s pipeline, including its lead candidates SB-030 ... and includes the participation by all existing major investors, ... brings the total capital raised by Symic to over ...
(Date:12/1/2015)... 1, 2015 Dr. Harry Lander , President of Regen, ... Chief Science Officer and recruits five distinguished ... , President of Regen, expands his role to include ... recruits five distinguished scientists to join advisory team ... his role to include serving as Chief ...
(Date:12/1/2015)... (PRWEB) , ... December 01, 2015 , ... Matthew “Tex” ... new post, VerMilyea will oversee all IVF lab procedures as well as ... fertility preservation. , “We traveled 7,305 miles to Auckland, New Zealand to bring home ...
(Date:11/30/2015)... ... 2015 , ... Global Stem Cells Group Chile ... Central America and abroad for the first Iberoamerican Convention on Aesthetic Medicine, Cosmetology ... Testart will present and discuss new trends in anti-aging stem cell treatments, regenerative ...
Breaking Biology Technology: