Editing Origin of language (section)

== Cognitive development and language ==
Language users have high-level reference (or [[deixis]])—the ability to refer to things or states of being that are not in the immediate realm of the speaker. This ability is often related to theory of mind, or an awareness of the other as a being like the self with individual wants and intentions. According to Chomsky, Hauser and Fitch (2002), there are six main aspects of this high-level reference system:
* [[Theory of mind]]
* Capacity to acquire non-linguistic conceptual representations, such as the object/kind distinction
* Referential vocal signals
* Imitation as a rational, intentional system
* Voluntary control over signal production as evidence of intentional communication
* [[Numerical cognition|Number representation]]<ref name="Hauser2002" />

=== Theory of mind ===
{{Main|Theory of mind}}
[[Simon Baron-Cohen]] (1999) argues that theory of mind must have preceded language use, based on evidence of use of the following characteristics as much as 40,000 years ago: intentional communication, repairing failed communication, teaching, intentional persuasion, intentional deception, building shared plans and goals, intentional sharing of focus or topic, and pretending. Moreover, Baron-Cohen argues that many primates show some, but not all, of these abilities.{{Citation needed|date=January 2014}} Call and Tomasello's research on chimpanzees supports this, in that individual chimps seem to understand that other chimps have awareness, knowledge, and intention, but do not seem to understand false beliefs. Many primates show some tendencies toward a theory of mind, but not a full one as humans have.<ref>{{Cite journal |last1=Tomasello |first1=Michael |last2=Call |first2=Josep |last3=Hare |first3=Brian |date=April 2003 |title=Chimpanzees understand psychological states – the question is which ones and to what extent |journal=Trends in Cognitive Sciences |volume=7 |issue=4 |pages=153–156 |doi=10.1016/S1364-6613(03)00035-4 |pmid=12691762 |s2cid=3390980}}</ref>

Ultimately, there is some consensus within the field that a theory of mind is necessary for language use. Thus, the development of a full theory of mind in humans was a necessary precursor to full language use.<ref>{{Cite journal |last1=Hale |first1=Courtney Melinda |last2=Tager-Flusberg |first2=Helen |date=June 2003 |title=The influence of language on theory of mind: a training study |journal=Developmental Science |volume=6 |issue=3 |pages=346–359 |doi=10.1111/1467-7687.00289 |pmc=1350918 |pmid=16467908}}</ref>

=== Number representation ===
In one particular study, rats and pigeons were required to press a button a certain number of times to get food. The animals showed very accurate distinction for numbers less than four, but as the numbers increased, the error rate increased.<ref name="Hauser2002" /> In another, the [[Primatology|primatologist]] [[Tetsuro Matsuzawa]] attempted to teach chimpanzees Arabic numerals.<ref>{{Cite journal |last=Matsuzawa |first=Tetsuro |date=1985 |title=Use of numbers by a chimpanzee |url=https://www.nature.com/articles/315057a0 |journal=[[Nature (journal)|Nature]] |volume=315 |issue=6014 |pages=57–59 |bibcode=1985Natur.315...57M |doi=10.1038/315057a0 |pmid=3990808 |s2cid=4361089}}</ref> The difference between primates and humans in this regard was very large, as it took the chimps thousands of trials to learn 1–9, with each number requiring a similar amount of training time; yet, after learning the meaning of 1, 2 and 3 (and sometimes 4), children (after the age of 5.5 to 6) easily comprehend the value of greater integers by using a [[successor function]] (i.e. 2 is 1 greater than 1, 3 is 1 greater than 2, 4 is 1 greater than 3; once 4 is reached it seems most children [[Eureka effect|suddenly understand]] that the value of any integer ''n'' is 1 greater than the previous integer).<ref>{{Cite journal |last1=Cheung |first1=Pierina |last2=Rubenson |first2=Miriam |last3=Barner |first3=David |date=February 2017 |title=To infinity and beyond: Children generalize the successor function to all possible numbers years after learning to count |url=https://www.sciencedirect.com/science/article/abs/pii/S0010028516302006 |journal=Cognitive Psychology |volume=92 |pages=22–36 |doi=10.1016/j.cogpsych.2016.11.002 |pmid=27889550 |s2cid=206867905 |via=Science Direct}}</ref> Put simply, other primates learn the meaning of numbers one by one, similar to their approach to other referential symbols, while children first learn an arbitrary list of symbols (1, 2, 3, 4...) and then later learn their precise meanings.<ref>{{Cite journal |last=Carey |first=Susan |year=2001 |title=Cognitive Foundations of Arithmetic: Evolution and Ontogenisis |url=http://www.wjh.harvard.edu/~lds/pdfs/carey2001c.pdf |url-status=dead |journal=Mind and Language |volume=16 |issue=1 |pages=37–55 |doi=10.1111/1468-0017.00155 |archive-url=https://web.archive.org/web/20130725071406/http://www.wjh.harvard.edu/%7Elds/pdfs/carey2001c.pdf |archive-date=25 July 2013 |access-date=13 January 2014}}</ref> These results can be seen as evidence for the application of the "open-ended generative property" of language in human numeral cognition.<ref name="Hauser2002" />