In cognitive psychology, the word superiority effect (WSE) refers to the phenomenon that people have better recognition of letters presented within words as compared to isolated letters and to letters presented within nonword (orthographically illegal, unpronounceable letter array) strings. Studies have also found a WSE when letter identification within words is compared to letter identification within pseudowords (e.g. "WOSK") and pseudohomophones (e.g. "WERK").

The effect was first described by Cattell (1886), and important contributions came from Reicher (1969) and Wheeler (1970). Cattell first wrote, "I find it takes about twice as long to read...words which have no connexion as words which make sentences, and letters which have no connexions as letters which make words. When the words make sentences and the letters words, not only do the processes of seeing and naming overlap, but by one mental effort the subject can recognize a whole group of words or letters".

G. Reicher and D. Wheeler developed the basic experimental paradigm to study the WSE, referred to as the Reicher-Wheeler paradigm. In this paradigm, an observer is presented with a word or nonword string that is followed by a mask (brief stimulus to measure effects on behavior). The observer is then asked to name one of the letters from the cued position in that word or string making the test a two-alternative forced choice (2-AFC). For example, for the letter R in the word "card", an observer might be asked to choose between the letter R and T, and will usually be more efficient in doing so than if they are asked to make the same choice with the string of letters such as "cqrd". Each possible completion with the two possible letters in the word condition produce a word.

The WSE has since been exhaustively studied in the context of cognitive processes involved during reading. Large amounts of research have also been done to try to model the effect using connectionist networks.

Experimental task
The WSE has traditionally been tested using a tachistoscope, as the durations of the letter string presentations need to be carefully controlled. Recently, stimulus presentation software has allowed much simpler manipulation of presentation durations using computers. The WSE has also been described without a tachistoscope.

A string of letters, usually four or five, is flashed for several milliseconds onto a screen. Readers are then asked to choose which of two letters had been in the flashed string. For example, if "WOSK" had been flashed, a reader might have to decide whether "K" or "H" had been in "WOSK". A WSE arises when subjects choose the correct letter more consistently when letter strings are real words rather than nonwords (e.g. "WKRG") or single letters.

Hypotheses
The existence of a WSE generally implies that there is some type of access or encoding advantage that words have in the mind that pseudowords or single letters do not have. Various studies have proposed that the distinction is a result of pronounceability differences (nonwords are not pronounceable and therefore are not as easily remembered), frequency (real words are more frequently encountered and used), meaningfulness (real words have semantic value and therefore are better retained in memory), orthographic regularity (real words follow familiar spelling conventions and are therefore better retained in memory), or neighborhood density (real words tend to share more letters with other words than nonwords and therefore have more activation in the mind).

Other studies have proposed that the WSE is heavily affected or even induced by experimental factors, such as the type of masking used after the presentation of the word, or the duration of the masks.

Models
The two popular models claiming to explain the WSE are the interactive activation model (IAM) and the dual-route coding model (DRC) Neither of these models takes attention into account; This is a relationship looked into through research on the WSE. Evidence shows that the WSE persists without an observer's conscious awareness of the word presented, which implies that attention is neither necessary for WSE nor involved in this phenomenon. However, attentional focus has been demonstrated to modulate the WSE which agrees with recent neurophysiological data explaining that attention, in fact, modulates early stages of word processing.

The activation-verification model (AVM) is another model that was developed to account for reaction time data from lexical decision and naming tasks. The basic operations explored in the AVM that are involved in word and letter recognition are encoding, verification, and decision. Both the IAM and the AVM share many basic assumptions such as the fact that stimulus input activates spatially-specific letter units, that activated letter units, modulate the activity of word units, and that letter and word recognition are frequently affected by top-down processes (e.g. Reading the phrase "A cow says..." a person would guess "moo" and in checking that the word begins with 'm' ignores the rest of the letters).

The WSE and an interactive-activation model

The WSE has proven to be an important finding for word recognition models, and specifically is supported by Rumelhart and McClelland's interactive-activation model of word recognition.  According to this model, when a reader is presented with a word, each letter in parallel will either stimulate or inhibit different feature detectors (e.g. a curved shape for "C", horizontal and vertical bars for "H", etc.). Those feature detectors will then stimulate or inhibit different letter detectors, which will finally stimulate or inhibit different word detectors. Some words can be activated through these stimulations. However, the fact that there is no meaning to the combination of letters can inhibit these words which were previously activated. Each activated connection would carry a different weight, and thus the word "WORK" in the example would be activated more than any other word (and therefore recognized by a reader).

According to this interactive-activation model, the WSE is explained as such: When the target letter is presented within a word, the feature detectors, letter detectors and word detectors will all be activated, adding weight to the final recognition of the stimulus.  However, when only the letter is presented, only the letter detector level will be activated. Therefore, we may remember the presented stimulus word more clearly, and thereby be more accurate in identifying its component letters, as observed in the WSE.

Activation-verification model
The AVM deals with encoding, verification, and decision operations. Encoding is used to describe the early operations that lead to the unconscious activation of learned units in memory. After encoding, verification occurs. Verification often leads to the conscious recognition of a single lexical entry from the respondents. Verification is to be viewed as an independent, top-down analysis of stimulus that is guided by the stored, or previously learned, representation of a word. Real-time processing in verification can be mimicked by a computer simulation. Lastly, the factors affecting speed and accuracy of performance in a particular paradigm depend on whether decisions are based primarily on information from encoding or verification.

Adverse word superiority effect
One of the findings of the Johnston and McClelland report was that the WSE does not occur inevitably whenever we compare a word and a nonword. Rather, it depends somewhat upon the strategies that readers use during a task. If readers paid more attention to the letter in a particular position, they would experience the adverse word superiority effect. This is because the reader would no longer have the benefit of having the word detector level activated with as much weight if they neglected to focus on the full word.

See also
Tachistoscope
Missing letter effect

References

Further reading

Sternberg, Robert J.  (2006).  Cognitive Psychology; fourth edition.
Crowder, Robert G. and Wagner, Richard K.  (1992).  The Psychology of Reading, second edition.  p. 79.
Harris, Margaret and Coltheart, Max.  (1986)  Language Processing in Children and Adults.  p. 155.
Francis, Greg, Neath, Ian, Mackewn, Angie, and Goldthwaite, Danalee. (2004).  Belmont: Wadsworth, p. 73–74.

External links
"The Science of Word Recognition" by Kevin Larson, 2004

Cognitive psychology
Reading (process)
단어 우월 효과(單語優越效果, )는 어떤 단어를 구성하는 동일한 문자들이 단어 속에 비정상적인 순서로 배열되어 나타나도 가독성에서 이를 무리없이 정확하게 인지할 수 있는 현상을 말한다. 즉, 문자 정보의 인지 과정에서 단어를 구성하고 있는 문자에 대한 정확한 지각보다 단어 전체의 지각을 통해 인지하게 된다는 것이다.

단어 우월 효과는 단어윤곽인지론(Word Shape Effect 또는 word shape 인지론)의 탄생에 결정적 역할을 했다.
라틴 문자의  단어윤곽인지론이란 단어를 인지과정에서 단어를 구성하는 개별 낱글자의 지각을 통하지 않고, 개별 낱글자들로 구성된 단어의 외곽 형태를 결정지어 보여주는 문장이나 문맥의 인지를 통해 이루어진다는 것이다. 즉, 단어의 인지과정은 단어를 구성하는 각각의 낱글자를 지각하는 과정이 아니라는 것을 보여줌으로서, 단어의 총체적인 이미지 인지를 통해 단어를 인지한다는 이론이 나타난 것이다.

아래 문장을 읽어보자.

Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.

위와 같이 사람의 인식과정 중 실제로 지각기관으로부터 얻은 지각과는 별도로 주위 환경의 맥락에 영향을 받는 맥락 효과라는 것이 있는데, 단어 우월 효과 역시 맥락 효과(context effect)의 일종이라고 할 수 있다.

예를 들어, WORK라는 단어와 ORWK라는 비단어의 마지막 문자는 둘 다 K이지만, K는 전자에서 더 정확하게 인지된다. 또한 ‘K’라는 문자가 단독으로 제시될 때보다도 ‘WORK’같은 단어의 구성문자로서 제시될 때 더 정확하게 인지되는 것이다.

라이처(Reicher, G. M.)는 그의 단어 연구에서 정상적인 단어와 비단어(오자), 단독문자(탈자)로 단어우월효과와 관련을 보여주었다.

위 실험에서 비단어속의 철자나 단독으로 사용된 문자보다 단어속의 문자가 더 쉽게 인지된다는 것을 확인했다.

라틴문자로 작성된 문장의 경우 대소문자로 작성된 문장이 대문자만으로 작성된 문장에 비해 가독성이 높은데 이 원인에 대하여는 2가지 견해가 공존한다.
익숙성과 소문자자체가 가지고 있는 우월성에 관한 것으로 라틴문자를 사용하는 사람들에게 대문자로 작성된 문장은 소문자로 작성된 문장에 비해 상대적으로 낯선 문장이며 이것이 곧 가독성에 반영된다.
우월성은 단어윤곽인지론과 연결된 것으로 소문자는 각 글자간의 외형적 차이가 크기 때문에 소문자로 작성된 단어들은 각각의 단어마다 특징적인 단어윤곽인지(word shape)를 형성해 변별력이 생긴다.

한글은 영어와 같은 표음문자이면서도 모아쓰기나 글자유형에 따라 같은 낱자라도 형태가 변화하는 점, 네모틀 외곽꼴을 유지하는 점과 같은 독특한 특징이 있어 국내 연구를 통해 한글의 단어우월효과를 확인할 수 있다. 또한 최근 한글 글꼴이 다양해지면서 모아쓰기를 하면서도 네모틀의 외곽꼴을 탈피하는 글꼴들이 등장하고 있어 네모틀 글꼴과 탈네모틀 글꼴의 경우 단어우월 효과를 비교할 필요가 있다.

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참고

(한글의 시각적 동일성과 친숙성에 따른 단어 우월 효과 Word Superiority Effect Based on the Hangeul Font Types 인지과학 Korean journal of cognitive science v.18 no.1 , 2007년, pp.15 - 34
박수진-충북대학교 사회과학대학 ,  정우현- 연세대학교 인지과학연구소) https://scienceon.kisti.re.kr/srch/selectPORSrchArticle.do?cn=JAKO200716419431725&dbt=NART
(한글의 시각적 동일성과 친숙성에 따른 단어 우월 효과. 인지과학, 18(1), 15-34. 박수진,  정우현   한국인지과학회  인지과학 제18권 제1호 2007.03, 15 - 34 KCI등재 UCI(KEPA) : I410-ECN-0101-2009-051-014634895)https://www.dbpia.co.kr/Journal/articleDetail?nodeId=NODE00986236
(The Significance of Letter Position in Word Recognition
Publisher: IEEE,Graham Rawlinson,Published in: IEEE Aerospace and Electronic Systems Magazine ( Volume: 22, Issue: 1, Jan. 2007)Page(s): 26 - 27 Date of Publication: 12 March 2007 )https://ieeexplore.ieee.org/document/4126417
(Rawlinson, Graham (2012). Davis, Matt (ed.). "The Significance of Letter Position in Word Recognition" PhD Thesis, 1976, Nottingham University, by Graham Rawlinson
. MRC - Cognition and Brain Sciences Unit - People. Retrieved 2016-07-04.)http://www.mrc-cbu.cam.ac.uk/people/matt.davis/cmabridge/
(본문용 한글서체의 구조와 인지요인 상관성 연구   구본영 단국대학교 2010년 )https://academic.naver.com/article.naver?doc_id=38953593
(상호활성화모형을 이용한 한글에서의 글자우월효과 특성 분석 Analysis of Character Superiority Effects of Korean characters using Interactive Activation Model,인지과학 = Korean journal of cognitive science v.11 no.2 , 2000년, pp.69 - 78  박창수 포항공과대학교 컴퓨터공학과,  방승양 포항공과대학교 컴퓨터공학과) https://scienceon.kisti.re.kr/srch/selectPORSrchArticle.do?cn=JAKO200011920269683&dbt=NART

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