Seminaire: Harald BAAYEN - 8 fevrier 2013, Simon KIRBY - 15 fevrier 2013, Marseille (Labex BLRI)

[Thierry Hamon]

Date: Thu, 24 Jan 2013 16:20:48 +0100
From: Nadéra Bureau <nadera.bureau at lpl-aix.fr>
Message-ID: <006401cdfa46$639f2040$2add60c0$@bureau at lpl-aix.fr>


Brain & Language Research Institute

Vendredi 8 février 2013

16h Salle des Voûtes Fédération de Recherche 3 C (Comportement, Cerveau,
Cognition)

3 place Victor Hugo, Marseille (Labex BLRI) 

Harald BAAYEN

(Tübingen, Germany)

(with Victor Kuperman, and Michael Ramscar) 

Decomposition makes things worse: A discrimination learning approach to
the time course of understanding compounds in reading.

Résumé : The current literature on morphological processing is dominated
by the view that reading a complex word is a two-staged process, with an
early blind morphemic decomposition process followed by a late process
of semantic recombination (Taft, 2004; Rastle and Davis, 2008a). Various
behavioral and magneto- and electroencephalography studies suggest
semantic recombination would take place approximately 300-500 ms post
onset of the visual stimulus (Lavric et al., 2007). However,
eye-tracking studies show that both simple and complex words are read at
a rate of 4 to 5 words/second (Rayner, 1998).  We report an eye-tracking
experiment tracing the reading of English compounds in simple
sentences. For about 33% of the trials, a single fixation sufficed for
understanding the meaning of the compound. For such trials, the meaning
of the compound was available already some 140 ms after the eye first
landed on the modifier. All first fixations also revealed an effect of
the semantic relatedness of the modifier and head constituents, gauged
with a latent semantic analysis (LSA) similarity measure. These results
indicate a much earlier involvement of semantics than predicted by the
first-form-then-meaning scenario. Second and subsequent fixation
durations revealed that at later processing stages very different
semantic processes were involved, gauged by modifier-compound and
head-compound LSA similarity measures. Computational modeling of the
first fixation with naive discrimination learning (Baayen et al., 2011)
indicated that the early (and only the early) semantic effect arises due
to the model's connection weights' sensitivity to the collocational
co-occurence statistics of orthographic and semantic information carried
by word trigrams. We understand the LSA effects arising at later
fixations as reflecting semantic processes seeking to resolve the
uncertainty about the targeted meaning that arises as an unintended and
time-costly side effect of later fixations causing the head's meaning to
be co-activated along with the compound's meaning. Instead of viewing
blind morphological decomposition as the gateway through which meaning
can be reached, we think that when the meaning of the head becomes
available, due to the (non-morphological) nature of visual information
uptake when the initial landing position of the eye is non-optimal,
understanding comes with greater cognitive costs: Decomposition makes
things worse. We speculate that the late semantic effects in the
electrophysiological literature, especially those around the N400 time
window, reflect late semantic cleaning operations.

References

Baayen, R., Milin, P., Durdevic, D., Hendrix, P., and Marelli,
M. (2011). An amorphous model for morphological processing in visual
comprehension based on naive discriminative learning. Psychological
Review, 118:438-481.

Lavric, A., Clapp, A., and Rastle, K. (2007). ERP evidence of
morphological analysis from orthography: A masked priming study. Journal
of Cognitive Neuroscience, 19:866-877.

Rastle, K. and Davis, M. (2008a). Morphological decomposition based on
the analysis of orthography. Language and Cognitive Processes,
23:942-971.

Rayner, K. (1998). Eye movements in reading and information processing:
20 years of research. Psychological Bulletin, 124:372-422.

Taft, M. (2004). Morphological decomposition and the reverse base
frequency effect. The Quarterly Journal of Experimental Psychology,
57A:745-

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Brain & Language Research Institute

Vendredi 15 février 2013

11h Salle des Voûtes Fédération de Recherche 3 C (Comportement, Cerveau,
Cognition)

3 place Victor Hugo, Marseille (Labex BLRI) 

Simon KIRBY

(Univ. Edinburg) 

Simplicity and Expressivity Compete in Cultural Evolution: Linguistic
Structure is the Result.

Résumé : Language, like other human behaviours, exhibits striking
systematic structure. For example, two central design features of human
language are the way in which sentences are composed of recombinable
words, and the way in which those words in turn are created out of
combinations of reusable sounds. These properties make language unique
among communication systems and enable us to convey an open-ended array
of messages.

Recently, researchers have turned to cultural evolution as a possible
mechanism to explain systematic structure such as this in language. In
this talk, I will briefly present a series of experiments and a
computational model that demonstrate why this is a promising avenue for
research. Using diffusion chain methods in the laboratory, we can
observe how behaviour evolves as it is transmitted through repeated
cycles of learning and production (a process known as "iterated
learning"). Across a wide range of experimental contexts, we observe an
apparent universal: behaviour transmitted by iterated learning becomes
increasingly compressible. When combined with a pressure to also be
expressive, this may be sufficient to deliver up the structural design
features of language.

Although this work is focussed on human language as a test case, the
conclusions are quite general. Cultural transmission by iterated
learning is an adaptive process that delivers systematic structure for
free.

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