title: The psychological validity of collocation
title: evidence from event-related brain potentials
titleType: Subtitle
Creators: name: Hughes, Jennifer Joy
Publisher: name: Lancaster University
Year: 2018

description: Previous studies have used psycholinguistic techniques such as
      eye-tracking and selfpaced reading in order to investigate the
      psychological validity of corpus-derived collocations (e.g. Conklin
      &amp; Schmitt 2008; McDonald &amp; Shillcock 2003a; 2003b;
      Underwood et al. 2004; Huang et al. 2012). The results of these studies
      reveal that sequences of words which form collocations are read more
      quickly and receive fewer fixations than sequences of words which do not
      form collocations. However, behavioural data and eye-tracking data can
      only ever provide an indirect measure of what is going on in the brain
      during language processing. In this thesis, I therefore investigate the
      psychological validity of corpus-derived collocations using a direct
      measure of neural activity, namely electroencephalography (EEG). More
      specifically, I use the event-related potential (ERP) technique of
      analysing brainwave data. Very few ERP studies focus on collocation, and
      those that do focus on collocation conceptualize and operationalize the
      notion differently from how it is conceptualized and operationalized in
      this thesis, or indeed in most corpus linguistics work. For example,
      although Molinaro and Carreiras (2010:179-180) use corpus-derived
      collocations for an ERP study, they explicitly state that they only
      extract collocations which are “idioms or clichés”. By contrast, in this
      thesis, collocation is conceptualized as a more fluid phenomenon, as
      compositional or non-compositional word pairs where the words have a high
      probability of occurring together. In Experiment 1, which is the first of
      four ERP experiments presented in this thesis, I aim to pilot a procedure
      for determining whether or not there is a neurophysiological difference in
      the way that the native speaker brain processes collocational
      adjective-noun bigrams compared to non-collocational adjective-noun
      bigrams. In Experiment 2, I aim to replicate the results of the pilot
      study using another group of native English speakers; while, in Experiment
      3, I aim to investigate the processing of collocational adjective-noun
      bigrams and noncollocational adjective-noun bigrams in non-native speakers
      of English (specifically, native speakers of Mandarin Chinese). In
      Experiment 4, the final experiment of this thesis, I then aim to
      investigate the gradience of the ERP response as well as the psychological
      validity of different association measures, namely transition probability,
      mutual information, loglikelihood, z-score, t-score, Dice-coefficient,
      MI3, and raw frequency. The results of these studies reveal that there is
      a neurophysiological difference in the way that the brain processes
      corpus-derived collocational bigrams compared to matched noncollocational
      bigrams, suggesting that the phenomenon of collocation can be seen as
      having psychological validity. An important finding of this thesis is the
      discovery of the ‘Collocational N400’: an ERP component reflecting the
      increase in cognitive load associated with reading a collocational
      violation. This increase in cognitive load is greater for non-native
      speakers compared to native speakers, as non-native speakers have less
      flexibility than native speakers in their use of (non-)collocational
      patterns. Moreover, while there is a strong correlation between the
      amplitude of the collocational N400 and all of the measures of collocation
      strength that I investigate in Experiment 4, the strongest correlations
      exist between amplitude and the hybrid association measures, including
      z-score, MI3, and Dice co-efficient. This suggests that mutual information
      and log-likelihood, which are two of the most commonly used association
      measures in corpus linguistics (Gries 2014a:37), are not necessarily
      always the optimal choice. I discuss these results in relation to prior
      literature from the fields of corpus linguistics and cognitive
      neuroscience.