An Experimental Study On The Representation Of Bilingual Mental Lexicons: Testing The Episodic L2 Hypothesis

Bilingual mental lexicon research is a crucial component of psycholinguistic research.Aside from the debates pertaining to the representations of bilingual mental lexicons as well as how they are recognized and retrieved,a more specific question regarding which type of memory is utilized to store L1 and L2 words has been raised.The Episodic L2 Hypothesis predicts that L2 words are stored in episodic memory for unbalanced bilinguals,which is a qualitatively different memory system in comparison to lexical memory where L1 words are represented.This hypothesis is based on a double dissociation obtained in masked translation priming studies.L1–L2 translation priming is observed in lexical decision tasks rather than episodic recognition tasks,whereas L2–L1 translation priming is obtained in episodic recognition tasks but not lexical decision tasks.Depending on the bidirectional asymmetry in translation priming,the researchers propose that L1 and L2 words are stored in two separate memory systems.Based on this hypothesis,it is logical to expect some differences in visual word recognition between L1 and L2 for unbalanced bilinguals.Qiao and Forster's studies in 2013 and 2017 succeed in obtaining such differences,but they do not further investigate whether it is because L1 and L2 words are stored in two separate memory systems.This study,therefore,carries out a lexical decision task to examine whether lexical competition,as indexed by inhibition among orthographically similar words,operates when unbalanced Chinese-English bilinguals recognize both L1(Chinese)and L2(English)words in the first place.Then,an episodic recognition task will be adopted to further testify the Episodic L2 Hypothesis.In the present study,two online experiments were conducted in which a total of fifty-two postgraduate students specializing in English participated.Research materials encompassing English words and Chinese characters were programmed via DMDX,a psycholinguistic software package.SPSS 25.0 was employed to analyze error rates and response latencies of the correct responses following the test.Experiment 1 which was comprised of two sub-experiments examined whether lexical competition,i.e.,inhibitory neighbor priming effect,occurred in both L1 and L2 neighbor recognition process.Using 2(prime type: orthographic neighbors vs.unrelated control words)× 2(prime lexicality: words vs.non-words)within-subjects design,Experiment 1a investigated whether L2 English orthographic neighbor primes inhibited participants' recognition of the corresponding targets and whether the lexicality of primes had an effect on the recognition of targets.Experiment 1b probed into whether lexical competition which was consistently found in L1 alphabetic languages also operated in L1 Chinese character recognition by adopting 2(prime type: orthographic neighbors vs.unrelated control characters)× 2(relative frequency: higher prime–lower target pairs vs.lower prime–higher target pairs)within-subjects design.Experiment 2 was also composed of two sub-experiments,aiming at recruiting more direct support for the Episodic L2 Hypothesis.It employed 2(study status: trained vs.untrained)× 2(prime type: repeated vs.unrelated)within-subjects design to test repetition priming effects in episodic recognition tasks.Research findings of Experiments 1 and 2 were as follows:Firstly,Experiment 1a revealed a successful replication of Qiao and Forster's findings in 2017.Orthographic neighbor primes was found to facilitate the recognition of targets rather than inhibiting them when unbalanced Chinese-English bilinguals processed L2 English words.In addition,facilitory neighbor priming effects in this experiment were virtually identical for the targets primed by word and non-word neighbors.These findings helped establish that lexical competition did not occur in L2 neighbor recognition.Secondly,analytical data in Experiment 1b showed statistically significant effects of prime type and relative prime–target frequency.Also,an interaction effect between prime type and relative prime–target frequency was obtained.The recognition of lower-frequency targets was inhibited by their higher-frequency neighbor primes,whereas this was not the case for higher-frequency targets preceded by lower-frequency neighbor primes.It was clear that lexical competition played a role in L1 Chinese neighbor recognition when orthographic primes were higher in frequency than targets.Thirdly,Experiment 2a demonstrated that statistically significant repetition priming effects were obtained for L2 words irrespective of their study status in an episodic recognition task.Fourthly,a more convincing finding was evidenced in Experiment 2b,showing repetition priming effects were ascertained for “trained” L1 Chinese characters which were temporarily kept in episodic memory rather than “untrained” ones.Overall,the predominant finding in Experiment 1 was that lexical competition occurred in L1 neighbor recognition but not in L2 neighbor recognition,indicating that the underlying mechanisms of neighbor recognition might be different for L1 and L2 words.Further investigation was then implemented in Experiment 2 to verify this finding appeared to be due to the fact that L2 words were stored in episodic memory.The findings were consistent with predictions of the Episodic L2 Hypothesis,which theorized that L2 words were stored in episodic memory and L1 words were represented in lexical memory because only episodically-stored words would produce repetition priming in episodic recognition tasks.To sum up,experiments conducted in the present study lend support to the Episodic L2 Hypothesis.As this hypothesis postulates,L1 and L2 words are stored in two separate memory systems,with L1 words in lexical memory and L2 words in episodic memory for unbalanced bilinguals.Moreover,lexical competition plays no role as to orthographic neighbor recognition in episodic memory.