Cognitive control-e.g. the abilities to pay attention, to ignore irrelevant input, and to switch between tasks- has received much attention in recent literature. Since both of their languages are activated in parallel, bilinguals have been suggested to have improved cognitive control skills in both the linguistic and non-linguistic domain (e.g., Bialystok, 2017), but inconsistent results (e.g., Hilchey, Saint-Aubin, & Klein, 2015) have lead to a heated debate in the field. However, when found, the effects of bilingualism on cognitive control appear to be generally positive (Valian, 2015). Furthermore, earlier bilingualism has been linked to greater cognitive benefits (Yow & Li, 2015), and Green and Abutalebi's (2013) Adaptive Control Hypothesis (ACH) suggests that the bilingual environment also plays a role. The aim of the current study is to investigate the role of the Age of Acquisition (AoA) of the second language on cognitive control in young adult bilinguals in two different linguistic environments, as well as to examine the underlying processes of cognitive control via event-related brain potentials (ERPs). Two research questions are focused on: 1) Which, if any, cognitive control abilities are enhanced by bilingualism? and 2) Does the type of bilingual experience modulate observed effects? The present study uses the non-linguistic Attention Network Test (ANT; Fan et al., 2002), in which sets of arrows appear with a central target arrow in either a congruent (e.g. ← ← ← ) or incongruent (e.g. ← → ← ) condition, to examine Alerting, Orienting, and Executive Control networks, and a linguistic Stroop task (Stroop, 1935), in which colour terms appear in congruent (i.e. the word "red" presented in red font) and incongruent (i.e. the word "red" presented in green font) conditions, to examine language processing of English-French bilinguals in Canada and in Japanese-English bilinguals in Japan. In addition, Canadian participants also completed an ERP version of the Stroop task to examine possible underlying differences. The results of this series of experiments revealed a complex, yet interesting picture of bilingual cognitive control: although bilingual advantages were not consistent, there was support for earlier bilingualism being more beneficial to cognitive control. Particularly, results show Executive Control advantages for Simultaneous bilinguals, and significant differences between Simultaneous and Early Sequential bilinguals (typically grouped together as "early") in the Stroop task, demonstrating that balanced, proficient bilingualism enhances both linguistic and non-linguistic control. Interestingly, these effects only become apparent when both languages are mixed in the task, in line with suggestions that young adults’ cognitive resources need to be maximally taxed before advantages become apparent. Indeed, ERP results confirmed a greater engagement of cognitive resources in the more difficult version of the task. Although AoA and environment turned out to be confounded, there were still differences between Canadian and Japanese participants. Most notably, Canadian participants appeared to have better Executive Control. Taken together, the current work concludes that despite increased processing load, bilingual cognition does not suffer. Instead, cognition may receive a boost from dual language experience in some cases. Several rarely-explored factors were examined, and the complex results suggest possible areas that would benefit from further exploration, as well as raise interesting questions for future research.

One of the main findings of research on bilingualism in the last twenty years is the fact that both languages are always active, to some extent, and interact with each other. This interaction gives rise to a computationally complex feature of the bilingual mind, namely that the two languages compete with each other. Many studies have addressed the linguistic consequences of this competition (e.g. differences in linguistic attainment), while others have instead addressed the cognitive consequences (e.g. training effects on cognitive control). These two strands of research, when brought together, can shed light on the dynamics of language processing and of its relationship with other cognitive abilities; however, they do not often converge. The first aim of this thesis is to seam them together. The second aim of this thesis is to understand the effects of specific aspects of language experience on linguistic and non linguistic abilities. A critical assumption I make is that bilingualism is not a dichotomous variable, but rather a continuum, characterised by several aspects such as linguistic proficiency, age of acquisition, and daily exposure. All of these factors interact with each other to give rise to potentially infinite types of bilingual experiences, and arguably modulate how bilinguals deal with competing languages. However, the effects of these factors on linguistic and non linguistic abilities are poorly understood. Hence, in this thesis I examine if the bilingual experience affects other cognitive abilities (study 1), how the ability to handle this competition is modulated by experience (study 2), and how it affects language processing (study 3). To examine how specific dimensions of the bilingual continuum affect these abilities, I compare four populations of bilinguals, whose linguistic experience ranges from late bilinguals who are immersed in their native language and are passive users of their second language, to early highly proficient bilinguals who use both languages actively. My first study examines cognitive control performance and shows that high active proficiency and early age of acquisition, together, represent beneficial circumstances for the ability to modulate cognitive control; however, their effects are not strong enough to override individual variability. The second study investigates how the bilingual experience modulates the ability to access the two languages separately, overcoming the competition between them at different levels. This could be at a local level, i.e. the level of the individual linguistic representation (e.g. naming time of a specific word), or at a global or whole language level (e.g. overall naming latencies across languages). The results show that proficiency affects local competition, and age of acquisition affects global competition, whereas daily language exposure regulates competition at both the local and the global levels. My third study examines the processing of pronouns, which are particularly demanding linguistic structures. It shows that active proficiency and age of acquisition, together, define circumstances in which pronoun processing may vary between individuals, independently of structural differences between their languages. This suggests that bilinguals with long-term exposure to more than one language and high active proficiency may use some linguistic structures in the same way as individuals with different linguistic backgrounds, i.e. explicitly interpret them in similar ways, but process them in marginally different ways. Through these studies, this thesis brings together research on linguistic and cognitive aspects of bilingualism by identifying three dimensions of the bilingual experience - proficiency, exposure and age of acquisition - and their effects on language processing, language control and cognitive control.

Seit etwa zwei Jahrzehnten stellt die kognitive und neuronale Verarbeitung von Nomen und Verben einen bedeutsamen Forschungsschwerpunkt im Bereich der Neurolinguistik und Neuropsychologie dar. Intensive Forschungsbemühungen der letzten Jahre erbrachten eine Reihe von Ergebnissen, die jedoch überwiegend inkonsistent und widersprüchlich sind. Eine häufig vertretene Annahme im Bezug auf die neuronale Basis der Nomen und Verb Verarbeitung ist die so genannte anterior-posterior Dissoziation. Demnach werden Nomen in temporalen und Verben in frontalen Regionen der sprachdominanten, linken Hemisphäre verarbeitet. Die vorliegende Dissertation untersucht mit Hilfe der funktionellen Magnetresonanztomographie, welche kortikalen Regionen in den Abruf von Nomen und Verben beim stillen Bildbennen involviert sind. Ferner wird der Einfluss des Faktors age-of-acquisition (Erwerbsalter) auf die Hirnaktivierung beim Bildbenennen überprüft. Die Ergebnisse der Studie zeigen, dass der Abruf von Nomen und Verben ähnliche kortikale Aktivierungen in bilateral okzipitalen sowie links frontalen, temporalen und inferior parietalen Regionen hervorruft, wobei für Verben stärkere Aktivierungen in links frontalen und bilateral temporalen Arealen beobachtet wurden. Dieses Ergebnis widerspricht der Annahme einer anterior-posterior Dissoziation. Die beobachteten Aktivierungsmuster unterstützen dagegen die Auffassung, dass ein gemeinsames Netzwerk bestehend aus anterioren und posterioren Komponenten für die Verarbeitung von Nomen und Verben beim Bildbenennen verantwortlich ist. Die Studie ergab ferner, dass kortikale Aktivierungen beim Bildbenennen durch das Erwerbsalter moduliert werden. Dabei zeigten sich Aktivierungen für später erworbene Wörter im linken inferioren Frontallappen und im basal temporalen Sprachareal. Die Ergebnisse werden diskutiert und interpretiert vor dem Hintergrund aktueller kognitiver und neuroanatomischer Modelle der Sprachverarbeitung. / The cognitive and neuronal mechanisms underlying the retrieval of nouns and verbs are a complex issue, which has attracted the interest of neurolinguists and cognitive neuroscientists during the last two decades. Unfortunately, the results emerged from previous studies are often contradictory. A frequent claim in neurolinguistic literature is the anterior-posterior dichotomy of the noun and verb retrieval. Within this framework nouns are associated with left temporal brain areas whereas verbs rely on structures in the left frontal lobe. This thesis investigates the brain areas which are involved in silent naming of German noun and verb pictures by means of event related fMRI. In addition the influence of age-of-acquisition on brain activity during picture naming was examined. Noun and verb retrieval revealed a similar pattern of bilateral occipital, left frontal, temporal and inferior parietal cortical activation, albeit verb naming resulted in stronger activation in left frontal and bilateral temporal areas. The results do not confirm the anterior-posterior hypothesis. They support rather a similar cortical network for the processing of nouns and verbs in picture naming. Furthermore the results indicated that age-of-acquisition modulates brain activation during silent picture naming. Cortical activation for late learned words was detected in the left inferior frontal cortex and in the left basal temporal language area. The data were discussed and interpreted on the basis of current cognitive and neuroanatomical models of language processing.

xv, 169 p. ; ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Improvements in neuroimaging techniques have made it possible to answer questions regarding the neural organization for the processing of syntax in normal participants. In this series of experiments we examined the effects of linguistic proficiency and age of second language acquisition on neural organization for syntactic processing. We examined these factors using two complementary methodologies: event-related potentials (ERPs), which affords a temporal resolution on the order of milliseconds, and functional magnetic resonance imaging (fMRI), with spatial resolution on the order of millimeters. In order to compare results across methodologies, we used an auditory syntactic violation paradigm with similar experimental parameters in each methodology. In Chapter II we examined neural organization for syntactic processing using ERPs in monolingual native speakers of higher and lower proficiency and found that violations elicited an early onset (100 ms) anterior negativity (EOAN) followed by a later positivity (P600) in all participants. Compared to lower proficiency participants, higher proficiency participants showed an EOAN that was more focal spatially and temporally, and showed a larger P600. These results were supported by a correlational analysis of a larger group of monolingual native speakers with a wide range of proficiency scores. This analysis also found a relationship between childhood socioeconomic status and the recruitment of the EOAN over left hemisphere sites, raising the hypothesis that effects of childhood experience may endure into adulthood. In Chapter III we examined the effects of age of acquisition on syntactic processing by recruiting a group of late learners of English who were matched for proficiency with a group of monolingual native speakers from Chapter II. While in native speakers violations elicited a robust EOAN, this effect was absent in the late learner group, suggesting that early language exposure is important for the recruitment of resources reflected in this effect and independently of proficiency. In Chapter IV we gathered ERP and fMRI data from monolingual native speakers and found proficiency differences in the recruitment for syntactic processing of left inferior frontal and posterior regions. We linked proficiency-related modulations in the different ERP syntactic effects to specific fMRI activations indexing syntactic processing. / Adviser: Helen J. Neville

Significant research has been done regarding the influence of age of acquisition (i.e., the age at which one is exposed to a second language (L2)) on L2 learning (e.g., Johnson & Newport, 1989; Bialystock & Hakuta, 1999). Some researchers have shown that bilinguals who have learned their second language early in life may differ in their fluency from bilinguals who learned their second language later in life (White & Genesee, 1996; Flege, 1999). Specifically, studies have suggested that bilinguals who have not acquired their L2 by puberty will never acquire native-like proficiency (Lenneberg, 1967); however, others claim that there is not one particular age after which native-like language proficiency cannot be achieved (Birdsong and Molis, 1998; Flege; 1999). However, little research has been done regarding the effect that age of acquisition has on how bilinguals code switch and what rules govern this code-switching. Early research by Poplack (1980) found that late (i.e., those who learned the L2 in adulthood), less fluent bilinguals had different code switching tendencies than early (i.e., those who learned L2 in childhood), more fluent bilinguals. Lipski (1985) suggested that early bilinguals will engage in intrasentential switching while late bilinguals will rarely do so. In the present study, 26 early and late Spanish-English bilingual speakers made acceptability judgments on intra- and intersentential switches. Results indicate that there is no statistical difference between early and late bilinguals when responding to whether a mix was good or bad, and how good or bad a mix was. There were, however, trends in the results which indicate that early bilinguals may respond faster to code switches than late bilinguals, suggesting that early and late bilinguals may process language differently. Further research is needed to confirm this finding.

A primary purpose of second language (L2) research is to determine what factors hinder or help L2 acquisition. One aspect that has a strong effect on L2 proficiency is learners' age of onset of acquisition (AOA) (Johnson & Newport, 1989). These studies and others suggest that younger learners are more adept than older learners at learning an L2, especially to a near-native level. However, some older learners can become quite proficient in an L2 (Ioup, et al. 1994; Bialystok, 1997; Bongaerts, 1999), although learners who have acquired the L2 over the age of 30 are rarely studied. Why is it that some older learners are more adept at learning a second language than others? Some argue cognitive abilities (Hyltenstam & Abrahamsson, 2002; DeKeyser, 2006) while others argue social and affective factors (Moyer, 1999) differ across the lifespan, causing younger learners to achieve a higher proficiency than older learners. Little research, however, has examined both these factors, especially in learners who acquired a language beyond early adulthood. Therefore, the purpose of this study was to determine 1) if there are age effects between groups of older adults learning an L2 and 2) what causes any differences found. This study examines a variety of both cognitive, affective and demographic factors that have been previously shown to affect language learning. The participants included 38 native Spanish speakers placed into four AOA groups: 10-19, 20-29, 30-39, and over 40. In order to test cognitive factors a working memory task as well as a switch task were included (Abrahamsson, 2012; Paradis, 2009). Other factors were assessed using a survey that inquired about motivation, amount of time using the L1 versus the L2, and musical ability (Slevc & Miyake, 2006). Subjects also participated in an elicited imitation task to assess global proficiency in the L2 (Erlam, 2009).Results suggest that age effects are found even in older learners. Participants with a younger AOA who spend more time speaking the L2 (English) tended to have greater proficiency in the L2. Attentional control was also a predictor.

No / There is clear evidence of a deficit in episodic memory for older adults compared to younger adults. Using an intertrial technique previous research has investigated whether this deficit can be attributed to a decline in encoding or consolidation. On standard memory tests, these two aspects of memory function can be measured by examining the items forgotten or acquired across multiple learning trials. The present study assessed whether age deficits in episodic memory were affected by stimulus characteristics, specifically age of acquisition (AoA). A standard intertrial design was implemented whereby participants studied word lists over several study-test trials. The stimulus characteristics of AoA were manipulated using a pure-list technique. Our findings showed that older adults demonstrate an overall recall deficit which appeared to be a consequence of both an encoding deficit and consolidation weakness. Earlier-acquired words were recalled significantly better than later-acquired words and this was apparently due to both enhanced encoding and consolidation of earlier- over later-acquired words. The key finding is that older adults show a recall advantage for earlier- compared to later-acquired words over the entire experiment to a greater degree than younger adults.

Die Arbeit untersucht die Annahme einer unterschiedlichen Gewichtung von distinktiven enzyklopädischen, funktionalen und sensorischen Merkmalen innerhalb der Repräsentationen von Objekten der belebten und unbelebten semantischen Domäne. Hierzu wurde ein Reaktionszeitexperiment zur Merkmalsverifikation durchgeführt. Vorab wurden deutsche Normen über das geschätzte Erwerbsalter für 244 Stimuli aus dem Korpus von Snodgrass & Vanderwart (1980) erhoben. Weiterhin wurde eine Datenbank von Merkmalsnormen für 80 konkrete Objektbegriffe erstellt. Insgesamt wurden zwei Reaktionszeitexperimente durchgeführt, die sich lediglich durch die Darbietungsdauer des Konzeptbegriffes unterschieden. Der Konzeptbegriff wurde entweder 1000 ms (lange Darbietung) oder 250 ms (kurze Darbietung) präsentiert, bevor das zu verifizierende semantische Merkmal erschien. Bei langer Präsentationszeit des Objektbegriffes zeigten sich für Objekte der unbelebten Domäne schnellere Reaktionszeiten beim Verifizieren von distinktiven funktionalen Merkmalen als beim Verifizieren von distinktiven enzyklopädischen Merkmalen. Dieser Effekt wurde bei kurzer Darbietungsdauer des Konzeptbegriffes repliziert. Bei kurzer Darbietung konnten für Objekte der unbelebten Domäne zusätzlich kürzere Reaktionszeiten beim Verifizieren distinktiver funktionaler Merkmale als beim Verifizieren distinktiver sensorischer Merkmale beobachtet werden. Für Objekte der belebten Domäne lagen weder nach kurzer noch nach langer Präsentation des Objektbegriffes Unterschiede in den Reaktionszeiten beim Verifizieren der semantischen Merkmale vor. Die Ergebnisse werden vor dem Hintergrund aktueller neurolinguistischer Modelle zur Organisation des semantischen Gedächtnisses diskutiert. Die Ergebnisse deuten darauf hin, dass innerhalb der Objektrepräsentationen belebter Objekte alle drei Merkmalstypen interkorrelieren. Für Objekte der unbelebten Domäne werden starke Interkorrelationen zwischen funktionalen und sensorischen Merkmalen angenommen. Zusätzlich wird davon ausgegangen, dass distinktive funktionale Merkmale innerhalb der Repräsentationen unbelebter Objekte besonders stark gewichtet sind. / The study investigates the assumption of a differential weighting of distinctive encyclopaedic, functional and sensory semantic attributes within the concept representations of living and nonliving objects. A speeded feature verification task was conducted. In order to control the stimuli for various aspects, German norms were collected of estimated age of acquistion for 244 stimuli of the Snodgrass and Vanderwart (1980) pictures. In addition, a feature listing study was carried out for 80 concrete living and nonliving concepts. Two reaction time experiments were conducted with different duration times of the presented object name. In Experiment 1 (long duration time), the object name was presented for 1000 ms, whereas in Experiment 2 (short duration time), the object name was presented for 250 ms before the semantic feature appeared. With long duration time, distinctive functional features of nonliving objects were verified faster than distinctive encyclopaedic features. This effect was replicated in Experiment 2 after short presentation of the object names. In addition, in Experiment 2, shorter reaction times were observed for functional features than for sensory features of nonliving objects. For living objects, no differences were observed in verifying the different feature types neither in Experiment 1 nor in Experiment 2. The results are discussed within the framework of different models of semantic memory. The results suggest that within the category of living objects, distinctive encyclopaedic, functional and sensory features are highly intercorrelated. For nonliving objects, it is assumed that distinctive sensory and functional but not encyclopaedic features are highly intercorrelated. In addition, distinctive functional features of nonliving objects seem to be weighted more strongly than distinctive sensory features within the object representations of nonliving objects.

Diese Dissertation untersucht den Einfluss des Erwerbsalters und des Kenntnisstandes auf die Verarbeitung semantischer und syntaktischer Strukturen des Deutschen als Zweitsprache. Gegenstand sind drei EKP Studien, die die Verarbeitung von semantischen Anomalien, Doppel-Nominativ Verletzungen und nicht-lizenzierten negativ polaren Elementen untersuchen. Neben den Fragen, welchen Einfluss das Erwerbsalter und der Kenntnisstand auf die Verarbeitung der Zweitsprache nehmen und welche daraus resultierenden Unterschiede sich bezüglich der Dissoziation zwischen der Verarbeitung semantischer und syntaktischer Strukturen ergeben, widmet sich diese Arbeit zentral der Frage, ob die Einflüsse von Erwerbsalter und Kenntnisstand unabhängig oder interaktiv auftreten und ob sie eher auf einen kontinuierlichen Verlauf oder sichtbare Grenzen hinweisen. / This dissertation presents research on how the age of acquisition (AoA) and the proficiency level influence the processing of a second language. Three ERP studies (event related potentials) were conducted investigating on the processing of semantic incongruity, the processing of double nominative violation, and the processing of negative polarity item (NPI) licensing in German as a second language. Three central questions were in focus: (i) whether second language learners, like native speakers also show the dissociation between semantic and syntactic processing; (ii) whether and how AoA and / or proficiency influence second language processing, independently or interactively; and (iii) whether this influence appears gradual or discontinuous. According to (i) results largely confirm previous research on this topic suggesting that second language processing is sensitive to the semantic-syntactic dissociation. Regarding (ii) outcomes suggest interactive influences between the AoA and proficiency on second language processing especially when syntactic and semantic-syntactic demands are enhanced as to the language processing system. This contributes to recent suggestions and augments the argument that relative to the activation and retrieval of neural resources associated with syntactic processing mechanisms proficiency may compensate for the impact of age of acquisition. With respect to (iii) the present outcomes strongly support a continuity approach indicating that changes in the activation and retrieval of processing mechanisms appear gradual.

Cognate words have a shared orthographic and semantic representation across languages: kniv (‘knife’) in Danish means the same as kniv in Swedish. Their shared form and meaning give cognates a special status in the bilingual mental lexicon and there is robust evidence that because of this special status they are processed faster than non-cognate words. This effect is called the Cognate Facilitation Effect and represents strong evidence that bilinguals do not have two separate mental lexicons, but rather one integrated lexicon for both of their languages with nonselective access. The present study is a replication of Vanlangendonck et al. (2020) with a different language constellation. For the aims of this project, early and late Danish-Swedish bilinguals were recruited to examine the effect of stimulus list composition on the Cognate Facilitation Effect by means of two experiments: one language-specific visual lexical decision task that contained control words from the participants’ L2 (Swedish), a set of cognates, interlingual homographs and pseudowords, and a second task in which half of the pseudowords were replaced by Danish (L2) words that had to evoke a “no” response. This change from a pure to a mixed list was expected to increase response competition and turn cognate facilitation into inhibition. However, the results showed a null Cognate Facilitation Effect both for early and for late bilinguals. These findings are discussed in terms of the assumptions of the BIA+ model of bilingual lexical processing and it is suggested that the presence of language-specific diacritics in the stimulus list has hindered the emergence of the Cognate Facilitation Effect.