Angela de Bruin

Cognitive Advantage in Bilingualism An Example of Publication Bias

It is a widely held belief that bilinguals have an advantage over monolinguals in executive-control tasks, but is this what all studies actually demonstrate? The idea of a bilingual advantage may result from a publication bias favoring studies with positive results over studies with null or negative effects. To test this hypothesis, we looked at conference abstracts from 1999 to 2012 on the topic of bilingualism and executive control. We then determined which of the studies they reported were subsequently published. Studies with results fully supporting the bilingual-advantage theory were most likely to be published, followed by studies with mixed results. Studies challenging the bilingual advantage were published the least. This discrepancy was not due to differences in sample size, tests used, or statistical power. A test for funnel-plot asymmetry provided further evidence for the existence of a publication bias.

The importance of language use when studying the neuroanatomical basis of bilingualism

ABSTRACTStudies on the neuroanatomical basis of bilingualism have yielded various but inconsistent differences between bilinguals and monolinguals. In this commentary, we will discuss how differences in background variables between language groups could explain part of this variation. We will furthermore argue that besides language proficiency and age of acquisition, more research needs to be done on the effects of language use and language context. Green and Abutalebis Adaptive Control Hypothesis could guide the investigation of how language use and context could affect the structure of the brain. Lastly, given the inconsistency in (the direction of) neuroanatomical effects of bilingualism, we discuss how structural differences are difficult to interpret in the absence of behavioural data. A more theory-driven approach is needed to interpret the potential effects of bilingualism on a behavioural as well as neural level.ABSTRACT Studies on the neuroanatomical basis of bilingualism have yielded various but inconsistent differences between bilinguals and monolinguals. In this commentary, we will discuss how differences in background variables between language groups could explain part of this variation. We will furthermore argue that besides language proficiency and age of acquisition, more research needs to be done on the effects of language use and language context. Green and Abutalebis Adaptive Control Hypothesis could guide the investigation of how language use and context could affect the structure of the brain. Lastly, given the inconsistency in (the direction of) neuroanatomical effects of bilingualism, we discuss how structural differences are difficult to interpret in the absence of behavioural data. A more theory-driven approach is needed to interpret the potential effects of bilingualism on a behavioural as well as neural level.

The effects of language use on lexical processing in bilinguals

ABSTRACT Bilingualism has been associated with slower lexical processing in both languages, but it remains unclear to what extent this effect may be modulated by language use. We compared older English monolinguals with two groups of older bilinguals on lexical processing tasks. Both acquired English and Gaelic during childhood, but while active bilinguals continued to use both languages, inactive bilinguals mostly used English. All three groups showed similar accuracy in English. However, in reaction times, active but not inactive bilinguals were slower than monolinguals. We conclude that language use can modulate effects of bilingualism on lexical tasks.

The Connection Is in the Data: We Should Consider Them All

We recently published an article examining the existence of a publication bias in the literature on bilingualism and executive functioning and found that results supporting a bilingual advantage were more likely to be published than results challenging such an advantage (de Bruin, Treccani, & Della Sala, 2015). We are not part of a camp that is for or against the bilingual-advantage hypothesis and have in fact published a study supporting this hypothesis ourselves (Treccani, Argyri, Sorace, & Della Sala, 2009). However, we think that publication biases should be taken seriously and that researchers should not shy away from investigating their possible sources (cf. Ferguson & Heene, 2012). In our article, we argued that all the data should be considered, not just selected data supporting a particular theory. Bialystok, Kroll, Green, MacWhinney, and Craik (2015) questioned the importance and reliability of our findings. Bialystok and her colleagues hold very strong views on the argued cognitive advantage of bilingualism. This may be why they label our conclusions, which are dissonant with their views, as “errors.”

The decline effect: How initially strong results tend to decrease over time

Paap, Johnson, and Sawi (2015) argue that a bilingual advantage in executive functioning (EF) either does not exist or only occurs infrequently and in undetermined circumstances. They furthermore argue that biases may have inflated the evidence for a bilingual advantage. Their overview of published results shows that more than 80% of the tests conducted after 2011 showed no effect of bilingualism, especially in studies with larger sample sizes. In this commentary, we will describe how evidence for a bilingual advantage has changed over time and which reasons may underlie a decline of positive evidence. The relatively short but extensive history of research on bilingualism and EF has seen a shift from initial studies presenting strong evidence for a bilingual advantage to more recent studies criticising the reliability or even the existence of such an advantage. One of the first and most influential studies on this topic (Bialystok, Craik, Klein, & Viswanathan, 2004) reported the highest effect sizes observed in this literature (ranging up to d 1⁄4 3). In the following years, further studies reported positive effects of bilingualism but with smaller effect sizes. The average effect size in published studies now seems to be substantially smaller (around d 1⁄4 .30; de Bruin, Treccani, & Della Sala, 2015). In 2011, Hilchey and Klein concluded that their review showed limited evidence for an inhibitory effect of bilingualism, but ‘robust’ evidence for a global bilingual advantage. In an updated review (Hilchey, Saint-Aubin, & Klein, in press), however, they conclude that the evidence for a global advantage has evaporated since their initial review. This change in conclusions is compatible with Fig. 1 presented by Klein (2015), who compared reaction times on Simon and flanker tasks between bilinguals and monolinguals. Large bilingual-monolingual differences were predominantly found in earlier studies, but less so in recent publications. To examine this apparent decline in support for a bilingual advantage, we created an overview of studies on bilingualism and EF published between 2004 and 2014 (Fig. 1). Based on the overall conclusions presented in these papers, we classified them as ‘supporting’ or ‘challenging’ a bilingual advantage, or as ‘mixed’ if no conclusion was drawn. The pattern of supporting versus challenging studies has indeed changed over time. Whereas earlier studies largely supported a bilingual advantage, recent years (especially 2014) have shown an upsurge in studies challenging this view. Thus, the support for a bilingual advantage appears to have diminished in recent years. A decrease in positive evidence after a strong initial finding is not uncommon in science and is dubbed the ‘decline effect’. In many research fields, initial studies have shown large effects whereas later studies struggle to replicate these findings or only find effects in restricted circumstances. For example, the decline effect accounts for the lack of confirmation of a widely used treatment

Compulsive foreign language syndrome: A clinical observation not a mystery

An Italian 50 year old right-handed man, JC, with 17 years of education affected by the consequences (obstruction hydrocephalus, surgically treated with a shunt, and brain stem vascular encephalopathy) of mega dolicho basilar artery anomaly, abruptly started to speak French even though his knowledge of the language was only cursory. He had no personal or family history of psychiatric disorders; he had always been an upright person, very conscientious in his job. He did not show sensory or motor deficits and no impairments of the cranial nerves. At onset he showed signs of depression which faded with time without therapy. He had superficially learned French at school, used it in his 20s due to a flingwith a French girl but he has not spoken it for about 30 years. In his professional life he used English as his second language. Before brain damage he never manifested a particular attachment to French culture or French cuisine. His accent is not due to dysarthria and he speaks polished and correct Italian, his mother tongue. However, he now states that French is his preferred language refusing to speak in Italian spontaneously. Similar cases have been reported in the popular press and discussed as improbable cases of cryptomnesia (Flournoy, 1900) or xenoglossy (Richet, 1905). Hints can also be gleaned from the classics where they are mentioned in passim as literary comments (Chaucer, ca 1387; Melville, 1891). However, none have been formally assessed in a clinical setting. JCs French is maladroit and full of inaccuracies, yet he speaks it in a fast pace with exaggerated intonation using a movie-like prosody and posing as a typical caricature of a French man. His French vocabulary is reduced and he commits several grammatical errors but he does not speak grammelot or gibberish and never inserts Italian terms in his French sentences. He uses French to communicate with everybodywho is prepared to listen; he speaks Frenchwith his bewildered Italian relatives, with his hospital inmates, with the consultants; he spoke French even in front of the befuddled Committee deciding on his pension scheme. He claims that he cannot but speak in French, he believes that he is thinking in French and he longs to watch French movies (which he never watched before), buys French food, reads French magazines and seldom French books, but he writes only in Italian. He shows no irritation if people do not understand him when he speaks in French. His score in the Italian version of the BostonNaming Test is 60/60, he performs verbal fluency tests in Italian well over the median of his matched control group, he is very fast and does not showproblems inword retrieval. However, when assessed with Italian tests, he first attempts to answer in French even though he uses generic terms, like ‘vegetable’ for ‘asparagus’ (he does so also in spontaneous conversation); when asked again he responds correctly in Italian. He shows persistent episodic memory impairments (including forgetting of autobiographical episodes from the last three years, whereas his autobiographical memory for the past is spared) but performs well and fast on a range of other cognitive tests including those assessing executive functions (see Table 1). He never reported hallucinations and delirium was never observed. However, he presents with some delusions of grandeur, sleep disturbances and has some compulsive behaviours: he buys unnecessarily large quantities of objects (e.g., needing two

Effects of age on inhibitory control are affected by task-specific features

Older adults have been argued to have impoverished inhibitory control compared to younger adults. However, these effects of age may depend on processing speed and their manifestation may furthermore depend on the type of inhibitory control task that is used. We present two experiments that examine age effects on inhibition across three tasks: a Simon arrow, static flanker and motion flanker task. The results showed overall slower reaction times (RTs) for older adults on all three tasks. However, effects of age on inhibition costs were only found for the Simon task, but not for the two flanker tasks. The motion flanker task furthermore showed an effect of baseline processing speed on the relation between age and inhibition costs. Older adults with slower baseline responses showed smaller inhibition costs, suggesting they were affected less by the flanker items than faster older adults. These findings suggest that effects of age on inhibition are task dependent and can be modulated by task-specific features such as the type of interference, type of stimuli and processing speed.