Rachel Hull

Executive function in older adults: A structural equation modeling approach.

Confirmatory factor analysis (CFA) and structural equation modeling (SEM) were used to study the organization of executive functions in older adults. The four primary goals were to examine (a) whether executive functions were supported by one versus multiple underlying factors, (b) which underlying skill(s) predicted performance on complex executive function tasks, (c) whether performance on analogous verbal and nonverbal tasks was supported by separable underlying skills, and (d) how patterns of performance generally compared with those of young adults. A sample of 100 older adults completed 10 tasks, each designed to engage one of three control processes: mental set shifting (Shifting), information updating or monitoring (Updating), and inhibition of prepotent responses (Inhibition). CFA identified robust Shifting and Updating factors, but the Inhibition factor failed to emerge, and there was no evidence for verbal and nonverbal factors. SEM showed that Updating was the best predictor of performance on each of the complex tasks the authors assessed (the Tower of Hanoi and the Wisconsin Card Sort). Results are discussed in terms of insight for theories of cognitive aging and executive function.

Laterality and language experience

A meta-analysis was conducted on studies that examined hemispheric functional asymmetry for language in brain-intact monolingual and bilingual adults. Data from 23 laterality studies that directly compared bilingual and monolingual speakers on the same language were analysed (n = 1234). Variables examined were language experience (monolingual, bilingual), experimental paradigm (dichotic listening, visual hemifield presentation, and dual task) and, among bilinguals, the influence of second language proficiency (proficient vs nonproficient) and onset of bilingualism (early, or before age 6; and late, or after age 6). Overall, monolinguals and late bilinguals showed reliable left hemisphere dominance, while early bilinguals showed reliable bilateral hemispheric involvement. Within bilinguals, there was no reliable effect of language proficiency when age of L2 acquisition was controlled. The findings indicate that early learning of one vs. two languages predicts divergent patterns of cerebral language lateralisation in adulthood.

Getting a joke: the time course of meaning activation in verbal humor

Two lexical decision semantic priming experiments examined when, in the course of reading a joke, the initial and the intended meanings are primed; whether the meanings overlap in time; and what happens to the initial reading when the punchline is encountered. In Experiment 1, probes related to the first activated sense (S1) vs. the second sense (S2), or true meaning, were presented at each of three temporal sites for visually displayed joke tests: shortly after joke onset, at an intermediary position, and at punchline offset, whereas in Experiment 2, probes were presented at joke offset following prolonged viewing. The results from Experiment 1 showed S1 priming effects at the initial and intermediary time point. Priming for S2 also emerged at the intermediary time point and persisted at the final time point. In Experiment 2, the priming effect at joke offset was reliable only for S2. The results are taken to support a concurrent meaning activation view [in line with Attardo, Humor 10 (1997) 395] at incongruity detection, and a selective activation view [in line with Giora, Journal of Pragmatics 16 (1991) 465] at incongruity resolution.

Near-Infrared Spectroscopy and Cortical Responses to Speech Production

This research demonstrates near-infrared spectroscopy (NIRS) as a flexible methodology for measuring cortical activity during overt speech production while avoiding some limitations of traditional imaging technologies. Specifically, language production research has been limited in the number of participants and the types of paradigms that can be reasonably investigated using functional magnetic resonance imaging (fMRI) – where a sensitivity to motion has encouraged covert (i.e., nonvocalized) production paradigms – and positron emission tomography (PET), which allows a greater range of motion but introduces practical and ethical limitations to the populations that can be studied. Moreover, for these traditional technologies, the equipment is expensive and not portable, effectively limiting most studies to small, local samples in a relatively few labs. In contrast, NIRS is a relatively inexpensive, portable, noninvasive alternative that is robust to motion artifacts associated with overt speech production. The current study shows that NIRS data is consistent with behavioral and traditional imaging data on cortical activation associated with overt speech production. Specifically, the NIRS data show robust activation in the left temporal region and no significant change in activation in the analogous right hemisphere region in a sample of native, English-speaking adults in a picture-naming task. These findings illustrate the utility of NIRS as a valid method for tracking cortical activity and advance it as a powerful alternative when traditional imaging techniques are not a viable option for researchers investigating the neural substrates supporting speech production.

Linking behavioral and neurophysiological indicators of perceptual tuning to language.

Little is known about the neural mechanisms that underlie tuning to the native language(s) in early infancy. Here we review language tuning through the lens of type and amount of language experience and introduce a new manner in which to conceptualize the phenomenon of language tuning: the relative speed of tuning hypothesis. This hypothesis has as its goal a characterization of the unique time course of the tuning process, given the different components (e.g., phonology, prosody, syntax, semantics) of one or more languages as they become available to infants, and biologically based maturational constraints. In this review, we first examine the established behavioral findings and integrate more recent neurophysiological data on neonatal development, which together demonstrate evidence of early language tuning given differential language exposure even in utero. Next, we examine traditional accounts of sensitive and critical periods to determine how these constructs complement current data on the neural mechanisms underlying language tuning. We then synthesize the extant infant behavioral and neurophysiological data on monolingual, bilingual, and sensory deprived tuning, thereby scrutinizing the effect of these three different language profiles on the specific timing, progression, and outcome of language tuning. Finally, we discuss future directions researchers might pursue to further understand this aspect of language development, advocating our relative speed of tuning hypothesis as a useful framework for conceptualizing the complex process by which language experience works together with biological constraints to shape language development.

Hemodynamic responses to speech and music in preverbal infants

Numerous studies have provided clues about the ontogeny of lateralization of auditory processing in humans, but most have employed specific subtypes of stimuli and/or have assessed responses in discrete temporal windows. The present study used near-infrared spectroscopy (NIRS) to establish changes in hemodynamic activity in the neocortex of preverbal infants (aged 4–11 months) while they were exposed to two distinct types of complex auditory stimuli (full sentences and musical phrases). Measurements were taken from bilateral temporal regions, including both anterior and posterior superior temporal gyri. When the infant sample was treated as a homogenous group, no significant effects emerged for stimulus type. However, when infants’ hemodynamic responses were categorized according to their overall changes in volume, two very clear neurophysiological patterns emerged. A high-responder group showed a pattern of early and increasing activation, primarily in the left hemisphere, similar to that observed in comparable studies with adults. In contrast, a low-responder group showed a pattern of gradual decreases in activation over time. Although age did track with responder type, no significant differences between these groups emerged for stimulus type, suggesting that the high- versus low-responder characterization generalizes across classes of auditory stimuli. These results highlight a new way to conceptualize the variable cortical blood flow patterns that are frequently observed across infants and stimuli, with hemodynamic response volumes potentially serving as an early indicator of developmental changes in auditory-processing sensitivity.

What's so funny? Modelling incongruity in humour production

ABSTRACT Finding something humorous is intrinsically rewarding and may facilitate emotion regulation, but what creates humour has been underexplored. The present experimental study examined humour generated under controlled conditions with varying social, affective, and cognitive factors. Participants listed five ways in which a set of concept pairs (e.g. MONEY and CHOCOLATE) were similar or different in either a funny way (intentional humour elicitation) or a “catchy” way (incidental humour elicitation). Results showed that more funny responses were produced under the incidental condition, and particularly more for affectively charged than neutral concepts, for semantically unrelated than related concepts, and for responses highlighting differences rather than similarities between concepts. Further analyses revealed that funny responses showed a relative divergence in output dominance of the properties typically associated with each concept in the pair (that is, funny responses frequently highlighted a property high in output dominance for one concept but simultaneously low in output dominance for the other concept); by contrast, responses judged not funny did not show this pattern. These findings reinforce the centrality of incongruity resolution as a key cognitive ingredient for some pleasurable emotional elements arising from humour and demonstrate how it may operate within the context of humour generation.

Bilingual laterality and the matter of degree: A response to Paradis (2008)

In his comment on Hull and Vaid (2007), Paradis (this issue) argues that whereas behavioral laterality paradigms are reasonably reliable and valid for specifying group differences in direction of hemispheric dominance, differences in degree of performance advantage have not been shown to correspond to differences in degree of functional asymmetry and that, therefore, individual bilingual laterality studies and meta-analytic treatments thereof are based on a claim that is unfounded. In our response we argue that (a) interpreting outcomes of significance tests from individual experimental studies often obscures underlying relationships in the data; these relationships are better detected through meta-analysis, (b) inferring different degrees of underlying lateralization from quantitative differences in meta-analytic effect sizes of performance asymmetries is appropriate when random variance is reasonably controlled, and (c) moderator analysis in meta-analytic data treatments allows confidence in drawing inferences about the relationship between their outcomes and underlying constructs such as degree of asymmetry. Paradis argues that the sources cited by Hull and Vaid (2007), while intended to show that behavioral laterality measures are generally reliable and valid indicators of hemispheric dominance, in fact highlight the pitfalls of unwanted variance arising from participant heterogeneity, attentional demands, etc. He quotes Segalowitz (1986, p. 363) comment that “it would be helpful to know how much variation in neurolinguistic scores, such as those of dichotic listening, is due to neurolinguistic organization, and not stemming from a variety of sources as discussed above” (Paradis, p. TBA). Our citing of sources such as Segalowitz and Bryden (1983) was to demonstrate that laterality measures, despite their acknowl