Conor T. McLennan

Representation of Lexical Form

The authors attempted to determine whether surface representations of spoken words are mapped onto underlying, abstract representations. In particular, they tested the hypothesis that flaps--neutralized allophones of intervocalic /t/s and /d/s--are mapped onto their underlying phonemic counterparts. In 6 repetition priming experiments, participants responded to stimuli in 2 blocks of trials. Stimuli in the 1st block served as primes and those in the 2nd as targets. Primes and targets consisted of English words containing intervocalic /t/s and /d/s that, when produced casually, were flapped. In all 6 experiments, reaction times to target items were measured as a function of prime type. The results provide evidence for both surface and underlying form-based representations.

Mouse tracking reveals that bilinguals behave like experts

We used mouse tracking to compare the performance of bilinguals and monolinguals in a Stroop task. Participants were instructed to respond to the color of the words (e.g., blue in yellow font) by clicking on response options on the screen. We recorded participants’ movements of a computer mouse: when participants started moving (initiation times), and how fast they moved towards the correct response (x-coordinates over time). Interestingly, initiation times were longer for bilinguals than monolinguals. Nevertheless, when comparing mouse trajectories, bilinguals moved faster towards the correct response. Taken together, these results indicate that bilinguals behave qualitatively differently from monolinguals; bilinguals are “experts” at managing conflicting information. Experts across many different domains take longer to initiate a response, but then they outperform novices. These qualitative differences in performance could be at the root of apparently contradictory findings in the bilingual literature.

Examining Talker Effects in the Perception of Native- and Foreign-Accented Speech

Understanding the circumstances under which talker (and other types of) variability affects language perception represents an important area of research in the field of spoken word recognition. Previous work has demonstrated that talker effects are more likely when processing is relatively slow (McLennan & Luce, 2005). Given that listeners may take longer to process foreign-accented speech than native-accented speech (Munro & Derwing, Language and Speech, 38, 289–306 1995), talker effects should be more likely when listeners are presented with words spoken in a foreign accent than when they are presented with those same words spoken in a native accent. The results of two experiments, conducted in two different countries and in two different languages, are consistent with this prediction.

Representation of lexical form: evidence from studies of sublexical ambiguity.

The authors examined the role of intermediate, sublexical representations in spoken word perception. In particular, they tested whether flaps, which are neutralized allophones of intervocalic /t/s and /d/s, map onto their underlying phonemic counterparts. In 2 shadowing tasks, the authors found that flaps primed their carefully articulated counterparts, and vice versa. Because none of the flapped stimuli were lexically ambiguous (e.g., between rater and raider), these results provide evidence that such priming is sublexically mediated. Therefore, the current study provides further insights into when underlying form-based representations are activated during spoken word processing. In particular, the authors argue that phonological ambiguity, inherent in their flapped stimuli, is one of the conditions leading to the activation of underlying representations.

The time course of variability effects in the perception of spoken language: changes across the lifespan.

Although spoken language is communicated via a rapidly varying signal, human listeners recognize spoken words both quickly and accurately. Nonetheless, variability in speech does have implications for both the processes and representations involved in spoken language perception. Moreover, variability effects have been observed across the lifespan, ranging from infants to older adults. Many factors could potentially modulate the degree to which variability affects spoken language perception. In particular, recent findings demonstrate that variability effects follow a time course, manifesting themselves at predictable points during perceptual processing. However, time course investigations are currently limited to young adults. Therefore, the current paper explores how the time course of variability effects might differ throughout the lifespan, based on predictions derived from an adaptive resonance framework.

Hemispheric Differences in the Recognition of Environmental Sounds

Recent work has found support for two dissociable and parallel neural subsystems underlying object and shape recognition in the visual domain: an abstract-category subsystem that operates more effectively in the left cerebral hemisphere than in the right, and a specific-exemplar subsystem that operates more effectively in the right hemisphere than in the left. Evidence of this asymmetry has been observed for linguistic stimuli (words, pseudoword forms) and nonlinguistic stimuli (objects). In the auditory domain, we previously found hemispheric asymmetries in priming effects using linguistic stimuli (spoken words). In the present study, we conducted four long-term repetition-priming experiments to investigate whether such hemispheric asymmetries would be observed for nonlinguistic auditory stimuli (environmental sounds) as well. The results support the dissociable-subsystems theory. Specificity effects were obtained when sounds were presented to the left ear (right hemisphere), but not when sounds were presented to the right ear (left hemisphere). Theoretical implications are discussed.

Examining the Effects of Variation in Emotional Tone of Voice on Spoken Word Recognition

Emotional tone of voice (ETV) is essential for optimal verbal communication. Research has found that the impact of variation in nonlinguistic features of speech on spoken word recognition differs according to a time course. In the current study, we investigated whether intratalker variation in ETV follows the same time course in two long-term repetition priming experiments. We found that intratalker variability in ETVs affected reaction times to spoken words only when processing was relatively slow and difficult, not when processing was relatively fast and easy. These results provide evidence for the use of both abstract and episodic lexical representations for processing within-talker variability in ETV, depending on the time course of spoken word recognition.

Famous Talker Effects in Spoken Word Recognition

Previous work has demonstrated that talker-specific representations affect spoken word recognition relatively late during processing. However, participants in these studies were listening to unfamiliar talkers. In the present research, we used a long-term repetition-priming paradigm and a speeded-shadowing task and presented listeners with famous talkers. In Experiment 1, half the words were spoken by Barack Obama, and half by Hillary Clinton. Reaction times (RTs) to repeated words were shorter than those to unprimed words only when repeated by the same talker. However, in Experiment 2, using nonfamous talkers, RTs to repeated words were shorter than those to unprimed words both when repeated by the same talker and when repeated by a different talker. Taken together, the results demonstrate that talker-specific details can affect the perception of spoken words relatively early during processing when words are spoken by famous talkers.

The Effect of Priming a Thin Ideal on the Subsequent Perception of Conceptually Related Body Image Words

Our research examined the effects of thin ideal priming on the perception of body image words in participants without an eating disorder. Half of the participants were primed by viewing thin models, and half were primed with gender-neutral shoes. Subsequently, all participants (N=56) completed a Stroop task for three categories of words: neutral (BOOKS), shoe (CLOGS), and body (THIGHS). Lastly, all participants completed a body dissatisfaction questionnaire. We predicted that body dissatisfaction scores would be correlated with the Stroop effect. We found a significant correlation between body dissatisfaction and the body effect of slower color naming times for the body related words compared to the neutral words. Our study demonstrates that body dissatisfaction and a brief priming with thin models results in subsequent differences in performing a Stroop task in a non clinical population of female participants.

The time course of within and between-language interference in bilinguals

Purpose: Recent research has provided support for linguistic coactivation, the view that the two languages of a bilingual are simultaneously active. Importantly, even if the system is fundamentally nonselective, the two languages of a bilingual can be activated to different degrees. The main contribution of the present paper is to empirically test what “different degrees of activation” really means. Differences could emerge in the timing or the magnitude of language activation. Methodology: Most of the research to date has been based on experiments using reaction times. In the present experiment participants responded to a bilingual Stroop task using a computer mouse. We argue that mouse tracking can provide new insights into the temporal dynamics of cognitive processes. Data and analysis: We used a series of t-tests to analyze participants’ mouse trajectories (n = 20). We compared the x-coordinates over time for each of the four experimental conditions (Congruent-Within, Congruent-Between, Incongruent-Within, Incongruent-Between) with the x-coordinates over time for the control trajectory. Findings: Differences in the timing, but not the magnitude, of interference are at the root of the differential effects within and between languages. Within-language interference emerged 80 ms earlier than between-language interference. Originality: To our knowledge, the current experiment is the first to use the dynamic mouse-tracking paradigm to compare the time course of the two languages of a bilingual participant. Implications: The mouse-tracking paradigm can help to distinguish between the timing and the magnitude of interference, informing current theories of the bilingual mind.