Project Description

Background: As we are comprehending language, we develop interpretations without waiting until the ends of words, phrases or sentences. This process requires predictive and continuous coordination of different types of linguistic as well as non-linguistic information. Recent studies have proposed that this information coordination mechanism is further modulated according to the comprehender's assumptions about the speaker. For instance, when comprehenders believe that the speaker has an impairment that causes language and social problems, they may expect the linguistic input to be less reliable and adjust their comprehension behavior accordingly. This line of research uncovers how the bottom-up linguistic input and the top-down expectations and assumptions may constrain each other to guide real-time language processing.

PI: Kurumada (Tanenhaus)

Paper: Grodner, D. J., & Sedivy, J. C. (2011). The effect of speaker-specific information on pragmatic inferences. In E. Gibson., & N. Pearlmutter (Eds.) The processing and acquisition of reference. pp. 239-272.

Study: Experiment 1: Suspension of predictive eye-movements based on pronominal adjectives

Summary: Subjects are randomly assigned to one of two conditions and eye-tracked as they follow verbal instructions to manipulate objects on a computer screen. Target instructions contain a pre-nominal adjective (e.g., "Click on a tall glass"), which usually triggers anticipatory eye movements to a target object (e.g., a tall glass) when a contrasting object (e.g., a small glass) is also present. However, when subjects are told that the speaker has an impairment that prevents her from making logical uses of prenominal adjectives, such anticipatory eye movements were no longer observed. The results suggest that subjects' real-time language comprehension behavior is modulated in a speaker-specific fashion according to their expectations about the utility of linguistic signals.

Impact: This is a pioneering study that opened up a number of avenues of research questions regarding the rationality and automaticity of pragmatic processing in real-time sentence comprehension. This is, however, the only study thus far that showed effects of top-down information about the speaker on the time-course of real-time eye movements. It is yet to be established whether the results are reliably replicable.

Skills Required

Simple stimulus/response programming, R

Project Description

Background: Economic choice is often believed to be pure, rational, and emotionless. A newer strain of behavioral economics, taking ideas from psychology, has shown that it is not immune to psychological influences. Quite the contrary, even extremely simple factors can influence choices. One of these is anchoring, or the subtle priming of quantities, which has been shown to bias both willingness to pay measures and reported enjoyment afterwards. Recently, much of this work has come under scrutiny with failures to replicate. Thus, it is important for the field to establish a ground truth for these experiments by determining which of them is sufficiently robust that they can replicate.

PI: Hayden

Book: Ariely, Dan. Predictably Irrational.

Study: Experiment 1: Wine purchases

Summary: Subjects will be primed with a random number generator (such as the last two digits of their SSN) and then asked how much they would pay for a bottle of wine (maybe we can use chocolates instead. Willingness-to-pay will be assessed using standard incentive-compatible econometric techniques (e.g. a Becker-DeGroot-Marshak auction). Experimenters will assess the influence of the prime on the WTP and on the reported enjoyment afterwards.

Impact: This is a classic study in the field whose implications for our understanding of economic choice are profound. Nonetheless, its replicability is uncertain.

Skills Required

Simple stimulus/response programming, basic statistics, working with human subjects

Project Description

Background: Researchers are interested in understanding the cognitive processes that enable humans to understand spoken language, despite the fact that massive pronunciation variability exists across talkers due to factors like regional and foreign accent. Current evidence suggests that humans can dynamically adjust how speech input (e.g., spoken sounds, words) is mapped to linguistic representations in memory based on experience with particular talkers and accents. This general ability is referred to as 'adaptation'. While some studies suggest that adaptation to unusual pronunciations in speech perception can be very fast, there are also clear limits to this ability. This study investigates the timing of adaptation to foreign-accented speech: how quickly are listeners able to identify and adjust for patterns of variation in an unfamiliar accent?

PI: Jaeger (w/ Kodi Weatherholtz & Zach Burchill)

Paper: Clarke, C. M., & Garrett, M. F. (2004). Rapid adaptation to foreign-accented English. The Journal of the Acoustical Society of America, 116(6), 3647-58.

Study: Experiment 1: Changes in processing efficiency following brief exposure to foreign-accented speech (p. 3649)

Summary: Subjects are given a task in which they listen to Spanish-accented English sentences and then must identify whether the final word of the sentence matches a visually presented target word. Subjects initially tend to be slower to make accurate responses when presented with Spanish-accented speech, relative to control conditions in which the speech materials are presented in a native English accent. However, this response time difference rapidly diminishes as subjects gain experience with Spanish-accented English, and there is no significant difference between response times for foreign-accented and native-accented speech after one minute of exposure to the foreign accent. This result indicates that listeners rapidly adapt to foreign accented speech. Further, the results suggest that adaptation can occur after exposure to as little as one sentence.

Impact: This is an influential study in research on spoken language processing (228 citations on Google Scholar). In particular, it helped spark a large body of behavioral, computational and (to some extent) neuropsychological research on the nature of the representations and mechanisms that underlie flexibility in speech processing. However, it has to this day not been replicated.

Skills Required

Simple stimulus/response programming, ANOVA

Resulting conference presentations and papers

• Xie, X., Weatherholtz, K., Bainton, L., Rowe, E., Burchill, Z., Liu, L., & Jaeger, T. F. 2018. Rapid adaptation to foreign-accented speech and its transfer to an unfamiliar talker. JASA 143(3), p. XXX-XXX. DOI: 10.1121/1.5027410

Project Description

Background: Humans (and animals) constantly have to make decisions based on information obtained from the outside world – be it through their eyes, ears, or other senses. Optimal decision-making in many case requires the computation of information not simply about the target itself (e.g. the identity of a person or object) but also knowledge of one's uncertainty about being correct. This is important for instance, to avoid catastrophic outcomes ("am I sure I didn't see a car coming from the left?" before deciding to cross a street), but also to combine the information from one source with the information from other sources. The details of these uncertainty-related computations in the brain are still very poorly understood.

PI: Haefner

Paper: Barthelme & Mamassian, Evaluation of Objective Uncertainty in the Visual System, PLoS Computational Biology 5(9)

Summary: Subjects are given the task to identify a pattern embedded in a noisy visual stimulus presented on the screen. At any one time, 2 such stimuli are shown and the subject has the choice for which stimulus to answer the question. By comparing the responses of subjects with the predictions of different mathematical models for computing uncertainty one can learn about the actual strategy used by the brain.

Impact: While the chance that the results from this study cannot be replicated is very small, it a) teaches essential psychophysical techniques applicable to most studies in the field and b) lays the foundation for a number of interesting extensions that probe the limits of, and even neural representation of, those uncertainty-related computations.

Skills Required

Simple stimulus/response programming