Stephen D. Goldinger - US grants

DESCRIPTION (Adapted from the Investigator's Abstract): This research project investigates lexical representations in long-term memory and the processes that access those representations. Most theories assume that the speech wave form is converted to a string of phonemes which is then compared to the mental lexicon. When comparison yields a match, the word is "recognized". This typical view emphasizes the abstract properties of words. A speech signal containing idiosyncratic information (speaker's voice, ambient noise, etc.) is converted to a sequence of ideal, abstract phonemes, which is used to access ideal, abstract words. Few theories consider idiosyncracies of speech as more than "noise" in the signal. However, multiple-trace memory models posit that details of perceptual experience are not forgotten; instead, they are integral to later perception. The proposed research will test a multiple-trace model of the mental lexicon, using speech perception and memory data (Project 1), and speech production data from a novel shadowing paradigm (Project 2). Preliminary research and pilot simulations of Hintzman's (1986) MINERVA 2 model have already produced encouraging results. The investigators plan to test the predictive limits of the extant model, and to test embellished versions as necessary. In Project 1, perception and memory experiments will test the level of detail and the durability of episodic memory traces produced in spoken word recognition, and will carefully assess the relationship of memory and perception. In Project 2, the model is tested against speech production data from a single-word shadowing task. The typical dependent measure in shadowing is response time; an alternative, rarely- used measure is the acoustic-phonetic content of the Ss' speech responses. Project 2 will examine changes in speech acoustics during single-word shadowing. Stimulus words for Ss to shadow will be produced by multiple speakers, including males and females.

[unreadable] DESCRIPTION (provided by applicant): This research investigates lexical representations in long-term memory and the processes that both encode and retrieve those representations. Most theories assume that speech waveforms are converted to phoneme strings, which are then compared to the mental lexicon. When comparisons yield matches, words are "recognized." This typical view emphasizes the abstract properties of words: Speech signals containing idiosyncratic information (e.g., speaker's voice, ambient noise) are normalized into a canonical form, then matched to abstract lexical entries. Few theories consider idiosyncrasies of speech as more than "noise" in the signal. However, episodic memory models posits that details of perceptual experiences are not forgotten; instead, they are integral to later perception. The proposed research further tests the episodic view, using speech perception, memory, and production experiments, coupled with model simulations. In Project 1, perception and memory experiments will test factors governing episodic content, examining roles of selective attention and working memory. The experiments will assess the nature and extent of perceptual-conceptual tradeoffs in trace formation. In Project 2, multidimensional scaling experiments are coupled with memory tests, with a goal of discovering the similarity-distance function in episodic word priming. Project 3 provides a critical test of the episodic view, using eye-tracking procedures to assess the timecourse of episodic effects in perception. The experiments in Project 4 will examine memory for larger episodic units, using full sentences as stimuli. In addition to standard tests, sentence memory will also be assessed using a novel speech-production method, examining the acoustic-phonetic content of spoken responses. As in previous research, we expect people to spontaneously imitate acoustic patterns of the stimulus sentences. The episodic theory predicts that degrees of imitation will be affected by "abstract" characteristics of the sentences, such as semantic complexity, suggesting that speech acoustics reflect a complex interplay of linguistic stimuli and their episodic representations. [unreadable] [unreadable]

DESCRIPTION (provided by applicant): The proposed research will examine episodes of mindless reading, with special focus on the novel insights that such episodes may offer into bilingual cognition. Mindless reading (MR) is a daydream mode wherein readers continue moving their eyes across the text, but their attention has disengaged from text processing. In some regards, MR is similar to other automatized processes, such as driving a familiar route while having a conversation. People are adept at decoupling thought from action, allowing well-practiced behaviors to proceed in the background, while the conscious mind is elsewhere occupied. Indeed, it is estimated that mind-wandering occupies anywhere from 30-50% of everyday cognition. In recent years, numerous studies have documented a broad set of cognitive benefits that occur in bilingualism, ranging from superior low-level, perceptual categorization to superior high-level executive functioning. A prominent hypothesis is that bilinguals constantly engage neural circuitry to control language selection, even when the dominant language is being used. This juggling act promotes robust neural systems for cognitive control, even in non-linguistic tasks. The proposed research is a synthesis of these fields, and represents the first investigation of mind-wandering (or MR) in bilinguals. We will conduct foundational experiments on MR in monolinguals and bilinguals, as an ecologically valid means to investigate one potential source of their cognitive differences. According to recent theory, mind-wandering reflects activity of the brain's default network, which cyclically trades off with more controlled activity in frontal-parietal networks. We suggest a working hypothesis that, as a function of constant language selection, bilinguals are less likely to mind-wander, especially during language processing. We will also test the counter-intuitive hypothesis that mind-wandering will occur more often when people read in their dominant language. The scientific study of mind-wandering poses methodological challenges, as it often requires self-report by the participant, who is typically unaware that attention has lapsed. In MR, however, there are characteristic changes in eye-movements that allow early, covert detection. Our research will use eye-tracking to identify MR in an unobtrusive manner during natural reading. Our specific aims are (1) to continue developing a Bayesian network that classifies eye-movement patterns as indicating MR, in real-time, without requiring participants to self-report MR or respond to external prompts; (2) to determine the frequency and duration of MR episodes during natural reading, with special focus on bilinguals reading in their dominant and non-dominant languages; (3) to determine whether monolinguals and bilinguals differ in detection rates for gaze-contingent display changes during MR; (4) to directly assess the role of cognitive load in MR, by comparing MR rates when passages are presented in print versus natural handwriting, which increases the need for top-down processing in reading; and (5) to complete theoretical simulations of the experiments using the E-Z Reader model of eye-movement control.