Speech Research Laboratory ../ Just another WordPress weblog Fri, 31 Oct 2008 20:58:38 +0000 http://wordpress.org/?v=2.0.11 en Two SRLers present at the 6th Conference on the Mental Lexicon ../news/2008/10/20/two-srlers-present-at-the-6th-conference-on-the-mental-lexicon/ ../news/2008/10/20/two-srlers-present-at-the-6th-conference-on-the-mental-lexicon/#comments Mon, 20 Oct 2008 20:54:45 +0000 admin ../news/2008/10/20/two-srlers-present-at-the-6th-conference-on-the-mental-lexicon/ Robert Felty and Volya Kapatsinski recently gave presentation at the 6th conference on the Mental Lexicon in Banff, Alberta, Canada, October 7th-10th. Over 100 leading scholars in psycholinguistics and word recognition came together to discuss their research on trying to discover how humans store and access words.

Sample slide from Felty's 2008 Mental Lexicon presentation

Robert gave an oral presentation with co-authors Adam Buchwald and David B. Pisoni entitled Constructing neighborhood density from spoken word recognition errors. Click on the image to download slides from the presentation in pdf format.

Kapatsinskis 2008 mental lexicon poster

Volya presented a poster entitled Product and source-oriented generalization over an (artificial) lexicon. Click on the image to download a pdf version of the poster.

Congratulations to our honor students ../news/2008/04/29/honors/ ../news/2008/04/29/honors/#comments Tue, 29 Apr 2008 19:03:02 +0000 admin http://robfelty/srlTest/?p=1 Two honor students working in the SRL, Althea Bauernschmidt and Melissa Troyer, recently defended their honors theses.

Audiovisual Phonological Fusion and Temporal Asynchrony
Melissa Troyer

In her thesis, Melissa investigated the perception and detection of timing asynchronies in a newly discovered phenomenon known as audiovisual phonological fusion (AVPF). In this type of fusion, visual information (e.g., back) combines with auditory information (e.g., lack) to create a fused percept (i.e., black).

Subjects were presented with stimuli that different in the amount of temporal offset ranging from 300 ms of auditory lead to 500 ms of visual lead and completed two tasks. In the asynchrony judgment task, subjects were asked to determine whether the auditory and visual portions of a stimulus occurred at the same time (”in sync”) or at different times (”out of sync”). The stimuli presented in both tasks were the same, but the ordering of the tasks was manipulated in order to see whether performing one task first would have an effect on the other task.

We found that (1) perception of fusion from AVPF stimuli is only moderately robust to temporal asynchrony; (2) AVPF stimuli are judged as synchronous more often they are fused; and (3) even though AVPF stimuli are not often fused in a perceptual task, exposure to the stimuli may involve implicit integration which effects an increased likelihood that the asynchronous stimuli will subsequently be judged as synchronous.

These findings suggest that audiovisual fusions (in particular, AVPF) do not reflect the operation of impenetrable, encapsulated modules but rather can be modulated both by bottom-up (in the case of temporal asynchrony) and top-down (in the case of modulations due to previous exposure to AVPF stimuli) processes. In addition, the present findings support an integrative network model of audiovisual speech perception in which the probability of integration of the auditory and visual streams is modulated by both stimulus-driven and cognitive constraints based on prior experience.

Melissa will be pursuing a PhD in Cognitive Science in the Department of Brain and Cognitive Sciences at MIT in the fall. She will continue to study language processing under the guidance of Professor Edward Gibson.

Working Memory Training and Implicit Learning
Althea Bauernschmidt

Recent studies have shown that working memory can be improved through
training and this improvement generalizes to other cognitive measures.
Working memory studies typically focus on the retention of random sequences;
however, a lot of what working memory is used for is not random. The goals
of the study were to determine what effect probabilistic structure has on
adaptive training of working memory and how differing levels of structure
affect generalization to other cognitive tasks. Participants received four
days of working memory training that was either adaptive or non adaptive
with sequences that were constrained or pseudo-random. A battery of
cognitive measures was taken at pre- and post- test. The results showed that
probabilistic structure provided beneficial effects on adaptive training of
working memory in as little as four hours of training. Moreover, these
benefits carried over to improvements on several measures of non-verbal
reasoning and executive function.

Honors Thesis Committee: David Pisoni, Chris Conway, Rob Goldtone

Althea will be pursuing a PhD in cognitive psychology at Purdue University.
She will be studying memory and learning with Jeff Karpicke.