astrayLv1

27 Mar 2023

Procedural details:

1. The continuous EEG of thirteen unique participants were recorded over 12 experimental sessions. One participant took part twice. All participants natively spoke a language that made the [tha] versus [da] distinction.
2. Stimuli were natural productions of [tha] and [da]. Stimuli were produced by a native female speaker of North American English.
3. There was only one experimental block. The aspirated [tha] was the repeated standard and unaspirated [da] was the infrequent deviant.
4. Data from Fp1, Fp2, Cz and Fz were recorded.
5. Two mastoid channels were recorded and linked in post-processing to create an average mastoid reference.
6. The participants heard 60 repetitions of the deviant [da] and approximately 420 repetitions of the standard [tha]. This was a ratio of approximately seven standards for every deviant that was presented to the participant.
7. Offline, the data was epoched, with 100 ms before the presentation of the stimulus and 800 ms after the presentation of the stimulus.

Questions:

 

1. Consult EEG and speech processing. What kind of experimental design is this? How do you know? 
2. Given the Procedural details above and course content, provide specific predictions for what you expect? Assume that the participants can contrast [tha] and [da].
1. Do you predict there to be differences? 
2. If so, at what time points? 
3. Which response do you anticipate to be more negative? 
4. What is the unit of Time measurement on the x-axis in a plot based on the experiment?
3. Now imagine that the participants were speakers of a language that did not contrast [tha] and [da], e.g., Spanish or Russian. State explicitly your predictions along the same lines as the answer to Question 2. 
4. According to the experiment/procedures, which predictions are met? Be specific. Make particular reference to the imaginary plot and identify any parts of the ERP responses that might be different between the two conditions.

 

 

1. Is this in the time window that you expect?  
2. Is it in the appropriate direction? That is, is the response that is expected to be more positive, indeed more positive and the response that is expected to be more negative, indeed more negative? Also, did you expect to observe a more pronounced peak to the standard or to the deviant? 

 

1. 1. Can you conclude that the particular design is tapping into phonetic or phonological representations? Make specific reference to the potential levels of sound representations (e.g., acoustic, phonetic, phonological). Explain why you can or cannot conclude that this design taps into a specific level of representation.  

 

Use references: 

1. Kazanina, N., Phillips, C., & Idsardi, W. (2006). The influence of meaning on the perception of speech sounds. Proceedings of the National Academy of Sciences, 103(30), 11381-11386.
2. Phillips, et al. (2000). Auditory cortex accesses phonological categories: an MEG mismatch study. Journal of Cognitive Neuroscience, 12(6), 1038-1055.