Stimulus 3: Visiting Hours by Shane Koyczan

These graphs report per stimulus the time course of responses across the 24 listening sessions. Some report the general patterns of responses, other show how the listener’s responses changed over successive exposures

s3_beh01

The continuous ratings of Felt Emotional Valence and Arousal, plotted three different ways. First as individual lines with the cross listening average, then layered per session with colour marking the scale values, and finally the activity-level times series reporting the proportion of listenings showing rating changes up or down per 2 s interval.

These responses were collected Visiting Hours, a studio recording of spoken word poetry by Shane Koyczan. The recording had been in the listener’s library for a few years, but it was not regularily heard. The following is a different performance of the same piece.

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Expressive EMG activity to stim 1: Sigur Ros’s Varuo

One clue as to how we feel while listening to music is in how we move, from dance-like motions to brows furrowed in concentration. Surface electromyography sensors  (sEMG) are very useful in picking up muscle contractions which generate these expressive behaviours. In the solo response project, two typical sensors on the face to capture brow furrowing and smiling (see the set-up post) and an additional sensor tracking contractions of the trapezius muscle up the back of my neck, to capture tension in the back and head nodding. While there is much to say about each signal, this post is about what these sensors measured of my responses to Varuo, by Sigur Ros.

sEMG activity of the Corrugator Supercilious, Zygomaticus, and Trapezius through the 24 listenings of Sigor Ros' Varuo. Session X Time heat plots and normalised activity-levels per signal.

sEMG activity of the Corrugator Supercilious, Zygomaticus, and Trapezius through the 24 listenings of Sigor Ros’ Varuo. Session X Time heat plots and normalised activity-levels per signal.

In the analysis post, I mentioned that the B section, starting around 220s, was really intense, and often overwhelming.  These sensors agree with that, all shwing more instances of high muscle activity across sessions from 250s to 350s. Sublime face, yawning, and an explanation of how to read this graph below the cut.
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Felt emotion ratings to Stimulus 1

Felt emotion ratings to Stimulus 1

Continuous ratings of felt emotion, valence and arousal dimensions. The top graph shows the average rating against the related reports for felt emotional arousal, the second shows the ratings in heat values, each horizonal a single session’s response. The bottom pair are the same for the felt emotional valence ratings.

While arousal is very consistent across sessions, with perhaps an incremental intensification of response, valence shows striking variation in felt valence over the successive listenings. Though not a simple break, the later listenings show a greater proportion of time reporting felt negative valence. The intensity of valence seems similar, whether high or low, as visible in the symmetry around the Valence midpoint in the third plot.


Stimulus 1: Varuo by Sigor Ros, music review

Note: music review posts discuss the stimulus selection, structure, and general response patterns, giving an overview of the stimulus before digging into the responses.

Stimulus number 1, numbered for convenience not playlist order–each session’s music was randomly ordered–was a track from 2012 Sigur Rós album Valtari. I’d been enjoying the band’s previous work in the last year, taken by the textures, slow builds, and dramatic extremes of intensity. When I saw a new album had been release a month or two before the scheduled response recordings, I chose a track to reserve for the experiment. The 24 response session are my first 24 full listenings to this epic piece of music, and it was a really intense experience almost every time. Read the rest of this entry »


Figshared data

ImageI’ve finally got a version of these responses in a format I’m willing to post. The responses, organised by stimulus as matlab data structures, are being added now on figshare. I’m also planning on releasing them in a more flexible format, but I’mnot yet decided how (suggestions welcome). In its current format, the responses and all interesting extracted features accumulate to nearly 3 gigs of numbers, this isn’t a data pile for the faint of heart.

In my own files, I have other structurings of the data, specifically sensor-wise structures which allow for between stimulus comparisons and downsampled versions to look at everything at once, but these are not necessarily in sharable good shape.


Advantages of experimenting on yourself

(This is a repost from April 2013, as I was preparing to bring this experimental data to conferences)

In the coming months, I’ll be taking results from the solo response project to several conferences, and reviewer feedback has me worried about people dismissing this data because I collected the data from myself. I keep getting distracted by these imaginary confrontations with suspicious researchers so it’s time I lay down some concisely-expressed arguments to appease the hypothetical skeptics.

Problem 1: One subject = bad empirical research

I don’t like this one because the premise is wrong, but I’ve gotten it a lot already, so here goes. Read the rest of this entry »


Project planning

(This is a repost from during the recording sessions in July 2012)

How else does a grad student get 40+ hours of experimentation time over 20 sessions from one human subject?

I thought someone might have an issue with my idea of using myself, but apparently not. The NYU ethics review office didn’t even want to hear about what responses I’d be recording, or what protocols I’d be following. Maybe they assumed that music is a harmless stimulus, or that I knew I wasn’t allergic to the glue we use to attached electrodes, or that I was very unlikely to sue the school because of research I’d planed myself. I hope they didn’t care because the data collection is happening at another institution, in collaboration with someone who’s standing ethics certificate does cover this type of experiment.

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