Table 1.
Tonalness values for the three sound conditions.
Fig 1.
(Left) Time waveforms (High-resolution images; gridlines represent milliseconds).
Each six-second sound block (Upper blue representation) consisted of 41 musical interval presentations (42 individual notes) for a particular condition. Each note (Lower blue representation) had a total duration of 128 milliseconds (ms), including 10-ms raised-cosine onset and offset ramps. Notes were separated by 15-ms gaps, producing an overall presentation rate of 7 notes per second. (Right) Spectral representation for a six-second sound block [Matlab, plotted Fourier transform expression fft(x)] belonging to the consonance condition and to the intermediate dissonance condition. Abbreviations: Hz: Hertz.
Fig 2.
(Left) Sound stimuli and paradigm design.
(Right) Laboratory version of the experiment: subjects viewed the above image of a radio-telescope and were given the following instruction: “A radio-telescope located in Cambridge captured a series of radio signals from outer space. You will listen to these sounds and your task is to think and decide if they were produced by good-friendly or bad-aggressive aliens”. Participants had to select their answer for each sound block using an 11-point scale (mouse click), which appeared onscreen immediately after a sound block was played (the side of ‘good’ and ‘bad’ alien was semi-randomized).
Table 2.
Valence and reaction time means for the three sound conditions (Laboratory Experiments conducted in the UK and in Argentina).
Table 3.
Valence means and 95% confidence intervals for the three sound conditions (post-scan questionnaire).
Table 4.
fMRI results.
Fig 3.
FMRI results (FWE-corrected P < 0.05 for cluster-level inference) [High resolution image].
Coloured areas (red) reflect: (a) Statistical parametric maps (SPM) showing voxels in the right Heschl’s gyrus in which the response was higher during the evaluation of intermediate dissonant sounds compared to consonant sounds, superimposed onto a standard brain in stereotactic MNI space (from left to right: sagittal, coronal and axial views; 3D render view below). (b) Statistical parametric maps showing voxels in right anterior cingulate cortex and bilateral anterior insula in which the response was higher during the evaluation of strong dissonant sounds compared to intermediate dissonant sounds.
Fig 4.
Psychophysiological Interaction Analysis: Blue color show voxels in bilateral Superior Temporal Gyrus (Secondary Auditory Cortex), which exhibited stronger functional connectivity with seed voxels (6mm sphere) located in the right Heschl’s gyrus (red) during the evaluation of intermediate dissonant compared with consonant sounds.