
Werts, Daniel. (1997). "Good, Fair, and Bad Chord Progressions: A Regression-Analysis of Some Psychological Chord Progression Data Obtained in an Experiment by J. Bharucha and C. Krumhansl." Music, Gestalt and Computing., Ed. Marc Leman. Berlin; Heidelberg; New York; Barcelona; Budapest; Hong Kong; London; Milan; Paris; Santa Clara; Singapore; Tokyo: Springer, 1997. 200-213.
Main research focus: systematic and cognitive musicology (how music generates meaning in the sensorial, perceptive, cognitive, motoric and emotional domains); multimedia technology applied to the arts.
Y(est)= 0.320 + 0.013 (X1) + 0.433 (X2) + 0.262 (X3) + 0.227 (X4) - 0.244 (X5) - 0.266 (X6)
-Y is Krumhansl's data.
-Y(est) is approximated value for each chord progression.
-X1 through X6 are six musical properties (factors) chosen for Wert's formula after a long period of trial and error in which many factors, all of which seemed musically relevant, were tested.
Description of the experiment. Playing IV-V-I cadence in C major and later in F# major. After listening to a cadence, the subjects stated how well a triad-pair "fits" after the cadence. Ratings: 1 (worst) -- 7 (best)
X1(Sum of Ideal Chord Weights) - most powerful factor, accounting for 54.1% of the explained variance in data. X1 = W1 + W2. W1 is the assumed psychological weight for the first chord in the progression, and W2 is the assumed psychological weight for the second chord.
X2 (Chord - Order Condition) – accounts for 13.9%. X2 can have two values: 1 (for progressions that meet the condition) and 0 (for those progression for all others)! Meeting the condition means that the pair of chords can be extracted from this model:
Am Em F Dm Bo G C
X3 (Subdominant-Dominant Condition) -- accounts for 8.4%. X3 can have two values: 1 (for progressions that meet the condition) and 0 (for those progression for all others)! Meeting the condition means that a chord pair has to contain at least one chord from S group and one from D group.
X4 (Root Movement By Upward Or Downward 5th). 7.3%. Can be 1 (for 14 chord progression) or 0 (for remaining 28)! Condition: The root of the 2nd chord has to be 5th above or below that of the 1st chord. (This has a positive effect on listeners' perception).
X5 (Problematic resoution of the leading tone). -- 7.8%. Negative factor. Can be 1 or 0. For 1 leading note cannot resolve to tonic because either 2nd chord does not contain it (Em-G) or conventionally does not (Em-F).
X6 (Parallel Minor Condition). -- 8.5%. Negative factor. 1 or 0 again. Condition: progression must be part of, or lead smoothly to, a cadence in the parralel minor key, or otherwise create an impression of that key. This threatens the stability of the original key.
In closing- Werts shows how the ideal chord weights can be derived, in the sense of being almost perfectly approximated, from set of other, seemingly unrelated, vaues.