Emotional Processing in Music: Study in Affective Responses to Tonal Modulation in Controlled Harmonic Progressions and Real Music

The pitch material of virtually all the musics of the world is organized into tonal hierarchies in which the pitch classes of a tonal scale divide the octave into (typically) five to seven steps of a tonal scale, with a stable "home base" in the tonic pitch, and a variety of tonal functions and tendencies assigned to the remaining pitch classes (Dowling & Harwood, 1986). In western music, the tonal hierarchy is organized in terms of two principal modes, major and minor, defined in terms of tonal scales of seven pitch classes (Krumhansl, 1990). The seven pitch classes of a mode are selected from the set of 12 logarithmically equal steps (semitones) into which the octave has been divided by the system of equaltempered tuning adopted in Europe beginning in the early 18th century (Robinson & Needham, 1962). All the intervals defined by a mode are defined in terms of numbers of semitones, so any of the 12 possible pitch classes can be chosen as the tonic pitch of a musical "key" (e.g., C major or E minor). Hence, a melody played in one key can be shifted to another key without distorting its melodic intervals. This system makes possible a shift of keys within a piece, which is called "modulation."Tonal modulation involves a shift of tonal center within the same musical composition, involving a transition to a different key (tonality) with a new scale of pitch classes. Modulation is one of the main structural and expressive aspects of music in the European musical tradition. Relationships among tonalities are described in terms of the circle of fifths (Diletsky, 1677; see Figure 1). The circle of fifths arises because you can start with any pitch class and go up or down by 7 semitones (a musical "fifth") and arrive at a tonal center whose major scale differs from the original scale by just one altered pitch. In Figure 1, this is illustrated by going from C up a fifth to G. The key of G major has one altered pitch (F#) with respect to the key of C major. The second example in Figure 1 shows what happens if we go up clockwise by five fifths around the circle, landing on B and adding five sharps (#) to alter the pitches of the scale. The more steps (in the shortest direction) between two pitches on the circle of fifths, the more differences between the two pitch sets that define the tonalities represented by these letters. Modulations can thus vary in the distance over which they travel in tonal space from one key to another. The greater the distance, the more complicated and surprising they are likely to be.Modulations can also vary in the relationships between the original and target modes. Each of the 12 available steps around the circle of fifths can be the center for two tonalities, one in a major mode and another in a minor mode, so that there are four possible modal relationships involved in modulations: Major- Major, Major-minor, minor-Major, and minor-minor. The major mode is generally characterized as happy, and the minor mode as sad. The affective influence of the major and minor modes has been thoroughly investigated (Gagnon & Peretz, 2003; Halpern, Martin, & Reed, 2008; Hevner, 1935; Kastner & Crowder, 1990; Panksepp & Bekkedal, 1997; Webster & Weir, 2005).Previous studies have demonstrated that listeners are able to track modulations in that their cognitive responses in terms of tonal-hierarchy profiles and ratings of tonal distance or tension are differentially affected (Firmino, Bueno, & Bigand, 2009; Krumhansl & Kessler, 1982; Lerdahl & Krumhansl, 2007; Thompson & Cuddy, 1989, 1992; Toiviainen & Krumhansl, 2003). The process of following the reorientation of a tonal center is guided by musical expectations and by perceived tonal tension (Lerdahl & Krumhansl, 2007; Meyer, 1956). In modulation, the degree of the perceived change in tonal tension increases with key distance (Bigand & Parncutt, 1999; Firmino et al., 2009) and is greater with clockwise (vs. …