Akor Hazırlama Etkisi

Bu makalede, akor hazırlama etkisini inceleyen, günümüze kadar yayınlanmış40’a yakın çalışma, kapsamlıbir biçimde anlatılmıştır. Akor hazırlama, armonik ilişkilerin algılanmasınıaraştırmak için kullanılan temel yöntemlerden birisidir. Akor hazırlama yönteminde katılımcılar bir takım hazırlayıcıakorlar dinlerler ve bunların ardından dinledikleri hedef akor hakkında bir karar vermeleri istenir. Katılımcıların verdiği cevapların doğruluğu ve cevap verme süresi hedef akor için geliştirmişolan beklentiyi ölçer. Hazırlayıcıve hedef akor armonik olarak ilişkili olduğunda cevaplar daha hızlıve daha doğru olarak verilmektedir. Bu duruma akor hazırlama etkisi adıverilir. Akor hazırlama etkisi hazırlayıcıve hedef akorlar arasında akustik bir benzerlik olmadığıdurumlarda hem müzisyen ve hem de müzisyen olmayan katılımcılardan gözlemlenmiştir. Bu durum bu etkinin psiko-akustik süreçlerden değil, öğrenilmişarmonik ilişkilerin yarattığıbilişsel süreçlerden kaynaklandığınıgöstermektedir. Akor hazırlama etkisi, hazırlayıcıakor ile hedef akorun armonik olarak ilişkili olmasının getirdiği bir hızlanma neticesinde gözlemlenmektedir. Armonik olarak ilişkili akorlar dinlendiğinde başka bilişsel süreçlerde de bir hızlanma gözlemlenmiştir. Bu da akor hazırlama etkisine yol açan bilişsel süreçlerin dikkat mekanizmasınıetkilediğinin göstergesidir. Akor hazırlama etkisinin gözlemlendiği hasta gruplarıçeşitlidir. Bu etki split-brain, amusic ve serebellar hastalardan gözlemlenmiş, Broka afazik bir hastadan gözlemlenmemiştir. Bu da akor hazırlama etkisinin beyindeki dil mekanizmalarıyla ilişkili olduğunu düşündürmektedir. Son yıllarda popülerlik kazanan akor hazırlama etkisini kapsamlıbiçimde anlatan bir derleme çalışmasıTürkçe’de bulunmamaktadır. Bu çalışmada bu eksiklik giderilmeye çalışılmıştır.

Music perception is one of the fundamental areas of human cognition. Listening to music is made possible by recognition of discrete events that are sequenced in time. There are many aspects of music perception, such as perception of melody, grouping of musical events, perception of tension and relaxation, perception of tonality, perception of pitch, perception of chord, and perception of harmony etc. see Bharucha, Curtis, Paroo, 2006 for a comprehensive review . Chord is a simultaneous sounding of three or more pitches. Harmony is the art of chordal organization Piston, 1978 . Perception of harmony is one of the popular topics of music perception. Perception of harmony has been investigated with subjective reports Krumhansl, Bharucha & Kessler, 1982 , recognition memory experiments Bharucha & Krumhansl, 1983 and chord priming paradigm Bharucha & Stoeckig, 1986, 1987 . In this paper, studies investigated chord priming effect are reviewed, by surveying more or less 40 publications since 1986, when the first article on this effect “Reaction time and musical expectancy: Priming of chords” was published by Bharucha and Stoeckig. There exist many reviews on the perception of chord, harmony and tonality in the literature see Koelsch, 2009; Koelsch ve Siebel, 2005; Krumhansl, 1990, 2000, 2005; Justus ve Bharucha, 2002; Tillmann, Bharucha ve Bigand, 2000 . However, the lack such an article in the Turkish language calls for the review of chord priming effect. Chord priming paradigm Bharucha & Stoeckig, 1986, 1987 is designed to investigate perception of chordal relations or perception of harmony , and became one of the fundamental methods in this area of investigation. In chord priming paradigm, participants listen to a chord sequence. The last chord is called the target, and the preceding chord s prime. Participants make a binary judgment on the target chord, which is usually a consonance/dissonance Bigand & Pineau, 1997; Tillmann, Bigand, & Pineau, 1998 or in-tune/out-of-tune discrimination judgment Bharucha & Stoeckig, 1986, 1987; Tekman & Bharucha, 1992, 1998 . Reaction time and accuracy of responses reflect the expectation towards the target chord. Responses are faster and more accurate, when the prime and the target are harmonically related. This is chord priming effect and it has been observed consistently Bharucha & Stoeckig, 1986, 1987; Bigand & Pineau, 1997; Escoffier & Tillmann, 2008; Tekman & Bharucha, 1998; Justus & Bharucha, 2001 . According to Bharucha 1987; see also Tillmann, et al., 2000 , chord priming effect is a result of learning and representing harmonic relations between chords. Harmonic relations are learned by mere exposure to music is, and this knowledge is represented with tonal-harmonic schema Tillmann, et al., 2000 . Upon listening to a chord, harmonically related chords are activated in the tonal-harmonic schema, which enabled faster processing of related chords. Alternative hypothesizes has been examined in several studies, and the learning and representation account of chord priming has been confirmed. Bharucha and Stoeckig 1987 and Tekman and Bharucha 1998 showed that chord priming effect is not due to the acoustical similarity between prime and target. Tekman and Bharucha 1998 observed that harmonic relation overshadows acoustical similarity. Chord priming did not change by the short term memory of and explicit knowledge about the target chord Justus & Bharucha, 2001 . Bigand, et al., 2003 showed that chord priming effect is not due the representation of pitches in short-term memory. Several other results also support the learning and representation account of harmonic priming: Chord priming has been observed from non-musician, musically educated and musician participants Atalay, 2002, 2007; Bharucha & Stoeckig, 1987; Tekman & Bharucha, 1992, 1998; Justus & Bharucha, 2001; Bigand & Pineau, 1997; Tillmann, et. al, 1998 and from nonmusician and musically educated children Schellenberg, et. al, 2005 . Chord priming effect has been observed in parallel to the circle of fifths except for one case . In other words, primes that were closer to the target on the circle of fifths facilitated responses compared to distant ones. The exception was reported in Atalay 2002 and 2007 . In these studies, harmonically related chords Neapolitan and dominant are the most distant chords on the circle of fifths. Participants responded to the dominant chords faster and more accurately after the Neapolitan chord Atalay, 2002, 2007 , which shows that the learned harmonic relations are not limited to the circle of fifths. Furthermore, chord priming has been found to be a combination of facilitation of the processing of the tonic and inhibition of the processing of the subdominant targets Tillmann, Janata, Birk, & Bharucha, 2003 . Listening to harmonically related target chord affects other cognitive processes, namely, phoneme monitoring Bigand, et al., 2001; Escoffier & Tillmann, 2008 , timbre discrimination Tillmann et al., 2006 , and semantic priming Poulin-Charronnat, et al., 2005 . Poulin-Charronnat, et al. 2005 proposed that cognitive processes that govern chord priming affect the attention mechanism. Escoffier and Tillmann 2008 corroborated this theory by reporting the finding that that visual processing also is affected by listening to harmonically related chord. This theory purports that related chords function as an attentional marker, and they capture attentional resources more. A further support of this theory comes from the positive correlation between effects of chord priming on visual processing and the Stroop effect Atalay & Misirlisoy, 2009 . Atalay and Misirlisoy 2009 reported that participants with high Stroop performance were better at blocking the interference of chordal processing on their phoneme monitoring capacity. Studies conducted with split-brain and brain damaged patients suggested that right-hemisphere is responsible of chord priming effect Tramo & Bharucha, 1991; Tramo, et al., 1990 . Chord priming effect was observed from autistic Heaton, et al., 2007 amusic Tillmann vd., 2007 , and cerebellar patients Lebrun-Guillaud, et al., 2008; Tillmann, et al., 2008 . Observing the chord priming effect from an amusic patient suggests that representation and access of tonal-harmonic knowledge depend on distinct cognitive processes. On the other hand, a Broca aphasic patient did not show chord priming effect Patel, et al., 2008 , which suggests a relation between linguistic and musical capacities. In this article, artificial neural network models, fMRI, EEG, and PET findings on chord priming were not reviewed. There were numerous publications that investigated chord perception with these techniques. It would be more appropriate to review them comprehensively in a separate article