2009/05/07

Ladd, D. R. (1988). Declination The perception of fundamental frequency declination. Journal of Acoustical Society of America, 66(2), 363–369.

Presentation: Shelly

Summary: Sally

It is believed that longer sentences may contain multiple intonational phrases, each with its declination slope. This study investigated F₀ in utterances where boundary strength was manipulated at certain reset points. Test sentences of three clauses taking the forms A and B but C and A but B and C were used in the first experiment (e.g.  Ryan has a lot more money, but Warren is a stronger campaigner, and Allen has more popular policies). In the second experiment, a fourth accented word was added to the same sentences (e.g.  Congressman Ryan…, but Senator Warren…, and Governor Allen ….) with the intention to test whether individual downward trends were independent of the general declination. Results of these experiments confirmed the existence of “partial reset” in that declination of the individual clauses was observed within the general downward trend. In addition, this pattern was merely shown via the toplines (F₀ peaks associated with major accented syllables), not the endpoints (F₀ valley). 

In the last experiment, the author further differentiated whether the results were resulted from local effects or based on a hierarchical structure. Sentences of three clauses were designed with the final section always immediately preceded by but, but with a different hierarchical structure between two conditions (e.g. Their dog was ten years old, and had a lame leg and a white muzzle, but still kept a fierce watch. vs. They had a ten-year-old dog, who had a lame leg and a white muzzle, but still kept a fierce watch.). Result supported that hierarchical organization has a complex effect on F₀ since different degrees of boundary strength were observed on the toplines of the two conditions. To better interpret this nonlocal dependency, the author proposed a more powerful model in which downstep is related to the constituency of a metrical tree.