Analyzing frame element definitions

As described in a previous post, a major step in laying out the frame element (FE) hierarchy involves an examination of the frame element definitions included in the characterizations of each frame in FrameNet. This step has now been completed, at least in a preliminary manner, with the result that the frame element hierarchy has been reduced to 12 primitives and the resulting digraph can now be viewed. The examination of frame element definitions has been both productive and instructive. This post describes how this analysis has proceeded.

As indicated earlier, frame elements with the same name may appear in many frames; the rigor of the FrameNet lexicographers in laying out a frame has resulted in a definition for each frame element. Thus, for example, there are 125 definitions of the Agent frame element. The FrameNet lexicographers are careful to point out that just because frame elements have the same name in different frames, the meaning of the frame element is not guaranteed to be the same. Nonetheless, as a working hypothesis, it is assumed that the meanings are the same. The practical effect of this hypothesis at the moment is that no detailed examination is made of the 125 definitions of the Agent frame element.

After applying initial steps in analyzing the frame element digraph, described in an earlier post, we had identified 261 primitives, consisting of 202 primitives not used as hypernyms and 59 used as hypernyms in deriving 750 frame elements. These frame elements are the ones whose definitions were examined. Frame element names are all nouns or noun phrases. In addition, many of the FE definitions use a typical noun hypernym that is present in the FE dictionary, e.g., Required is a State_of_Affairs. Since the FEs not used as hypernyms occur only infrequently in the frames, usually once or twice, these received the initial focus of my efforts. However, many FEs that are used as hypernyms (i.e., as identified in previous steps) also occur infrequently, these were also analyzed. The general goal of this analysis of FE definitions was to place the frame elements at an appropriate position in the frame element hierarchy.

To carry out this analysis, I created two files to keep track of the hypernym assignments I made, one for the unused FEs and one for the used FEs (both of these consisted of only the primitive FEs). These files contained, in tab-separated fields, the FE name, its frame, the FE type, and the FE definition. When I made an assignment, I copied all the elements from the initial files and put them in a pair of “assigned” files, adding the hypernym as another tab-separated field after the frame element type. I also modified the frame element dictionary to reflect the assignment. By changing the dictionary, I was able to immediately perform a new digraph analysis to determine the effect of my hypernym assignments, particularly to identify any circularities that may have arisen as a result and the progress I was making.

When I began examining the FE definitions, I found that I could make some assignments following previous steps, but where I had some doubts about making the assignment based only on the frame element name. When making hypernym assignments based on the FE definition, a general principle is to choose the most specific rather than the most general hypernym. This has the effect of spreading out the image, rather than having a large number of nodes directly adjacent to the primitive.

I made approximately 250 hypernym assignments based on the FE definitions. Many of these were quite straightforward, as in the following examples:

• Route: “The Route is the usual path that the Vehicle travels” (Hypernym Path)
• Honoree: “The person for whom the Social_event is held” (Hypernym Person)
• Vividness: “The degree of detail and/or immediacy of a remembered Experience” (Hypernym Degree)
• Motivation: “The Reason for which an intentional act is performed” (Hypernym Reason)

In making these assignments, the hypernym was immediately identified as being the name of another frame element in the dictionary, so there was little ambiguity in making the selection.

In examining the definitions, there eight frame elements that had no definitions. These frame elements came from frames that were themselves incomplete, i.e., they appeared to be frames in the process of development and not yet completely instantiated in FrameNet. Their deletion at this time does not appear to be problematic.

After about one-third of the FEs had been assigned hypernyms, the process became somewhat more difficult. Many FEs have definitions which are not really definitional, such as

• Artist: “The Artist works off-stage to help make the Production”
• Accuracy: “This FE indicates the Accuracy of the prediction”
• Trigger: “The Trigger most commonly occurs in a PP Complement headed by _to_”
• Case: “The Case which a Trial is convened to decide”

Clearly, these definitions are not useful in identifying an appropriate hypernym. To deal with such situations, I found that I could make use of an ordinary dictionary, where the noun frame element element names could be looked up and where their definitions would identify a noun hypernym. I chose to use an online version of the Oxford Dictionary of English, in which each noun definition is also placed into a noun hierarchy. I chose this dictionary rather than WordNet because its noun hierarchy was based on lexicographic principles, guided by the tops of the WordNet nouns.

After making local decisions about each of the low-frequency frame elements, the digraph analysis resulted in the identification of 12 primitives: Cause, State, Degree, Entity, Role, Purpose, Instrument, Phenomenon, Time, Path, Reason, and Topic. These primitives look valid on their face. However, it needs to be noted that there are several hypernymic links, particularly those generated automatically based on the frame-to-frame relations, that need to be re-examined.

The frame element digraph consists of 1003 nodes, with the 12 primitive frame elements and 991 frame elements shown in a derivational path from the primitives. The resultant image is quite large (4.0 MB) and may take some time to load in a browswer.