Representing constructional metaphors (2020)

Abstract: This paper introduces a representation and annotation scheme for argument structure constructions that are used metaphorically with verbs in different semantic domains. We aim to contribute to the study of constructional metaphors which has received little attention in theoretical and computational linguistics. The proposed representation consists of a systematic mapping between the constructional and verbal event structures in two domains. It reveals the semantic motivations that lead to constructions being metaphorically extended. We demonstrate this representation on argument structure constructions with Transfer of Possession verbs and test the viability of this scheme with an annotation exercise.

## introduction verbal semantics has received much attention in theoretical and computational linguistics. representing the event structure evoked by verbs has been at the heart of recent theoretical and computational linguistic models @xcite @xcite . verb meaning is a crucial determinant of the syntactic realization of arguments and their semantic interpretation within events @xcite @xcite . conversely, argument structure constructions contribute much of the semantic structure of events @xcite . most event representations do not explicitly address metaphorical extensions across domains or metaphorical correspondences between constructional meanings. for example, the syntactic realization of arguments associated with certain verbs in the physical domain, e.g. place verbs (1a), remove verbs (2a), cover verbs (3a), or uncover verbs (4a) is also used with transfer of possession and communication verbs in the social domain (the (b) and (c) sentences) @xcite : transfer of possession verbs use the same inventory of argument structure constructions as physical verbs to describe the semantic relations between participants. communication verbs use only some of the figure 1 : a mapping of a place causal chain to the application network physical argument structure constructions foot_0 . as shown above, verbs of giving and telling use the physical placing argument structure construction (1), verbs of taking use the physical removal construction (2), verbs of providing use the physical covering construction (3), and verbs of depriving use the physical uncovering construction (4). 2 metaphorical cross-domain mappings of constructional patterns are not uncommon. the use of metaphor in language is pervasive @xcite and a structured representation for various types of figurative language is crucial to many nlp tasks @xcite . as the examples (1-4) show, there is a need for a systematic representation that makes metaphorical correspondences between argument structure constructions explicit. in this paper, we propose a model that captures shared semantic elements that lead to argument structure constructions being extended across semantic domains. we argue that allowing for metaphorical use of argument structure constructions will prevent a proliferation of distinct constructional semantic annotations. ## semantic representation of the source domain: application events the semantic representation adopted in this paper distinguishes verbal event structure from constructional semantics @xcite . we follow @xcite in recognizing the separate contributions of argument structure constructions and verbal semantics to the specification of event structure. our representation builds on the notion of transmission of force and its relevance to argument realization @xcite @xcite . we identify a limited set of force-dynamic relations between event participants (cf. @xcite . the relations can be causal @xcite , e.g. a force relation between an agent and a theme in she hit the ball, or non-causal @xcite , e.g. a spatial path relation between two physical entities, as in italy borders france. force-dynamic relations are used to construct verbal semantic networks and constructional causal chains. the event structure representations also include information about the type of change that each participant undergoes over the course of the event. application events, which subsume removal as well as placement events, describe a spatial configuration relation between two entities. unlike motion events (e.g. she rolled the ball down the hill), which describe the path of motion, application events describe the co-location, including attachment, of two entities. application events proceed incrementally part by part -mereologically @xcite -while motion events proceed incrementally along the path of motion (dowty's "holistic theme"). each physical example in (1-4) is represented by a distinct causal chain which specifies which participant is construed as the incremental theme in the argument structure construction. we illustrate the causal chain for the place construal only, due to limitations of space. the constructional representation for place (see figure 1 ) identifies a causal force relation between the initiator linda and the theme picture which undergoes motion. the theme is in a path relation with the ground wall. depending on the argument structure construction, either the ground or the moved entity is construed as the incremental theme. in the placing construal, example (1a), the incremental theme is the moved entity because it is syntactically realized as the direct object. the moved entity is labeled +mer to indicate that the path of motion is to the ground. this notation contrasts with removal events, in which the incremental theme moves away from the ground and is labeled -mer. the ground in the placing construal is exist; it doesn't undergo any change in the event. placing and removal verbs share the same verbal event structure which is referred to as the application network in this paper, see figure 2a . the motivation for having a single network for these verbs is that they share the same force-dynamic relations between participants, and both construe the incremental theme as mereological. the moved entity and the ground are both labeled mereological (mer) in the verbal network. this label does not specify whether the verb describes a placing or removal event and allows for either constructional construal to map to the network. the type of change that the phys entity undergoes in the verbal network is unspecified. its specification is dependent on the volitionality of the initiator and is therefore determined contextually. some application events describe a different type of event in which the figure's movement results in a co-location relation with the agent (or a physical entity that initiates the application event). verbs such as pick up or drop describe this type of self-directed action, as shown in figure 2b . the result state of such an event is a holding event expressed in english with verbs such as hold. @xcite refers to this type of force-dynamic relation as 'extended causation of rest' in contrast to other physical application events. we describe this type of application event as a constrain event. the constrain event structure evokes two participants: a phys entity and theme. in our analysis, we use a superordinate force relation to describe the force-dynamic interaction between the phys entity and the theme. the argument realization of participants in force and constrain events is the same. hence, there is no constructional motivation to distinguish these force-dynamic types from each other. a complete representation of the event structure consists of a mapping between the verbal network and the constructional causal chain. when all participants are syntactically evoked, there is a nearly complete correspondence in the mapping from the constructional semantics to the verbal network. figure 1 shows a mapping from the place argument structure construction associated with the example in (1a) to the application network. in the place construal, the label mer on the incremental theme picture matches the label of the corresponding participant in the network. however, the label on the ground in the verbal network is 'overridden' by the role that the ground wall is assigned in the constructional semantics. the following sections develop a model for representing the metaphorical extensions of the application and constrain argument structure constructions to verbs in the social domain. ## metaphorical analysis the use of metaphor in language has been extensively discussed in theoretical linguistics @xcite @xcite @xcite . various frameworks have been put forth in recent years with the aim of explaining underlying cognitive principles that lead to the use of figurative language. however, metaphorical extensions of argument structure constructions (which we refer to as "constructional metaphors") have not received much attention. one of the most prominent theories of metaphor is the conceptual metaphor theory (cmt) @xcite . the cmt has primarily addressed metaphors that involve stable and systematic correspondences between two conceptual domains. metaphorical mappings are analyzed as originating in a 'source' domain and being extended to a 'target' domain. for example, the conceptual metaphor time is money originates in our understanding of time as a valuable commodity that can be wasted, spent, or invested. this metaphor reflects a connection between concepts in two domains: time (in the target domain) and money (in the source domain). our discussion of metaphorical mappings that motivate the syntactic realization of participants with transfer of possession verbs is guided by cmt. we consider constructional metaphors to reflect knowledge structures that are regular and follow conventional patterns of metaphorical conceptualization. the physical argument structure constructions with application events are source domain representations. they are metaphorically extended to verbs in social domains which are the target domains. the role of metaphor in constructions has been addressed in the linguistics literature to some extent but theoretical accounts of this phenomenon are fairly limited @xcite @xcite . relevant descriptions lack depth and do not provide explanations for underlying semantic motivations that lead to metaphorical extensions. for example, @xcite argues that there is a metaphor "that involves understanding possession as the 'possessed' being located next to the 'possessor,' transferring an entity to a recipient as causing the entity to move to that recipient, and transferring ownership away from a possessor as taking that entity away from the possessor." she uses application argument structure constructions to provide evidence for her claim. @xcite and other scholars provide only a verbal description of the phenomenon rather than a formal representation that would make explicit the semantic motivations that lead to metaphorical extensions. ## annotation exercise to see how well our representation could be developed into an annotation scheme, we asked three linguistics graduate students who are familiar with our research to annotate a random sample of 123 examples from the red and bolt corpora foot_3 . the annotators did not participate in the development of the annotation scheme. only one of the annotators had previous experience annotating linguistic corpora. the annotation sample was restricted to verbs that describe possession and transfer events and physical application and send verbs which can be used to describe physical events as well as social possession events. we used the verbnet verb classification @xcite to extract examples with verbs from verbnet's possession classes. we later added send examples and additional physical examples with application verbs to have a more balanced number of physical and metaphorical examples in the dataset. the sample excluded idiomatic examples with possession verbs (e.g. i'm pretty calm about things and like to take things as they come), examples in which the verb was followed by the preposition without (e.g. i had to leave without a refund) and other examples with leave that describe metaphorical motion, not possession (e.g. [...]only 15 months until we can leave nationwide and move over to a proper btl mortgage). a carefully pre-sorted annotation sample was needed to ensure that annotators encountered only examples that were addressed in the guidelines. the primary goal of the exercise was to test how well annotators can correctly identify metaphorical events given that the constructions used with metaphorical and non-metaphorical events are the same and are annotated the same way. high interannotator agreement for the semantic domain (annotated as event domain in the exercise) would support our proposed simplified representation for constructional semantics which relies on accurate semantic domain identification. the annotation scheme used in the exercise is an extension of our existing annotation scheme devised for examples in verbnet classes with verbs in the physical domain @xcite . each example was annotated for event domain and the constructional semantics by using fd1 and fd2 labels. event domain was not previously used in our annotation scheme. it was introduced in the current scheme to distinguish metaphorical uses of argument structure constructions from non-metaphorical ones. the full inventory of annotation labels is listed in event domain specifies the domain and the subdomain of the example. the target domain is frequently implicit in the verb, as is the case with find in (5). find is a possession verb and the event domain of the example is annotated social:possession. however, verbal semantics alone cannot always accurately determine the target domain. for instance, the verb take can be used to describe a physical mereological event (6), annotated as physical:mereological, or a possession event (7), annotated as social:possession. the fd1 label identifies whether the initiator of the event is internal or external to the core event. it also specifies whether the initiator acts volitionally or not. 6 the fd2 label describes the 'core' event, i.e. the event that the incremental theme is engaged in. for instance, example (6) was annotated volitional remove. the constructional semantics describes a causal chain in which the subject one is an external (volitional) initiator that causes the remove event in which the direct object white eggs is removed from a container, a null-instantiated participant. the annotators were presented with written annotation guidelines foot_5 . due to time constraints, we did not verbally go over the guidelines nor did we do a trial annotation prior to this annotation exercise. the types of disagreements detected in the test annotation indicate that improved annotation guidelines could lead to higher inter-annotator agreement scores in the future. to assess inter-annotator agreement, we used cohen's kappa on each of the annotated units. the reported values are averages of the cohen's kappa scores for each annotator. the event domain annotation was the most accurate (0.73). lower fd1 (0.47) and fd2 (0.57) agreement scores resulted from recurring errors that could be prevented with improved annotation guidelines, as discussed below. ## error analysis about 40% of errors in the event domain annotation resulted from incorrectly identifying whether an event was physical or social with take and grab verbs. this was particularly problematic when these verbs occurred with a theme that referred to a physical object. in such contexts, both verbs evoke temporary control over the object as well as a physical force event. there were two main types of these errors. in one case, the error with take and grab verbs resulted from incorrectly recognizing whether the physical event or the social control relation was more salient to the interpretation of the event. for instance, in i quickly grabbed sentence strips out of the closet, the verb describes a physical removal event; however, the event also evokes that the agent has control over the object by being spatially colocated with it. the annotation of this example as physical:mereology reflects that the physical event is more salient in the interpretation when compared to the control relation between the agent and the moved entity, which is only a precondition for the physical event to take place. in other cases, take occurred in a context in which the verb described a use-type relation, e.g. if you take a flash light and shine it through the eggs [...]. alerting the annotators to the fact that take could be used to describe a force relation in physical manipulation events in the annotation guidelines should result in fewer errors of this type. additionally, including a more detailed description of how to annotate physical verbs that evoke both domains at the same time should lead to higher inter-annotator agreement. another common type of error (about 15%) in the event domain resulted from choosing the wrong subdomain label when an event took place in the physical domain. many take verbs were incorrectly annotated as physical:mereology when they occurred in constrain events, e.g. i was told to take my coffee to go. fd1 and fd2 labels were more challenging to annotate given the larger inventory of annotation labels associated with these categories. to correctly annotate the fd2 label, the annotators had to correctly determine the core event and, in many cases, take into account null instantiated participants. additionally, the choice of fd2 impacted the annotation of fd1. approximately 37% of all fd1 errors were due to an incorrect choice of an fd2 label. about 43% of fd1 errors resulted from annotators incorrectly distinguishing internal initiators from external initiators. many of the fd1 errors had to do with distinguishing external and internal initiators. for example, various examples with force fd2, e.g. i just grab the blender and pop in some other stuff, were annotated volitional fd1 despite the semantic incompatibility of force and the presence of an external initiator in transitive argument structure constructions. 8 as noted above, annotators sometimes chose a wrong fd2 label which then led to an incorrect fd1 annotation. about 14% of fd2 errors resulted from annotators incorrectly including a null instantiated participant in the annotation. for example, some annotators annotated the example what year did mussolini seize power in italy? as volitional remove, assuming that an original possessor was part of the constructional semantics. however, in this context, take does not describe a removal event, it describes an obtaining event, i.e. mussolini gaining power. the correct annotation label for fd1 and fd2 was therefore self-volitional force. approximately 25% of fd2 errors resulted from a null instantiated participant not being included in the annotation when it should have been. for example, in we are collecting a premium up front and their total cost is known up front, the original possessor from whom the premium is collected should be part of the constructional semantics leading to the annotation volitional remove. if an annotator did not recognize that a null instantiated participant was semantically evoked, the fd2 label would have been incorrectly annotated as force. the guidelines should clarify when a null instantiated participant ought to be included in the annotation and provide more examples to supplement the explanations. about 16% of fd2 errors included a wrong incremental theme construal. annotators frequently annotated a remove fd2 example (e.g. [they] actually care about the customers safety rather than taking their money) as deprive fd2. this error resulted from incorrectly identifying the original possessor as the incremental theme, rather than the possession. this type of error was also common with place and provide construals. the decision which of the participants is the incremental theme should be guided by which participant is expressed as the direct object in the construction. another 17% of fd2 errors resulted from interpreting a motion event as mereological. some annotators incorrectly identified examples with send verbs as mereological, rather than motion events. although it was clearly stated in the annotation guidelines that the fd2 label in examples such as he might have sent it to me today is motion, having more time to go over the guidelines with the annotators would have probably resulted in fewer errors. the guidelines should also include a more detailed description of various application examples and the syntactic realization of the incremental theme. ## conclusion the use of constructional metaphors in the social domain is pervasive. communication verbs use the same inventory of application argument structure constructions as transfer of possession verbs. other common constructional metaphors in the social domain include motion metaphors with verbs that describe entering or leaving a social role, status, or an institution. for example, firing and resigning verbs occur in motion argument structure constructions (e.g. he resigned from the military). locative metaphors are common with verbs of social membership and employment (e.g. he is employed at ibm). recognition of the many metaphorical argument structure constructions in social events will allow us to simplify the annotation of the semantic contribution of argument structure constructions to event structures for social events. it will also allow us to capture an important dimension of meaning that will be useful for building computational models that reason over social events, a goal of future work. the annotation exercise indicates that annotators can reliably identify a literal use of argument structure constructions from their metaphorical use. this finding supports our hypothesis that a simplified representation of constructional metaphors that relies on a correct identification of the semantic domain of the example can be used to determine the event structure of a particular example.