Understanding Theta Roles: Agent, Patient, Theme, and More

Understanding Theta Roles in Linguistics

Theta roles, also known as semantic roles, describe the role a word or phrase plays in relation to the verb in a sentence. Here's a breakdown of common theta roles:

1. Agent

   The agent is the active instigator or causer of an action. Agents are typically animate (animals or people) and possess volition and cognitive ability.

   Examples:

   • Mary killed Peter.
   • Peter was killed by Mary.

2. Patient

   The patient is the entity undergoing a process or physically affected by an action. It's the affected party of an action instigated by an agent or simply the undergoer of a process.

   Examples:

   • Peter melted the ice. / The ice was melted by Peter.
   • The ice melted.

3. Theme

   The theme is something or someone that is located in a place or that is seen as moving from one place to another.

   Examples:

   • The ball is in the park.
   • We put the box on the shelf.

4. Location

   Location designates where a situation takes place or where an object is located.

   Examples:

   • The boys are playing in the park.
   • The money is on the table.

5. Instrument

   The instrument is the thing used by an agent or experiencer, usually in order to do something to a patient or theme or to perceive a content.

   Examples:

   • The carpenter hit the nail with a hammer.
   • I gently moved the cup with my right hand.

6. Experiencer

   The experiencer is the sentient being (a volitional being who has a mental experience of something) that perceives or conceives something. It appears with psychological or perception verbs.

   Example:

   • John understood the problem.

7. Stimulus

   The stimulus is whatever causes a psychological response in the experiencer; this response can be either positive or negative.

   Example:

   • The situation scared me.

8. Content

   The content is the content of a psychological state or of a representation. It expresses an idea or a mental representation that is entertained or perceived. Content is assigned only to NPs.

   Example:

   • We saw the robbery.

9. State of Affairs (SoA)

   State of Affairs (SoA) is a subclass of content that is used with X-Complements and complement clauses.

   Example:

   • I saw Liz take the cookie.
   • I thought that he'd already done it.

10. Source

    The source expresses the starting point of a trajectory. The preposition FROM is a prototypical marker of a source, but there are verbs such as LEAVE, EXIT, FLEE, etc. that do so too.

    Example:

    • John left the office.

11. Goal

    The goal expresses the endpoint of a trajectory.

    Example:

    • John drove to the station.

12. Path

    The path expresses the portion of a trajectory that lies between the source and the goal.

    Example:

    • The burglar entered through the window.