Title Page

Does the Thematic Hierarchy hold in people with aphasia and across the lifespan? Evidence from the Event Task.

by

Sophia Norvilas

Submitted to the Graduate Faculty of the

Dietrich School of Arts and Sciences and

Fredrick Honors College in partial fulfillment

of the requirements for the degree of

Bachelor of Philosophy

University of Pittsburgh

2022

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Commit tee Membership Page

UNIVERSITY OF PITTSBURGH

DIETRICH SCHOOL OF ARTS AND SCIENCES

This thesis was presented

by

Sophia Norvilas

It was defended on

November 11, 2022

and approved by

Dr. Tessa Warren, Professor, Psychology

Dr. Julie Fiez, Professor, Psychology

Dr. Jamie Reilly, Professor, Communication Science and Disorders

Thesis Advisor: Dr. Michael Walsh Dickey, Professor, Communication Science and Disorders

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Copyright © by Sophia Norvilas

2022

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Abstract

Does the Thematic Hierarchy hold in people with aphasia and across the lifespan? Evidence from the Event Task.

Sophia Norvilas

University of Pittsburgh, 2022

Aphasia is a neurological disorder that can disrupt language production and

comprehension, impairing both written and spoken language (Dresang et al., 2019). This condition

is typically brought on by brain damage following a stroke. Research indicates that people with

aphasia sometimes rely on event knowledge to compensate for their language impairment

(Caramazza & Zurif, 1976). However, we know little about event processing in people with

aphasia (PWA), even though event knowledge supports a multitude of crucial cognitive processes,

including language comprehension, language production, memory, and perception. One type of

event knowledge that has been studied thoroughly in linguistics is the entities, objects, and

locations (event roles) that are involved in events. Linguists have developed a hypothesis, known

as the Thematic Hierarchy, that some of these event roles are more cognitively salient than others.

The research I present here uses evidence from a new assessment that measures event knowledge

(the Event Task) to evaluate whether this thematic knowledge is maintained in older adults and

people with aphasia, while also examining whether the performance of PWA on the Event Task is

aligned with the Thematic Hierarchy. PWA (N = 26) and neurologically healthy adults (N = 182)

completed the Event Task, which instructed participants to identify whether a depicted event was

plausible or implausible. Analyses showed that the Thematic Hierarchy did not appear to guide

the performance of PWA or neurologically healthy adults across the lifespan. However, PWA and

neurologically healthy controls alike displayed the same patterns of both accuracy and reaction

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time performance. In neurologically healthy adults, increased age was correlated with decreased

accuracy and increased reaction times. In addition, neurologically healthy adults with 12+ years

of education were found to have increased accuracy and decreased reaction times. The current

findings could be the foundation for future research regarding aphasia and event knowledge.

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Table of Contents

Preface ………………………………………………………………………………………………………………………….. x

1.0 Introduction …………………………………………………………………………………………………………….. 1

1.1 Semantic memory and event knowledge ……………………………………………………………. 1

1.2 The Thematic Hierarchy …………………………………………………………………………………… 2

1.3 The Event Task ………………………………………………………………………………………………… 5

1.4 The Current Study …………………………………………………………………………………………… 7

2.0 Methods …………………………………………………………………………………………………………………… 8

2.1 Participants ……………………………………………………………………………………………………… 8

2.2 Event Task Stimuli and Procedure ……………………………………………………………………. 8

2.3 Data Compilation ……………………………………………………………………………………………… 9

2.4 Event Taxonomy Questionnaire ………………………………………………………………………. 10

2.5 Data Analysis …………………………………………………………………………………………………. 11

3.0 Results …………………………………………………………………………………………………………………… 12

3.1 PWA and Matched Controls Analyses …………………………………………………………….. 12

3.2 PWA Analyses ………………………………………………………………………………………………… 14

3.3 Lifespan Analyses …………………………………………………………………………………………… 17

3.3.1 Age Analyses ………………………………………………………………………………………….18

3.3.2 Mini-Mental State Examination Analyses ……………………………………………….20

3.3.3 Years of Education Analyses …………………………………………………………………..22

4.0 Discussion………………………………………………………………………………………………………………. 24

4.1 PWA and Matched Controls …………………………………………………………………………… 25

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4.2 Neurologically Healthy Adults Across the Lifespan ………………………………………….. 27

4.3 Clinical Application ………………………………………………………………………………………… 30

4.4 Limitations …………………………………………………………………………………………………….. 34

5.0 Conclusion …………………………………………………………………………………………………………….. 35

Bibliography ……………………………………………………………………………………………………………….. 37

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List of Tables

Table 1: Canonical and Exclusive Event Role Violations ………………………………………………. 11

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List of Figures

Figure 1: PWA and matched control participants' accuracy performance. ……………………. 13

Figure 2: PWA and matched control participants’ reaction time performance. ……………… 14

Figure 3: Individual PWA accuracy performance per event role violation type. …………….. 16

Figure 4: Individual PWA reaction time performance per event role violation type ………. 17

Figure 5: Healthy participants’ accuracy performance in relation to age. ……………………… 18

Figure 6: Healthy participants’ reaction time performance in relation to age. ……………….. 19

Figure 7: Healthy participants’ accuracy performance in relation to MMSE Score. ………. 20

Figure 8: Healthy participants’ reaction time performance in relation to MMSE Score. … 21

Figure 9: Healthy participants’ accuracy performance in relation to years of education. .. 22

Figure 10: Healthy participants’ reaction time performance in relation to years of education.

…………………………………………………………………………………………………………………………. 23

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Preface

First and foremost, I would like to express my gratitude to Dr. Michael Walsh Dickey, my

mentor and Bachelor of Philosophy advisor. Thank you for the years of guidance, encouragement,

and insight. I will never forget the invaluable lessons he taught me and the countless hours he

dedicated to my project. Joining the Language and Brain Lab and learning under his guidance truly

changed the trajectory of my career, and I cannot express the full extent of my appreciation. In

addition, I am so lucky to have studied under Dr. Tessa Warren, my incredible Honors in

Psychology advisor. Her mentorship has been imperative in honing my writing skills and finding

my voice in the scientific community. Her dedication and expertise have been instrumental in

helping me become the researcher I am today.

I am very grateful to Dr. Julie Fiez and Dr. Jamie Reilly, for their enthusiasm and

willingness to serve on my thesis committee. I would like to acknowledge the University of

Pittsburgh Honors College for providing this wonderful opportunity and supporting my work with

resources such as the Brackenridge Fellowship. I am extremely appreciative of Emily Goldberg,

for assisting with data compilation efforts and cheering me on since my very first lab presentation

over two years ago. Finally, I would like to thank my friends and family, for providing unwavering

support and encouragement as I pursued this project.

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1.0 Introduction

1.1 Semantic memory and event knowledge

Semantic memory is an individual’s long-lasting memory for general knowledge about the

world (Dresang et al., 2019). From birth, we begin collecting knowledge about the world. Semantic

memory is critical when trying to produce or understand language. For example, when you hear a

word or sentence, you consult your knowledge about objects, people, actions, and things to

understand the meaning of that sentence. Semantic memory is often impaired in PWA, and an

accurate measure of semantic memory impairment is crucial for treatment (Antonucci & Reilly,

2008). Existing picture-based assessments of object-related semantic memory include Pyramids

and Palm Trees (PPT) (Howard et al., 1992) and the Camels and Cactus Test (CCT) (Bozeat et al.,

2000). There is also a picture-based assessment of action-related semantic memory called the

Kissing and Dancing Test (KDT) (Bak & Hodges, 2003). However, there are few tests to measure

semantic memory for events in PWA (Dresang et al., 2019).

Events can be defined as collections of people, objects, actions, places, and the context in

which they occur (Dresang et al, 2019). Event roles (or thematic roles) are the people, places, and

things that play a role in an event. The agent is the initiator of an action (Ünal et al., 2021). The

patient is the entity undergoing the effect of some action, often undergoing some change in state

(Ünal et al., 2021). The instrument is the tool used to perform an action (Ünal et al., 2021). The

location is the place in which something is situated (Saeed et. al, 1996). The goal is the entity

towards which something moves, either literally or metaphorically (Ünal et al., 2021). An example

of this would be the following sentence: “The boy hit the baseball with his bat on the field.” The

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agent would be “the boy” as he is the one doing the act. The action is hit. The patient is the baseball

because it is moved by the action. The instrument is the bat because the boy uses the bat as a tool

to hit the ball. The location is the baseball field on which he is playing the game.

Event role knowledge is activated during language processing. Some evidence for this

comes from a study in which adult participants were given line drawings of two-participant

events—for example, a man throwing a football to a woman—and were asked to describe the

events (Griffin & Bock, 2000). Eye-tracking data showed that the participants’ eye movements

were guided by event features prior to sentence formulation. Participants gazed at the agent prior

to speech, then looked to the patient as they began speaking, and finally returned their gaze to the

agent. The results showed that participants “rapidly extract roles of event participants” while

describing the line drawing (Griffin & Bock, 2000). Event knowledge provides context that helps

individuals understand novel events by providing prototypical events for comparison (McRae &

Matsuki, 2009). Language processing is reliant on event knowledge, as it supports verb retrieval

and thematic-role processing (Dresang et al., 2019).

1.2 The Thematic Hierarchy

The Thematic Hierarchy is the idea that certain event roles are more prominent than others

(Ünal et al., 2021). An event role near the top of the hierarchy would have more prominence,

meaning that it should be identified earlier and processed more quickly than a non-prominent event

role. Agents are at the top of the hierarchy and are most salient or prominent. Next are Patients,

followed by Goals. Instruments are second-to-lowest on the thematic hierarchy. Finally, locations

are the least prominent role. Linguistic research indicates that agents are most prominent because

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they are linguistically encoded as subjects (Baker, 1997; Jackendoff, 1990). Patients are next

because they are direct objects of the verb. Goals, instruments, and locations are the least likely to

be in these syntactic positions, leading to a lower prominence on the thematic hierarchy.

Instruments are rarely selected as verb arguments and even referred to as “secondary roles” (Baker,

1997). This hierarchy naturally predicts that event roles towards the top of the Thematic Hierarchy

will be mentioned more frequently or identified more easily than event roles from the bottom of

the Thematic Hierarchy.

I will now outline the experimental evidence supporting the Thematic Hierarchy. Agents

and patients are expected to be prioritized over other event roles because of their positions towards

the top of the Thematic Hierarchy. Consistent with this, Hafri et al (2018) found that information

about agents and patients is often extracted even when it is not directly encouraged by a task or

while the participant is preoccupied with another task (Hafri et al., 2018). Participants viewed an

array of stimuli images depicting a simple interaction between a male and a female and were

instructed to answer which character, the male or the female, was on the left or right half of the

screen. When presented with subsequent images in which the event role of the target character

differed from one trial to the next, the participants displayed an event role switch cost, a delay in

reaction time caused by the shift in event role. Hafri et al.’s study found that although task

instructions did not explicitly refer to event roles, participants’ reaction times were affected by the

event role change, indicating that event role information is spontaneously encoded even when not

directly related to the task at hand.

Research suggests that instruments are not prioritized unless the instrument is deemed

particularly relevant to the story being told. Studies show that English speaking adults consistently

omit instruments in retelling stories involving instrument events (Lockridge & Brennan, 2002).

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The instrument is even more likely to be omitted from the retelling if it is a common or typical

instrument. Lockridge and Brennan (2002) found that during story retellings, atypical instruments

were most often explicitly disclosed to the partner early in the story, whereas an instrument that is

inferable from the story was not mentioned as frequently. These findings suggest that although

instruments can provide crucial information about an event, they are not attended to with the same

focus that an agent or patient would receive, which is consistent with their low role on the Thematic

Hierarchy.

Locations are positioned at the bottom of the Thematic Hierarchy. Ferretti et al (2001) used

single word priming to investigate how verbs activate event role knowledge (Ferretti et al., 2001).

Results showed that verbs primed all event roles except for locations (Ferretti et al., 2001). These

findings are consistent with the idea that locations are the least salient of all event roles, resulting

in location’s place at the bottom of the Thematic Hierarchy.

From a cognitive perspective, the Thematic Hierarchy would predict that entities in more

prominent event roles would be remembered better and identified more easily than entities in less

prominent roles. This claim is supported by a study by Ünal et al. (2021) that tested young learners

of English and Turkish in order to determine whether asymmetries in event role prominence

generalize to other languages. The study had two parts: a linguistic description task and a change-

blindness task. In the linguistic description task, participants were asked to describe event stimuli

images. Event role prioritization was measured by how frequently participants mentioned each

event role when describing a stimuli image. For the change-blindness task, four new stimuli images

were created from each original stimuli image by changing the color of one event role. In the task,

the original stimuli image was displayed, followed by a grey screen. Next, the new stimuli image

featuring the color change was shown, followed by another grey screen. The cycle would then

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repeat. Participants were instructed to respond as soon as they detected the changing object. In this

task, event role prioritization was measured by how quickly the participant responded to the

changed event role.

Findings suggested that agents were prioritized in both language groups. Patients and goals

tended to be similarly prioritized over instruments in both languages as well. The relative salience

of event roles was similar across young learners of both English and Turkish (Ünal et al., 2021).

This is particularly interesting because even though there is variation in the way these event roles

are encoded across the two languages, event roles were prioritized in similar ways, which aligns

with the Thematic Hierarchy. My thesis explores the theory that people should be faster and more

accurate to detect incongruency when it appears in more prominent roles than in less prominent

roles.

1.3 The Event Task

The Event Task is a picture-based assessment of semantic memory. The preliminary

version of the assessment was developed in the Language and Brain Lab at the University of

Pittsburgh. The task’s goal is to measure how functional or impaired an individual’s ability to

access their semantic memory for events is. In the task, the participant is given photographs of

events that are either plausible or implausible. Plausible events would be those that would

commonly occur in everyday life, such as a person doing work at a desk or boxing in a gym.

Implausible events are impossible or unlikely, and do not match our everyday experience or our

world knowledge based in semantic memory. Images like a man playing the violin underwater and

a woman with her head in a bag are clear examples of implausible events taken directly from the

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Event stimuli. In each implausible image, at least one event role is incongruent with the event

depicted. Participants were shown one image at a time and were asked to indicate if this scene was

something that may normally happen.

A study conducted by Dresang et al. (2019) assessed the preliminary validity of the Event

Task. The study’s first aim was to characterize typical performance and distinguish stimulus

characteristics of the Event Task. To that end, it gathered data from 90 neurologically healthy

adults across the lifespan and identified both average performance at multiple age-ranges and

variation in processing time across the plausible and implausible images (Dresang et al., 2019).

The second aim was to establish the Event Task’s sensitivity to neurological impairment. Findings

concluded that the Event Task was successful in detecting those participants afflicted with aphasia,

indicated by distinctions between neurologically healthy age-matched controls and PWA (Dresang

et al., 2019). The third and fourth aims were to demonstrate that the Event Task shows preliminary

evidence of convergent validity with measures of language processing and assessments of action

and object knowledge. Poor Event Task performance was correlated with greater deficits in verb

retrieval (specifically, verb production) and thematic-role processing (specifically, producing

agent, patient, and other thematic roles in sentences), and Event Task performance was predicted

by KDT (action based semantic memory assessment) performance and PPT (object based semantic

memory assessment) performance (Dresang et al., 2019). These findings suggest that Event Task

performance is indicative of verb retrieval abilities and thematic-role processing abilities, which

are crucial for language processing. The current study expands upon the foundational work of

Dresang et al. by examining whether the Thematic Hierarchy’s predictions regarding the salience

of various event roles hold for Dresang et al.’s Event Task data.

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1.4 The Current Study

My research investigated performance on the Event Task in relation to the Thematic

Hierarchy. My research tested whether there was a correlation between the relative prominence of

event roles according to the Thematic Hierarchy (agents > patients > instruments > locations) and

accuracy and reaction time for implausible Event Task pictures which contain violations of our

expectations about those event roles. For example, the stimulus image of a man playing the violin

in the ocean would be a location violation, as the location (the ocean) is not a typical place for that

event to occur. I hypothesized that there would be a positive correlation between Thematic

Hierarchy position and accuracy, with higher accuracy for more prominent event roles. I

hypothesized that there would be a negative correlation between Thematic Hierarchy position and

reaction time, with lower (or faster) reaction times for more prominent event roles.

If the event roles identified as incongruent most accurately and quickly were those event

roles near the top of the Thematic Hierarchy, that would suggest the Thematic Hierarchy is a good

indicator of event role prominence. If the Thematic Hierarchy proves to be a good indicator of

which event roles elicit the fastest or most accurate responses in the Event Task, then it might

suggest that aphasia treatment could be adjusted to focus on improving comprehension of those

event role categories that PWA respond to inaccurately or slowly. If the predicted relationship

between the Thematic Hierarchy and Event Task performance is not found, that would suggest

that the Thematic Hierarchy does not guide event roles in relation to PWA.

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2.0 Methods

2.1 Participants

As reported in Dresang et al. (2019), Event Task data was collected from 208 participants,

including 26 PWA and 182 neurologically healthy participants across the lifespan. These healthy

participants were divided into groups of 15 in the following age ranges: 20-29, 30-39, 40-49, 50-

59, 60-69, 70-79. The healthy control groups allowed for Event Task performance analysis across

the lifespan. All healthy participants were required to have no history of language, speech, or

neurological impairments. All participants attained a score of >24 on the Mini-Mental State

Examination, an assessment of cognitive function (MMSE) (Folstein et al., 1975). All participants

were monolingual native English speakers with normal or corrected-to-normal hearing and vision.

All participants provided informed consent and received compensation for their participation in

the study (Dresang et al., 2019). 4 participants were found to have incomplete Event Task data,

resulting in exclusion from the analysis.

2.2 Event Task Stimuli and Procedure

The Event Task is composed of 260 colored images, including 256 experimental images

and 4 practice images (Dresang et al., 2019). The photographs depict people engaging in basic

actions in a variety of environments. Half of these images portray plausible events, such as a person

boxing at a gym, and the other half portray implausible events, such as a man playing the violin

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underwater. Implausible events are impossible or unlikely, and do not match our everyday

experience or our world knowledge based in semantic memory. Implausible event images were

characterized as stimuli that “violates so-called ‘world knowle