The Effect of Semantic, Phonological and Visual Distortions on Eye Gaze in the Moses, Armstrong ...

48 Pages·2015·2.07 MB·English

The Effect of Semantic, Phonological and Visual Distortions on Eye Gaze in
the Moses, Armstrong, and Mega-Moses Illusions.

Daisy van den Broek
ANR 940279

Master thesis
Communication- and Information Sciences
Specialization: Business Communication and Digital Media

Faculty of Humanities
Tilburg University, Tilburg

Supervisor: Prof. Dr. M.M. Louwerse
Second Reader: Dr. Ir. P.H.M. Spronck
Acknowledgement
This master thesis is the final product of the Master Communication –and Information
Sciences with a specialization in Business Communication and Digital Media at Tilburg
University. It helped me put to use the theoretical knowledge I had gathered during the three
years of my bachelor degree and this last master year of my studies.
First of all, I would like to thank my supervisor Prof. Dr. Max Louwerse for his guidance. For
helping me form a clear idea of what I wanted to research and encouraging me to keep with
an eye-tracking experiment even though it meant quite a lot of extra work. I would like to
thank him for thinking along with me and for giving me input and feedback when needed.
I would also like to thank Dr. Rein Cozijn for his guidance with everything concerning eye-
tracking. For introducing me to the SMI eye-tracking system and helping me understand it.
And also for helping me understand the data that later came out of the eye-tracking
experiment.

2
Abstract
The theory behind the Moses illusion has been studied a lot by previous studies, both
recently and a long time ago. The Armstrong and Mega-Moses illusions however have not
been studied by a lot of people. While the Moses illusion has been studied a lot, no eye-
tracking experiment has been conducted using this illusion until now and the same is true for
the Armstrong and Mega-Moses illusions. In this thesis a comprehensive eye-tracking
experiment has been conducting using all three of these illusions to first of all see if they
‘work’ within an eye-tracking experiment. And secondly if they each have similar or different
effects on the duration of eye gaze and the number of regressions. Additionally the effect of
visual stimuli has been included in this study to see what the effect of unrelated or related
pictures has on the three illusions.
In the experiment participants answered 20 questions while their eye movement and
answers were recorded. These questions either had a target word that was high on semantic
relatedness (Moses illusion), phonological relatedness (Armstrong illusion), semantic and
phonological relatedness (Mega-Moses illusion) or a target word that was low on both.
Results showed that the effect of each illusion differed over the type of area of interest.
For target words the Armstrong illusion decreased the gaze duration, while for control words
it increased the gaze duration and gaze count. Furthermore through an interaction effect
between semantic and phonological relatedness we found that the Mega-Moses illusion
increased the gaze duration and gaze count for control words, while the other two illusions
separately decreased the factors. Lastly an interaction between semantic and picture
relatedness for target words and picture area of interests showed that related pictures either
increase the gaze duration and gaze count or decrease it. The gaze duration and gaze count
increased when the questions were low on semantic relatedness, while they increased when
the questions were high on semantic relatedness.
These findings support both the Moses and Armstrong illusions, but not the Mega-
Moses illusion. However the illusions do not always affect the same areas of interest, which
consisted of target word, control word and picture.

3
Table of Contents
Acknowledgement ................................................................................................................................ 2
Abstract ................................................................................................................................................. 3
1. Theoretical Framework ............................................................................................................... 5
1.1 The Moses Illusion ................................................................................................................ 6
1.2 The Armstrong Illusion ........................................................................................................ 8
1.3 Mega-Moses Illusion ............................................................................................................. 9
1.4 The Moses Illusion and Eye-tracking .................................................................................. 9
1.5 Change blindness and the Moses illusion .......................................................................... 11
2. Experiment.................................................................................................................................. 13
3. Method ........................................................................................................................................ 14
3.1 Participants ......................................................................................................................... 14
3.2 Materials ............................................................................................................................. 14
3.3 Design .................................................................................................................................. 15
3.4 Procedure ............................................................................................................................ 15
4. Results and Discussion ............................................................................................................... 17
4.1 Total fixation time .............................................................................................................. 18
4.2 Regressive eye movements. ................................................................................................ 24
5. General Discussion ..................................................................................................................... 30
5.1 Limitations & Implications for Future Research ............................................................. 31
6. Conclusion ................................................................................................................................... 33
References ........................................................................................................................................... 34
Appendix A ..................................................................................................................................... 36

4
1. Theoretical Framework
The Moses illusion (Erickson & Mattson, 1981) is a phenomenon which occurs when
a term in a sentence or question has been replaced by a semantically similar but incorrect
term, causing people to have difficulty recognizing the change (Park & Reder, 2003). The
prime example where the illusion got its name from is “How many animals of each kind did
Moses take on the Ark?”. Most people respond with “two” as the answer, except that it was
not Moses, but Noah who took animals on the Ark. This occurrence can be seen as a form of
visual blindness in both textual and auditory contexts. While this phenomenon has been
studied before in multiple studies, these studies seem to focus on the effect of visual or
auditory aspects on the recognition of the illusion. An example of the visual aspects can be
found in Song and Schwarz (2008), who used different text fonts to see if this affected the
effect of the illusion. Reading the questions in a font that is more difficult to read results in
more detections of the distortion, but also increases false recognitions of distortions (i.e.
noticing a ‘distortion’ in an undistorted sentence). Bredart and Modolo (1988) focus on
auditory aspects by using different focalization of the distorted words in their study. Instead of
questions Bredart and Modolo made use of statements, where emphasis was either put on the
distorted word by placing this word at the beginning of the sentence or no emphasis was put
on the distorted word by moving it to the end of the sentence. The found that more people
notice the distortion when focalization was put on the distorted word compared to when the
distorted word did not receive any focalization.
A possible other explanation for this phenomenon will be explored in this thesis, using
eye-tracking technology. A possible explanation might be the fact that we unconsciously do
notice the distortion in the questions, but our brain does not actually process observation. This
unconscious observation might be noticeable in a person’s eye movements, one’s eyes may
linger longer on the distorted word. Another possibility might be that people may not read the
whole sentence (carefully), because after reading the first few words they think “Oh I know
the answer to this” thus letting the distortion go unnoticed. Both of these possibilities can be
studied using eye-tracking technology, which allows for an analysis of the amount of time one
looks at the words in the sentence as well as the regressive movements of one’s eyes.
Furthermore, most studies have focused on semantically similar words when looking
at the effect of the Moses illusion. Perhaps words that are phonologically similar have an
effect as well, this illusion is known as the Armstrong illusion (Shafto & Mackay, 2000). This
illusions could even increase the effect of the distortions, for example when it is combined
with the Moses illusion and forms what is known as the Mega-Moses illusion (Shafto &
5
Mackay, 2000).
Lastly visual stimuli might increase detections of the distortions in the sentences. If
one is visually stimulated with the correct form of the erroneous word while reading a
sentence that uses an incorrect form of the word, one might detect the distortion more easily.
This leads us to the research question of this study which asks whether the effect of
semantic, phonologic and perceptual change affect eye gaze in the Moses, Armstrong and
Mega-Moses illusions. This research will try to provide new insights into the Moses,
Armstrong and Mega-Moses illusions and explore new reasons for the occurrence of this
phenomenon.

1.1 The Moses Illusion
As stated in the previous section the Moses illusion is a phenomenon that occurs when
people do not recognize a change in semantically similar words in a sentence or question
presented to them (Park & Reder, 2003).
Reder and Kusbit (1991) considered four possible explanations for the Moses illusion.
The Conversational Cooperation Theory, the Imperfect Encoding Hypothesis, the Inadequate
Retrieval Hypothesis, and the Partial-Match Hypothesis. The Conversational Cooperation
Theory, which was drawn from the Conversational Postulate (Grice, 1975). This postulate
suggests that people choose not to comment on the distortion in the sentence, because they
know what people intend to say. With the Conversational Cooperation Theory they thus
explored the possibility that the listener does notice the mistake but simply correct it in their
heads to what they think the speaker must have meant, thus being cooperative. The Imperfect
Encoding Hypothesis suggests that participants simply skip over the distorted word when they
encode the sentence because they already know what the questioner is going to ask. The
Inadequate Retrieval Hypothesis states that people might not notice the distortions because
they do not have enough knowledge about the target words. Finally the Partial-Match
Hypothesis states that “people often do incomplete matches between a complete
representation of the question and a complete representation of the stored proposition that
contains the answer” (Reder & Kusbit, 1991, p. 385). This partial-matching involves concepts
and features rather than just words, since people do in fact notice differences that are too
different from each other.
Various experimental studies demonstrated evidence for the Partial-Match Hypothesis,
but not for the other hypotheses. For instance, no evidence was found for the Imperfect
6
Encoding Hypothesis with participants being asked to point out distortions if they noticed
them, thus eliminating the cooperation factor (Bredart & Modolo, 1988; van Oostendorp & de
Mul, 1990; Reder & Kusbit, 1991), but participants still answered with the false positive
answer and took longer to answer.
The Imperfect Encoding Hypothesis suggested that people may simply skip over the
distorted word, because they already think they know the correct answer. However when
asked to read the sentences out loud, thus not being able to skip over the distorted word
(Erickson & Mattson, 1981) the participants still answered with the ‘incorrect’ answer.
Reading times for sentences with distortions were also faster when people noticed the
distortion than when they did not (Reder & Kusbit, 1991).
No evidence was found for the Inadequate Retrieval Hypothesis either, where
participants did not notice the distortions even when they were able to study the correct
versions of the facts that they were answering questions about later. While the participants
gave more ‘correct’ answers to the question (i.e. two animals instead of three), studying
sentences like “Noah took two animals of each kind on the Ark.” (Reder & Kusbit, 1991)
beforehand did not eliminate the effect of the Moses illusion.
Evidence for the Partial-Match Hypothesis, which explained that people often do
incomplete matches between a complete representation of the question and a complete
representation of the stored proposition that contains the answer, was found however. Reder
and Kusbit (1991) suggest that the aforementioned process is sensitive to similarity between
the concept words in the sentence and the stored representation of the answer. If the features
of the erroneous word overlap heavily with the features of the original word the distortion will
go unnoticed. The similarity between concept words that Reder and Kusbit (1991) describe in
their reasoning for the partial-matching theory is also found in other studies. Van Oostendorp
and de Mul (1990) study the differences in the effect of the illusion with words that were
either high or low-related. They describe semantic relatedness as; facts that are primarily
based on world knowledge and word concepts. Words with high levels of relatedness thus
have a high overlap in semantic features that people have stored for them, causing people to
make more mistakes in detecting a distortion. In their experiment Van Oostendorp and de Mul
(1990) made use of statements instead of questions, which had to be answered with true or
false, which eliminated the possibility that people gave unrelated answers. The results from
their experiment showed that sentences with high-related inaccurate words were judged to be
true more often than sentences with low-related inaccurate words. Furthermore they found
7
that when participants did notice the inaccuracy in the sentence they took longer to notice this
error when the words were high on relatedness then when they were low on relatedness.
1.2 The Armstrong Illusion
Most studies pertaining to the Moses illusion only focus on semantically similar words
in the Moses sentences and not on phonologically similar words. This is most likely due to the
fact that Erickson and Mattson (1981) did not find any significant effects when they used
phonologically similar words in their study. However Shafto and Mackay (2000) pointed out
that these findings could be considered problematic due to fact that only two sentences were
used and only one semantic context, in this example a biblical context. Erickson and Mattson
(1981) themselves pointed out that the effect of phonologically similar words could not be
fully dismissed. The non-significant fact that they had found was problematic because it was
based on just one semantic context, a phonological manipulation that was primitive, and
confounds between semantic and phonological factors (Shafto & Mackay, 2000). Even though
this was mentioned in the original article about the Moses illusion, no other studies before
Shafto and Mackay (2000) have looked further into the possible effects of phonologically
similar on the Moses illusion.
Shafto and Mackay (2000) named the illusion based on phonologically similar words
the Armstrong illusion, because of the following example that triggers an illusion that is
similar to the Moses illusion, but not because of the meaning, but because of the sound of the
target word: What was the famous line uttered by Louis Armstrong when he first set foot on
the moon? In which Louis Armstrong replaces Neil Armstrong. Shafto and Mackay (2000)
worked with a principle known as the most-primed-wins principle. This principle explains
that Noah and Moses share a number of connections; namely they are both male, biblical
figures, who spoke with God and saved their people. Therefore when one hears the name
Moses one is indirectly primed for Noah as well. However since Noah is also primed through
the concepts “built the Ark” and “animals of each kind” it receives more priming and thus
wins even when Moses is used in the sentence. For Armstrong questions similar convergent
priming was predicted, this partly due to their shared phonology. The name phrase Neil
Armstrong receives priming from both the name Armstrong and the semantic memory one has
(“moon”, “first set foot on”, etc.). Whereas Louis Armstrong only receives priming from the
name, thus causing the name phrase Neil Armstrong to win in accordance with the most-
primed-wins principle.
Using the partial shadowing procedure they established the Moses and Armstrong
8
illusions in identical syntactic and semantic contexts. They could rule out inattention to the
critical names as possible explanations for the illusions, since extra focus is put on the critical
names during partial shadowing procedures. The results found by Shafto and Mackay (2000),
indicate that purely semantic theories can be ruled out as explanations for the Armstrong
effect, since more “Can’t say” answers were given in unrelated conditions than in
phonologically related conditions. However Shafto and Mackay (2000) argued state that
purely phonological theories cannot be ruled in either, since the phonological similarity was
not the sole factor for the miscomprehensions. The phonological aspects do influence the
priming of the ‘correct’ form, but so do the semantic aspects of shared lexical nodes and
semantic-level sentence context. Shafto and Mackay bring up a good example of these shared
phonological and semantic aspects with the original Moses sentence. Namely Moses and
Noah also share a number of phonological nodes, whereas Abraham only shares a semantic
node with Noah causing the effect of the illusion to diminish.
1.3 Mega-Moses Illusion
After conducting their first experiment using the Armstrong illusion Shafto and
Mackay (2000) came up with the Mega-Moses illusions in which they combined both
semantic and phonological factors. Here they use the example The 1868 impeachment trial
involving former vice president Andrew Johnson followed what major American war?. To
create the normal Armstrong illusion they replaced Andrew Johnson with Samuel Johnson.
Then to create the normal Moses illusion they replaced Andrew Johnson with Theodore
Roosevelt. And lastly to create the Mega-Moses illusion they replaced Andrew Johnson with
Lyndon Johnson, in which they combined the phonological similarity of the last name with
the semantic similarity of their career (both vice presidents and then presidents after a
presidential assassination). Shafto and Mackay (2000) found that the effects of the Mega-
Moses illusion were indeed stronger than the effects found for normal Moses and Armstrong
illusion. The number of “Can’t say” responses were higher for both the unrelated and only
semantically related conditions in comparison to the combined (Mega-Moses) condition.
Significant effect were again found for the normal Moses and Armstrong conditions in this
test when compared to the unrelated condition.
1.4 The Moses Illusion and Eye-tracking
The Moses illusion (or Armstrong or Mega Moses illusion) has been studied in a lot of
different contexts; read to the participants by the experimenter or read and spoken by the
participants themselves, with different focalizations or with different fonts. And while the
9
reading times have been recorded by some studies, no studies (that we are aware of) have
conducted the Moses illusion experiment using eye-tracking to actually look at the behavior
of our eyes while we read the sentences. While the fact that this illusion is to some extent
auditory might explain why eye-tracking has not been used to test this illusion before,
multiple studies have only used a textual version of the illusion. While the same effects are
expected to occur in an eye-tracking experiment as in a solely textual study it has the added
value of having insights in the actual movements of eyes. Information like total fixation times
or number of regressions towards the target word, could further prove or instead discredit
earlier theories. When one reads Moses illusion (or Armstrong or Mega Moses illusion)
sentences and detects the error one might fixate longer on the erroneous word (i.e. Moses) and
make a regression, while those that do not notice this difference do not fixate longer on the
word and make no regression. However it could be that people who do not notice this
difference do unconsciously fixate longer on the word. In this case our eyes might have
noticed something was wrong, but our brain did not process this.
Three major components of eye movement are commonly distinguished (Rayner,
Chace, Slattery & Ashby, 2006) saccades, fixations and regression. Rather than gliding
through the text our eyes make a series of rapid movement when we are reading. These rapid
movements are called saccades and often span seven to nine letter spaces. Between these
saccades our eyes pause and fixate on words, this is the period where we encode what we are
reading. When texts get more difficult readers make longer fixations and often make
regressions to read previous parts of the text again (Rayner et al., 2006). This means that
when readers make more regression it indicated that the text is harder for them to decode.
That is, if one makes more regressions or fixates longer on words while reading a Moses
question this might mean that the brain cannot encode and decode the meaning of the
sentence. Because the sentence is wrong encoding should be impossible since there is no
answer stored for it, yet most people will still give the false answer.
Rayner et al. (2006) bring up a study by Cook (2005) who conducted an eye-tracking
experiment with sentences with distortions. They concluded that the Moses illusion did not
hold true for this eye-tracking study. However, while Rayner et al. (2006) describe this study
as a Moses illusion study the experiment conducted in fact was not a Moses illusion
experiment. In Cook’s experiment the example sentences had an antecedent and anaphor. This
meant that there were two sentences were the anaphor in the second sentence did not
correspond with the antecedent in the first sentence. In this case participants noticed that there
was a difference between the antecedent and the anaphor. However when using Moses
10