Day-dreaming,
fantasizing, and other forms of mind wandering constitute 30%
of our daily lives, according to Reichle et. al., and thus
have naturally attracted a great deal of attention in the psychological field.
In today’s post, we will examine four studies on mind-wandering, and more
specifically, their views and proposed models on the
factors that contribute to mind wandering as well as the balance
between exogenous and external contributors. We begin with a summary
of these studies, with particular focus on their primary point of
view/proposed model and a description of their key methods. We will also
address some of their key findings and the implications of those findings.
Afterwards, we move on to a comparative analysis of these
studies, in which we will point out key parallels and distinctions between the
proposed models/points of views as well as integrate ideas from the different
studies. A questions and comments section will follow, in
which we revisit the methods employed and examine whether they’re
sufficient in addressing the questions asked. We will also suggest alternative
approaches that may more fully address the questions or just provide a
different avenue of investigation into these questions. Lastly, we will
conclude with an examination of the links between these studies and
neuroscience.
Summary of Studies
Antrobus’
seminal 1966 study on streams of consciousness, or task-irrelevant events (let
us call these TIEs from henceforth), describes a model for relating the
relationship between generation of TIEs to one’s response to external stimuli.
Antrobus’ model is one of information processing and thus centers upon the
assumption that a Central Executive with limited resources is responsible for
processing both endogenous and external information. Thus, under conditions
of high demand from external stimuli, production of TIEs will be diminished as
the Central Executive must focus its resources on responding to the external
stimuli. Similarly, under conditions of high demand from internal stimuli,
production of TIEs will also be diminished according to this model. To test
this hypothesis, Antrobus performed three experiments in which he altered the
external and internal demands and examined the corresponding production of
TIEs. More specifically, he examined the impact
of short-term memory load (by increasing signal rate in signal detection
tasks), financial reward, and
distressing information (by showing the subjects a fake radiocast
describing imminent war between China and the US) on the probability of TIE generation. The researchers found
increasing speed of signal presentation or demands on short-term memory led to reduced
reports of TIE generation. Similarly, in the second experiment, graded
financial award also led to a decrease in TIEs whereas subjects given the
distressing information prior to the tasks exhibited increased TIEs.
Giambra et. al. came up with a laboratory method for studying
Task-unrelated images and thoughts (TUITs). We will think of these as the
equivalents of the TIEs described earlier. He contends that TUIT production
occurs when external stimuli imposes a relatively low cognitive demand; the
excess cognitive capacity is utilized to generate TUITs. As Giambra (1995) puts
it, “…TUIT occurrence and unused capacity, when performing a task, are directly
proportional.” Interestingly, and as a departure from Antrobus’ study, Giambra
notes that there exist more than one method of TUIT generation: as the result
of one’s conscious attention shift and involuntary shifts of attention. In the
former case, the TUIT is described as “more compelling” than the task at hand
and controlled by higher centers in the brain. On the contrary, the latter case
is described as involving lower orders of control and information-processing as
they are not “motivationally determined.” To test his resource theory centered
hypothesis, Giambra conducted two experiments; in the first experiment,
subjects performed a vigilance task that allowed for “the expression of a wide
range of TUIT propensities.” Results indicated that vigilance tasks can provide
reliable measures of TUITs. The second experiment examined the “stability of
TUIT likelihood differences.” Giambra et.
al. found that TUIT generation was shown to be dependent on aging,
hyperactivity, time of day, and level of depression.
Teasdale
followed up with a study that indicated stimulus-independent thought (SITs)
depends on central executive resources. Specifically, he agrees with several
aspects of Antrobus’ study, most prominently the resource theory centered
theory. Teasdale supports the view that a Central Executive with limited
resources is responsible for information processing and generation of SITs. It
is important to note that Teasdale adopts the Baddeley-Hitch description of
working memory, which consists of three components: a central executive and two
peripheral systems, namely the visuospatial scratchpad and the
loop-phonological store system. To investigate the role of each component in
the generation of SITs, Tesasdale et. al.
performed four experiments using the interference methodology. Specifically,
subjects performed a task with interventions designated specifically to
correlate to each of the three working memory components, as described by
Baddeley-Hitch. Experiment 1 focused on the phonological loop and experiment 2
focused on the visuospatial sractchpad.
Results indicated no significant differences between the control and experimental
groups in the generation of SITs, thus suggesting that their generation is not
dependent on the phonological loop or the visuospatial scratchpad. Experiments
3 and 4 focused on the central executive and results indicated that generation
of SITs was dependent on central executive resources.
Reichle et. al. did an interesting variation on
the mind wandering theme: he tracked and compared eye movements during normal
and mindless reading. Specifically, he defines “mindless reading” as “ when the
eyes continue moving across the page even though the mind is thinking about
something unrelated to the text” (Reichle, 2012). This study investigated both
local and global eye movement patterns in both self-caught and probe caught
mindless reading. Method wise, Reiche et.
al. monitored the gaze location of the participants’ right eye during
reading (an excerpt from Sense and
Sensibility) using an EyeLink 1000 eye tracker. Participants reported
“zoning out” 8 to 36 times during the excerpt. Even more interestingly,
analysis of participants’ eye-movements indicated that fixation duration is
longer during mindless reading and fixations were also less affected by
“lexical and linguistic variables” than fixations in non-mindless reading.
There were more off-text fixations during the probe-caught mindless reading
than normal reading and self-caught mindless reading. Furthermore,
eye-movements immediately before “self-caught” mindless-reading were also very
erratic, even compared to those in probe-caught mindless reading.
Comparative
Analysis
I
found this weeks’ papers especially interesting both because of their subject
matter but also in the ways that they relate to each other. Specifically,
relative to the papers from previous weeks, this week’s papers represent a set
of the most harmonious/least-contested viewpoints. Whereas previous weeks’
papers featured papers with polar opposite viewpoints on a given issue, this
week’s papers offer similar viewpoints, though with important variations (and
naming systems…). Indeed, all three papers echo the idea of a central executive
system that has limited resource and information processing capacity in some
way. Antrobus (1966) directly
references this as being responsible for information processing: “Under most
conditions of moderate activation and wakefulness we may postulate that the
external stimuli have a somewhat greater priority for processing by a Central
Executive.” Giambra (1995) also echoes
this idea in his study; indeed, he notes “TUIT occurrence and unused capacity,
when performing a task, are directly proportional.” For Giambra, however, it is
the left over cognitive capacity of the central executive during an undemanding
task that is used for the production of TUITs. Similarly, Teasdale (1995)
articulates “stimulus-independent thought depends on central executive
resources.” Thus, clearly, the authors for this week are in agreement about the
existence of an information processing central executive that is critically
involved in the generation of mind wandering. Despite the similarities of the
authors’ viewpoints, however, there were some important differences, in both
their inferences and methodologies, most of which will be covered in the next
section. For instance, whereas Antrobus was focused primarily on daydreaming,
Giambra (1995) was interested in several forms of TUITs. Furthermore, whereas
Antrobus assigned the label “daydreaming” to account for any mind wandering
exhibited by the participants, Giambra took account the possibility of
different types of TUITs with different origins and processing centers. I found
this insight to be very enlightening, although I do feel that more definitive
experiments need to be done to support this theory.
Questions
and Comments: Methods, Revisited and Alternative Explanations
The most concerning problem I had with this weeks’ papers were the
methods and result interpretation. While I think the research topic is
extremely fascinating and the questions clearly relevant to daily life, I feel
that many of the methods employed were insufficient in addressing the question
and that the results could have been interpreted in a more rigorous manner. For
instance, Antrobus (1966) relies on participant reports of daydreaming
and mind wandering as a key portion of his result. This approach poses obvious
problems as participants can have different interpretations of “daydreaming.”
While some may consider daydreaming just slightly “zoning out,” another may
consider it to mean completely detaching from the task at hand. Thus, without a
strict and enforced definition of daydreaming, the reports cannot be
consistent. Furthermore, the fact that the reports are exactly
that—self-reports—also raises several problems. Participants can choose not to
report daydreaming instances or may over-report daydreaming instances in the
absence of a strict definition of daydreaming. Furthermore, I felt that the
result interpretation of experiment 2 (involving the financial reward and
penalty) was partially unsubstantiated. For instance, he found a payoff effect
(participants in the group with the highest financial penalty); however, this
was only the case for the male participants, as indicated by graph 2. He
explains this by “perhaps the reward for mastering the task and satisfying E’s
instructions overrides the monetary payoff, particularly for high-achieving
college girls.” Yet, this is not substantiated by any experiment and seems
almost like a second thought. The graphs below show these results; graph 1
shows the payoff effect and graph 2 shows the same “effect” for the male and
female participants.
Giambra
(1995) et. al. went one step beyond
Antrobus’ original study by accounting for two types of TUITs: those to which
subjects consciously switch attention and those that subjects involuntarily
arrive at. He posits that the former is more compelling than the task at hand
and is processed by higher order brain centers and that the latter is processed
by lower brain centers. I found this rather illuminating because it takes into consideration
the relative excitement level between the task at hand the TUIT. Furthermore,
it also harks back to the vigilance decrement that we covered in previous
classes. In particularly monotonous tasks, perhaps the subject experiences a
vigilance decrement as a result of TUITs formation, or visa versa? It’s
definitely an interesting possibility to explore. However, Giambra (1995)
also falls prey to the same self-reporting utilized by Antrobus. Subjects are
asked to press a button every time they experience task-unrelated thoughts.
This poses a clear problem because of the reasons discussed above. Reichle
(2010) solves this problem in his study on mindless reading by utilizing
probes to detect mindless reading. The incorporation of probe-caught mindless
reading in Reichle (2010) was very compelling; even more compelling was his
comparative analysis of probe-caught and self-caught mindless reading. In this
way, he can not only provide a more accurate and consistent report on the
mindless reading, he can also provide a reliable description on the “accuracy”
of self-reports by analyzing the overlap between self-caught and probe-caught
mindless reading. However, as compelling as I found Reichle’s study, I did have
one important concern with it: it only had four
participants!! While I felt the general experimental design of the study was
very well done, four participants is nowhere near enough to make a conclusion.
It is a good start for sure, but a larger scale study must be done first to
truly substantiate his contention. I also found this to be a similar problem in
Antrobus’ 1966 study as well as Giambra’s 1995 study. With so few
participants, a few outliers would be sufficient to skew the data and confound
the results, especially in the presence of such uncontrolled factors such as
self-reporting.
Links
to Neuroscience and Future Directions
I think it would extremely interesting to
translate some of the studies discussed in this weeks’ papers into neuroscience
experiments. For instance, I brought up the possibility that self-reports may
not always be accurate or consistent. A possible way of testing this and of
providing a more consistent bar for mind wandering could be to have the
subjects perform similar tasks while inside an fMRI machine. This way, we could
monitor the dynamic and changing brain activation patterns during focused task
performance as well as during mind wandering. Furthermore, we can compare
verbalized self-reports with fMRI activation and deactivation patterns to
determine whether a strong correlation exists.
Clearly, the subject would have to remain perfectly still for a
prolonged period of time, and the consequences of this would have to be taken
into account during result analysis. Other less restrictive forms of brain
imaging could also be employed. It is important to remember, however, that this
provides a global view of brain activation and deactivation patterns during
mind wandering. It would be interesting to the biological realm and try to
identify physiological changes associated with mind wandering (such as a
reduced heart rate, etc.)
References
Image
References
Question? http://cuteoverload.com/2012/08/15/question/
Accessed 19/02/2013.
Cat Man Do.
Testing Testing 1…2…3? (Part 1) http://catexpert.blogspot.com/2012/03/testing-testing-123-part-1.html
Accessed 19/02/2013.
Frontoparietal
Cortical networks for Directing Attentiion and The Eye to Visual Locations:
Identical, Independent, or Overlapping Neural Systems? http://www.pnas.org/content/95/3/831/F3.expansion.html
Accessed 20/02/2013.
http://keykristinedm310.blogspot.com/
Accessed 20/02/2013
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