situations some theorists suggest that this area plays an important role.
Deficits in goal directed behavior
The last part that is affected by the breakdown of executive functions we want to discuss are the
problems in goal-directed behavior. This topic is closely related to the area of problem solving since this is nothing else than organizing behavior towards a goal.
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To make this more plastic, for the course of this topic we want to introduce an example that
requires an individual to behave goal-directed. Let us imagine that a person, call him John, has just got
up in the morning and wants to get dressed, in this case John’s goal is being dressed. For neurologically
intact people this task is not at all hard to master, they might not even realize that it is any task because
it is so trivial. But if you look closely, there are a lot of things that have to be taken into account while
working towards being fully dressed and any other task – trivial or not – in general.
What characterizes goal directed behavior?
Now, in the case of John, which are these?
Goal must be kept in mind
During the whole process it is improtant to always remember what it actually was that John wanted
to do. If he starts getting dressed and forgets that he wanted to get dressed quickly because he might
have oversplept and is late in time, and starts making his breakfast, he definitely will not reach his goal
of getting fully dressed.
Dividing into subtasks and sequencing
Most tasks have to de divided into subtasks, in John’s case: getting clothes, such as underwear, a
shirt, trousers, socks and a tie, and putting them on one after the other in a sensible order. This means
that John has to sequence the subtasks. He has to think about the fact that he cannot put on any clothes
that are still inside of the wardrobe and that he cannot put on the underwear after he has put on his
trousers.
Completed portions must be kept in mind
John has to remember which of the subtasks he has performed already, meaning that he need not
do them again. He only needs to get one piece (or pair) of clothes of each kind out of the wardrobe and
after he has put on his tie he must know that he does not have to look for another one and put this on as
well.
Flexibility and adaptability
Imagine that John has a shirt that is his favourite one and he plans on wearing it today. He looks
into the wardrobe and does not find it. Now he has to realize that the shirt is not inside the wardrobe
and has to develop alternative ways to complete the task of getting dressed. Maybe his wife has put the
shirt into the laundry because it was dirty? In this case, John has to adapt to this situation and has to
pick another shirt that was not in his plan originally.
Evaluation of actions
Along the way of reaching his ultimate goal John constantly has to evaluate his performance in
terms of ‘How am I doing considering that I have the goal of being dressed?’. If he is looking for socks
or is working on the knot of his tie (after he has put on all the other clothes), he should know that he is
doing perfectly fine in completing the subtasks required to reach his goal. But if he is distracted by his
new tuxedo inside the wardrobe and starts getting dressed in it just to see how it looks on him, he has to
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realize that he is not working towards his goal of being properly dressed for a day at the office. He also
will not reach his goal if he has the opinion that he is done getting dressed when he is only wearing his
underpants and socks.
As we have seen, goal directed bahaviour is by far not as easy as it looks on first sight. Most
people still will not have any trouble though, but think about what we have said about executive
functions already.
Executive dysfunction and goal directed behavior
The breakdown of executive functions impairs goal directed behavior to a large extend. In which
way cannot be stated in general, it depends on the specific brain regions that are damaged. So it is quite
possible that an individual with a particular lesion has problems with two or three of the five points
described above and performs within average regions when the other abilities are tested, however, if
only one link is missing from the chain, the whole plan might get very hard or even impossible to
master. Furthermore, the particular hemisphere affected plays a role as well. Patients with lesions in the
left hemisphere have difficulties with one aspect of a task and patients with lesions ind the right
hemisphere have difficulties with other aspects of the same tasks.
Problems in sequencing
For example, in an experiment (Milner, 1982) people were shown a sequence of cards with
pictures. The experiment included two different tasks: recognition trials and recency trials. In the
former the patients were shown two different pictures, one of them has appeared in the sequence
before, and the participants had to decide which one it was. In the latter they were shown two different
pictures, both of them have appeared before, they had to name the picture that was shown more
recently than the other one. The results of this experiment showed that people with lesions in temporal
regions have more trouble with the recognition trial and patients with frontal lesions have difficulties
with the recency trial since anterior regions are important for sequencing. This is due to the fact that the
recognition trial demanded a properly functioning recognition memory, the recency trial a properly functioning memory for item order. These two are dissociable and located in different areas of the brain.
Another interesting result was the fact that lesions in the frontal lobes of left and right hemisphere
impaired different abilities. While a lesion in the right hemisphere caused trouble in making recency
judgements, a lesion in the left hemisphere impaired the patient’s performance only when the presented
material was verbal or in a variation of the experiment that required self-ordered sequencing. Because
of that we know that the ability to sequence behavior is not only located in the frontal lobe but in the
left hemisphere particularly when it comes to motor action.
The frontal lobe is not only important for sequencing but also for working memory because the patient has to keep track of the items presented to them to make recency judgements. This idea is
supported by the fact that lesions in the lateral regions of the frontal lobe are much more likely to
impair this ability than damage to other areas of the frontal cortex.
But this is not the only thing there is to sequencing. For reaching a goal in the best possible way it
is important that a person is able to figure out which sequence of actions, which strategy, best suits the
purpose, in addition to just being able to develop a correct sequence. This is proven by an experiment
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called 'Tower of London' (Shallice, 1982) which is similar to the famous 'Tower of Hanoi' task with the
difference that this task required three balls to be put onto three poles of different length so that one
pole could hold three balls, the second one two and the third one only one ball, in a way that a
changeable goal position is attained out of a fixed initial position in as few moves as possible.
Especially patients with damage to the left frontal lobe proved to work inefficiently and ineffectively
on this task, they needed many moves and engaged in actions that did not lead toward the goal. But in
the end, although there are differences in how executive functions are affected depending on the
particular hemisphere where the frontal lobe lesion is located, abilities connected with sequencing are
mostly provided by overlapping structures in both frontal lobes.
Problems in shifting and modifying strategies
The intact neuronal tissue in the frontal lobe is also crucial for another exectuvie function
connected with goal directed behavior that we described above: flexibility and adaptability. This means
that a person with frontal lobe damage will have difficulties in shifting in set - meaning creating a new
plan after it has been found out that the original one cannot be carried out for some reason - and in
modifying the initial strategy according to this new set. In what particular way this can be observed in
patients can again not be stated in general but depends on the nature of the shift that has to be made.
An experiment (Owen, 1991) that presented patients with pictures that required different kinds of
conceptual shifts, discrimination between two black shapes, between two black shapes while ignoring
intermingled white shapes ('intradimensional') and between the two white shapes ('extradimensional'),
showed that patients with lesions in the frontal lobe have difficulties only with the extradimensional
shift. This shows that these people cannot apply general rules to situations that are different from the
origninal situations when these rules were learned. Besides, they are unable to create alternatives to
their original plans because they stay fixed on their original way of dealing with a situation and cannot
disengage from it. This is also part of the usual perseveration problems found in patients with executive
dysfunction.
Another problem of patients with frontal lobe damage is that they do not use as many appropriate
hypotheses for creating a strategy as people with damage to other brain regions do or they suddenly
abandon it when they have found an appropriate hypothesis. Also, it seems not very surprising that they
have big trouble switching beteen hypotheses indicated by Owen's experiment. Even when it is clear
that one hypothesis cannot be the right one, patients will stick to it nevertheless and are unable to
abandon it (called 'tunnel vision').
These earlier described problems of 'redirecting' of one's strategies stand in contrast to the atcual
'act of switching' between tasks. This is yet another problem for patients with frontal lobe damage.
Since the control system that leads task switching as such is independent from the parts that actually
perform these tasks, the task switching is particularly impaired in patients with lesions to the
dorsolateral prefrontal cortex while at the same time they have no trouble with performing the single
tasks alone. This of course, causes a lot of problems in goal directed behavior because as it was said
before, most tasks consist of smaller subtasks that have to be completed.
Problems with the interpretation of available information
Quite often, if we want to reach a goal, we get hints on how to do it best. This means we have to be
able to interpret the available information in terms of what the appropriate strategy would be. For many
patients of executive dysfunction this is not an easy thing to do either. They have trouble to use this
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information and thus, engage in inefficient actions and it takes them much longer to solve a task than it
would if they took into account the extra information and developed an effective strategy.
Problems with self-criticism and -monitoring
The last problem for people with frontal lobe damage we want to present here is the last point in
the above list of properties important for proper goal directed behavior. It is the ability to evaluate one's
actions, an ability that is missing in most patients. These people are therefore very likely to 'wander off
task' and engage in behavior that does not help them to attain their goal. In addition to that, they are
also not able to determine whether their task is already completed at all. Reasons for this are thought to
be a lack of motivation or lack of concern about one's performance (frontal lobe damage is usually
accompanied by changes in emotional processing) but these are probably not the only explanations
there are for these problems.
Another important brain region in this context – the medial portion of the frontal lobe – is
responsible for detecting behavioral errors made while working towards a goal. This has been shown
by ERP experiments where there was an error-related negativity 100ms after an error has been made. If this area is damaged, this mechanism cannot work properly anymore and the patient loses the ability to
detect errors and thus monitor his own behavior.
However, in the end we must add that although executive dysfunction causes an enormous number
of problems in behaving correctly towards a goal, most patients when assigned with a task are indeed
anxious to solve it but are just unable to do so which can manifest in all the various ways discussed in
the passages above.
Theories of Frontal Lobe Function in Executive Control
In order to explain that patients with frontal lobe damage have difficulties in performing executive
functions, four major approaches have developed. Each of them leads to an improved understanding of
the role of frontal regions in executive functions, but none of these theories covers all the deficits
occurred.
Role of Working Memory
The most anatomically specific approach assumes the dorsolateral prefrontal area of the frontal
lobe to be critical for working memory. The working memory which has to be clearly distinguished
from the long term memory keeps information on-line for use in performing a task.
Not being generated for accounting for the broad array of dysfunctions it focuses on the three
following deficits. Sequencing information and directing behavior toward a goal, understanding of
temporal relations between items and events, and some aspects of environmental dependency and
perseveration.
Research on monkeys has been helpful to develop this approach (the delayed-respone paradigm,
Goldman-Rakic, 1987, serves as a classical example.
In 2000 the working memory was defined by Baddeley as “a limited capacity system for temporary
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storage and manipulation of information for complex tasks such as comprehension, learning, and
reasoning” (Goldstein) consisting of three components. The central executive coordinating the activity
of the phonological loop (which holds verbal and auditory information) and the visuospatioal sketch
pad (which holds visual and spatial information) and pulling information from long-term memory is the
most important part.
Role of Controlled Versus Automatic Processes
There are two theories based on the underlying assumption that “the frontal lobes are especially
important for controlling behavior in nonroutine situations and for overriding typical stimulusresponse
associations, but contribute little to automatic and effortless behavior.” (Banich, p. 397).
Stuss and Benson (1986) consider control over behavior to occur in a hierarchical manner. They
distinguish between three different levels, of which each is associated with a particular brain region. In
the first level sensory information is processed automatically by posterior regions, in the next level
(associated with the executive functions of the frontal lobe) conscious control is needed to direct
behavior toward a goal and at the highest level controlled self-reflection takes place in the prefrontal
cortex.
This model is appropriate for explaining deficits in goal-oriented behavior, in dealing with novelty,
the lack of cognitive flexibility and the environmental dependency syndrome. Furthermore it can
explain the inability to consciously control action and to self-criticize.
The second model developed by Shalice (1982) proposes a system consisting of two parts to
influence the choice of behavior. The first part, a cognitive system called contention scheduling, is in
charge of more automatic processing. Various links and processing schemes cause a single stimulus to
result in an automatic string of actions. Once an action is initiated, it remains active until inhibited.
The second cognitive system is the supervisory attentional system which directs attention and
guids action through decision processes and is only active “when no processing schemes are available,
when the task is technically difficult, when problem solving is required and when certain response
tendencies must be overcome” (Banich).
This theory supports the observations of few deficits in routine situations, but relevant problems in
dealing with novel tasks (e.g. the Tower of London task, Shallice), since no schemes in contention
scheduling exist for dealing with it. Impulsive action is another characteristic of patients with frontal
lobe damages which can be explained by this theory. Even if asked not to do certain things, such
patients stick to their routines and cannot control their automatic behavior.
Use of Scripts
The approach based on scripts, which are sets of events, actions and ideas that are linked to form a
unit of knowledge was developed by Schank (1982) amongst others.
Containing information about the setting in which an event occurs, the set of events needed to
achieve the goal and the end event terminating the action, such managerial knowledge units (MKUs)
are stored in the prefrontal cortex. They are organized in a hierarchical manner being abstract at the top
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and getting more specific at the bottom.
Damage of the scripts leads to not being able to behave goal-directed, finding it easier to cope with
usual situations (due to the difficulty of retrieving a MKU of a novel event) and deficits in the initiation
and cessation of action (because of MKUs specifying the beginning and ending of an action.)
Role of a goal list
The perspective of artificial intelligence and machine learning introduced an approach which
assumes that each person has a goal list, which contains the tasks requirements or goals. This list is
fundamental to guiding behavior and since a frontal lobe damage disrupts the ability to form a goal list,
the theory helps to explain difficulties in abstract thinking, perceptual analysis, verbal output and
staying on task. It can also account for the strong environmental influence on patients with frontal lobe
damages, due to the lack of internal goals and the difficulty of organizing actions toward a goal.
References
• Goldstein, E. Bruce (2005). Cognitive Psychology - Connecting, Mind Research, and
Everyday Experience. Thomson Wadsworth.
• Marie T. Banich (1997). Neuropsychology. The neural bases of Mental Function. Houghton
Mifflin.
• Wilson, Robert A.& Keil, Frank C. (1999). The The MIT Encyclopedia of the Cognitive
Sciences. Massachusetts: Bradford Book.
• Schmalhofer, Franz. Slides from the course: Cognitive Psychology and Neuropsychology,
Summer Term 2006, University of Osnabrueck.
Links
Reasoning
Quizz to check whether you understood the difference of deduction and induction
Decision making
Web-published journal by the Society for Judgement and Decision Making
Executive functions
Elaborate document (pdf) from the Technical University of Dresden (in German)
Text from the Max Planck Society, Munich (in English)
Short description and an extensive link list
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Chapter 14
14 PRESENT AND FUTURE OF RESEARCH
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"It's hard to make predictions - especially about the future." — Robert Storm Petersen
Introduction
Until now
eveloping from the information processing approach, today's cognitive psychology differs from
Dclassical psychological approaches in the methods they use as well as in the interdisciplinary
connections to other sciences. Apart from rejecting introspection as a valid method to analyze mental
phenomenon, cognitive psychology introduces further, mainly computer-based, techniques that had not
been in the range of methods used by classical psychology so far.
Introducing new methods
By using imaging-techniques like fMRI scans cognitive psychology is able to analyze the relation
between the physiology of the brain and mental processes. In the future cognitive psychology will even
more concentrate on computer-related methods. Hereby it profits from improvements in this area. E.g.
fMRI scans nowadays still have many possible error sources, which should be solved in the future.
Thereby the approach becomes more powerful and precise. In addition to that the computer approach
can be combined with the classical behavior approach, where one inferes a participant's mental states
from the behavior that is shown.
Possible development
Apart from using the methods developed by other sciences cognitive psychology also collaborates
with topic-related sciences like artificial intelligence, neuroscience, linguistics and philosophy. The
different perspectives on the topic made it possible to confirm one's results as well as gaining new
accesses to the study of the mind. Modern studies of cognitive psychology more and more critize the
classical information processing approach. Instead of that other theories acquire more importance. E.g.
the classical approach is modified to a parallel information processing approach, which more resembles
the method of working of the mind. Furthermore different theor