Transcript ppt presentation

ECONOMIC PAST. A DEAD LOCK OR A PROLOGUE?
Roberta Patalano
Parthenope University (Naples) and Luiss (Rome)
Glasgow, 7-9/1/2009
The talk will address two topics:
1. The relationship between path dependence and memory.
This part will be based on
R. Patalano (2007), Mind Dependence. The Past in the Grip of the Present,
Journal of Bioeconomics, 9,2, 85-107.
2. The relationship between future, expectations and memory.
This part will summarize briefly what I’m working on at the moment.
Path dependence develops the insight that ‘history matters’.
Later decisions rely on, and are constrained by, earlier decisions.
In very general terms, path-dependence must involve:
(1) An irreversible process, that is a process which develops through history; and
(2) The existence of multiple equilibria that are attainable under different initial
conditions. Equilibria take the form of asymptotic states which the system
might attain in its evolutionary trajectory.
In a path dependent dynamic the outcome is determined by the whole sequence of events
that unfold through time.‘Small events’ are never forgotten and can lock-in the system into
a suboptimal equilibrium.
At an individual level, path-dependence emerges when history irreversibly influences
the choice set and the behavioral algorithms of agents.
At a system level, irreversibility is mainly caused by dynamic increasing
returns which, in turn, may be due to economies of scale, sunk costs and asymmetrical
information. ‘More generally, they are likely to be a common property of
learning and accumulation of technological capabilities with their typical features
of locality and cumulativeness’ (Bassanini & Dosi 1999, p. 19).
Sources of path dependence
are also likely to exsist on the demand side of the market. Among
them, network externalities (Katz & Shapiro 1994) and endogenous evolution of
preferences (Dosi & Metcalfe 1991; Brock & Durlauf 1999) have been receiving
increasing attention.
At a macro level, conventions and shared norms, such as those which influence
and shape institutions are also an important ‘carrier of history’ (David 1994). They
give rise to a cumulative and self-enforcing process of development because, by
structuring the social context, they also shape the cognitive and behavioral patterns
which support their existence (Coriat & Dosi 1998; North 2000; Patalano 2007).
Recent developments in economic literature have pointed out that path dependence
also has a neuro-cognitive dimension. This approach has important roots in the history of
economic thought and, in particular, in the work by Nobel Laureate Friedrich A. von Hayek.
In The Sensory Order (1952) Hayek deals with the psychology of perception and compares
the mind to a classifying structure which does not receive sensorial stimuli passively but
directs and interprets them according to the connections among neurons. The latter
continuously take form throughout the history of the individual and are influenced
by both his/her genetic heritage and his/her personal living.
Recent neurobiological research confirms Hayek’s major ideas (David 1994; Fuster 1997;
Paller 2001). The development of the mind and, specifically, its ability to create meanings on the
basis of perceived information depends on the presence of neural connections which have
existed since the individual’s birth. They are inelastic (but not rigid) and change according to new
experiences. Changes include functional evolution of neural groups, learning how to perform
new tasks when the individual faces unexplored situations and the recombining
of synaptic connections into a configuration that is more suitable for current situations.
Perception of the external environment is based upon personal experience. All that is perceived
is then compared with already recorded data and interpreted in the light of previous subjective
classifications. The past perceptual experience orients the present one.
On these grounds, microfoundations of path dependence can be traced in the
neuropsychological dimension of cognition (Rizzello 2003). The human brain and mind evolve
by following a path that strongly depends on innate pre-existing structures but can also evolve in
novel and unpredictable ways.
In spite of the increasing attention paid by cognitive economists to the path dependence
of mind and brain activities, the role played by memory in
shaping individual attitude toward the past has not yet been considered
in the literature.
An aspect that may be of particular interest for economist is the dynamic
dimension of remembering.
The construction of memories is commonly made up of three steps: the acquisition
of new information (encoding), the process by which this new information
is stocked (storage), and the process through which it is recalled (retrieval).
Initially, information is encoded as patterns of neural activity which are still weak and
not yet persistent. Only later, is it stored in more persistent molecular or structural
formats by undergoing a series of neurophysiological processes (e.g., glutamate
release, protein synthesis, neural growth and rearrangement) that render the
memory representations progressively more stable. It is these processes that are
generally referred to as ‘consolidation’. Once consolidation has taken place, the memory
is assumed to be ‘fixed’.
Recently, however, the idea has been gaining support that recalling or
‘reactivating’ a previously consolidated memory renders it fragile and susceptible
to interference once again, therefore requiring periods of re-consolidation
(Miller & Matzel 2000; Walker et al. 2003).
This adds new support to the idea that memory
does not simply consist of a replay of the past but involves a genuine reorganization
of data into new representations (Neisser 1967; Edelman 1992; Schacter
1996). Retrieval is in fact a dynamic process during which new information modifies
the existing representation. According to the hypothesis of re-consolidation,
memories never reach a fixed state as they are subject to change every time they
are activated (also without conscious awareness).
To summarize, memory dynamic includes:
• The initial encoding process, when new information is perceived and held
precariously;
• The later encoding processes, when new connections between nerve cells grow to
guarantee a more permanent storage of information;
• The consolidation process through which a memory becomes increasingly resistant
to time;
• The retrieval processes, when old information is reactivated and combined with
new information into a new memory;
• The re-consolidation process, which shapes re-construction of memories over
time.
IMPLICATIONS FOR ECONOMICS
As suggested by the literature, path-dependence allows social scientists to interpret ‘the present
in the grip of the past’. It seems, however, that this quotation can also be reversed, once the
cognitive roots of path-dependence have been made explicit.
Due to the reconstructive nature of memory processes and to the relevance of memories in
defining personal identity (Schacter 1996), it’s also the past which appears to be in the grip of
the present.
Different from biological organisms, economic agents do not passively inherit
traits of past evolution. Instead, they are tied to their memories by one-to-one
feedback which dynamically develops through time.
On the one hand, the past acts on the individual
by shaping his neurocognitive structures and the mental models through which
he makes sense of his environment and adapts to it. On the other hand, the current
experience of the individual can selectively retrieve memories from the past which
then overcome a process of re-consolidation.
This latter process consists of merging present
information with that previously stored and brings new images of the past into
emergence. As a result, the memory of past experiences is modified and enriched
by present experiences.
The human mind plays an active role in
orientating the individual’s subjective attitude towards the past.
Let us consider some implications for lock in.
As argued by Arthur (1989, p. 128), ‘increasing returns can cause the economy
gradually to lock itself into an outcome not necessarily superior to alternatives, not
easily altered, and not entirely predictable in advance.’
In biological systems the only possibility to escape lock in is a favourable gene mutation.
Random mutations allow for new species to develop and unlock evolution from its current stage.
They represent, thus, the driving-forces of change.
In a socio-economic environment, evolution differs in important respects from the biological
model, as it depends on the active behavior of individuals (Frenken et al. 1999). Lock or
de-lock may be interpreted as a result of individual and collective wills and strategies
(Bassanini & Dosi 1999; David 1987; Perez & Soete 1988).
The functioning of memory may help in defining a different
concept of lock-in and new ways out of it.
Certainly there exists a past whose events cannot be changed, due to the irreversibility
of time. Nevertheless, the image of the past that stems from individual
and shared memories is not a fixed and unchangeable entity. It grows
continuously and modifies itself under the influence of the one-to-one feedback
between the present and the past.
Any act of remembering involves a change. By acting on the present it is possible
to influence the image of the past, thus eventually increasing our freedom
from the grip of past events.
Our main claim concerns the existence of endogenous forces which,
together with external factors, may drive the process of change.
A key resources for endogenous change may be found in the
constructive processes which underlie remembering
In the working of memory, the present seems to act on the past through different
mechanisms:
•
By way of the retrieval clue which guides the search for memories selectively.
Human beings do not remember all their past at any one time. Recall requires
a searching process that allows only part of stored information to reach conscious
awareness.
•
After retrieval has occurred, the process of remembering takes place. It
involves the costruction of memories from the available retrieved information
plus information that is extracted from the present life of the individual
and does not consist of a verbatim reproduction of a fixed content. Quoting
Bartlett (1932, p. 213), ‘remembering is not the re-excitation of innumerable
fixed, lifeless and fragmentary traces. It is an imaginative reconstruction, or
construction.’
From this perspective, the memory of the past does not appear to be exogenous
and not even defined once and for all. Certainly, time is not reversible.
Nevertheless, the individual and collective
image of ‘what has happened’ continuously evolves under the drive of the
one-to-one feedback which connects present with past.
The process of remembering
has a mainly reorganizing nature, it involves recombination of memory traces
with present information and leads to the emergence of a new representation of
past events.
As a single image of history does not exist, neither can a unique and stable
modality of dependence from history be defined.
Path dependence and lock-in appear to have a relative meaning that has to be defined case by
case for it pertains to a specific, and to some extent modifiable, reconstruction of past events.
Second Part.
MEMORY & FUTURE
MEMORY ERRORS
Neuropsychological research has shown that memory is
fallible, for it is prone to various kinds of errors, illusions and
distorsions. Most importantly, it has shown that memory fails
sistematically.
Schacter (1999) has classified memory’s most common
mistakes into 7 basic “sins”:
TRANSIENCE; ABSENT-MINDEDNESS; BLOCKING;
MISATTRIBUTION; SUGGESTIBILITY; BIAS; PERSISTENCE.
The first 3 sins reflect different types of forgetting.
TRANSIENCE reflects the decreasing accessibility of memories over time. Gradual
forgetting has been attributed both to retrieval failure –a difficulty to access information
that is stored- and to the actual loss of information from storage. The latter is likely to
occurr when a memory is not “used”and not recalled for a long time.
ABSENT-MINDEDNESS occurs when insufficient attention is paid to a stimulus during
encoding and/or retrieval. Absent-mindedness during encoding is the source of common
everyday memory failures as when, for example, one does not remember a recent
action (e.g. where I placed the mobile phone when I arrived at home). Furthermore,
absent-mindedness is related to automaticity because it is likely to occurr when attention
is not focused on the action that is undertaken and the latter is guided by habits.
BLOCKING occurs when the subject is unable to retrieve an information that he has and
is aware of such difficulty. The most common example is the tip-of-the-tongue state.
Retrieval blocks increase their frequency with aging.
The next three sins involve distorsions and inaccuracy.
MISATTRIBUTION occurs when a memory is attributed to the wrong source. Schacter
(1999) identifies three main types of misattribution:
1) in the first case, people correctly remember an episode of their past but attribute it to
an incorrect source. For example, they may remember that they perceived an event that
was only imagined, or that they met a person in a context instead of another;
2) in the second case, people are unable to perceive a memory as part of their
experience. For example, they think to have imagined a fact without remembering that
they experienced it;
3) in the third case, individuals falsely recall facts that never happened.
SUGGESTIBILITY refers to the tendency to incorporate in the memory of an event
information that was provided by others after the event. A typical example is the
suggestion on eyewitness testimony that derives from having seen Tv programs on the
crime, or having read newspapers article.
Another example are the false confessions that are based on the illusion to rember when
such illusion is induced by suggestive interrogations frome police.
BIAS refers to the distorting influence of present beliefs and information on the
recollection of past events. It has been observed, for example, that individuals tend to
homogeneize past and present beliefs/feelings as if nothing had changed in their way of
thinking and perceiving.
PERSISTENCE involves the intrusive remembering of episodes that we wish to forget.
Typical example are traumatic experiences such as war traumas and rumination over
negative episodes. In the case of persistence, one wishes to decrease the accessibility of
his/her memories without success.
WHY DOES MEMORY FAILS SYSTEMATICALLY?
“As tempting as such views may be, I suggest that it is a mistake to view the seven sins
as flaws in system design that ought to have been corrected during the course of
evolution. Instead, building on the analyses of J. R. Anderson and Bjork and their
colleagues, the seven sins can be usefully viewed as by-products of otherwise adaptive
features of memory” (Schacter 1999, p. 196).
“SAVING HYPOTHESIS”: if memory was not prone to forgetting, it would be
overwhelmed by useless information. The costs of retaining the myriad of contextual
details that define our daily experiences would be an impairement of its healthy
functioning and, in particular, of its ability to support higher cognitive functions.
Let us consider, for example, false recall and recognition.
“False recall and recognition often occur when people remember the semantic or
perceptual gist of an experience but do not recall specific details. However, memory for
gist may also be fundamental to such abilities as categorization and comprehension and
may facilitate the development of transfer and generalization accross tasks”
(Schacter 1999, p. 197).
This argument is very similar to that of “saving” cognitive effort through the creation of an
incomplete, and necessarely biased, representation of the problem.
Another hypothesis has been gaining support that extends this result and provides
further insights:
SIMULATION HYPOTHESIS: the main function of episodic memory is not
reminescensce but future thinking.The use of past experiences to build up future
scenarious requires a flexible system that can easily gain access to the gist of events. To
preserve such flexibility details are gradually eliminated.
“Although the function of the episodic system is typically conceived of as a retrieval of
past events, as demonstrated by the abundance of research on episodic memory, it is
possible that the primary role of this system is not reminescence, but rather, future
thinking (…). According to the constructive episodic simulation hypothesis, some of the
vulnerabilities of episodic memory, such as memory distortions and illusions, may be
attributable to the role of the episodic system in allowing us to mentally simulate our
personal futures by flexibly drawing on elements of the past” (Addis, Wong & Schacter
2006, p.1374-1375).
Why does memory work reconstructively rather than reproductively?
One possible answer addresses the role that memory plays in imagining future episodes,
happenings and scenarios.
“Since the future is not an exact repetition of the past, simulation of future episodes may
require a system that can draw on the past in a manner that flexibility extracts and
recombines elements of previous experiences –a constructive rather than reproductive
system. If this idea has nerit, then there should be considerable overlap in the
psychological and neural processes involved in remembering the past and imagining the
future” (Schacter & Addis 2007, p. 774).
In the last decade, research in cognitive neuroscience has been contributed to the study
of memory by using neuroimagining tecniques.
Coherently with the simulation hypothesis results have shown that (Addis et al. 2007, p.
1364):
- past and future events engage common neural regions;
- amnesic patients have great difficulties imagining their personal futures;
- “in healthy individuals, manipulations that reduced the specificity of past events (e. g.,
instructions or cues which induce a general retrieval style) also reduced the specificity of
subsequently generated future events”.
What are the implications for economics?
How is the approach of economists to time modified by these results?
Can the functioning of memory inform the economic approach to expectations?
MAIN REFERENCES
Addis D. R., Wong A. T. & Schacter D. L. (2006), Remembering the past and
imagining the future: Common and distinct neural substrates during event
construction and elaboration, Neuropsychologia, 45, 1363-1377.
Patalano R. (2007), Mind-Dependence. The Past in the Grip of the Present,
Journal of Bioeconomics, 9, 2, 85-107.
Patalano R. (2009), Imagination and economics at the crossroad. Materials
for a dialogue, History of Economic Ideas, forthcoming.
Rizzello S. (2004). Knowledge as a path-dependence process. Journal of
Bioeconomics, 6, 255â?"274.
Schacter D. L. & Addis D. R. (2007), The cognitive neuroscience of
constructive memory: remembering the past and imagining the future,
Philosophical Transactions of the Royal Society B, 362, 773-786.