Τρίτη, 9 Οκτωβρίου 2007

ΠΟΙΟΥΣ ΕΙΧΑΝ ΣΤΟ ΜΥΑΛΟ ΤΟΥΣ ΟΙ ΕΡΕΥΝΗΤΕΣ?

Getting to Know You: Reputation
and Trust in a Two-Person
Economic (or Political) Exchange
(Casas, Tomlin, Anen, Camerer, Quartz, Montague)

(SCIENCE VOL 308 1 APRIL 2005)

The expression and repayment of trust is an
important social signaling mechanism that
influences competitive and cooperative behavior
The idea of trust typically conjures
images of complex human relationships, so it
would seem to be a difficult part of social
cognition to probe rigorously in a scientific
experiment. Nevertheless, instances of trust can
be stripped of complicating contextual features
and encoded into economic exchange games
that preserve its essential features . For
example, in a game in which two players send
money back and forth with risk, trust is operationalized
as the amount of money a sender
gives to a receiver without external enforcement
Such trust games now enjoy widespread
use both in experimental economics and
neuroscience experiments .
To measure neural correlates of trust using
functionalmagnetic resonance imaging (fMRI),
we first made a simple modification to a singleexchange
trust game in order to improve the
ecological validity of the task (10). Specifically,
we changed the single-round format to a multiround
format in which the same two individuals
(one designated the Binvestor,[ and
the other the Btrustee[) played 10 consecutive
rounds. This modification reflects the fact that
significant social exchanges are rarely singleshot,
and the assumption that algorithms in
our brains are tuned to this fact Thus,
by adapting the multiround format, (i) trust
becomes bidirectional, in that both the investor
and trustee assume the risk that money
sent might not be reciprocated by their partner;
and (ii) reputation building can be probed,
as players develop models of one another
through iterated exchange Participants
were informed that individual rounds of
the trust game would be implemented as follows:
One player (investor) could invest any
portion of $20 with the other player (trustee),
the money appreciated (three times the investment),
and the trustee then decided how much
of the tripled amount to repay
Players maintained their roles throughout the
entire 10-round game. Responses were encoded
only in monetary units and player identities
were never revealed, thus stripping away many
of the confounding elements of context and
communication known to influence trust
Volunteers were recruited from separate subject
pools at Baylor College of Medicine in Houston, TX, and California Institute of Technology
in Pasadena, CA. Volunteers were instructed
identically, but separately, at each
institution (instructors read a script describing
the task).
We used event-related hyperscan-fMRI (hfMRI)
to monitor homologous regions of two
subjects_ brains simultaneously as they played
the multiround trust game
The motivating idea behind this approach is simple:
To probe neural substrates of social interactions,
we scan the brains of multiple subjects engaged
in a social interaction. Social decision-making
critically depends on internally representedmodels
of social partners. In principle, such covert
knowledge might be inferred from behavioral
observations. However, behavioral signals are
intrinsically lower dimensional than their underlying
neural responses, and so behavior alone is
an insufficient signal source for inferring neural
representations. Put another way, an inference
based only on the observable behavior of a social
partner ignores many observable neural
processes that give rise to that behavior. The
measurement of both interacting brains directly
sidesteps this problem and allows us to probe the
cross correlation of internal models—replacing
inference with a measurement.
by adapting the multiround format, (i) trust
becomes bidirectional, in that both the investor
and trustee assume the risk that money
sent might not be reciprocated by their partner;
and (ii) reputation building can be probed,
cross correlation of internal models—replacing
inference with a measurement.

6 σχόλια:

vagnes είπε...

Φιλε elias
τα αγγλικα μου δεν ειναι πολυ καλα και δυσκολευομαι να βγαλω το νοημα.
Σ' ευχαριστω παντως για την προσκληση.

ΚΑΠΙΤΑΛΙΣΤΙΚΟ ΚΟΥΜΜΟΥΝΙ είπε...

ναι θα ήταν καλή μια σύντομη παρουσίαση στα ελληνικά

Γιωργος Σακελλιων είπε...

Εν όψει της επικείμενης Εθνικής Συνδιάσκεψης του ΠΑΣΟΚ και της εκλογής Προέδρου, καταθέτω σήμερα ένα κείμενο με 39 βασικά σημεία και σκέψεις σχετικά με το ΠΑΣΟΚ και το μέλλον του.

Σκοπός του κειμένου είναι να εμπλουτιστεί από τα σχόλιά σας και στη συνέχεια, με την έκφραση της υποστήριξης όσων από τους αναγνώστες του το επιθυμούν, να κατατεθεί ως κείμενο - τοποθέτηση των υπογραφόντων, στην Εθνική Συνδιάσκεψη του ΠΑΣΟΚ. Διαβάστε το στο blog μου.

ΚΑΠΙΤΑΛΙΣΤΙΚΟ ΚΟΥΜΜΟΥΝΙ είπε...

ti moy ekanes ellias, xanapiasa lexiko..
einai kalo to keimeno.

Blogger είπε...

Hey Ya'll,

I've created a list of the most recommended FOREX brokers:
1. Best Forex Broker
2. eToro - $50 minimum deposit.

Here is a list of the best forex tools:
1. ForexTrendy - Recommended Probability Software.
2. EA Builder - Custom Strategies Autotrading.
3. Fast FX Profit - Secret Forex Strategy.

Hopefully these lists are benificial to you.

Blogger είπε...

I have just installed iStripper, and now I enjoy having the best virtual strippers on my taskbar.