!
Comparing apples and pears:
The Neurobiology of Value-based Choice
Benedetto De Martino
- The problem of value computation
!
- The neural circuit that allows value
comparison
!
- Can humans introspect into the value
computational process? (metacognition)
!
- Can metacognitive strategies improve
decisions? (possible use in rehabilitation ??)
It is possible to compare
Apples with Pears?
Of course YES !!!!!
Two different types of choice
Perceptual choice
Value-based choice
What is Value?
What is Value?
What is Value?
What is Value?
Where does Value belong in the DM
process?
Different Value systems (sometime in conflict)
Phineas P. Gage
A serious brain damage
Neuroanatomy
ventro-medial prefrontal cortex
(vmPFC)
- Alzheimer's disease
!
- Parkinson’s disease
!
- Schizophrenia
!
- Depression (anhedonia)
Value not perception
perceptual error
>
preference transitivity error
⧽
⧽
⧽
Fellows, L. K., & Farah, M. J. (2007).
Neurons in the orbitofrontal cortex encode
economic value
Neurons in the orbitofrontal cortex encode
economic value
Padoa-Schioppa, C., & Assad, J. (2006) Nature.
OFC Encodes Willingness to Pay in Everyday
Economic Transactions
Plassmann, H.,. (2007) The Journal of neuroscience
OFC Encodes Willingness to Pay in Everyday
Economic Transactions
Chib et al. (2009) The Journal of neuroscience
Social value signals
Hare et al. (2010) The Journal of neuroscience
Value is represented during passive exposure
Leberton et al. (2009) Neuron
Are value signals stable?
Plassmann, H.(2008). Marketing actions can modulate neural
representations of experienced pleasantness. PNAS
Social interactions during financial markets
can shape value representation
De Martino et al. (2013) Neuron
Do you know what do you want?
(can we introspect values?)
Metacognition
“I am thinking
about my thinking”
Implicit-explicit relationship
(metacognition )
Subjective confidence
Self-knowledge
μ
P(r)
θ
Decision-making
σ
V(r)
ξ
Task
Predicting choice
Value Confidence Dissocia0on
Confidence
Value in vmPFC
group R2 = 17.7%
|Difference in value|
(De Martino et al Nature Neuroscience 2013)
(De Martino et al Nature Neuroscience 2013)
Threshold
100
Evidence
∆e, confidence
50
Right Item
Left Item
0
0
40
80
Time
120
Vickers (1970) ; Kepecs et al. (2008)
0
DV
(De Martino et al Nature Neuroscience 2013)
Model
Data
(De Martino et al Nature Neuroscience 2013)
Confidence emerges during
the construction of value in vmPFC
Metacognitive access
Value
Confidence
“Metacognitive access”
1
P(Chose Right item)
low confidence
high confidence
all data
PPI
0.5
y = 47
t value
2.8
0
−2
−1
0
Value Right item − Value Left item
1
2
3.2
3.6
Suboptimal choice and metacognition
Peter Bossaerts
Steve Fleming
Deb Ray
John O’Doherty
Ray Dolan
Colin Camerer
Neil Garrett