Proceeding in Cognitive Science Autumn 2010 Xuan Zhao Zhejiang University E-mail:...

Proceeding in Cognitive ScienceAutumn 2010

Xuan ZhaoZhejiang University

E-mail: zhaoxuanzju@gmail.com

WHAT

WHY

HOW

Bayesian InferenceBayesian Inference

Flip a coin.

Event: A, B

A: One head at least

B: Both heads or tails

Question:

P(B|A)?

He didn’t say “hi” when passing by.

Compare P(h1|D) and P(h2|D) to reach the most likely assumption.

P(h2|D)=P(h2)*P(D|h2)/P(D)

P(h1|D)=P(h1)*P(D|h1)/P(D)

P(Bi|A) P(Bi) * P(A|Bi) ∝

P(hi|D) P(h∝ i) * P(D|hi)

priori probability

WHAT

WHY

HOW

Bayesian InferenceBayesian Inference

• Complexity• Ambiguity• Duplicity• Insufficiency

One object? Two objects?

What is perceived are essentially those objects and events that under normal conditions would be most likely to produce the received sensory stimulation.

What is perceived are essentially those objects and events that under normal conditions would be most likely to produce the received sensory stimulation.

WHAT

WHY

HOW

Bayesian InferenceBayesian Inference

P(h|D) P(h) * P(D|h) ∝

‘‘Calling some skill or behavior innate tends to stop analysis of how it

develops’’ (Fischer & Stewart, 1999, p. 150).

WRONG!

Ina

Innate assumptions validated by comparative research (Hershberger, 1970)

•Single light source.•Light source above.

Natural Image Parsing

N: non-terminal nods (models)

Evidence from behavioral research

Evidence from neural science• ERP and fMRI (Murray, et al, 2002): Dorsal regions provide input to lateral occipital complex (LOC), where

signatures of illusory contour completion first appear, then followed by activity in V1/V2.

• MEG and fMRI (Bar et al, 2006): Low spatial frequency specific activity appeared in left orbitofrontal

cortex 50 ms earlier than in fusiform gyrus of temporal cortex.

• Bayesian Ideal Observer

• And more…

Vision as Bayesian inference: analysis by synthesis? Alan Yuille and Daniel Kersten, 2006

ReferencesReferences

平凡而又神奇的贝叶斯方法刘未鹏 , 2008

Innateness (and Bayesian) Visual PerceptionBrian Scholl, 2005

Proceeding in Cognitive ScienceAutumn 2010

Xuan ZhaoZhejiang University

E-mail: zhaoxuanzju@gmail.com