Some YouTube movies:

1. Some YouTube movies: • The Neocognitron Part I: • http://www.youtube.com/watch?v=Qil4kmvm2Sw • The Neocognitron Part II: • http://www.youtube.com/watch?v=oVYCjL54qoY • Automatic license plate recognition: • http://www.youtube.com/watch?v=3GJWvsUIiyk • Evolution of neural network robotic controllers: • http://www.youtube.com/watch?v=lmPJeKRs8gE Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

2. Review of Neural Network Facts • In biological systems, neurons of similar functionality are usually organized in separate areas (or layers). • Often, there is a hierarchy of interconnected layers with the lowest layer receiving sensory input and neurons in higher layers computing more complex functions. • For example, neurons in macaque visual cortex have been identified that are activated only when there is a face (monkey, human, or drawing) in the macaque’s visual field. Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

3. “Data Flow Diagram” of Visual Areas in Macaque Brain Blue:motion perception pathway Green:object recognition pathway Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

4. Receptive Fields in Hierarchical Neural Networks neuron A receptive field of A Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

5. Receptive Fields in Hierarchical Neural Networks receptive field of A in input layer neuron A in top layer Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

6. Visual Attention • The attentional cueing task introduced by Michael Posner gives insight into the dynamics of visual attention. • Subjects are instructed to fixate on the central cross. • One of the two boxes flashes to capture the subject’s attention (an automatic, involuntary response). • After some a short delay (stimulus onset asynchrony - SOA) an asterisk appears in one of the boxes. • The subject has to report as quickly as possible in which box the asterisk appeared. Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

7. The Posner Attention Task x Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

8. The Posner Attention Task x Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

9. The Posner Attention Task x Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

10. The Posner Attention Task • * x Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

11. The Posner Attention Task x Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

12. The Posner Attention Task • For short SOAs (< 200 ms), subjects respond faster if flash and asterisk appear on the same side. • Cueing of attention to relevant location allows faster response. • For longer SOAs, subjects respond more slowly if flash and asterisk appear on the same side. • Inhibition-of-Return mechanism makes attention less likely to remain on the side of the flash until the asterisk appears. Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

13. The Fröhlich Effect • The Fröhlich effect is a localization error that occurs when observers are asked to indicate the initial position of a fast moving stimulus. • Compared to the actual starting location, the perceived starting location is shifted in the direction of motion. • This perceptual illusion was named after Friedrich Fröhlich, a German physiologist who discovered the phenomenon more than 80 years ago. Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

14. The Fröhlich Effect • Today the most widely accepted explanation of this effect is given by the “Asynchronous Updating Model” (Scharlau & Neumann, 2003). • This model states that the stimulus onset triggers an attention shift towards its location. • During the shift the stimulus changes its location, and because the conscious perception depends on the stimulus being attended, a later position is consciously perceived as being the first position. Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

15. The Fröhlich Effect • We tried to build a quantitative, neural model of the relevant parts of the visual system to explain this effect. • This model includes a vision hierarchy (simple features and small receptive fields in lower layers, complex features and large receptive fields in higher layers). • In this hierarchy, processing of visual input is done in bottom-up direction, and attentional modulation (selective enhancement of processing) works in a top-down fashion. Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

16. The Fröhlich Effect Model Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

17. The Fröhlich Effect - Results Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

18. The Fröhlich Effect - Results Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes

19. The Fröhlich Effect - Results Introduction to Cognitive Science Lecture 22: Neural Models of Mental Processes