1. ACT-R Workshop Schedule Opening: ACT-R from CMU ’ s Perspective 9:00 - 9:45 Overview of ACT-R -- John R. Anderson 9:45 – 10:30 Details of ACT-R 6.0 -- Dan Bothell Break: 10:30 – 11:00 Presentations 1: Architecture 11:00 – 11:30 Functional constraints on architectural mechanisms -- Christian Lebiere 11:30 – 12:00 Retrieval by Accumulating Evidence in ACT-R -- Leendert van Maanen 12:00 – 12:30 A mechanism for decisions in the absence of prior reward -- Vladislav D. Veksler Lunch: 12:30 – 1:30 Presentations 2: Extensions 1:30 – 2:00 ACT-R forays into the semantic web -- Lael J. Schooler 2:00 – 2:30 Making Models Tired: A Module for Fatigue -- Glenn F. Gunzelmann 2:30 – 3:00 Acting outside the box: Truly embodied ACT-R -- Anthony Harrison 3:00 - 3:30 Interfacing ACT-R with different types of environments and with different techniques: Issues and Suggestions.-- Michael J. Schoelles Break: 3:30 – 4:00 Panel: 4:00 – 5:30: Future of ACT-R from a non-CMU Perspective Danilo Fum, Kevin A. Gluck, Wayne D. Gray, Niels A. Taatgen, J. Gregory Trafton, Richard M. Young

2. Retrieval by Accumulating Evidence in ACT-R Leendert van Maanen University of Groningen leendert@ai.rug.nl

3. Memory is vital for behavior

4. Picture-word interference

5. Giraffe

6. Picture-word interference data (Glaser & Düngelhoff, 1984) Giraffe giraffe 0.1

7. ACT-R model of PWI task

15. Expected model of PWI task

16. The ACT-R retrieval process Giraffe

17. Sequential Sampling framework Accumulators threshold 

18. Sequential Sampling framework Accumulators threshold  Giraffe

19. Sequential Sampling ›Response time = Decision time + Additional processes

20. RACE/A ›Retrieval by accumulating evidence ›Accumulates activation ›Until a decision criterion ›Integration of cognitive architecture and sequential sampling model Both the control structure of ACT-R And the level of detail from sequential sampling models (specifically, Leaky Competitive Accumulator, Usher & McClelland, 2001)

21. The RACE/A retrieval process

24. Picture-word Interference Model Van Maanen & Van Rijn, 2007 (Glaser & Düngelhoff, 1984) Giraffe giraffe 0.1

25. RACE/A Parameters :race-saliency external activation :ratio-ratio decision boundary :race-a decay rate (complements d) :race-b spreading activation scaling factor Baselevel activation Spreading activation (Sji)

26. RACE/A Parameters :race-saliency external activation :ratio-ratio decision criterion :race-a decay rate (complements d) :race-b spreading activation scaling factor Baselevel activation Spreading activation

27. :race-saliency :race-ratio

28. RACE/A Parameters :race-saliency external activation :ratio-ratio decision boundary :race-a decay rate (complements d) :race-b spreading activation scaling factor Baselevel activation Spreading activation

29. Baselevel activation differences :race-ratio

30. RACE/A Parameters :race-saliency external activation :ratio-ratio decision boundary :race-a decay rate (complements d) :race-b spreading activation scaling factor Baselevel activation Spreading activation (Sji)

31. Spreading activation differences :race-ratio Giraffe giraffe

32. RACE/A Parameters :race-saliency external activation :ratio-ratio decision boundary :race-a decay rate (complements d) :race-b spreading activation scaling factor Baselevel activation Spreading activation

33. :race-a :race-ratio

34. Sequences of retrievals ›RACE/A: dependencies between declarative retrievals :race-ratio Retrieval 1Retrieval 2

35. RACE/A may be useful for ›Models of competitive processes Stroop task / Picture-word interference (Van Maanen & Van Rijn, 2008) Classification Absolute identification ›Models of sequences of retrievals Language production/interpretation (Diagnostic) reasoning Psychological refractory period (Van Maanen et al, in press, PB&R)

36. Summary RACE/A ›Integration of cognitive architecture and sequential sampling model ACT-R Leaky Competitive Accumulator ( Usher & McClelland, 2001 ) ›Meant to explain Competitive processes in memory retrieval Sequential processes in memory retrieval ›Especially useful in complex tasks For example: PWI-PRP (eg. ICCM talk)

37. More information ›Download module + documentation http://www.ai.rug.nl/~leendert/race ›Contact me leendert@ai.rug.nl ›Read my thesis

38. Thank you for your attention! Collaborators: Leendert van Maanen (leendert@ai.rug.nl) Niels Taatgen Hedderik van Rijn

39. Multilink priming ›Mediated priming effects found (Becker, Moscovitch, Behrmann, & Joordens, 1997; Joordens & Besner, 1992) Bull primes milk (via cow) Evidence for spreading activation over multiple connections

40. Activation in ACT-R and RACE/A ›Activation in ACT-R: based on rational analysis Neural implementation (ACTR/NN) Neural interpretation (Anderson, 2007) Shows that ACT-Rs latency equation make similar predictions as accumulator models (in the one-chunk case!) ›Activation in RACE/A: based on neurally inspired accumulator models the RACE/A decision process is an estimate of the optimal (=rational) decision time (MSPRT, McMillen & Holmes, 2006 )