ACT-R Workshop Schedule

Opening: ACT-R from CMU’s Perspective9:00 - 9:45 Overview of ACT-R -- John R. Anderson9:45 – 10:30 Details of ACT-R 6.0 -- Dan Bothell

Break: 10:30 – 11:00Presentations 1: Architecture

11:00 – 11:30 Functional constraints on architectural mechanisms -- Christian Lebiere11:30 – 12:00 Retrieval by Accumulating Evidence in ACT-R -- Leendert van Maanen12:00 – 12:30 A mechanism for decisions in the absence of prior reward -- Vladislav D. Veksler

Lunch: 12:30 – 1:30Presentations 2: Extensions

1:30 – 2:00 ACT-R forays into the semantic web -- Lael J. Schooler2:00 – 2:30 Making Models Tired: A Module for Fatigue -- Glenn F. Gunzelmann2:30 – 3:00 Acting outside the box: Truly embodied ACT-R -- Anthony Harrison3:00 - 3:30 Interfacing ACT-R with different types of environments and with different techniques: Issues and Suggestions.-- Michael J. Schoelles

Break: 3:30 – 4:00Panel: 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

Retrieval by Accumulating Evidence in ACT-R

Leendert van Maanen

University of Groningen

leendert@ai.rug.nl

Memory is vital for behavior

Picture-word interference

Picture-word interference

Giraffe

Picture-word interference data

(Glaser & Düngelhoff, 1984)

Giraffe

giraffe

giraffe

0.1

ACT-R model of PWI task

ACT-R model of PWI task

ACT-R model of PWI task

ACT-R model of PWI task

ACT-R model of PWI task

ACT-R model of PWI task

ACT-R model of PWI task

ACT-R model of PWI task

Expected model of PWI task

The ACT-R retrieval process

Giraffe

Sequential Sampling framework

Acc

um

ula

tors

threshold

Sequential Sampling framework

Acc

um

ula

tors

threshold

Giraffe

Sequential Sampling

› Response time = Decision time + Additional processes

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)

The RACE/A retrieval process

The RACE/A retrieval process

The RACE/A retrieval process

Picture-word Interference Model

Van Maanen & Van Rijn, 2007(Glaser & Düngelhoff, 1984)

Giraffe

giraffe

giraffe

0.1

RACE/A Parameters

:race-saliencyexternal activation

:ratio-ratiodecision boundary

:race-adecay rate (complements d)

:race-bspreading activation scaling factor

Baselevel activationSpreading activation (Sji)

RACE/A Parameters

:race-saliencyexternal activation

:ratio-ratiodecision criterion

:race-adecay rate (complements d)

:race-bspreading activation scaling factor

Baselevel activationSpreading activation

:race-saliency

:race-ratio

€

eAi

eAj

j

∑≥ θ

RACE/A Parameters

:race-saliencyexternal activation

:ratio-ratiodecision boundary

:race-adecay rate (complements d)

:race-bspreading activation scaling factor

Baselevel activationSpreading activation

Baselevel activation differences

:race-ratio

:race-ratio

RACE/A Parameters

:race-saliencyexternal activation

:ratio-ratiodecision boundary

:race-adecay rate (complements d)

:race-bspreading activation scaling factor

Baselevel activationSpreading activation (Sji)

Spreading activation differences

:race-ratio

:race-ratio

Giraffe

giraffe

RACE/A Parameters

:race-saliencyexternal activation

:ratio-ratiodecision boundary

:race-adecay rate (complements d)

:race-bspreading activation scaling factor

Baselevel activationSpreading activation

:race-a

:race-ratio

:race-ratio

Sequences of retrievals

› RACE/A: dependencies between declarative retrievals

:race-ratio

Retrieval 1 Retrieval 2 Retrieval 2

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)

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)

More information

› Download module + documentationhttp://www.ai.rug.nl/~leendert/race

› Contact meleendert@ai.rug.nl

› Read my thesis

Thank you for your attention!

Collaborators:

Leendert van Maanen (leendert@ai.rug.nl)

Niels TaatgenHedderik van Rijn

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

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)