Performance of 40 participants in a simple lexical decision task was simulated.

1. IFARM: A Model of Intention Formation and Retrieval SeldaEren-KanatGene A. Brewer B. Hunter Ball Arizona State University Representational Structure Abstract Simulations This study is a preliminary implementation of the Intention Formation and Retrieval Model (IFARM). The IFARM incorporates theorizing from episodic memory, cognitive control, and prospective memory literatures to provide a mechanistic account for the role of context in encoding and retrieving intentions for delayed behavior. In this computational implementation of IFARM, a set of contextual elements is presented at each time point, triggering a chain of encoding events in the representational system. During retrieval, bottom-up and top-down activations determine controlled and automatic processing of intentions. A simulation of IFARM was performed and simulation results were compared with the performance of human participants in a prospective memory task where encoding conditions were manipulated. Simulated participants displayed the same contextual association effect observed in human participants. • Performance of 40 participants in a simple lexical decision task was simulated. • Association condition • prospective memory intentions and task intentions were included in the same contextual stimulus given to the model during the encoding phase • simulates the condition when intentions and task instructions are explained together • No-association condition • prospective memory intentions and task intentions were presented in separate contextual stimuli • simulates the condition when they are presented at different time points, decreasing the connection between them Results Specifications of IFARM Cognitive Processes • IFARM is a hierarchical associative network model of prospective memory combining distributed and localized representational systems • distributed - features that form an item are represented in different regions according to their modalities • localist - bindings of these features that represent an item are encoded by single units • hierarchical – simultaneously activated features bind into units that represent an item • Episodic representations are at the top of the hierarchy. They represent bindings of high-level representations of • environmental context, e.g. objects, people • internal context, e.g. emotions Prospective Memory Performance Encoding Presentation of an intention activates semantic and action representations in memory An association between semantic features and action features is built, to form intention representations An association between the intention representation and other contextual elements is built, to form episodic representations Retrieval – Bottom Up Activation Simulated performance in association condition was better than in the no association condition, F(1, 38) = 18.12, p<.001, ηp2 = 0.32 This pattern resembled human performance where association conditions are better than no association conditions Presentation of a new context activates semantic representations If semantic representations have connections to intention representations, intention representations will be activated Intention representations will activate related actions Assumptions Episodic memories are feature-basedrepresentations Context drifts through time and can be bound to episodic representations Cognitive control can be exerted on contextual drift Intentions are presented as cue-action pairs Encoding and retrieval are separate processes Discussion By modeling the effect of contextual associations built during encoding, the IFARM could simulate differential cue detection performance observed in human participants Interaction of bottom-up and top-down activatios predicts many prospective memory phenomena, such as intention superiority effect, which will be tested at the next stage of the study Retrieval – Top Down Activation If contextual elements match with a previous context, the episodic representation will be activated Episodic representation will activate all the elements connected to it, including intention representations References Brewer, G. A., & Marsh, R. L. (2010). On the role of episodic future simulation in encoding of prospective memories. Cognitive Neuroscience, 1(2), 81-88.