<html>
<head>
<style>
.sw_message P{margin:0px;padding:0px;}
.sw_message {FONT-SIZE: 12pt;FONT-FAMILY:Tahoma,Arial,Helvetica,sans-serif;background:white;}
.sw_message blockquote{margin-left:5px;padding-left:5px;border-left:2px solid #144fae;color: #144fae;}
.sw_message blockquote blockquote{border-left:2px solid #006312;color: #006312;}
.sw_message blockquote blockquote blockquote{border-left:2px solid #8e5656;color: #8e5656;}
.sw_message blockquote blockquote blockquote blockquote{border-left:2px solid #888;color: #888;}
</style>
</head>
<body class="sw_message">
<p>Hi,<span></span></p><p> </p><p>I have only basic level in ACT-R or similar models of memory functioning. The aspect I am most interested in is the "spreading activation" part of ACT-R. <span></span></p><p><span></span> </p><p>Here is my question. In earlier versions of the model (i.e., ACT*) there was a parameter p to account for the fact that "the total activation emitted by a node is less than its own activation, that is, if a<font size="1">i</font> is the activation of node i, it sends p*a<font size="1">i</font> units of activation to all connected nodes where p<1. Because of this factor, the amount of activation decreases exponentially with distance from source" (Anderson & Pirolli 1974: 794).<span></span></p><p> </p><p>In later versions (i.e., ACT-R), this parameter p had dropped from the equations. What are the (theoretical or empirical) reasons for removing p? Or is the idea behind factor p somehow still accounted for, but in a different form?<span></span></p><p> </p><p>Thanks a lot in advance for your help on this particular point !<span></span></p><p> </p><p>Best regards,<span></span></p><p>Lionel Marquis<br><br><span><span><span><span></span></span></span></span></p><div id="editor_signature"><p>==================================</p><p>Lionel Marquis</p><p>Institut d'Etudes Politiques et Internationales</p><p>University of Lausanne<span></span></p><p>Switzerland</p><p>Bâtiment Géopolis 4779</p><p>Tél: +41 21 692 31 56</p><p>Fax: +41 21 692 31 45</p><p>E-mail: <a href="mailto:Lionel.Marquis@unil.ch">Lionel.Marquis@unil.ch</a></p><p>Web: <a href="http://www.unil.ch/iepi/page14150.html">http://www.unil.ch/iepi/page14150.html</a></p><br><br><br></div><br><br>
</body></html>