Abstract not found

this article are also gratefully acknowledged

Future research on cognitive control must precisely characterize the supervisory functions of executive mental processes. The achievement of this objective will be facilitated by formal concepts and algorithms from contemporary computer operating systems. In particular, operating-system fundamentals can help to advance work with the Executive-Process Interactive Control (EPIC) architecture, a theoretical framework for computational modeling of human multiple-task performance. EPIC models that incorporate general executive processes like those of operating systems provide insights about how people schedule tasks, allocate perceptual-motor resources, and coordinate task processes during multiple-task performance under both laboratory and real-world conditions. Such insights may lead to discoveries about the acquisition of procedural task knowledge and efficient multitasking skills.

When subjects switch between a pair of stimulus–response tasks, reaction time is slower on trial N if a different task was performed on trial N � 1. We present a parallel distributed processing (PDP) model that simulates this effect when subjects switch between word reading and color naming in response to Stroop stimuli. Reaction time on ‘‘switch trials’ ’ can be slowed by an extended response selection process which results from (a) persisting, inappropriate states of activation and inhibition of task-controlling representations; and (b) associative learning, which allows stimuli to evoke tasks sets with which they have recently been associated (as proposed by Allport & Wylie, 2000). The model provides a good fit to a large body of empirical data, including findings which have been seen as problematic for this explanation of switch costs, and shows similar behavior when the parameters are set to random values, supporting Allport and Wylie’s proposal. © 2001 Elsevier Science Key Words: task switching; task set; Stroop effect; parallel distributed processing; executive functions. Atkinson and Shiffrin (1968) proposed a distinction between relatively permanent cognitive structures, such as short- and long-term memory, and control processes which harness those fixed structures in order to attain specific goals. This distinction was elaborated in the following years (e.g.,

Abstract not found

this article. We also thank Rob McCann and Eric Ruthruff for their valuable discussions

Direct manipulation involves a large number of interacting psychological mechanisms that make the performance of a given interface hard to predict on intuitive or informal grounds. This paper applies cognitive modeling to explain the subtle effects produced by using a keypad versus a touchscreen in a performance-critical laboratory task.

The authors assume that individuals adapt rationally to a utility function given constraints imposed by their cognitive architecture and the local task environment. This assumption underlies a new approach to modeling and understanding cognition—cognitively bounded rational analysis—that sharpens the predictive acuity of general, integrated theories of cognition and action. Such theories provide the necessary computational means to explain the flexible nature of human behavior but in doing so introduce extreme degrees of freedom in accounting for data. The new approach narrows the space of predicted behaviors through analysis of the payoff achieved by alternative strategies, rather than through fitting strategies and theoretical parameters to data. It extends and complements established approaches, including computational cognitive architectures, rational analysis, optimal motor control, bounded rationality, and signal detection theory. The authors illustrate the approach with a reanalysis of an existing account of psychological refractory period (PRP) dual-task performance and the development and analysis of a new theory of ordered dual-task responses. These analyses yield several novel results, including a new understanding of the role of strategic variation in existing accounts of PRP and the first predictive, quantitative account showing how the details of ordered dual-task phenomena emerge from the rational control of a cognitive system subject to the combined constraints of internal variance, motor interference, and a response selection bottleneck.

Abstract not found

Language processing is influenced by multiple sources of information. We examined whether the performance in simultaneous interpreting would be improved when providing two sources of information, the auditory speech as well as corresponding lip-movements, in comparison to presenting the auditory speech alone. Although there was an improvement in sentence recognition when presented with visible speech, there was no difference in performance between these two presentation conditions when bilinguals simultaneously interpreted from English to German or from English to Spanish. The reason why visual speech did not contribute to performance could be the presentation of the auditory signal without noise (Massaro, 1998). This hypothesis should be tested in the future. Furthermore, it should be investigated if an effect of visible speech can be found for other contexts, when visual information could provide cues for emotions, prosody, or syntax. In press, Interpreting Biosketch Alexandra Jesse is a doctoral candidate in the cognitive psychology program at the University of California, Santa Cruz. She received her MS (2000) in psychology at the University of California, Santa Cruz and completed her undergraduate studies (1998) in psychology at the PhilippsUniversity in Marburg, Germany. She works as a member in the Perceptual Science Laboratory on bimodal speech perception and written word recognition. She is also interested in investigating and modeling the time-course of language perception processes. Nick Vrignaud received his BA in psychology at the University of California, Santa Cruz in 2001. The third experiment reported here was part of his senior thesis.