One of the most basic assumptions in cognitive psychology is that speeded decision making or """"""""choice reaction time"""""""" (RT) tasks are carried out using a sequence of distinct mental processes or """"""""stages"""""""" like perception, decision, and response execution. Traditionally, the field has attempted to identify and describe such stages, specifying each in terms of its input information, operations performed, and output produced. Recently, many researchers have begun to ask how these stages fit together to perform complex tasks, and how they communicate with one another. Two quite different types of models, commonly referred to as discrete and continuous, have been suggested (e.g., McClelland, 1979; Sternberg, 1969). It is crucial to determine which of these models better describes performance in human information processing tasks. The development of sophisticated models for normal cognitive processes is a prerequisite for understanding cognitive deficits, including those resulting from aging, injury, and disease. At present, such model development is hindered by fundamental uncertainty about whether discrete or continuous models more accurately describe normal cognition. Although both models are compatible with available evidence about human performance, they are fundamentally different in operation, and they prescribe very different strategies for conducting new experiments and interpretating the results. The proposed research will investigate two critical differences between discrete and continuous models. One is that discrete models require stages to operate in a strictly sequential manner. Each stage begins when it receives input, processes until it is finished, and then transmits a single output to the next stage in the processing sequence. Conversely, continuous models allow successive stages to operate at the game time (i.e., with some """"""""temporal overlap""""""""), even when the output of one stage is the input to the next. A stage transmits preliminary partial output to its successor, thereby allowing the later stage to begin before the earlier one is finished. The second critical difference concerns the nature of the outputs transmitted from stage to stage. According to discrete models, outputs are discrete (""""""""all-or-none"""""""") activations of categorical internal representations. According to continuous models, however, stage outputs vary gradually in strength or """"""""activation level"""""""", and possibly in other respects as well. The immediate aims of this research are to develop methods for finding out whether (1) the different stages used in performing choice RT tasks operate in strict sequence, and (2) the output of each stage is all-or-none rather than graded. The proposed methods use convergent measures of response time, response force, and psychophysiological measures derived from EEG activity, and will be used to examine human information processing in a number of scientifically important cognitive tasks, especially those involving attention.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
5R01MH040733-07
Application #
3379072
Study Section
Perception and Cognition Review Committee (PEC)
Project Start
1985-09-01
Project End
1994-08-31
Budget Start
1993-09-01
Budget End
1994-08-31
Support Year
7
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of California San Diego
Department
Type
Schools of Arts and Sciences
DUNS #
077758407
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Kunimoto, C; Miller, J; Pashler, H (2001) Confidence and accuracy of near-threshold discrimination responses. Conscious Cogn 10:294-340
Miller, J; Franz, V; Ulrich, R (1999) Effects of auditory stimulus intensity on response force in simple, go/no-go, and choice RT tasks. Percept Psychophys 61:107-19
Ilan, A B; Miller, J (1998) On the temporal relations between memory scanning and response preparation. J Exp Psychol Hum Percept Perform 24:1501-20
Band, G P; Miller, J (1997) Mental rotation interferes with response preparation. J Exp Psychol Hum Percept Perform 23:319-38
Mordkoff, J T; Miller, J; Roch, A C (1996) Absence of coactivation in the motor component: evidence from psychophysiological measures of target detection. J Exp Psychol Hum Percept Perform 22:25-41
Ruthruff, E; Miller, J (1995) Can mental rotation begin before perception finishes? Mem Cognit 23:408-24
Hackley, S A; Miller, J (1995) Response complexity and precue interval effects on the lateralized readiness potential. Psychophysiology 32:230-41
Ilan, A B; Miller, J (1994) A violation of pure insertion: mental rotation and choice reaction time. J Exp Psychol Hum Percept Perform 20:520-36
Mordkoff, J T; Miller, J (1993) Redundancy gains and coactivation with two different targets: the problem of target preferences and the effects of display frequency. Percept Psychophys 53:527-35
Miller, J (1991) Threshold variability in subliminal perception experiments: fixed threshold estimates reduce power to detect subliminal effects. J Exp Psychol Hum Percept Perform 17:841-51

Showing the most recent 10 out of 26 publications