Cognitive slowing in decision tasks in early and advanced Parkinson's disease.

Ten untreated patients with recently diagnosed Parkinson's disease (PD), 9 treated patients with more advanced pathology, and 17 matched normal controls were investigated with three reaction tasks with increasing cognitive load but identical motor requirements: simple reaction, choice reaction with indicative stimuli, and choice reaction with ambiguous stimuli. Times required until a home key was released (= reaction time) and from then until a response key was pressed (= movement time) were recorded. Estimates of pure decision time (overall response time minus movement time in a simple reaction time task) revealed a difference between advanced and early PD patients. Advanced PD patients showed an overall slowing of decision time in the reaction time tasks, but the effect of the cognitive load of the tasks on the decision time was comparable to a control group. The untreated early PD patients performed quite normally in the more simple decision tasks but showed a disproportionate slowing of decision time in tasks with higher cognitive load.     

Reply to Krellenstein on Parallel Computation

I recently argued that the position in the philosophy of mind called functionalism is undermined by the importance of recent work on parallel computation (Thagard, 1986). In reply, Krellenstein (1987) contends that parallelism does not have the philosophical significance I claimed for it. Although his contentions are plausible if one focuses on what is in principle computationally possible, they fail if one looks at real problems.     

A Cylindrical Model of Communication Behavior in Crisis Negotiations

This article integrates existing theoretical perspectives on message content and negotiator motivation to formulate a comprehensive definitional model of the interrelationships among communication behaviors in crisis negotiation. A sample of 189 nuclear dialogue spans were transcribed from 9 resolved cases of hostage negotiation and each utterance coded at the level of thought units across 41 behavioral variables. Results of a nonmetric, multidimensional scaling solution provided clear support for the hypothesized cylindrical structure of communication behavior, revealing 3 dominant levels of suspect‐negotiator interaction (Avoidance, Distributive, Integrative). At each level of the structure, interactions were found to modulate around 3 thematic styles of communication (Identity, Instrumental, Relational), which reflected the underlying motivational emphasis of individuals' dialogue. Finally, the intensity of communication was found to play a polarizing role in the cylinder, with intense, functionally discrete behaviors occurring toward the boundary of the structure.