Tuesday, December 25, 2012

Performance Based Navigation through Psychoeconomic Lens: Part II - the socioeconomic and organizational economic perspective

An overabundance of  visual stimuli can overwhelm the ATCO 
The previous post highlighted the psychological perspective of Performance Based Navigation (PBN): that PBN increases the risk of interference to the ATCO's attention. 
Much of our ATC is done with the superficial layers of memory: sensory memory -  short term memory (STM) - working memory which, is susceptible to interference that decrease attentiveness. What is the basis for the link between attention and our STM/working memory combined? Also what can a mosaic of Van Gogh's painting teach us about the socioeconomic cost of PBN to the controller? And are there any organizational economic implications to PBN? I invite you to read on...

Evidence from a neuropsychological study verifies that PBN can have a negative feedback effect upon an ATCO's attentiveness. 
A study done by Rizzolatti et al (1987) showed that divided attention as well as reorienting attention resulted in delayed responses. In the experiment, the subjects sat in front of a cue box and were required to quickly press a key with their right index finger, each time they detected a numeric signal. The time taken to respond as well as the eye movements to detect the signals were monitored. The subjects did 1600 trials over a period of 4 days. They were 8 healthy, right-handed, university males, with normal or corrected vision and who were ignorant of the exercise. 
Rizzolati incorporated geometric symbols as cues to some of the numeric signals.  The subjects took more time to press the key when they received numeric signals unexpectedly or without the geometric cues. Dividing attention by increasing the frequency of the numeric signals and widening the visual periphery or zone of vision in which the signals and the cues appeared, increased the response time.  
Rizzolatti also observed that the time taken to reorient attention increased.  Subjects took more time to respond to an expected signal that followed an unexpected signal or a numeric signal that appeared without the geometric cue.
This experiment highlights that while beneficial to ATM (Air Traffic Management), PBN does present with concerns of safety operation and it may not be universally advantageous to all ATC units. For it can induce a negative feedback effect in the operational scenario.
ATC involves the use of extensive hand-eye  coordination
With PBN, the ATCO will be able to accomodate more aircraft per unit airspace. This means that visual stimuli will increase, that is to say that the controller will be able to have more aircraft blips in the visual periphery. In turn, this will cause an increase in divided attention and evidently, the response time. The mosaic of Van Gogh's painting was employed to have the reader experience the overwhelming effect of many visual stimuli. (See second item, left side bar)
Similarly, accomodating more blips per unit airspace will 'overwhelm' or interefere with the ATCO's attention and can be a source of distraction thereby inducing a negative feedback effect. 
More time to process the stimuli delays the response that the ATCO should give. Delayed or increased response time will impact negatively upon situational awareness. 
Clinical aspects of psychology reveal that the same region of the brain - the prefrontal cortex, is responsible for visual attention and concentration which, requires sustained attention or alertness (http://www.kmpt.nhs.uk). Undoubtedly, fatigue and poor ATCO wellbeing will be of crucial  importance since these factors also reduce situational awareness or alertness. 

Visual stimuli, attention, situational awareness  and alertness  are co-located in the same region  of the brain
According to the ICAO manual of PBN (2008), the concept will allow ATCOS to utilize their airspaces more efficiently. Based on the foundations of GNSS and aircraft performance, ATCOs will operate separation methods based more on waypoints rather than on bearings from navigational aids. Thus a controller will be able to handle more aircraft per unit of airspace but in the face of increased risk of interferences to attention. There will be less delays overall, due to the process of ATC as PBN simplifies the operational procedure and will therefore facilitate Air Traffic Management (ATM). 
The recurring question that is worthy of our consideration concerns whether PBN is feasible for every ATC unit. 
Because of the dynamic nature of ATC, PBN is best implemented as a transitory process. Every substage of this process is costly. This implies that the cumulative transaction costs will be magnanimous. What are some factors that ATC units should consider throughout the formulation and implementation process of PBN? I invite you to read on in Parts III and IV...

PBN presents with socioeconomic and organizational transaction  costs.  

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