Power law model for subjective mental workload and validation through air traffic control human-in-the-loop simulation

Abstract

We provide evidence for a power law relationship between the subjective one-dimensional Instantaneous Self Assessment workload measure (five-level ISA-WL scale) and the radio communication of air traffic controllers (ATCOs) as an objective task load variable. It corresponds to Stevens’ classical psychophysics relationship between physical stimulus and subjective response, with characteristic power law exponent γ of the order of 1. The theoretical model was validated in a human-in-the loop air traffic control simulation experiment with traffic flow as environmental stimulus that correlates positively with ATCOs frequency and duration of radio calls (task load, RC-TL) and their reported ISA-WL. The theoretical predictions together with nonlinear regression-based model parameter estimates expand previously published results that quantified the formal logistic relationship between the subjective ISA measure and simulated air traffic flow (Fürstenau et al. in Theor Issues Ergon Sci 21(6): 684–708, 2020). The present analysis refers to a psychophysics approach to mental workload suggested by (Gopher and Braune in Hum Factors 26(5): 519–532, 1984) that was recently used by (Bachelder and Godfroy-Cooper in Pilot workload esimation: synthesis of spectral requirements analysis and Weber's law, SCL Tech, San Diego, 2019) for pilot workload estimation, with a corresponding power law exponent in the typical range of Stevens’ exponents. Based on the hypothesis of cognitive resource limitation, we derived the power law by combination of the two logistic models for ISA-WL and communication TL characteristics, respectively. Despite large inter-individual variance, the theoretically predicted logistic and power law parameter values exhibit surprisingly close agreement with the regression-based estimates (for averages across participants). Significant differences between logistic ISA-WL and RC-TL scaling parameters and the corresponding Stevens exponents as ratio of these parameters quantify the TL/WL dissociation with regard to traffic flow. The sensitivity with regard to work conditions of the logistic WL-scaling parameter as well as the power law exponent was revealed by traffic scenarios with a non-nominal event: WL sensitivity increased significantly for traffic flow larger than a critical value. Initial analysis of a simultaneously measured new neurophysiological (EEG) load index (dual frequency head maps, DFHM, (Radüntz in Front Physiol 8: 1–15, 2017)) provided evidence for the power law to be applicable to the DFHM load measure as well.

Plithogenic multi‐criteria decision making approach on airspace planning scheme evaluation based on ATC‐flight real‐time simulation

“…Edwards et al utilized a high fidelity realtime en-route air traffic control simulation to investigate the relationship between workload, situation awareness and air traffic control performance [31]. Fürstenau et al studied subjective mental workload through air traffic control real-time simulation [32]. Dulchinos et al evaluated the usability and workload associated with paper strips comparing with new virtual flight strips used for ramp operations, by means of a real-time simulation experiment [33].…”

“…Fürstenau et al. studied subjective mental workload through air traffic control real‐time simulation [32]. Dulchinos et al.…”

“…In summary, real‐time simulation in ATM is a salient topic of research, but most of the existing real‐time simulations were conducted using single ATC simulation software [19, 24, 25, 33] or with simplified pseudo pilot software with low simulation accuracy [21–23, 26, 30–32]. Some critical human factors, especially the pilot workload, can not be truly assessed.…”

Optimal system configuration for integrated air traffic system

“…For example, before the flight is ready to depart, a number of minimum separations must be imposed. 24,25 The departure route considered below is composed by J single sub-segments, which are denoted by index j=1,2,…,J, and each of them is characterized by a finite capacity cj. Obviously, the buffer space corresponding to sub-segment j has capacity cj−1.…”

Logistic resource limitation model for quasi real-time measured subjective cognitive load predicts Hill function of hemoglobin-oxygen saturation

“…The methods used in the three previously published ATC-simulation experiments for testing the predictions of the LRL-model are reviewed briefly in a supplement that also includes tables with preprocessed data for experiments 2 and 3. For experiment 1 the data are available online in [1].…”