Specification of Multiple Processes in Metacontrast Masking

by Tomke Hajo Eike Klaas Trußner
Doctoral thesis
Date of Examination:2023-11-13
Date of issue:2024-09-13
Advisor:Prof. Dr. Uwe Mattler
Referee:Prof. Dr. Uwe Mattler
Referee:Prof. Dr. Annekathrin Schacht
Persistent Address: http://dx.doi.org/10.53846/goediss-10735

 

 

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Abstract

English

Metacontrast masking has been widely used as a tool to study visual perception, but there is still no comprehensive theory of the phenomenon. There is no lack of theories, but a synthesis of the different approaches seems difficult. This may be due to the fact that many theories focus on proposing one parsimonious mechanism for the reducing effect on target visibility observed in this phenomenon. A recently proposed multi-process approach to metacontrast masking presents an alternative. It extends the view to the various properties of the phenomenon and attempts to identify perceptual-cognitive processes that determine reportability and experience of the target stimulus under metacontrast masking. Methodologically, this approach is based on a factor analytic investigation of the qualitative and stable individual differences observed in masking effects. In two studies, this multi-process approach was used to investigate the relationship between the processes involved in metacontrast masking and a related masking paradigm, object substitution masking (OSM), as well as the effects of stereoscopic viewing conditions on the operation of the processes. In a third study, the effects of different display technologies on the metacontrast masking effect were examined, on the one hand to ensure the generalizability of the findings, and on the other hand to investigate possible effects arising from different stimulation properties of the devices. The results of these studies indicate that an integration-related process in metacontrast masking also play a role in overall performance, but not in the masking effect in OSM. Furthermore, all processes are fundamentally located at a central, i.e. cortical level of processing and are insensitive to effects of high-frequency flicker. Based on the current state of this multi-process approach, initial differentiations between existing theories can be made and the approach proves to be a promising way to systematically assess the various properties of metacontrast masking.
Keywords: vision; visual masking; metacontrast masking; object substitution masking; dichoptic viewing; display technology; individual differences
 
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