Investigating Redundant Encoding Methods for Tactile Messaging in Multitask Scenarios

Abstract

In domains characterized by high demand for visual resources of human operators, multitasking performance may be supported when some task-relevant data are communicated via nonvisual channels, such as the sense of touch. Previous research has shown that humans can interpret moderately complex tactile messages and gain performance benefits when when tactile displays are introduced in multitasking domains. The benefits are assumed to stem from a reduced competition for visual resources; however, multitasking performance can also be affected by competition for cognitive processing resources, such as spatial or symbolic working memory. Thus when selecting tactile signal dimensions for encoding messages (e.g., in spatial or temporal patterns), multitasking can be best supported when the cognitive processing demands of concurrent tasks are considered. This study sought to investigate tactile messages that were encoded redundantly and thus could be fully interpreted by engaging either spatial or symbolic processing resources. These messages should better support performance overall as the cognitive resources required for a concurrent visual task varied. Results showed that as expected, dual-task performance was worse when tactile and visual tasks required the same processing code. Redundantly encoded tactile signals showed some promise for offering a means to reduce processing interference but may also negatively affect performance due to a higher overall processing load due to signal complexity.