Using fMRI to Explain the Effect of Dual-Task Interference on Security Behavior

We examine how security behavior is affected by dual-task interference (DTI), a cognitive limitation in which even simple tasks cannot be simultaneously performed without significant performance loss. We find that security messages that interrupt users actually make users more vulnerable by increasing security message disregard—behaving against the recommended course of action of a security message. We study the previously unexamined effect of DTI on a secondary, interrupting task—a security message. In a security context, it is critical that his interruption be carefully heeded. We use functional magnetic resonance imaging (fMRI) to explore (1) how DTI occurs in the brain in response to interruptive security messages and (2) how DTI influences security message disregard. We show that neural activation in the medial temporal lobe (MTL)—a brain region associated with declarative memory—is substantially reduced under a condition of high DTI, which in turn significantly predicts security message disregard.