The impact of warning cues on detection decisions in continuous monitoring situations

In many real world situations, sensory events of interest might appear at any moment and require us to act. Perceptual decisions like these, especially when stimuli are ambiguous or noisy, are thought to be facilitated by the accumulation of perceptual evidence over time until reaching a decision bound - a criterion amount of evidence. Temporal uncertainty requires a fine balance between accumulating evidence for better accuracy while avoiding false-alarms based on noise alone, as well as accounting for the cost of continuously maintaining a state of readiness. The decision-maker can, however, use cues in the environment to make top-down dynamic adjustments of the decision-making process. Previous research has shown that cues can have multiple modulatory effects spanning the sensorimotor pathway, but how such effects translate to computational adjustments in the decision-making process remains unknown Here, we examine the effect of external auditory warning cues, while participants indicated the direction (left/right) of intermittent 1.4-second periods of coherent motion targets within otherwise incoherent, continuously moving dots. Behavioural modelling showed that participants respond to the cue by quickly lowering their decision bound, which is supported by a shifting of electroencephalogram signatures of motor preparation (β power) towards an action-triggering bound as response to the warning cue. However, this is unlikely to be the only adjustment. We further explore additional adjustments looking at neural signatures tracing 1) basic sensory encoding of evidence strength (steady state visual motion evoked potentials; SSMEPs), and 2) evidence accumulation (centro-parietal positivity; CPP). In ongoing work, these signals allow us to map out the multiple effects of the cue on the decision-making processes, using neurally-informed modelling.