EEG responses to camouflage objects

Many animals rely on visual camouflage to avoid detection and increase
their chances of survival. Edge disruption is commonly seen in the natural
world, with animals evolving high-contrast markings that are incongruent
with their real body outline to avoid recognition. Whilst many studies
have investigated how camouflage properties influence viewer performance
and eye movement in predation search tasks, researchers in the field have
yet to consider how camouflage may directly modulate visual attention and
object processing. To examine how disruptive colouration modulates
attention, we use a visual object recognition model to quantify object
saliency. We determine if object saliency is predictive of human
behavioural performance and subjective certainty, as well as neural
signatures of attention and decision-making. We show that increasing edge
disruption not only reduces detection and identification performance but
is also associated with a dampening of neurophysiological signatures of
attentional filtering. Increased self-reported certainty regarding
decisions corresponds with neurophysiological signatures of evidence
accumulation and decision-making. In summary, we have demonstrated a
potential mechanism by which edge disruption increases the evolutionary
fitness of the animals by reducing the brain’s ability to distinguish
signal from noise and, hence, to detect and identify the camouflaged
animal.