When people must identify two visual stimuli in quick succession, accuracy for the second stimulus is poor if it occurs within 200 to 500 ms of the first.
[6][7] The precise adaptive significance behind the attentional blink is unknown, but it is thought to be a product of a two-stage visual processing system attempting to allocate episodic context to targets.
Targets presented very close together in time with no intervening distractors (at "lag 1" or consecutively in the RSVP stream) are not affected by the attentional blink, even though items presented at greater lags with intervening distractors are significantly impaired.
[9] Lag-1 sparing can be explained by theories in which attentional engagement with the stream is suppressed upon detection of a non-target stimulus.
Eventually the neurons in the locus coeruleus enter a refractory period, due to the auto-inhibitory effect of norepinephrine.
According to the hypothesis, targets presented during this refractory period cannot trigger a release of norepinephrine, resulting in the attentional blink.
When the second target (T2) in an RSVP stream is an emotionally relevant stimulus it is more likely to be perceived during the period during which the AB typically occurs.
It is suggested that anything increasing the difficulty of processing of the first target will result in a greater attentional blink.