The brief gap after attention finds a target
In a rapid stream of letters, recognizing one target takes more than seeing it. The brain must identify what appeared and keep that information available long enough to report it. For a short time, that work makes it harder to register another target. Psychologists call this effect the attentional blink.
The name can be misleading: your eyes do not have to blink, and the second letter need not be faint or hidden. The bottleneck is in processing, not eyesight. A second target that appears while the first is still being consolidated—a process of stabilizing it in memory—may never make it into conscious report.
Why the second target slips through
Think of attention as a narrow channel rather than a camera that records everything equally. When the first target arrives, the mind prioritizes it over the surrounding letters. If another target follows almost immediately, it competes for the same limited processing resources. By the time attention is ready to handle it, the fast stream has moved on.
This helps explain why people can miss something they were actively watching for. Attention is not simply switched on or off; it is temporarily occupied by the task of making sense of what it has just selected. The missed target may have reached the eyes, yet failed to become a memory the viewer can confidently report.
A limitation with practical consequences
The effect is easiest to demonstrate with brief, tightly timed sequences, so it should not be treated as proof that people routinely miss every quick second event in everyday life. But it reveals a useful distinction: seeing a scene and consciously registering each important detail are not the same thing. In any fast sequence, the first noticed event can briefly make the next one harder to catch.
