When the participants in a visual search experiment have the task to detect if there is an item that belongs to another category among the distractors, or not, they show shorter reaction times (RTs) for fear-relevant target stimuli (snakes and spiders) when compared to fear-irrelevant target stimuli (flowers and mushrooms). This could be concluded to mirror a faster detection of the fear-relevant target stimuli. However, when the participants in this type of visual search task are requested to withhold their responses and respond to a probe presented at a fixed point in time after the search arrays, the difference in RTs between fear-relevant and fear-irrelevant target stimuli still remained. Over time the impact on RTs of fear-relevant distractors became stronger. This indicates a motor response preparation to potential biological threats and that it is building up over time. The notion that effect of distractors occur later in time is supported by a visual search experiment with heart rate measure, and that the shorter RTs to fear-relevant target stimuli are caused by a motor response preparation is supported by the time and location of an ERP component in another experiment. There are indications that the advantage in responding in relation to fear-relevance is caused by the possibility to automatize the responding. When the probe that followed the search arrays was randomized to different positions in time the effect disappeared, and a disadvantage was indicated. Other studies with randomized probe presentations also indicate a disadvantage caused by threat stimuli.