to pay attention. This is called Simon effect, which refers our innate tendency to respond faster and more accurately when stimuli occur in the same location. This can be explained by neuroscience in terms of neural facilitation and short-term plasticity. However, if the positions of the stimuli are not the same as before, it is no longer easy to attend to the target as it once was. The feature mismatch hypothesis states that inhibition occurs when there is a mismatch between the target and its location. This theory is explains the effects of location specific negative priming but lacks in its justification of negative priming when location is not involved. It deviates from the distractor inhibition model to describe location specific negative priming but has more loop holes than the other models. Temporal discrimination model Temporal discrimination model attempts to blend in both the selective attention and memory retrieval aspects of negative priming in a less complex model. It is based on the assumption that negative priming is caused only at the moment of response to a stimulus that was previously considered distractor. This model explains negative priming as the delayed response due to confusion in classifying a stimulus as old or new. A new stimulus is immediately classified as new and undergoes perceptual processing. A repeated old stimulus is familiar and cues the automatic retrieval of the prior episode. A stimulus that has been repetitively ignored prior to becoming the target is neither entirely new nor old. This ambiguity slows down the processing of the stimuli. The temporal discrimination model points to this ambiguity as the cause of slowed categorization of the stimulus leading to negative priming effect. Like feature mismatch hypothesis, this model also claims that negative priming is not due to selective attention of the target or the inhibition of the distractor. This model argues that "negative priming is an emergent consequence of a discrimination process that is inherent to memory retrieval". Temporal discrimination model explains negative priming without reference to inhibition of distractors or the "do not respond" tag and by simple discrimination of "old", "new" and "in between" categories. Characteristics of negative priming in experiments Experimental terminology Experiments on negative priming consist of two main components: prime and probe. Prime trial tries to mimic real life experiences of distractor stimuli in target selection but with more repetition to get quantifiable negative priming data. It comprises