Refractoriness in information processing

Two experiments on refractoriness were carried out in which the warning, first and second signals, S₀, S₁ and S₂ respectively, were all single-valued, and the distributions of random intervals between S₀ and S₁, and S₁ and S ₂ were the same. In the first experiment the intervals in a trial were statistically independent: the null hypothesis, that the latencies of the two responses would be similar, was rejected, but the results were also found to agree with no existing alternative hypothesis. In the second experiment the intervals in a trial were conditionally related and the second response was found to be faster than in the first experiment. This is discussed in the context of the issue of serial or parallel processing of information.