Scalar Timing Error and Reward vs. Nonreward

The literature on human and nonhuman animal interval timing error indicates a lack of consensus as to whether interval timing operates through either scalar or through linear systems, and to what extent reward influences timing performance. Two competing computational learning and timing models, Temporal Difference (TD, Schultz, 2013) and Sometimes Competing Retrieval (SOCR, Stout and Miller, 2007) are reviewed within these contexts. The proposed experiment will compare human interval timing accuracy in rewarded and non-rewarded conditions. Towards testing these competing explanations of interval timing, the resultant data will be compared to the predictions of computational models. It is hypothesized that 1) timing error is scalar, not linear, 2) that the SOCR model better fits the data than does the TD model, and 3) that interval timing performance is more accurate in rewarding situations than in non-rewarding situations. Timing trials shall involve the presentation of a reference duration, participants shall then indicate their estimate of that duration while under cognitive load (random number generation task) through key presses on a computer. Should the hypotheses be supported, it is suggested that timing is in fact scalar in nature, and is positively influenced by the presence of reward