Traditionally, studies of delayed matching-to-sample (DMTS) tasks in nonhuman species have focused on the assessment of the limits of the retrieval of information stored in short-and longterm memory systems. However, it is still unclear if visual recognition in these tasks is affected by very brief delay intervals, which are typically used to study rapidly decaying types of visual memory. This study aimed at evaluating if tufted capuchin monkeys' ability to recognise visual stimuli in a DMTS task is affected by (i) the disappearance of the sample stimulus and (ii) the introduction of delay intervals (0.5, 1.0, 2.0 and 3.0 seconds) between the disappearance of the sample and the presentation of the comparison stimuli. The results demonstrated that the simple disappearance of the sample and the introduction of a delay of 0.5 seconds did not affect capuchins' performance either in terms of accuracy or response time. A delay interval of 1.0 second produced a significant increase in response time but still did not affect recognition accuracy. By contrast, delays of 2.0 and 3.0 seconds determined a significant increase in response time and a reduction in recognition accuracy. These findings indicate the existence in capuchin monkeys of processes enabling a very accurate retention of stimulus features within time frames comparable to those reported for humans' sensory memory (0.5-1.0 seconds). The extent to which such processes can be considered analogous to the sensory memory processes observed in human visual cognition is discussed. We examine capuchin monkeys' ability to match visual stimuli after brief delays. 0.5 sec intervals do not affect either response accuracy or response time.  1.0 sec intervals do not affect response accuracy but increase response time. 2.0 and 3.0 sec intervals decrease response accuracy and increase response time. Effects consistent with those ascribed to iconic memory in humans. Research Highlights Responses to the ReviewerWe were extremely pleased that the reviewer was satisfied with the vast majority of our revisions and that s/he felt that we had been very responsive and addressed most of her/his concerns. We are also pleased to read that the reviewer felt that all her/his specific comments have been addressed.We have now further revised the article in several places (P 4 lines 46-48; P 6 lines 53-59; P 7 lines 1-3; P 13 lines 44-49; P 14 lines 1-7; P 18 lines 48-54; P 18 line 56 -P 19 line 1) in order to make it absolutely clear that we make no claims regarding the high-capacity of the memory system that we have observed in capuchin monkeys so that, in that respect it could be considered analogous to human iconic memory. All our claims are based on analyses of the effects of time delay which, because they suggest a discontinuous function of the delays, can be considered indicative of separate memory processes at early stages of the encoding of visual information in monkeys.As suggested by the reviewer we now present effect sizes for paired t tests and 95% confidence in...

Acknowledgements 21We thank two anonymous reviewers for their thoughtful suggestions and constructive comments on 22 the manuscript. We are also grateful to Tyrone Lucon Xiccato for his helpful statistical suggestions.