Attention and the Speed of Information Processing: Posterior Entry for Unattended Stimuli Instead of Prior Entry for Attended Stimuli

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Why are nearly simultaneous stimuli frequently perceived in reversed order? The origin of errors in temporal judgments is a question older than experimental psychology itself. One of the earliest suspects is attention. According to the concept of prior entry, attention accelerates attended stimuli; thus they have “prior entry” to perceptive processing stages, including consciousness. Although latency advantages for attended stimuli have been revealed in psychophysical studies many times, these measures (e.g. temporal order judgments, simultaneity judgments) cannot test the prior-entry hypothesis completely. Since they assess latency differences between an attended and an unattended stimulus, they cannot distinguish between faster processing of attended stimuli and slower processing of unattended stimuli. Therefore, we present a novel paradigm providing separate estimates for processing advantages respectively disadvantages of attended and unattended stimuli. We found that deceleration of unattended stimuli contributes more strongly to the prior-entry illusion than acceleration of attended stimuli. Thus, in the temporal domain, attention fulfills its selective function primarily by deceleration of unattended stimuli. That means it is actually posterior entry, not prior entry which accounts for the largest part of the effect.
Original languageEnglish
Article numbere54257
JournalPLoS ONE
Issue number1
Number of pages12
Publication statusPublished - 30.01.2013

Bibliographical note

Funding Information:
Before conducting the experiment, participants read and signed an informed consent. All data was de-identified and analyzed anonymously. Since the Founding Agency “Deutsche Forschungsgemeinschaft” did not request an ethical approval and Paderborn University has no board to review ethical standards, no ethical approval for the experiment was obtained. This proceeding is in line with the ethical guidelines of the “Deutsche Gesellschaft für Psychologie” which states on ethical approval :“ C.III.2 Formal ethical approval. If research projects need a formal ethical approval, psychologists provide precise information about their research project. They only begin with the research project after receiving the approval. They conduct their research project in line with the approved proceeding.” Which kind of research projects need an ethical approval is clarified by the ethical board of the Deutsche Gesellschaft für Psychologie: “In general a request for ethical approval of a psychological project is addressed to ethical board if a research funding body (i.e. DFG, VW-Foundation, FP7 of the EU, federal ministries or federal state ministries, foundations, universities) requests an ethical approval for the project. Such a request is usually to be expected if human participants are put at risks or for studies in which human participants are not fully aware about the aims and procedures of the study.” These conditions do not apply to the present experiment. Additionally, the experiment was conducted respecting the ethical standards for research with human participants of the American Psychological Association.