The Silent Period of Evidence Integration in Fast Decision Making

Abstract

In a typical experiment on decision making, one out of two possible stimuli is displayed and observers decide which one was presented. Recently, Stanford and colleagues (2010) introduced a new variant of this classical one-stimulus presentation paradigm to investigate the speed of decision making. They found evidence for “perceptual decision making in less than 30 ms”. Here, we extended this one-stimulus compelled-response paradigm to a two-stimulus compelled-response paradigm in which a vernier was followed immediately by a second vernier with opposite offset direction. The two verniers and their offsets fuse. Only one vernier is perceived. When observers are asked to indicate the offset direction of the fused vernier, the offset of the second vernier dominates perception. Even for long vernier durations, the second vernier dominates decisions indicating that decision making can take substantial time. In accordance with previous studies, we suggest that our results are best explained with a two-stage model of decision making where a leaky evidence integration stage precedes a race-to-threshold process.

Two primes priming: Does feature integration occur before response activation?

“…Hence, information persistence in a buffer stage might explain why Prime 2 remains dominant even when Prime 1 has a head start long enough to provoke a high rate of response errors under conditions of speeded instead of delayed responding. Such a twostage model was recently proposed for decision making (Rüter, Marcille, Sprekeler, Gerstner, & Herzog, 2012;Rüter, Sprekeler, Gerstner, & Herzog, 2013;Scharnowski, Hermens, Kammer, Ogmen, & Herzog, 2007) and is supported by transcranial magnetic stimulation experiments, which show that vernier fusion takes up to 400 ms (Rüter, Kammer, & Herzog, 2010;Scharnowski et al, 2009).…”

Long-lasting visual integration of form, motion, and color as revealed by visual masking

“…Finally, we like to mention that short interstimulus intervals between the two successively presented verniers lead to the perception of the individual verniers. In this case, TMS over visual cortex does not modulate performance, which again indicates that TMS interferes with vernier fusion (Rüter, Sprekeler, Gerstner, & Herzog, 2013).…”

“…For two reasons these results show that the individual verniers were not fully integrated before 420 ms. First, if the verniers had integrated immediately after presentation, by design of the experiment, performance would have been at 50%, which is both the point of equal dominance and chance level, given that vernier offsets were balanced. Second, if TMS had not affected vernier Citation: Pilz, K. S., Zimmermann, C., Scholz, J., & Herzog, M. H. (2013). Long-lasting visual integration of form, motion, and color as revealed by visual masking.…”

Information Integration and Information Storage in Retinotopic and Non-Retinotopic Sensory Memory

“…In addition, classic models of decision making need to be rethought, since decisions were made only after accomplishing integration in the nrSM. First, the nrSM represents a long-lasting buffer, in which information is integrated, before it is submitted to a driftdiffusion process (Figure 7, [35,36]). Second, information obtained later weighs stronger than that presented earlier (Figure 7), which is not easy to reconcile with classic models, in which earlier stimuli drive the evidence.…”