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Effects of Environmental Context on Temporal Perception Bias in Apparent Motion ⇑ Tomohiro Masuda A, Atsushi Kimura B, Ippeita Dan C, Yuji Wada A

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Effects of Environmental Context on Temporal Perception Bias in Apparent Motion ⇑ Tomohiro Masuda A, Atsushi Kimura B, Ippeita Dan C, Yuji Wada A View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Vision Research 51 (2011) 1728–1740 Contents lists available at ScienceDirect Vision Research journal homepage: www.elsevier.com/locate/visres Effects of environmental context on temporal perception bias in apparent motion ⇑ Tomohiro Masuda a, Atsushi Kimura b, Ippeita Dan c, Yuji Wada a, a Sensory and Cognitive Food Science Laboratory, Food Function Division, National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan b Department of Information Environment, Tokyo Denki University, Inzai, Chiba, Japan c Functional Brain Science Laboratory, Center for Development of Advanced Medical Technology, Jichi Medical University, Shimotsuke, Tochigi, Japan article info abstract Article history: We investigated whether the directional effect on the kappa effect can be attributed to the directional Received 7 May 2009 anisotropy of retinotopical space or to the representation of forces provided by environmental contexts Received in revised form 27 May 2011 (e.g., gravity) in an observed event. We examined whether different contexts with similar directional Available online 16 June 2011 changes (straight vs. reversed motion) influence the kappa effect in four experiments. The object’s motion appeared to depict only forces under the natural laws of physics on a slope (Experiment 1) or on a hor- Keywords: izontal plane (Experiment 2) in virtual 3D space. In Experiments 3 and 4, the motion appeared to be sub- Kappa effect jected to external or self-driving forces additionally influenced by internal forces on a slope (Experiment Event perception 3) or a horizontal plane (Experiment 4). Space–time dependency The results demonstrated that the directional effect on the kappa effect was observed only in Experi- ment 1, and not in Experiments 2 and 3, while the kappa effect was preserved. Furthermore, not even the kappa effect was observed in the reversed motion of Experiment 4. The results of the present study sug- gest that the determining factor of direction in the kappa effect is not a simple anisotropy, but rather the context of observed events. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Recently, Sarrazin, Giraudo, Pailhous, and Bootsma (2004) re- ported a situation where the constant velocity hypothesis was The kappa effect is a spatio-temporal illusion that substantiates not applicable. In their examination of the kappa effect in visual the strong relationship between perceived space and time (Abe, memory, participants observed eight white dots, which succes- 1935; Cohen, Hansel, & Sylvester, 1953, 1955; Noguchi, Kitaoka, sively appeared in one direction in horizontal alignment along a & Takashima, 2008; Price-Williams, 1954). A series of successive straight line at either a fixed or variable inter-stimulus interval targets, delimiting distance as variable and duration as fixed, (ISI). When the ISI was constant and the distances between dots causes an observer to experience the kappa effect, in which the were not, they observed the kappa effect, which followed the con- perceived temporal separation tends to vary in direct proportion stant velocity hypothesis. On the other hand, when both ISIs and to the distance of targets. distances of observed patterns were varied, they failed to observe In one well-known theory attempting to account for the kappa the response pattern predicted by the constant velocity hypothesis. effect, Jones and Huang (1982) proposed the constant velocity It might be difficult to perceive uniform motion from such compli- hypothesis. They theorized that an observer tends to impute uni- cated patterns. Given the disappearance of the kappa effect when form motion to discontinuously displayed successive stimuli. such complex spatio-temporal relations cause observers to be un- Observers expect the duration between successive stimuli to re- able to perceive uniform motion, they concluded that the constant flect uniform motion. Consequently, the observer estimates that velocity hypothesis could not adequately explain the spatio-tem- the traversing of a target for a given distance requires a duration poral integration phenomenon. However, from a different perspec- based on uniform motion. This pattern causes the observer to per- tive, their study may demonstrate that a simple spatio-temporal ceive a duration biased from the given physical duration. This phe- condition, exemplified as a constant ISI, may be a prerequisite, or nomenon seems related to the physical rules of time, distance, and at least a crucial factor, for the kappa effect. In other words, the dis- speed. appearance of the kappa effect suggests that context might be the determining factor for observed events such as constant velocity. The idea that the context of observed events affects our percep- ⇑ Corresponding author. Address: 2-1-12, Kannondai, Tsukuba, Ibaraki 305-8642, Japan. tion is also supported by studies of displacement in spatial mem- E-mail address: [email protected] (Y. Wada). ory (Hubbard, 1995, 2005). The most famous example of these 0042-6989/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.visres.2011.05.016 T. Masuda et al. / Vision Research 51 (2011) 1728–1740 1729 phenomena is known as ‘‘representational momentum,’’ which is pa effect, experimental evidence towards ruling out the possibility the tendency to displace the remembered location of a target: of anisotropy of retinotopical space was obtained in a study by Jin- the final position of a moving object is remembered as further for- gu (1999) examining the effects of gravitational representation on ward in the direction of movement (Freyd & Finke, 1984). There is a the kappa effect in a slope. great deal of evidence that dynamics implied not only by momen- In Jingu’s experiments, stimuli consisted of three targets that tum, but also by other environmental contexts, such as gravity, were sequentially presented on a slope: the first target was pre- friction, energy transfer, and driving force, affect observers’ percep- sented at the top of the slope and the second one was presented tion by facilitating their expectations of future target motion. For further down the slope. Under the descending condition, the third example, Bertamini (1993) revealed an effect of representational target was presented on the slope below the second target, and un- gravity by measuring the distortion of memory for the position der the descending-ascending condition the third target was pre- of an object on an inclined plane in which the angle of inclination sented on the slope between the first and second targets. He and retention interval were changed. As for energy transfer in col- observed the kappa effect under both conditions. Moreover, the lisions, Hubbard (2004) demonstrated that the perceived forward ISI between the second and third targets under the descending- displacement of a target object upon collision with another object ascending condition was perceived as longer than that between decreased if the motion of the target was attributable to an impe- the first and second targets, despite the fact that the distance tus imparted from the other object. This was attributed to the ob- moved in the former interval was shorter than that in the latter. server’s naïve expectation that the motion of the launched target This study suggested that the influence of context on the kappa ef- will stop when impetus drops below the level needed to maintain fect is present in a slanting, as well as vertical, direction. Therefore, its motion. These studies provided experimental evidence that con- the enlargement of the kappa effect in an upward direction or the text has an influence on the remembered location of a target. This reduction in a downward direction are less likely due to the direc- contextual effect might also affect temporal judgment based on ob- tional anisotropy in the retinotopical space, but very likely due to served motion. context. Some research has suggested that the kappa effect is influenced Taken together, this evidence shows that it is plausible that the by the context of an observed event, which can imply more com- kappa effect is influenced by several forces, such as gravitational plex dynamics than constant velocity. For example, Cohen et al. acceleration/deceleration, deceleration by air resistance, friction, (1955) observed the kappa effect when stimuli were arranged ver- or collision against other objects, under physical laws that are gen- tically as well as horizontally. Intriguingly, the kappa effect was eralized descriptions based on observations of physical behavior. greater when the stimuli were perceived as moving upward, while However, the schematic 2D pattern used in Jingu’s study was un- it was smaller when the stimuli were perceived as moving down- clear concerning the direction of gravitational force. In the sche- ward. They pointed out that this effect was due to expectations of matic 2D display, the direction of representational gravitational apparent downward acceleration and upward deceleration be- force changes depending on whether the observer perceived the cause of the implied gravitational force on the target’s movement. pattern as an overhead view or a lateral view. One promising idea Cohen et al. (1955) assumed that the duration of the decelerated is to introduce a virtual three-dimensional (3D) space that allows motion of a target was judged as shorter than expected
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