According to the traditional inferential theory of perception, percepts of object motion or stationarity stem from an evaluation of afferent retinal signals (which encode image motion) with the help of extraretinal signals (which encode eye movements). According to direct perception theory, on the other hand, the percepts derive from retinally conveyed information only. Neither view is compatible with a perceptual phenomenon that occurs during visually induced sensations of ego motion (vection). A modified version of inferential theory yields a model in (...) which the concept of extraretinal signals is replaced by that of reference signals, which do not encode how the eyes move in their orbits but how they move in space. Hence reference signals are produced not only during eye movements but also during ego motion (i.e., in response to vestibular stimulation and to retinal image flow, which may induce vection). The present theory describes the interface between self-motion and object-motion percepts. An experimental paradigm that allows quantitative measurement of the magnitude and gain of reference signals and the size of the just noticeable difference (JND) between retinal and reference signals reveals that the distinction between direct and inferential theories largely depends on: (1) a mistaken belief that perceptual veridicality is evidence that extraretinal information is not involved, and (2) a failure to distinguish between (the perception of) absolute object motion in space and relative motion of objects with respect to each other. The model corrects these errors, and provides a new, unified framework for interpreting many phenomena in the field of motion perception. (shrink)

In line with my model of object motion perception (Wertheim 1994) and in contradistinction to what Stoffregen (1994) states, Sauvan's data suggest that percepts of motion are not sense specific. It is here argued that percepts of object- or self-motion are neither sense specific nor do they necessarily stem from what Stoffregen calls “kinematic events.” Stoffregen's error is in believing that we can only perceive object- or self-motion relative to other objects, which implies a failure to realise that percepts of (...) absolute object- or self-motion in space (relative to the earth's surface) do exist as well, even when the earth's surface itself is not perceived. (shrink)

_Behavioral and Brain Sciences_ , 15, 183-247, 1992. Reprinted in _The Philosopher's Annual_ , Grim, Mar and Williams, eds., vol. XV-1992, 1994, pp. 23-68; Noel Sheehy and Tony Chapman, eds., _Cognitive Science_ , Vol. I, Elgar, 1995, pp.210-274.

Damasio remarks, it "informs virtually all research on mind and brain, explicitly or implicitly." Indeed, serial information processing models generally run this risk (Kinsbourne, 1985). The commentaries provide a wealth of confirming instances of the seductive power of this idea. Our sternest critics Block, Farah, Libet, and Treisman) adopt fairly standard Cartesian positions; more interesting are those commentators who take themselves to be mainly in agreement with us, but who express reservations or offer support with arguments that betray a continuing (...) allegiance to one or another tenet of the view we sought to discredit. (shrink)

Realism concerning a given domain of things is the view that the things in that domain exist, and are as they are, quite independently of anyone.

William James’ Principles of Psychology, in which he made famous the ‘specious present’ doctrine of temporal experience, and Edmund Husserl’s Zur Phänomenologie des inneren Zeitbewusstseins, were giant strides in the philosophical investigation of the temporality of experience. However, an important set of precursors to these works has not been adequately investigated. In this article, we undertake this investigation. Beginning with Reid’s essay ‘Memory’ in Essays on the Intellectual Powers of Man, we trace out a line of development of ideas about (...) the temporality of experience that runs through Dugald Stewart, Thomas Brown, William Hamilton, and finally the work of Shadworth Hodgson and Robert Kelly, both of whom were immediate influences on James (though James pseudonymously cites the latter as ‘E.R. Clay’). Furthermore, we argue that Hodgson, especially his Metaphysic of Experience (1898), was a significant influence on Husserl. (shrink)