Perception by effortful touch and a lawful approach to (the evolution of) perceiving and acting

Gone Fishin’: Perceiving the length of one object that is non-rigidly attached to a wielded object

“…When wielding a rigid object, I lawfully couples wielding forces to wielding movements (see Carello & Turvey, 2015, 2017; Wagman et al, 2023 for reviews). That is, I transforms a given force applied to a wielded object in a given direction into a given movement of that object in a given direction.…”

“…In such as task, the forces required to keep the target object from falling due to gravity (described by M ) are of much greater relevance than either the torques required to keep the target object from rotating due to gravity or the torques required to actively rotate an object in different directions (static moment or I , respectively). Second, it could mean that it would be difficult (if not impossible) for participants to generate the rotational movements of the target object required to detect either static moment or I (Arzamarski et al, 2010; Carello & Turvey, 2015, 2017; Debats et al, 2010; Wagman et al, 2023 for reviews). Consequently, the manipulations of mass distribution used in Experiment 3 (i.e., changing the location of an attached mass relative to the point of attachment) may have been ineffective in revealing sensitivity to static moment or I .…”

“…In Experiment 4, we manipulated mass distribution of the target object relative to the point of attachment by changing the location of the point of attachment relative to a (fixed) mass distribution. Both manipulations bring about changes in the mechanical invariant parameters related to mass distribution (static moment and I ) while leaving mass unchanged (Solomon & Turvey, 1988; see Carello & Turvey, 2015, 2017; Wagman et al, 2023 for reviews). In particular, just as placing a mass farther from the point of attachment increases the values of static moment and I , so too does placing the point of attachment farther from the mass distribution (at the “End” rather than at the “Midpoint”).…”

“…The ability to perceive properties of the target object ought to be grounded in the sensitivity of the touch system to these parameters with respect to the target object—in particular I and its various components (see Carello & Turvey, 2015, 2017; Wagman et al, 2023 for reviews). This hypothesis was investigated by Peck et al (1996).…”

“…Accordingly, a large body of research has shown that the ability to perceive properties of wielded objects is grounded in the sensitivity of the touch system to these parameters—in particular, I and its various components (see Carello & Turvey, 2015, 2017; Wagman et al, 2023 for reviews). For example, perception of the length of a freely wielded object is primarily supported by sensitivity to the major principal moment of inertia ( I xx , which describes the resistance to rotation of an object about an axis perpendicular to the object) and perception of the width of a freely wielded object is primarily supported by the minor principal moment of inertia ( I zz , which describes the resistance to rotation of an object about an axis parallel to the object) (Fitzpatrick et al, 1994; Turvey et al, 1998).…”