Behavioral Ecology Meets Motor Behavior: Choosing Between Walking and Reaching Paths

Abstract

Behavioral ecology is a field in which scientists try to predict behavioral choices, typically by estimating costs of behavioral alternatives even though those costs may involve different currencies. Researchers interested in motor behavior often have similar concerns, though the connections between these two fields have been largely unnoticed. The authors pursued a study of motor behaviors involving different currencies: walking over different distances and reaching over different distances. They found that the cost of reaching was much greater than the cost of walking. They also found that walking paths took into account hand preferences. The present study extends previous research on the neglected topic of the coordination of reaching and walking and provides a simple method that can be applied in other contexts.

Choosing Actions

“…In one of our experiments (Rosenbaum et al, 2011), we asked participants to pick up a child’s beach bucket on a table and carry it to either of two sites beyond the table (Figure 12). To pick up the bucket, the participant could either walk along the left or right side of the table.…”

“… Three arrangements used by Rosenbaum et al (2011) to study walking and reaching . In all cases, the participant stood at the site where these photographs were taken.…”

“…With the tasks used, which go beyond those reviewed above, Rosenbaum et al (2011) could estimate the relative costs of walking over some distance versus reaching over some distance, and they could estimate the relative cost of reaching with the left hand or right. The way they estimated the relative costs is reflected in Figure 13, which shows the probability, p ( L ), that participants walked along the left side of the table plotted as a function of the difference between two derived measures, “left path functional distance” and “right path functional distance.” Left path functional distance was defined as the sum of the walking distance (in meters) plus the right-hand reaching distance (also in meters), with the latter term being multiplied by an empirically fit constant.…”

Testing the concurrent validity of a naturalistic upper extremity reaching task

“…Point-to-point reaching studies have been foundational in establishing our understanding of upper extremity motor control (Fitts, 1954; Flash and Hogan, 1985; Woodworth, 1899), neural encoding (Georgopoulos et al, 1982; Schwartz et al, 1988), motor development (Konczak and Dichgans, 1997; Lee and Newell, 2013), motor adaptation (Brashers-Krug et al, 1996; Krakauer et al, 2000; Smith et al, 2006), perception (Goodale and Milner 1992; Rosenbaum et al 2011), and brain lateralization (Fisk and Goodale, 1988; Sainburg, 2014) in humans and animals (Fattori et al, 2010; Klein et al, 2012; Martin and Ghez, 1988). In addition to its contributions to basic neural mechanisms, the paradigm of targeted reaching has uncovered detailed deficits in a variety of clinical neurological populations, such as stroke (Beer et al, 2004; Dukelow et al, 2012; Velicki et al, 2000; Zackowski et al, 2004), Parkinson’s Disease (Kelly and Bastian, 2005; Semrau et al, 2014), Alzheimer’s Disease (Ghilardi et al, 1999; Tippett and Sergio, 2006; Verheij et al, 2012), and multiple sclerosis (Casadio et al, 2008; Solaro et al, 2007).…”

Pulling to scale: Motor planning for sequences of repeated actions by cotton-top tamarins (Saguinus oedipus).

“…This is an open question that must be addressed in future work. Recently, researchers have endeavored to develop an experimental paradigm to quantify the perception of cost of reaching and walking actions in human adults (e.g., Rosenbaum, Brach, & Seminov, 2011). This paradigm, or some variant thereof, might profitably be applied to the present work in order to delineate the types of computations and considerations that educe the scaling behavior.…”