Programming of Time-to-Peak Force for Brief Isometric Force Pulses: Effects on Reaction Time

Abstract

According to the parallel force unit model (PFUM) the programming of an isometric force pulse requires the specification of the number of force units and force unit duration. The programming of a force pulse with minimal time-to-peak force is an exception, however, as force unit duration is limited by the minimal possible value, which should be easier to adjust than larger force unit durations. Therefore, the duration of the programming process should be shorter for these force pulses and hence should result in shorter reaction time (RT). Four experiments assessed this prediction using a response precueing procedure. In each experiment the participants produced isometric flexions with their left or right index finger, and time-to-peak force was manipulated within a block. The results are consistent with the predictions of PFUM. The results, however, are at variance with alternative accounts which assume that RT depends primarily on response duration or rate of force production.

An inexpensive and accurate method of measuring the force of responses in reaction time research

“…Moreover, there is ample evidence to suggest that participants can systematically and strategically control the force of their responses tailored to the external situation (for a review, see Ulrich & Wing, 1991). Indeed, researchers have exploited participants' ability to control precisely the force dynamics of their responses by defining response force as an independent variable Mattes, Leuthold, & Ulrich, 2002;Schröter, 2006). In these studies, response forces have been controlled strategically by way of pretrial instructions and posttrial feedback about the desired force parameters of each response.…”

“…Participants responded to stimuli by changing the force of their finger grip. Still others (Giray & Ulrich, 1993;Miller & Franz, 2005;Mordkoff et al, 1996;Schäffer et al, 1989;Schröter, 2006;Stahl & Rammsayer, 2004;Ulrich & Mattes, 1996;Ulrich et al, 1998) describe a method whereby participants were required to press the free end of a metal bar onto which strain gauges were bonded.…”

“…One of the most popular methods of measuring response force is with electrical resistance strain gauges (Angel, 1973;Freund & Büdingen, 1978;Giray & Ulrich, 1993;Ivry, 1986;Kantowitz, 1973;Keele et al, 1987;Klemmer, 1957;Mattes, Ulrich, & Miller, 1997;Miller & Franz, 2005;Mordkoff, Miller, & Roch, 1996;Schäffer, Giray, & Ulrich, 1989;Schröter, 2006;Stahl & Rammsayer, 2004; An inexpensive and accurate method of measuring the force of responses in reaction time research…”

“…The force used to respond to stimuli is an additional dependent variable of considerable interest in interpretation of reaction time (RT) data (Angel, 1973;Schröter, 2006;Ulrich & Wing, 1991). In studies of mental chronometry, RT is measured from the onset of the reaction signal to the depression of a sensitive response key and closure of an electric circuit.…”

“…Response force is related physically to the speed of the response, 1 but can continue beyond switch closure and so vary independently of RT Giray & Ulrich, 1993;Haagh, Spijkers, van den Boogaart, & van Boxtel, 1987;Ivry, 1986;Keele, Ivry, & Pokorny, 1987;Schröter, 2006;Sommer, Leuthold, & Ulrich, 1994;van Boxtel, van den Boogaart, & Brunia, 1993). Consequently, the importance of response force as a dependent measure lies not only in the confounding potential of response force in accurate interpretation of RT data Delabarre, Logan, & Reed, 1897;Ulrich & Wing, 1991;Woodworth, 1938), but also in the potential of response force to shed light on stimulusresponse conductance processes (Giray & Ulrich, 1993;Jaśkowski & Włodarczyk, 2006;Mattes, Ulrich, & Miller, 2002;Schröter, 2006;Stahl & Rammsayer, 2004;Ulrich, Rinkenauer, & Miller, 1998;Ulrich & Wing, 1991). For instance, RT is known to decrease with increased stimulus intensity, and it is well established that stimulus intensity influences the speed of sensory and perceptual processes (for a review, see Miller, Ulrich, & Rinkenauer, 1999).…”