The opportunity cost model (OCM) aims to explain various phenomena, among which the finding that performance degrades if executive functions are used repeatedly (“resource depletion”). We argue that an OCM account of resource depletion requires two unlikely assumptions, and we discuss an alternative that does not require these assumptions. This alternative model describes the interplay between executive function and motivation.

We investigated the inhibitory regulation of perceptual–motor processing streams in a task that switched between spatially compatible and incompatible stimulus–response mappings. Thirty male and female college-aged participants performed a reaction time (RT) task in which the response was either spatially compatible or not depending on a cue immediately preceding the stimulus. The cue-to-stimulus interval (CI) was either 50 or 500 ms. Incompatible mapping yielded the typical slower responses than compatible mapping at 500 ms, but not at 50 ms. Changes in cardiac interbeat interval (IBI) and performance suggested that automatic responses to compatible stimuli were suppressed at 50 ms. Both performance and IBI changes as well as individual differences in these measures suggested a precue preparatory schema or set biased toward suppressing the compatible mapping. An alternate hypothesis of a cue-induced suppression was questioned. The results illustrate the operation of different supervisory processes in the anticipatory and online control of action.

This study examined the effects of visual selective attention and stimulus discriminability on phasic heart rate changes. Grating stimuli consisting of four vertical bars were presented left or right from fixation. Participants attended to one side of the screen and responded with a button press to attended target stimuli that were defined by shorter middle bars. Stimulus discriminability was manipulated by increasing the length of the middle bars of targets. To examine the time course of response inhibition, participants had to respond to auditory probe stimuli that were presented occasionally and unpredictably at varying intervals following the visual stimulus. Responses to targets and probes following attended nontargets were slower in the difficult condition. Heart rate slowed in anticipation of a target and accelerated back to baseline afterwards. Phase-dependent cardiac slowing was larger for attended nontargets compared to unattended nontargets and was more pronounced in the difficult condition. These findings were interpreted vis-à-vis inhibition accounts of phase-dependent cardiac slowing.

Heart rate was recorded from five different groups of children (ages 7, 10, 12, 14, and 20 years) while they were performing an auditory selective attention task. The participants were instructed to count rare tone pips embedded in a series of standard tone pips presented at one (attended) ear while ignoring rare and standard stimuli presented at the other (unattended) ear. A pattern of anticipatory heart rate deceleration followed by acceleration was associated with rare tone pips at the attended ear but not with rare tone pips that should be ignored. The absence of differential sensitivity of heart rate responses to rare tone pips presented at the unattended ear was observed for all age groups. These findings were interpreted to suggest that the ability to ignore irrelevant target stimuli has reached mature levels during middle childhood. The depth of anticipatory deceleration increased until age 14, suggesting that the ability to maintain attentional set continues to develop beyond childhood.

This study examined the hypothesis that global and selective inhibition are mediated by distinct mechanisms: respectively, a peripheral mechanism, indexed by heart rate slowing, and a central mechanism, indexed by cortical but not autonomic measures. Three varieties of a Go-NoGo task were presented in which the Go signal required an index finger response rapidly followed by a middle finger response. The NoGo signal required the inhibition of (a) both responses (global inhibition), (b) the middle finger response (simple selective inhibition), or (c) the index finger response of one hand and the middle finger response of the other hand (complex selective inhibition). As anticipated, global inhibition was indexed by heart rate slowing. Most importantly, heart rate slowing was also elicited by selective inhibition and was more pronounced for complex than simple selective inhibition. These findings suggest that global and selective inhibition are mediated by one rather than two mechanisms and that heart rate is sensitive to the demands placed on this inhibition mechanism.

Twenty-eight volunteers were instructed to attend stimuli presented at one side of the computer screen and to ignore stimuli presented at the other side. Both attended and unattended stimulus series consisted of targets (25%) and nontargets (75%) defined on the basis of stimulus shape. Attended targets required a binary choice based on stimulus color. Selective attention led to the expected increase in both midlatency (N2b) and late (P3) brain potential components. Furthermore, selective attention led to increased anticipatory cardiac slowing preceding the target stimulus and to increased primary bradycardia. Correlational analyses revealed a positive relation between the effects of selective attention on N2b amplitude and primary bradycardia suggestive of cortical involvement in the chronotropic control of heart rate.

Psychophysiological “preparatory” responses may or may not depend on a focused expectation of when a stimulus will occur. Changes in heart rate, pupillary diameter, and brain potentials were examined during trials in which foreperiod of a simple reaction time (RT) task was fixed or unpredictable. Trials were also included in which stimuli for the speeded motor reaction were triggered by psychophysiological changes occurring spontaneously in the foreperiod. Thirty-two college-aged volunteers equally divided by gender participated in the experiment. Reducing expectancy, by using nonaging foreperiods, eliminated transient prestimulus psychophysiological responses but failed to eliminate slow changes over the foreperiod—slowing of heart rate, dilation of the pupil, and cortical surface negativity. Triggering the reaction stimulus by physiological changes did not influence RT. Correlations between psychophysiological changes in the foreperiod and between these changes and RT were generally low. The results were consistent with a multiprocess view of preparation.