Which task will we choose first? Precrastination and cognitive load in task ordering

Physical effort precrastination determines preference in an isometric task

How the brain decides when to invest effort is a central question in neuroscience. When asked to walk a mile to a destination, would you choose a path with a hill at the beginning or the end? The traditional view of effort suggests we should be indifferent-all joules are equal so long as it does not interfere with accomplishing the goal. Yet, when total joules are equal across movement decisions, the brain's sensitivity to the temporal profile of effort investment remains poorly understood. Here, we sought to parse the interaction of time and physical effort by comparing subjective preferences in an isometric arm-pushing task that varied the duration and timing of high and low effort. Subjects were presented with a series of two-alternative forced choices, where they chose the force profile they would rather complete. Subjects preferred earlier physical effort (i.e., to precrastinate) but were idiosyncratic about preference for task timing. A model of subjective utility that includes physical effort costs, task costs, and independent temporal sensitivity factors described subject preferences best. Interestingly, deliberation time and response vigor covary with the same subjective utility model for preference, suggesting a utility that underlies both decision making and motor control. These results suggest physical effort costs are temporally sensitive, with earlier investment of effort preferred to later investment, and that the representation of effort is based on not only the total energy required but also when it is required to invest that energy.NEW & NOTEWORTHY We use a novel paradigm that differentiates physical effort costs, task costs, and time, where subjects choose between isometric arm-pushing tasks. Subjects prefer high physical effort earlier than later. They also decide faster and respond more vigorously the greater their preference. We find a generalizable subjective utility model that includes independent time-sensitivity of physical effort and task costs. Together, we demonstrate that subjective effort includes not only the total effort invested but also its timing.

Is precrastination related to updating and inhibition aspects of executive function?

ABSTRACTPrecrastination is the act of completing a task as soon as possible even at the expense of extra effort. Past research has suggested that individuals precrastinate due to a desire to reduce their cognitive load, also known as the cognitive load-reduction (CLEAR) hypothesis [VonderHaar, R. L., McBride, D. M., & Rosenbaum, D. A. (2019). Task order choices in cognitive and perceptual-motor tasks: The cognitive-load-reduction (CLEAR) hypothesis. Attention, Perception, & Psychophysics, 81(7), 2517-2525. https://doi.org/10.3758/s13414-019-01754-z]. This idea stems from the notion that it is taxing to hold intentions in working memory and completing a task as soon as possible releases cognitive resources for other tasks. Based on this hypothesis, we predicted that aspects of executive function may play a role in precrastination. We tested this prediction using a box-moving task developed in a previous study to measure precrastination. We also incorporated tasks measuring updating and inhibition aspects of executive function: the Stroop interference (both experiments) and Simon tasks (Experiment 2) to measure inhibition and the 2-Back memory task (Experiment 1) to measure updating. We found that the majority of participants precrastinated significantly throughout the box-moving task trials, consistent with results from past studies. However, no relation was found between the executive function tasks and rates of precrastination. These results may be due to the automaticity of precrastination when cognitive resources are limited.

Pre-crastination across physical and cognitive tasks

Pre-crastination refers to the tendency to begin a task as soon as possible, even at the cost of additional effort. This phenomenon is consistently observed in tasks in which participants are asked to select one of two buckets to carry to a target. Surprisingly, on a high proportion of trials participants choose the bucket that is closer to them (and further from the target) as opposed to the bucket that is further from them (and closer to the target). In other words, participants tend to complete the task of picking up a bucket as soon as possible, even when this requires additional physical effort. The purpose of the current experiment was to test whether an individual's tendency to pre-crastinate is stable across tasks. Participants performed a physical load task where they selected one of two buckets to carry to a target. The same participants performed a cognitive load task where they picked up number strings at one of the two bucket locations and mentally carried the number string to a target. We found that participants pre-crastinated in both tasks and this tendency was reduced as task difficulty increased. Importantly, we found a significant association between an individual's tendency to pre-crastinate in the physical load task and their tendency to pre-crastinate in the cognitive load task. Thus, an individual's tendency to pre-crastinate is consistent across tasks and suggests that this is a stable characteristic of how individuals choose to order tasks.

Where scrollbars are clicked, and why

Scrolling is a widely used mean to interact with visual displays, usually to move content to a certain target location on the display. Understanding how user scroll might identify potentially suboptimal use and allows to infer users' intentions. In the present study, we examined where users click on a scrollbar depending on the intended scrolling action. In two online experiments, click positions were systematically adapted to the intended scrolling action. Click position selection could not be explained as strict optimization of the distance traveled with the cursor, memory load, or motor-cognitive factors. By contrast, for identical scrolling actions click positions strongly depended on the context and on previous scrolls. The behavior of our participants closely resembled behavior observed for manipulation of other physical devices and suggested a simple heuristic of movement planning. The results have implications for modeling human-computer interaction and may contribute to predicting user behavior.

Does precrastination explain why some observers are suboptimal in a visual search task?

How do we decide where to search for a target? Optimal search relies on first considering the relative informational value of different locations and then executing eye movements to the best options. However, many participants consistently move their eyes to locations that can be easily ascertained to neither contain the target nor provide new information about the target's location. Here, we asked whether this suboptimal search behaviour represents a specific example of a general tendency towards precrastination: starting sub-goals of a task before they are needed, and in so doing, spending longer time on doing the task than is necessary. To test this hypothesis, we asked 200 participants to do two tasks: retrieve two heavy buckets (one close and one far) and search for a line segment. Precrastination is defined as consistently picking up the closer bucket first, versus the more efficient strategy of picking up the farther bucket first. Search efficiency is the proportion of fixations directed to more cluttered regions of the search array. Based on the pilot data, we predicted an association of precrastination with inefficient search strategies. Personality inventories were also administered to identify stable characteristics associated with these strategies. In the final dataset, there was no clear association between search strategy and precrastination, nor did these correlate strongly with any of the personality measures collected. This article received in-principle acceptance (IPA) at Royal Society Open Science on 29 January 2020. The accepted Stage 1 version of the manuscript, not including results and discussion, may be found at https://osf.io/p2sjx. This preregistration was performed prior to data collection and analysis.

Precrastination and Time Perspective: Evidence from Intertemporal Decision-Making

Although procrastination has been extensively studied, precrastination remains an unsolved puzzle. Precrastination is the tendency to start tasks as soon as possible, even at the cost of extra effort. Using the near bucket paradigm with 81 undergraduate students, this study examined the relationship between precrastination and time perspective, proactive personality, and subjects' differential performance in intertemporal decision-making. The results confirmed the cognitive-load-reduction (CLEAR) hypothesis. Precrastination was found to be positively predicted by the future time dimension of time perspective and negatively predicted by proactive personality. In addition, there is a significant positive correlation between precrastination and delay discounting of intertemporal decision-making, which exists only for the loss situation.

Carrying groceries: More items in early trips than in later trips or the reverse? Implications for pre-crastination

Returning home from the grocery store with a car full of groceries requires decisions about how many bags to carry when. If the decisions exemplify procrastination, people should carry more bags per trip in late trips than in early trips (putting the hard work off until later), but if the decisions exemplify the recently discovered phenomenon of pre-crastination (Rosenbaum et al. in Psychol Sci 25: 1487-1496, 2014), people should carry more bags per trip in early trips than in late trips (doing the hard work early). To distinguish between these possibilities, we asked university students to carry 5 or 11 dodgeballs from one bin to another 4, 8, 12, or 16 feet away in as many trips as they wished. A random half of the subjects did the tasks with an additional requirement to memorize and then recall 7 digits after carrying all the balls from the home to the target bin. Consistent with pre-crastination, participants carried the most balls per trip in early trips, and consistent with the hypothesis that pre-crastination relates to memory load, the number of balls carried per trip was affected by the presence of a memory load. The results add to the growing evidence for the generality of pre-crastination.

What matters in making demand-based decisions: Time alone or difficulty too?

Which task is easier, doing arithmetic problems of specified form for some specified duration, or carrying a bucket of specified weight over some specified distance? If it is possible to choose between the “more cognitive” task and the “more physical” task, how are the difficulty levels of the tasks compared? We conducted two experiments in which participants chose the easier of two tasks, one that involved solving addition or multiplication problems (Experiment 1) or addition problems with different numbers of addends (Experiment 2) for varying amounts of time (in both experiments), and one that involved carrying a bucket of different weights over a fixed distance (in both experiments). We found that the probability of choosing to do the bucket task was higher when the bucket was empty than when it was weighted, and increased when the cognitive task was harder and its duration grew. We could account for the choice probabilities by mapping the independent variables onto one abstract variable, Φ. The functional identity of Φ remains to be determined. It could be interpreted as an inferred effort variable, subjective duration, or an abstract, amodal common code for difficulty.

Precrastination and individual differences in working memory capacity

When ordering tasks, people tend to first perform the task that can be started or completed sooner (precrastination) even if it requires more physical effort. Evidence from transport tasks suggests that precrastination can reduce cognitive effort and will likely not occur if it increases cognitive effort. However, some individuals precrastinate even when it increases cognitive effort. We examined whether individual differences in working memory capacity (WMC) influence this suboptimal choice. Participants retrieved two cups of water along a corridor, in the order of their choosing. We measured the frequency of choosing the close cup first (precrastination) while varying water levels in each cup (attention demand) located at different distances. Results showed that the tendency to select the far cup first (avoid precrastination) increases when the close cup is full (high attention demand) vs. not full (low attention demand). Post-hoc results showed high (vs. low) WMC individuals more frequently bypass decisions with relatively higher costs of cognitive effort, avoiding precrastination when the attentional demand of carrying the close (vs. far) cup is relatively high (close-cup full and far-cup half full), but not when it is relatively low (far-cup full). However, there was no evidence that WMC could explain why some individuals always precrastinated, at costs of cognitive effort. Instead, individuals who always precrastinated reported automatic behavior, and those who avoided precrastinating reported decisions of efficiency. Learning, the relationship between precrastination and tendencies to enjoy/engage in thinking or procrastinate, and evidence that precrastination required more cognitive effort in our task, are discussed.

The influence of time constraints on posture choices during an end-state comfort task

People adopt comfortable postures for the end states of motor actions (end-state comfort; Rosenbaum & Jorgensen, 1992). The choice to end comfortably often elicits adoption of uncomfortable beginning states, demonstrating that a sequence of movement is planned in advance of movement onset. Many factors influence the choice of comfortable end-state postures including the greater precision and speed afforded by postures at joint angle mid-ranges (Short & Cauraugh, 1999). To date, there has been little evaluation of the hypothesis that postures are chosen based on minimizing the time spent in uncomfortable postures. The aim of this experiment was to examine how the relative time required to hold beginning and end-state postures influenced the choice of posture. Participants moved a two-toned wooden dowel from one location to another with the requirement to grasp the object and place a specified color down. Participants completed four conditions where no postures were held, only one posture was held, or both postures were held. We predicted more thumb-up postures for positions held longer regardless of whether these postures were at the end or beginning state. Results verified that the constraint of holding the initial posture led to decreased end-state comfort supporting the hypothesis that estimation of time spent in postures is an important constraint in planning. We also note marked individual differences in posture choices, particularly when the object was moved to the left.

Free-choice and forced-choice actions: Shared representations and conservation of cognitive effort

We examined two questions regarding the interplay of planned and ongoing actions. First: Do endogenous (free-choice) and exogenous (forced-choice) triggers of action plans activate similar cognitive representations? And, second: Are free-choice decisions biased by future action goals retained in working memory? Participants planned and retained a forced-choice action to one visual event (A) while executing an immediate forced-choice or free-choice action (action B) to a second visual event (B); then the retained action (A) was executed. We found performance costs for action B if the two action plans partly overlapped versus did not overlap (partial repetition costs). This held true even when action B required a free-choice response indicating that forced-choice and free-choice actions are represented similarly. Partial repetition costs for free-choice actions were evident regardless of whether participants did or did not show free-choice response biases. Also, a subset of participants showed a bias to freely choose actions that did not overlap (vs. did overlap) with the action plan retained in memory, which led to improved performance in executing action B and recalling action A. Because cognitive effort is likely required to resolve feature code competition and confusion assumed to underlie partial repetition costs, this free-choice decision bias may serve to conserve cognitive effort and preserve the future action goal retained in working memory.

Implicit task switching in Parkinson's disease is preserved when on medication

People with Parkinson's disease have been shown to have difficulty switching between movement plans. In the great majority of studies, the need to switch between tasks was made explicitly. Here, we tested whether people with Parkinson's disease, taking their normal medication, have difficulty switching between implicitly specified tasks. We further examined whether this switch is performed predictively or reactively. Twenty five people with Parkinson's disease continuously increased or decreased the frequency of their arm movements, inducing an abrupt-but unaware-switch between rhythmic movements (at high frequencies) and discrete movements (at low frequencies). We tested whether that precipitous change was performed reactively or predictively. We found that 56% of participants predictively switched between the two movement types. The ability of people with Parkinson's disease, taking their regular medication, to predictively control their movements on implicit tasks is thus preserved.

Precrastination and the cognitive-load-reduction (CLEAR) hypothesis

Precrastination is the tendency many individuals have to complete a task as soon as possible in order to get it out of the way [Rosenbaum, D. A., Gong, L., & Potts, C. A. (2014). Pre-crastination: Hastening subgoal completion at the expense of extra physical effort. Psychological Science, 25(7), 1487-1496. doi:10.1177/0956797614532657]. The current study (N = 48) examined whether precrastination is affected by a concurrent memory load as predicted by the cognitive-load-reduction (CLEAR) hypothesis. Participants completed a bucket-carrying task under different memory-load conditions. In addition, the amount of physical effort was manipulated by changing the distance people needed to walk while carrying the weighted buckets. The tendency to precrastinate by picking up a near bucket and carrying it further than necessary was affected by the memory load. People were more likely to precrastinate when doing so resulted in the more rapid renewal of cognitive resources and were less likely to precrastinate when this required that the memory load be held for a longer period of time. These data are consistent with the position that precrastination is linked with working memory resources and occurs in an attempt to clear items from a mental to-do list.

Understanding the cognitive miser: Cue-utilization in effort-based decision making

The notion that individuals adapt their behaviors in ways that are sensitive to the effortfulness of cognitive processing is pervasive in psychology. In the current set of experiments, we provide a test of a cue-utilization account of how individuals decide which course of action is more or less effortful. In particular, we contrast the influences of time costs and demands on executive control with the influence of an available effort cue. Using a variant of the demand selection task (DST) that specifically focused on making effort-based decisions, we provide evidence that effort-based decisions can be dissociated from both time costs and demands on executive control in a manner predicted by a cue-utilization account.

Task order choices in cognitive and perceptual-motor tasks: The cognitive-load-reduction (CLEAR) hypothesis

A core question in the study of the dynamics of cognition is how tasks are ordered. Given two tasks, neither of which is prerequisite for the other and neither of which brings a clearly greater reward, which task will be done first? Few studies have addressed this question, though recent work has suggested one possible answer, which we here call the cognitive-load-reduction (CLEAR) hypothesis. According to the CLEAR hypothesis, there is a strong drive to reduce cognitive load (to "clear one's mind"). Given two tasks, one of which is more cognitively demanding than the other, the more cognitively demanding task will tend to be done first. We tested this prediction using a novel method inviting participants to freely choose when to perform each of c = 5, 10, or 15 items per category in item-generation tasks relative to b = 10 box-moving tasks. The box-moving tasks were cognitively undemanding relative to the item generation tasks, whose cognitive difficulty presumably grew with c. A full half of our n = 122 participants chose to complete all of the c tasks before performing any of the b tasks, and most other participants chose to complete a majority of the c tasks before any of the b tasks. This result is consistent with the CLEAR hypothesis. Speed on the box-moving task decreased the later the category-generation task was completed, supporting another CLEAR prediction. The general method used here provides direction for future work on task order choices in cognitive and perceptual-motor tasks.

Sooner Rather Than Later: Precrastination Rather Than Procrastination

Putting things off as long as possible (procrastination) is a well-known tendency. Less well known is the tendency to attempt to get things done as soon as possible, even if that involves extra effort ( precrastination). Since its discovery in 2014, precrastination has been demonstrated in humans and animals and has recently been revealed in an analogous tendency called the mere-urgency effect. Trying to get things done as soon as one can may reflect optimal foraging, but another less obvious factor may also contribute—reducing cognitive demands associated with having to remember what to do when. Individual differences may also play a role. Understanding precrastination will have important implications for explaining why hurrying happens as often as it does and may help reduce the chance that haste makes waste.

End-state comfort meets pre-crastination

Research on motor planning has revealed two seemingly contradictory phenomena. One is the end-state comfort effect, the tendency to grasp objects in physically awkward ways for the sake of comfortable or easy-to-control final postures (Rosenbaum et al., Attention and Performance XIII: Motor representation and control, Lawrence Erlbaum Associates, Hillsdale, New Jersey, 1990). The other is pre-crastination, the tendency to hasten the completion of tasks even at the expense of extra physical effort (Rosenbaum et al., Psychol Sci 25:1487-1496, 2014). End-state comfort seems to reflect emphasis on final states, whereas pre-crastination seems to reflect emphasis on initial states. How can both effects exist? We sought to resolve this seeming conflict by noting, first, that the effects have been tested in different contexts. End-state comfort has been tested with grasping, whereas pre-crastination has been tested with walking plus grasping. Second, both effects may reflect planning that aids aiming, as already demonstrated for end-state comfort but not yet tested for pre-crastination. We tested the two effects in a single walk-and-grasp task and found that demands on aiming influenced both effects, although precrastination was not fully influenced by changes in the demands of aiming. We conclude that end-state comfort and precrastination are both aiming-related, but that precrastination also reflects a desire to hasten early task completion.