By Emily Reynolds

Deadlines, though stressful, can be a pretty good motivator. Knowing you have to submit some work by a particular date can make it easier to get things done; you simply have to get on with it. This also goes for non-professional deadlines — trying to get in shape by the time you run a specific race, for example, can be a lot more motivating than a more vague and nebulous desire to get fit.

But why is this the case? Maayan Katzir and colleagues at Tel Aviv University have investigated the phenomenon in a new paper, recently published in Cognition — and they suggest it may be down to how we conserve and use effort.

In an initial experiment, 64 undergraduate students were asked to perform a complex task, completing a series of trials in which they had to switch between four different activities: two Stroop tasks, in which participants were asked to name colours or read words, and two spatial tasks, in which they had to indicate the direction of arrows. In each trial, they also had to ignore distracting stimuli. Participants were told that those scoring in the top 25% on accuracy would receive a monetary reward.

Participants completed 10 blocks of 240 trials, making a total of 2400 trials. Importantly, one group was told that the experiment was split into blocks, and were given information about how many blocks of the total they had completed as they went along, while the other was not. Neither group received feedback on how well they were performing. After the third, sixth and ninth blocks, participants were also asked how tired, bored and energetic they felt, the answers to which were used to calculate a fatigue score.

Participants in the feedback condition — those who were aware of how far they had progressed through the experiment — had a higher level of performance, as measured by their speed and accuracy; this was particularly pronounced towards the end of the experiment, suggesting that knowing when a task is going to end does indeed make it easier to complete. Participants receiving feedback also spent less time taking breaks towards the end than their non-feedback peers, though they didn’t report feeling any less fatigued.

A second experiment replicated the design of the first — except, this time, there were even more blocks. Participants were asked to complete twelve blocks of 240 trials, bringing the total to 2880. And as in the first experiment, feedback on progress had a positive impact on performance. Participants in the no feedback condition also reported feeling more fatigued — but only towards the end of the experiment. This group also spent more time on breaks than those aware of how many blocks they had left.

So why do we perform better when we know a task is going to end? Our desire to engage in more interesting activities may have something to do with it. If we’re aware of the fact a tedious task is nearly finished, we also know that leisure activities are within our reach: remaining engaged in our task and taking fewer breaks means that those more tantalising opportunities are closer to hand.

It may also be to do with how much effort we allocate to particular activities, the team suggests. If we have no idea how much longer we’re going to be engaging in a particular task, we’re unlikely to put all of our energy into it; if we know the end is near, we feel more able to try our hardest without fear of running out of energy.

This could relate to how we conceptualise willpower, too: another recent study found that those who believe they possess a limited and finite amount of energy are less likely to motivate themselves to get to bed on time. So people who believe that our willpower is a limited resource may be particularly likely to try and conserve effort when they don’t know how much longer a task will last.

Those in the feedback condition did indeed perform better than their counterparts — but that doesn’t mean their performances were as high as they could be. It would be interesting to look at the timing of progress feedback — could introducing progress feedback only towards the end of a task push performance even higher?

What is clear, however, is that knowledge of how a task is progressing can have a significant impact both on how much effort you expend on it and how well you perform. So if you really want to get that boring bit of work out of the way? You may well benefit from setting yourself a deadline.

– Cognitive performance is enhanced if one knows when the task will end

Emily Reynolds (@rey_z) is a staff writer at BPS Research Digest