Paschal Sheeran

Paschal Sheeran

Paschal Sheeran is a health psychologist at the University of North Carolina at Chapel Hill whose subject is the intention-behaviour gap: the distance between deciding to do something and doing it. He documented the size of that gap, spent two decades developing if-then planning as a way to narrow it, and in 2024 was first author on the meta-analysis of 642 tests that cut the technique's headline effect from d = 0.65 to d = 0.15 once corrected for publication bias. He is also the second author on the 2009 experiments showing that intentions noticed by other people get acted on less.

Who they are

Paschal Sheeran is the Stephen J. Walsh Distinguished Professor in the Department of Psychology and Neuroscience at the University of North Carolina at Chapel Hill, working on self-regulation and health behaviour change.

His descriptive contribution came first. Intentions predict behaviour, but far less well than the people holding them expect, and his research established both the size of the shortfall and the kinds of self-regulatory failure that produce it: failing to get started, and failing to protect a goal from competing pulls once started. That is the problem statement the rest of the work answers.

The intervention side is his long collaboration with Peter Gollwitzer on implementation intentions, the if-then plans that attach an action to a specific cue so the decision does not have to be made under pressure. Their 2006 meta-analysis of 94 studies gave d = 0.65, a medium-to-large effect, and it is the number that travelled into trade books, health interventions and productivity software for the better part of twenty years.

He is also the person who corrected it. In 2024, with O. Listrom and Gollwitzer, Sheeran published a meta-analysis covering 642 tests in the European Review of Social Psychology. The sample-weighted raw effect was d = 0.36. Trim-and-fill moved it to 0.35. A robust Bayesian model correcting for publication bias put it at d = 0.15, with a confidence interval from 0.08 to 0.22, and Egger's regression indicated substantial bias in the literature the earlier figure had been drawn from. Somewhere between a fifth and a half of the effect that circulates is the best current reading.

That is worth saying without hedging: he published the correction to his own field, as first author, on the finding his own career is most associated with. The result is not that the technique fails. A bias-corrected d of 0.15, reliably distinguishable from nothing and produced by an intervention that costs a sentence, is a respectable place to land. The error was never the technique. It was two decades of quoting a 2006 estimate as though nothing had been learned since.

The other paper he appears on here is Gollwitzer, Sheeran, Michalski and Seifert (2009), the four experiments on what happens when identity-related intentions are noticed by somebody else. It sits oddly alongside the planning work and that is the interest of it: one line of his research is about closing the intention-behaviour gap and the other is about a condition that widens it. See Self-Completion Theory.

Key papers

Gollwitzer, P. M. & Sheeran, P. (2006), "Implementation intentions and goal achievement: A meta-analysis of effects and processes", Advances in Experimental Social Psychology, 38, 69-119. 94 studies, d = 0.65. Accurate as published, and superseded by the 2024 analysis below.

Gollwitzer, P. M., Sheeran, P., Michalski, V. & Seifert, A. E. (2009), "When Intentions Go Public: Does Social Reality Widen the Intention-Behavior Gap?", Psychological Science, 20, 612-618. Second author. Four experiments; identity-related intentions noticed by others were acted on less intensively than intentions ignored; held among the strongly committed and not the weakly committed.

Sheeran, P., Listrom, O. & Gollwitzer, P. M. (2024), "The when and how of planning: Meta-analysis of the scope and components of implementation intentions in 642 tests", European Review of Social Psychology. First author. Raw d = 0.36, 95 per cent CI 0.33 to 0.40; trim-and-fill d = 0.35; bias-corrected d = 0.15, 95 per cent CI 0.08 to 0.22.

Key ideas

The intention-behaviour gap: intending to act and acting are separated by self-regulatory failures that can be specified, and therefore targeted.

If-then planning is one such target, and it works by moving the decision off willpower and onto a cue.

The current honest number for that technique is d = 0.36 raw and d = 0.15 once publication bias is corrected for, and he is the author who established it.

Being noticed pursuing an identity-related intention can reduce how intensively it is pursued, among people to whom the identity matters.

Concepts on this site

Implementation Intentions, the technique and its correction

Self-Completion Theory, the framework behind the 2009 studies

Find them elsewhere

Both the LinkedIn and Scholar profiles are listed by him on his own Social Psychology Network page, and the Scholar profile states UNC Chapel Hill. No X or Bluesky account could be confirmed

Checked 2026-09-10. Handles and affiliations go out of date, so treat this block as a snapshot rather than a standing fact.

Sources

  1. Gollwitzer, P. M. & Sheeran, P. (2006), Advances in Experimental Social Psychology, 38, 69-119.
  2. Gollwitzer, P. M., Sheeran, P., Michalski, V. & Seifert, A. E. (2009), Psychological Science, 20, 612-618.
  3. Sheeran, P., Listrom, O. & Gollwitzer, P. M. (2024), European Review of Social Psychology. Full text read.
  4. University of North Carolina at Chapel Hill, Department of Psychology and Neuroscience faculty listing, for his position and title. Verified September 2026.