Can you tell who an object is for just by watching a hand move?
People could guess, better than chance, whether someone was moving an object for themselves or for a partner just from subtle timing differences in the movement, and those better at reading emotions from eyes were better at it.
Source
Individual differences in reading social intentions from motor deviants
Study at a glance
- Design
- Human experiment — Exp 1: observers categorised 30 context-free videos of pick-and-place moves as social or personal, and accuracy was correlated with RME and motor-imagery scores; Exp 2: within-subject manipulation of how much timing information (reaction time, first-movement duration) remained in the clips
- N
- Experiment 1: 25 adults; Experiment 2: 23 different adults, pre-selected for scoring at least 27 on the French RME test; stimuli came from one filmed actor per experiment
- Population
- Healthy young French adults with normal vision, mostly women
- Outcome
- Percentage of videos correctly categorised as social versus personal intention; correlations with Reading the Mind in the Eyes and Movement Imagery Questionnaire scores; self-rated confidence
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
An actor moved a small wooden dowel to the centre of a table either before using it himself (personal intention) or before his partner used it (social intention), while motion capture recorded his hand. In Experiment 1, 25 adults watched 30 cropped video clips showing only the arm and object and judged which intention each showed; they also completed the Reading the Mind in the Eyes test and a motor-imagery questionnaire. In Experiment 2, 23 new adults judged clips from a different actor in three versions: original, with reaction time equalised, or with both reaction time and the grasping phase equalised, and rated their confidence.
What they found
In Experiment 1 observers were right on 65.7% of clips, above the 50% chance level, and accuracy correlated strongly with Reading the Mind in the Eyes scores (r = 0.677) but not with visual or kinaesthetic imagery. In Experiment 2 accuracy was lower overall and fell as timing cues were removed: 57.5% for original clips, 54.3% with reaction time equalised, and 51.9% (not above chance) when both timing cues were equalised. Confidence did not change across versions, suggesting observers were not aware of which clips were more informative.
The limits
What it doesn't show
Both samples were small and mostly female, and each experiment used a single filmed actor, so the kinematic 'signature' of social intention may be specific to those individuals; the second actor's movements were less distinct and performance was only modestly above chance. The Experiment 1 link between social skill and accuracy is correlational, and Experiment 2 recruited only above-median RME scorers, so it cannot test that link. The task offered just two alternative intentions with no context, so it is unclear how well this ability works in real, richer interactions. Participants' feeling of guessing was only informally recorded in Experiment 1.
Key terms
- Social intention
- The intention to affect another person with an action, for example placing a glass so a partner can use it, as opposed to using it yourself.
- Motor intention
- The immediate goal of a movement, such as putting an object on a table, which can be the same for different social intentions.
- Kinematics
- The measurable features of movement such as speed, duration, trajectory height and reaction time.
- Reading the Mind in the Eyes test
- A test in which people choose which mental-state word best matches a photograph of someone's eye region; used as a measure of social cognition.
- Motor imagery
- Mentally simulating a movement, either by feeling it (kinaesthetic) or seeing it (visual), without performing it.
Flashcards
0 of 10 answers reviewed
Research intelligence for this paper
See its role on concept claims, tensions it is part of, placement history, and related discoveries.
Quiz yourself
What was the chance level for the categorisation task?
Common questions
Why did the researchers crop the videos to show only the arm and the object?
To remove every contextual clue, such as the partner's presence or face, so that any above-chance judgement had to come from the movement itself.
Does this mean motor experience does not matter for reading others' actions?
Not necessarily. Only a self-report imagery questionnaire was used, and the authors suggest it may tap explicit awareness of movement rather than implicit sensitivity to small timing differences.
How big were the movement differences observers used?
Very small: the authors describe differences of a few millimetres and a few tens of milliseconds, which observers seemed to pick up without being aware of it.
More on Social cognition