Modality and spatial selectivity of attentional capture by body shadows
Poster Presentation

*Francesco Pavani
Dipartimento di Scienze della Cognizione e della Formazione, Università di Trento

Giovanni Galfano
Dipartimento di Psicologia dello Sviluppo e della Socializzazione, Università di Padova

     Abstract ID Number: 92
     Full text: PDF
     Last modified: June 24, 2005

Abstract
We have recently shown that cast shadows of the body capture attention even when task-irrelevant. Here, we examined whether such phenomenon is selective for tactile stimuli at the body or rather involves any stimulus presented in the hemispace occupied by cast shadow. Participants performed an up-down discrimination task, while viewing the shadow of the left or right hand cast in front of them, lateralised and unpredictable. The target was either tactile (a touch to thumb or index finger of either hands), visual near the body (a light delivered near thumb or index finger of either hands), or visual far from the body but near the cast shadow (a light delivered near the thumb or index finger of the cast shadow). Time interval between shadow and target onset was 1750 ms. The three target conditions were equiprobable and varied on a trial by trial basis. The results revealed that up-down discrimination was significantly faster at the hand casting the shadow than at the no-shadow hand selectively for tactile targets. When participants wore shaped gloves that projected an unnatural shadow (Exp.2), a shadow-driven attentional capture emerged again selectively for tactile targets, but only with prolonged exposure to the unnatural cast-shadow.