XI Conference – European Congress of Methodology

Choose your own PAS? Studying the validity of the Perceptual Awareness Scale

24 Jul 2025, 15:00

15m

Faculty of Social Sciences and Communication. (The Pyramid)/12 - Room (Faculty of Social Sciences and Communication. (The Pyramid))

Oral Presentation Measurement Session 1 : "Development and validation of psychometric instruments"

Speaker

Alicia Franco-Martínez (Universidad Autónoma de Madrid)

Abstract

Any psychometrician knows how complex it is to measure constructs such as intelligence or personality. Psychological tests have addressed this task including various items and dimensions (ideally) representative of the construct under measurement. But now imagine that you intend to measure, not a trait, but a particular feature of a brief experience: the perceptual awareness of a certain stimulus. For many decades, the measure was simple: Did you see the stimulus? Seen / Unseen. The reasonable extension to a gradual measure came across by Ramsøy and Overgaard in 2004, who presented the “Perceptual Awareness Scale” (PAS), a 4-point scale with which participants had to report from ‘No experience’, ‘Brief glimpse’, ‘Almost clear image’, to ‘Absolutely clear image’ in each trial. Since then, some authors have explicitly discussed the validity of this scale and proposed crucial requirements (e.g., to include the specific stimulus’ feature in the PAS labels). However, most of the hundreds of papers using the PAS modify its labels and categories lacking a proper justification of these modifications. This is particularly problematic when researchers implicitly assume that different versions of the PAS are invariant measures (i.e., that a PAS=1 means the same regardless of the study), without empirical support for this assumption.

While pretesting the procedure of an ongoing replication study conducted by our team, we observed substantial changes in pilot participants' performance when varying the PAS labels and instructions. Following up on this unexpected finding, in the present work, we have run a typical unconscious processing experiment, where trials are always preceded by a PAS assessing the visual perception of the stimulus presented. In an experimental between-subjects design, we have randomly assigned one of the conditions to each participant, varying the instructions, the presence of labels, and the versions of the PASs employed. Our goal is to determine which combination is more appropriate to measure perceptual awareness. In doing so, we will propose different ways to obtain and study validity evidence in this experimental measuring context. Additionally, we will explore the stability of the PAS labels’ meanings across the experiment.