• Petersen, Anders
• Vangkilde, Signe
• Wiegand, Iris
• Bundesen, Claus
• Cooreman, Bart

Abstract

A bilateral change detection paradigm is often used to measure lateralized ERP-components, such as the Contralateral Delay Activity (CDA), believed to be associated with visual short-term memory (e.g. Vogel and Machizawa, 2004; Alvarez and Cavanagh, 2004; McCollough et al., 2007 ). Recently, Wiegand et al. (2014) developed a similar whole report paradigm in which participants reported the identity of four letters, presented in a pre-cued hemifield, showing a correlation between CDA amplitude and visual short-term memory capacity when modeled using Bundesen' s Theory of Visual Attention (TVA) (Bundesen, 1990) - in line with earlier findings suggesting that individuals with larger visual working memory capacity have larger CDA amplitudes than lower-capacity individuals (Vogel and Machizawa, 2004). In our EEG-study, we modeled healthy participants' visual attention performance in two versions of a five-letter whole report: a pre-cued version, similar to the paradigm used in Wiegand et al. (2014) in which a hundred percent valid symbolic cue preceded the letter display, and a blocked version, in which all letters in a given block were shown on the same side of the screen. The behavioral data were modelled by TVA, providing an estimate of perceptual threshold, processing speed, and visual short-term memory capacity for each participant. Our results show that the blocked design compared with the intermixed pre-cued design provided an equally good estimate of participants' TVA-parameters, and an equally prominent CDA. A clear advantage of the blocked design, however, is that participants seems to make less horizontal eye-movements compared with the intermixed design, and most important, the activity preceding our stimulus display is reduced in absence of a pre-cue, resulting in a more reliable baseline activity. A blocked design might therefore be considered a valid (and perhaps even slightly superior) alternative for cuing.

Topics

• impedance spectroscopy
• theory
• laser emission spectroscopy