Centre-of-Gravity Fixations in Visual Search: When Looking at Nothing Helps to Find Something

Table 1

Correlations of RT with the proportion of trials with stimulus fixations, central void fixations, and peripheral void fixations.

	Wide spacing			Narrow spacing
	Stim.	COG	Periph.	Stim.	COG	Periph.
Present trials	97.4%	65.5%	34.4%	91.4%	76.7	55.6%
Correl. (RT)	0.491*	−0.498 *	0.223	0.532*	−0.220	0.581*
𝑃 value (Regr.)	0.028	0.025	n.s.	0.016	n.s.	0.007
Absent trials	100%	85.1%	42.2%	91.5%	76.7%	74.8%
Correl. (RT)	NA	−0.251	0.300	0.587*	−0.179	0.687*
𝑃 value (Regr.)	NA	n.s.	n.s.	0.007	n.s.	0.007

Note. Mean proportion of trials with one or more stimulus fixations, one or more COG fixations, and one or more peripheral void fixations; the correlation of each of these values with the participants' mean RT, depicted separately for the wide and narrow spacing conditions and present and absent trials. Asterisks indicate significant correlations, as per linear regressions that were computed separately over the RT and the proportion of trials with stimulus fixations, COG fixations, or peripheral void fixations, respectively (exact 𝑃 values reported below). Bold font indicates negative correlations indicative of facilitation. Stim.: stimulus fixation; COG: central void fixation; periph.: peripheral void fixation.