Biomedical subjects

Cristina Meinecke

Publications and source records attributed to Cristina Meinecke.

5 recordsLinked to original sources

PubMed2006

Detecting emotional faces and features in a visual search paradigm: are faces special?

In 2 experiments, participants were presented schematic faces with emotional expressions (threatening, friendly) in a neutral-faces context or neutral expressions in an emotional-faces context. These conditions were compared with detection performance in displays containing key features of emotional faces not forming the perceptual gestalt of a face. Supporting the notion of a threat detection advantage, Experiment 1 found that threatening faces were faster detected than friendly faces, whereas no difference emerged between the corresponding feature conditions. Experiment 2 increased task difficulty with a backward masking procedure and found corresponding results. In neither of the studies was the threat detection advantage associated with reduced accuracy. However, features were, in general, detected faster than faces when task difficulty was high.

Adolescent↗

PubMed2006

A 'first stage' central performance drop in a Gabor luminance-modulation detection task.

In an experiment, 20 participants had to detect a backward masked Gabor luminance-modulation target imposed on a field of uniform luminance at varying eccentricities along the horizontal meridian. Different spatial frequencies were used as target modulations. Results for a 7.0 c/deg target patch showed peak detection performance at the center of the visual field and a steady decrease toward the periphery. For 1.0 c/deg, 0.75 c/deg, and 0.5 c/deg target patches, in contrast, the peak was several degrees off retinal center and decreased steadily toward the center. Findings not only confirmed the familiar sensitivity loss toward peripheral areas for high spatial frequencies, but also indicated a sensitivity loss toward central areas for low spatial frequencies. It is concluded that they further support Gurnsey et al.'s (1996) 'mismatch hypothesis' extending its scope to also include 'first-stage' stimuli.

Color Perception↗

PubMed2004

Texture segmentation and visual search for pop-out targets. An ERP study.

"Parallel" visual search and effortless texture segmentation were believed to rely on similar mechanisms until Wolfe [Vis. Res. 32 (1992) 757] demonstrated that efficient visual search and effortless texture segmentation are not always the same thing. In a recent study, Meinecke and Donk [Perception 31 (2002) 591] varied display size in a pop-out task and found that, albeit stimulus elements and the task remained the same, different set sizes led to different processing modes. These findings indicate that it may suffice to vary set size in an otherwise unchanged pop-out task to initiate different processing which may be similar to the processing in efficient visual search and in effortless texture segmentation. In four experiments, we further investigated this issue by presenting stimulus arrays of different set sizes while recording event-related brain potentials (ERPs). We found that when display size was increased, detection performance first decreased slightly before it then increased. ERP effects were observed for the posterior N2 (N2p), the N2pc and the P3 component. All three components showed variations with set size; N2p differential amplitude effects were confined to large set sizes, whereas an N2pc was obtained for a broader set size range except for very small set sizes and the largest set size (121 elements). We interpret both the non-monotonic relationship between set size and response data and the variations of ERP components with set size as evidence in favor of different processing occurring for stimulus arrays with small and large set sizes.

Adult↗

PubMed2002

Detection performance in pop-out tasks: nonmonotonic changes with display size and eccentricity.

We carried out three experiments to investigate detection performance in pop-out tasks and analysed how performance varied as a function of display size (number of elements) and retinal eccentricity of the target. Results showed that when display size was increased from 2 to 81 elements performance first decreased and then increased (replicating Sagi and Julesz, 1987 Spatial Vision 2 39-49). Performance variations differed as a function of eccentricity and often were more pronounced in the periphery than in the foveal area. This retinal-eccentricity influence suggests that processes underlying detection performance in small display sizes are different from those in large display sizes. One should be careful when using the variation of display size as an instrument to analyse visual-search processes because this analysis could be based on a comparison between non-equivalent conditions.

Adult↗

PubMed2002

A reversal in the direction of detection asymmetry: effects of spatial density, spatial regularity, and retinal eccentricity.

We analyzed detection asymmetry, using openand closed squares as target and contextelements. It was found that varying density, regularity, and target eccentricity not only can modulate the amount of asymmetry, but also can produce a reversal in the direction of the asymmetry. The results suggest that the different stimuli are processed with different grains of analysis,consisting of in some cases, single elements and their properties and, in other cases, larger units of the stimulus array and more globalproperties. A detection task that can utilize the properties that are available with a given grain of analysis would show an advantage over a task for which the given grain of analysis is not as favorable, resulting indetection asymmetry in one direction or another.

Adult↗