Taste modulator influences rare case of color-gustatory synesthesia

We investigated the effect of a sweetness blocker on the synesthetic taste experience of a rare color-gustatory synesthete, E.C., for whom specific colors elicit unique tastes. Blocking E.C.’s sweetness receptors while the tongue was otherwise unstimulated left other taste components of the synesthesia unaltered but initially reduced her synesthetic sweetness, which suggests a peripheral modulation of the synesthetic illusion

Is synesthesia a form of mental imagery?

Synesthesia occurs when the activation of one sense modality elicits an experience in another modality. Synesthetic experiences are often referred to as imagery, and indeed both mental imagery and synesthesia occur in many sense modes and can represent forms of internally generated sensory experiences. However, they differ in prevalence, effects on perception, how voluntary they are, and probably in sites of brain activation; moreover, imagery and synesthesia are clearly differentiated by synesthetes themselves. We conclude that they are best considered as related but distinct mental processes

Unmasking the Perky effect: Spatial extent of image interference on visual acuity

We have previously argued that visual mental images are not substitutable for visual per-cepts, because the interfering effects of visual stimuli such as line maskers on visual targets differ markedly in their properties from the interfering effects of visual images (the Perky effect ). Imagery interference occurs over a much wider temporal and spatial extent than masking, and unlike masking, image interference is insensitive to relative orientation. The lack of substitutability is theoretically interesting because the Perky effect can be compared meaningfully to real line masking in that both types of interference are visual, not due to optical factors (accommodative blur or poor fixation) or to high-level factors (attentional distraction, demand characteristics, or effects of uncertainty). In this report, however, we question our earlier position that spatial extents of interference are markedly different: when images and real lines are matched in contrast, which was not done previously, their interference effects have very similar spatial extents. These data add weight to the view that spatial properties of images and percepts are similar in respect to extent. Along with the wider temporal extent and the insensitivity to orientation, the new results remain com-patible with our older hypothesis that to create a clear mental image in a region of visual space, incoming signals from the eye must be suppressed (Craver-Lemley and Reeves, 1992). We have pursued this idea in this report using unmasking, in which adding ele-ments to the visual image in the region beyond the zone of suppression reduces the Perky effect. © 2012 Reeves and Craver-Lemley

Unmasking the Perky effect: Spatial extent of image interference on visual acuity

We have previously argued that visual mental images are not substitutable for visual per-cepts, because the interfering effects of visual stimuli such as line maskers on visual targets differ markedly in their properties from the interfering effects of visual images (the Perky effect ). Imagery interference occurs over a much wider temporal and spatial extent than masking, and unlike masking, image interference is insensitive to relative orientation. The lack of substitutability is theoretically interesting because the Perky effect can be compared meaningfully to real line masking in that both types of interference are visual, not due to optical factors (accommodative blur or poor fixation) or to high-level factors (attentional distraction, demand characteristics, or effects of uncertainty). In this report, however, we question our earlier position that spatial extents of interference are markedly different: when images and real lines are matched in contrast, which was not done previously, their interference effects have very similar spatial extents. These data add weight to the view that spatial properties of images and percepts are similar in respect to extent. Along with the wider temporal extent and the insensitivity to orientation, the new results remain com-patible with our older hypothesis that to create a clear mental image in a region of visual space, incoming signals from the eye must be suppressed (Craver-Lemley and Reeves, 1992). We have pursued this idea in this report using unmasking, in which adding ele-ments to the visual image in the region beyond the zone of suppression reduces the Perky effect. © 2012 Reeves and Craver-Lemley

Taste Modulator Influences Rare Case of Color-Gustatory Synesthesia

We investigated the effect of a sweetness blocker on the synesthetic taste experience of a rare color-gustatory synesthete, E.C., for whom specific colors elicit unique tastes. Blocking E.C.’s sweetness receptors while the tongue was otherwise unstimulated left other taste components of the synesthesia unaltered but initially reduced her synesthetic sweetness, which suggests a peripheral modulation of the synesthetic illusion

Self-generated visual imagery alters the mere exposure effect

To determine whether self-generated visual imagery alters liking ratings of merely exposed stimuli, 79 college students were repeatedly exposed to the ambiguous duck-rabbit figure. Half the participants were told to picture the image as a duck and half to picture it as a rabbit. When participants made liking ratings of both disambiguated versions of the figure, they rated the version consistent with earlier encoding more positively than the alternate version. Implications of these findings for theoretical models of the exposure effect are discussed. Copyright 2006 Psychonomic Society, Inc

Imagery-induced interference on a visual detection task

The literature on the interaction between visual imagery and visual perception provides conflicting outcomes. Some studies show imagery interferes with perception whereas others show facilitation on perceptual tasks. The effects of visual imagery on a detection task were examined in six experiments. When either a bar image (Experiment 1) or an image of the letter \u271\u27 (Experiment 3) overlapped with the targets, interference was discovered; however, images not overlapping the target did not effect detection (Experiments 2 and 4). Increasing the number of target locations caused the interfering effects of the image to disappear; however, there was no evidence of facilitation (Experiment 5). Physical stimuli interfered with detection whether there was overlap or not (Experiment 6). The results indicate that imagery induced interference may be lessened with more complex visual displays

Is it what you see, or how you say it? Spatial bias in young and aged subjects

Healthy subjects demonstrate leftward bias on visual-spatial tasks. However, young controls may also be left-biased when drawing communicatively, depicting the subject of a sentence leftward on a page relative to the sentence object, that is, a spatial-syntactic, implicit task. A leftward visual-spatial bias may decrease with aging, as right-hemisphere, dorsal, visual-spatial activation may be reduced in elderly subjects performing these tasks. We compared horizontal and radial (near-far) visual spatial bias, and spatial-syntactic bias, in healthy young and aged participants. Both horizontal and radial visual-spatial bias were smaller in aged participants when explicitly, but not implicitly assessed. Mean implicit far bias was greater in aged subjects, although this varied by task. We observed less implicit, spatial-syntactic left bias in aged than young participants. These results may be consistent with relatively less dominance of right hemisphere, dorsal spatial systems with aging. © 2008 Copyright © The International Neuropsychological Society 2008