Visual elements of subjective preference modulate amygdala activation - PubMed (original) (raw)

Visual elements of subjective preference modulate amygdala activation

Moshe Bar et al. Neuropsychologia. 2007.

Abstract

What are the basic visual cues that determine our preference towards mundane everyday objects? We previously showed that a highly potent cue is the nature of the object's contour: people generally like objects with a curved contour compared with objects that have pointed features and a sharp-angled contour. This bias is hypothesized here to stem from an implicit perception of potential threat conveyed by sharp elements. Using human neuroimaging to test this hypothesis, we report that the amygdala, a brain structure that is involved in fear processing and has been shown to exhibit activation level that is proportional to arousal in general, is significantly more active for everyday sharp objects (e.g., a sofa with sharp corners) compared with their curved contour counterparts. Therefore, our results indicate that a preference bias towards a visual object can be induced by low-level perceptual properties, independent of semantic meaning, via visual elements that on some level could be associated with threat. We further present behavioral results that provide initial support for the link between the sharpness of the contour and threat perception. Our brains might be organized to extract these basic contour elements rapidly for deriving an early warning signal in the presence of potential danger.

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Figures

Fig. 1. Examples of the stimuli used in the experiment

(A) Pairs of real objects; (B) Pairs of novel patterns; and (C) Control baseline objects, comprised of a mixture of curved and sharp angles. Pairs of objects and patterns were matched in appearance and in semantic meaning so that the contour was the critical difference between them. (D) A depiction of the experimental sequence.

Fig. 2. Decreased preference and increased amygdala activation for items with sharp angles

(A) Percent “Like” responses as a function of contour type; (B) Percent fMRI signal change in the amygdala, averaged across the left and right hemispheres of fifteen participants during the peak activation time interval (2-6 s). All error bars represent 95% confidence intervals; they reflect standard errors across participants. (C) Statistical map showing a significant differential activation in the amygdala when comparing the activity elicited by sharp- angled objects with their curved counterparts.

Fig. 3. Examples of the filtered stimuli used in Experiment 2

(A) Pairs of real objects filtered to include the low spatial frequencies (LSFs; up to ten cycles per image); (B) Pairs of real objects filtered to include the high spatial frequencies (HSFs; higher than 24 cycles per image); (C) Control baseline objects filtered to include the same LSFs; (D) Control baseline objects filtered to include the same HSFs. The contrast of the images has been modified slightly from the experimental version to optimize visibility in the figure. Recognition was equated between the two conditions in a pilot experiment.

Fig. 4. Low spatial frequencies drive the preference for curved objects

The difference in percent “Like” responses between curved and sharp contour objects (i.e., curved – sharp) for low spatial frequencies (LSFs) and for high spatial frequencies (HSFs). The difference for LSFs is significantly greater than the difference for HSFs.

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Visual elements of subjective preference modulate amygdala activation - PubMed (original) (raw)