Participants
Thirty-four participants were recruited from the National Chengchi University in Taipei.
Two participants were excluded because of the image interference of participants’ dental mouthpiece. Finally, thirty-two participants (mean age 21.6; 12 male and 20 female) were included in analyses. Participants had normal or corrected-to-normal visual acuity and no known neurological condition. After being informed about potential risks, participants gave informed written consent before participating. The experimental standards were approved by the local ethics committee of National Taiwan University in Taipei.
Materials
Totally 150 stimuli including 51 familiar and 99 novel logos selected by researchers were used in current study. The stimuli were divided into two groups. One group had 75 stimuli including 25 familiar and 50 novel logos. The other group had 75 stimuli including 26 familiar and 49 novel logos. These two groups of stimuli were counterbalanced among participants in the study. Event-related design with random ISI (inter-stimulus interval) was employed. Based on each participant’s aesthetic response, beautiful versus unbeautiful logos were grouped. Therefore, 2 (familiar versus novel) × 2 (beauty versus non-beauty) contrasts
were formed.
Procedure
fMRI experiment
The paradigm comprised two sets of experimental stimuli. One set contained familiar logos and the other set contained novel logos. Stimuli were presented in random order.
Background color of the screen was black throughout the experimental session. Within each trial, the screen-centered presentation of the target stimulus lasted until participants made the responses, and then was preceded by 2-second resting baseline condition. Participants were asked to judge whether the logo stimulus was beautiful or not beautiful. They were instructed to press one of the two response bottoms (“right” for beautiful or “left” for not beautiful) when they were ready for decision while the stimulus was presented. In the resting baseline condition, no stimulus was presented but only a black screen with a centered fixation cross.
Participants were instructed to fixate at the cross and wait for the next trial.
Data acquisition
Participants were briefed before the fMRI experiment. In the fMRI session, participants were supine on the scanner bed. To prevent postural adjustments, form-fitting cushions were used to prevent head motion. Participants were provided with earplugs to attenuate scanner noise. Imaging was performed at 3T. A set of two-dimensional (2D) anatomical images was acquired for each participant immediately before the functional experiment, using a modified-driven equilibrium Fourier transformation (MDEFT) sequence. In a separate session, high-resolution whole-brain images (160 slices and 1 mm slice thickness) were acquired from each subject to improve the localization of activation foci using a T1-weighted three-dimensional (3D) segmented MDEFT sequence covering the whole brain.
fMRI data analysis
Prior to statistical analysis, all images were reconstructed, aligned, and corrected (in the x and y dimension) for movement artifacts (Woods, Mazziotta, and Cherry 1993). A two-dimensional Gaussian filter (approximately 3 mm at half-height) was applied to enhance signal-to-noise characteristics for each voxel. Signal changes during brain activity were identified using a “block design” that compared average signal amplitude acquired during the activity epochs with average signals acquired during baseline epochs according to a general linear model. An “active” voxel was defined as one in which the average magnetic resonance signal acquired during the stimulation periods was significantly different from the average baseline levels, p < .005, corrected for multiple comparisons based on empirically validated false-positive rates obtained using both resting brain and copper sulfate phantoms (Hirsch et al. 2000). This particular analysis procedure was developed to map sensory/motor, language, and visual-sensitive areas for neurosurgical planning using fMRI, and has been validated by conventional mapping techniques such as direct cortical stimulation, somatosensory evoked potentials, and surgical outcome studies. An active area was defined for each subject as a cluster of at least 5 contiguous voxels each with a false-positive rate, p < .005.
To preserve the highest spatial resolution for each participant, an idiopathic strategy was applied for the first stage of data analysis where each subject was processed separately. A modified “forward transform” method was employed to assign labels to the active individual brain areas for each subject where the brain topology was employed as an index to labels of the Human Brain Atlas (Lancaster et al. 2000). Accordingly, the stages of assignment included identification of the brain slice passing through the AC/PC line and location of respective commissures of the axial view; assignment of an atlas plate to each brain slice;
location of the vertical AC/PC plane on all T2*-weighted images of brain slices; location of
the central sulcus and confirmation of those landmarks on all T1-weighted images of brain slices; assignment of the anatomical labels, Brodmann’s areas, and atlas sectors for each active cluster; and determination of each active cluster volume on the basis of voxel count.
RESULTS
Manipulation checks
The familiar versus novel logos were checked by participants’ post-test behavioral responses for whether they have seen the logo or not. Participants recognized the familiar logos more (mean = 5.20, s.d. = 1.52) than novel logos (mean = 1.87, s.d. = 1.11), t-value = 32.44, p <.001.
Beauty versus Non-Beauty Contrast
The contrast of beautiful versus unbeautiful novel logos indicated stronger activation of the medial and inferior frontal gyrus as well as inferior parietal lobule. On the other hand, the contrast of beautiful versus unbeautiful familiar logos involves lots areas. As predicted, frontal cortex activations were associated with beautiful versus unbeautiful judgment for logos. The main responsible areas were medial frontal gyrus (Brodmann area 6 and 46) and superior frontal gyrus (Brodmann area 9 and 10). The parietal cortex activation also
indicated in beautiful versus unbeautiful contrast among familiar logos. These areas involve frontal cortex that are associated with aesthetic evaluation from top-down cognitive
processing. Further, the stronger activation was found in inferior parietal lobule and supramarginal gyrus (Brodmann area 40) and precuneus (Brodmann area 7). Similar with Vartanian and Goel (2004), we found that right anterior cingulate gyrus (Brodmann area 10 and 32) and bilateral cingulate gyrus activation in beauty versus non-beauty contras. These
areas involve caudate cortex that are associated with reward value.
Figure 1. Beautiful versus Unbeautiful Contrast among Familiar Logos
Familiar versus Novel Contrast among Beautiful Logos
By comparison of brain area activation between familiar and novel, we explore the possible brand influencing aesthetic perception meaning within logos. As Figure 2 indicated, the contrast indicated mainly stronger activation of the medial and superior frontal gyrus (Brodmann area 9). Posterior cingulate (Brodmann area 31), middle temporal gyrus
(Brodmann area 39), and superior temporal gyrus (Brodmann area 22) had stronger activation while participants response to familiar than novel beautiful logos.
Figure 2. Familiar versus Novel Contrast among Beautiful Logos