Seeing Objects as Faces Enhances Object Detection

A behavioral advantage for the face pareidolia illusion in peripheral vision

Investigation of visual illusions helps us understand how we process visual information. For example, face pareidolia, the misperception of illusory faces in objects, could be used to understand how we process real faces. However, it remains unclear whether this illusion emerges from errors in face detection or from slower, cognitive processes. Here, our logic is straightforward; if examples of face pareidolia activate the mechanisms that rapidly detect faces in visual environments, then participants will look at objects more quickly when the objects also contain illusory faces. To test this hypothesis, we sampled continuous eye movements during a fast saccadic choice task-participants were required to select either faces or food items. During this task, pairs of stimuli were positioned close to the initial fixation point or further away, in the periphery. As expected, the participants were faster to look at face targets than food targets. Importantly, we also discovered an advantage for food items with illusory faces but, this advantage was limited to the peripheral condition. These findings are among the first to demonstrate that the face pareidolia illusion persists in the periphery and, thus, it is likely to be a consequence of erroneous face detection.

Relationship between autistic traits and letter-recognition under attention to face-likeness: study using a henohenomoheji-type compound stimulus

This study aimed to clarify the relationship between autistic traits and letter information processing, specifically, the components of faces when attention is paid to face-like information. We created a new "henohenomoheji-type compound stimulus," in which letters are placed in positions in such a way as to resemble a face. In Experiment 1, we examined the relationship between autistic traits and the participants' performance in a letter-recognition task in which a henohenomoheji-type compound stimulus was used. The results showed a significant moderate negative correlation between Autism-Spectrum Quotient-Japanese Version (AQ-J) scores and letter-recognition sensitivity when the compound stimuli were arranged like a face. The letter-detection task was employed in Experiment 2 to examine how autistic traits affect tasks' performance with a lower cognitive load than in Experiment 1. We found no correlation between AQ-J scores and letter-detection sensitivity with or without face-like features. These results suggest that paying attention to faces reduces the participants' performance in letter recognition, which represents a higher cognitive load in individuals with higher autistic traits. A major implication of this study is that the henohenomoheji-type compound stimuli can be applied to several cognitive tasks, such as cognitive processing in individuals with autistic traits.

Pareidolic faces receive prioritized attention in the dot-probe task

Face pareidolia occurs when random or ambiguous inanimate objects are perceived as faces. While real faces automatically receive prioritized attention compared with nonface objects, it is unclear whether pareidolic faces similarly receive special attention. We hypothesized that, given the evolutionary importance of broadly detecting animacy, pareidolic faces may have enough faceness to activate a broad face template, triggering prioritized attention. To test this hypothesis, and to explore where along the faceness continuum pareidolic faces fall, we conducted a series of dot-probe experiments in which we paired pareidolic faces with other images directly competing for attention: objects, animal faces, and human faces. We found that pareidolic faces elicited more prioritized attention than objects, a process that was disrupted by inversion, suggesting this prioritized attention was unlikely to be driven by low-level features. However, unexpectedly, pareidolic faces received more privileged attention compared with animal faces and showed similar prioritized attention to human faces. This attentional efficiency may be due to pareidolic faces being perceived as not only face-like, but also as human-like, and having larger facial features-eyes and mouths-compared with real faces. Together, our findings suggest that pareidolic faces appear automatically attentionally privileged, similar to human faces. Our findings are consistent with the proposal of a highly sensitive broad face detection system that is activated by pareidolic faces, triggering false alarms (i.e., illusory faces), which, evolutionarily, are less detrimental relative to missing potentially relevant signals (e.g., conspecific or heterospecific threats). In sum, pareidolic faces appear "special" in attracting attention.

Do chimpanzees see a face on Mars? A search for face pareidolia in chimpanzees

We sometimes perceive meaningful patterns or images in random arrangements of colors and shapes. This phenomenon is called pareidolia and has recently been studied intensively, especially face pareidolia. In contrast, there are few comparative-cognitive studies on face pareidolia with nonhuman primates. This study explored behavioral evidence for face pareidolia in chimpanzees using visual search and matching tasks. Faces are processed in a configural manner, and their perception and recognition are hampered by inversion and misalignment of top and bottom parts. We investigated whether the same effect occurs in a visual search for face-like objects. The results showed an effect of misalignment. On the other hand, consistent results were not obtained with the photographs of fruits. When only the top or bottom half of the face-like object was presented, chimpanzees showed better performance for the top-half condition, suggesting the importance of the eye area in face pareidolia. In the positive-control experiments, chimpanzees received the same experiment using human faces and human participants with face-like objects and fruits. As a result, chimpanzees showed an inefficient search for inverted and misaligned faces and humans for manipulated face-like objects. Finally, to examine the role of face awareness, we tested matching a human face to a face-like object in chimpanzees but obtained no substantial evidence that they saw the face-like object as a "face." Based on these results, we discussed the extents and limits of face pareidolia in chimpanzees.

How to Lay Bricks: Local-Global Alignment Predicts Preference for Shifted Tile Patterns

We examine the aesthetic characteristics of row tile patterns defined by repeating strips of polygons. In experiment 1 participants rated the perceived beauty of equilateral triangle, square and rectangular tilings presented at vertical and horizontal orientations. The tiles were shifted by one-fourth increments of a complete row cycle. Shifts that preserved global symmetry were liked the most. Local symmetry by itself did not predict ratings but tilings with a greater number of emergent features did. In a second experiment we presented row tiles using all types of three- and four-sided geometric figures: acute, obtuse, isosceles and right triangles, kites, parallelograms, a rhombus, trapezoid, and trapezium. Once again, local polygon symmetry did not predict responding but measures of correspondence between local and global levels did. In particular, number of aligned polygon symmetry axes and number of aligned polygon sides were significantly and positively correlated with beauty ratings. Preference was greater for more integrated tilings, possibly because they encourage the formation of gestalts and exploration within and across levels of spatial scale.

Face pareidolia in the brain: Impact of gender and orientation

Research on face sensitivity is of particular relevance during the rapidly evolving Covid-19 pandemic leading to social isolation, but also calling for intact interaction and sharing. Humans possess high sensitivity even to a coarse face scheme, seeing faces in non-face images where real faces do not exist. The advantage of non-face images is that single components do not trigger face processing. Here by implementing a novel set of Face-n-Thing images, we examined (i) how face tuning alters with changing display orientation, and (ii) whether it is affected by observers’ gender. Young females and males were presented with a set of Face-n-Thing images either with canonical upright orientation or inverted 180° in the image plane. Face impression was substantially impeded by display inversion. Furthermore, whereas with upright display orientation, no gender differences were found, with inversion, Face-n-Thing images elicited face impression in females significantly more often. The outcome sheds light on the origins of the face inversion effect in general. Moreover, the findings open a way for examination of face sensitivity and underwriting brain networks in neuropsychiatric conditions related to the current pandemic (such as depression and anxiety), most of which are gender/sex-specific.

Animals in the Brain

Background

Pareidolic associations are commonly used in medical education to enhance perception of radiological abnormalities. A number of animal-inspired neuroradiological pareidolias have been defined which should alert clinicians to specific movement disorder diagnoses.

Methods

A review of the published literature detailing neuroradiological abnormalities in movement disorder syndromes was conducted, looking specifically for established animal-inspired pareidolic associations.

Results

A number of animal-inspired neuroradiological patterns with specific movement disorder associations have been defined. These include eye of the tiger sign, face of the panda sign, swallow tail sign, hummingbird sign, Mickey Mouse sign, ears of the lynx sign, dragonfly cerebellum, tadpole sign, tigroid/leopard skin sign, and bat wing sign.

Conclusion

Pareidolias represent a quick and easy way of enhancing perception, thereby improving the efficiency and accuracy of image analysis. Movement disorder physicians should keep in mind these associations, given that they will likely facilitate scan analysis.

Neural mechanisms underlying visual pareidolia processing: An fMRI study

Objectives

Pareidolia is the interpretation of previously unseen and unrelated objects as familiar due to previous learning. The present study aimed to determine the specific brain areas that exhibited activation during real-face and face-pareidolia processing.

Methods

Functional Magnetic Resonance Imaging (fMRI) scans were performed on 20 healthy subjects under real-face and face-pareidolia conditions in National Magnetic Resonance Research Center (UMRAM), Ankara, Turkey from April 2016 to January 2017. FSL software was used to conduct a FEAT higher level (group) analysis to identify the brain areas activated during real-face and face-pareidolia processing.

Results

Under both the real-face and face-pareidolia conditions, activation was observed in the Prefrontal Cortex (PFCX), occipital cortex V1, occipital cortex V2, and inferior temporal regions. Also under both conditions, the same degree of activation was observed in the right Fusiform Face Area (FFA) and the right PFCX. On the other hand, PFCX activation was not evident under the real-face versus face scrambled or face-pareidolia versus pareidolia scrambled conditions.

Conclusions

The present findings suggest that, as in real-face perception, face-pareidolia requires interaction between top-down and bottom-up brain regions including the FFA and frontal and occipitotemporal areas. Additionally, whole-brain analyses revealed that the right PFCX played an important role in processing real faces and in face pareidolia (illusory face perception), as did the FFA.

The effects of presentation time on preference for curvature of real objects and meaningless novel patterns

Objects with curved contours are generally preferred to sharp-angled ones. In this study, we aim to determine whether different presentation times influence this preference. We used images of real objects (experiment 1) and meaningless novel patterns (experiment 2). Participants had to select one of two images from a contour pair, curved and sharp-angled versions of the same object/pattern. With real objects, the preference for curved versions was greatest when presented for 84 ms, and it faded when participants were given unlimited viewing time. Curved meaningless patterns were preferred when presented for 84 and 150 ms. However, in contrast to real objects, preference for meaningless patterns increased significantly in the unlimited viewing time condition. Participants discriminated poorly between the two versions (curved and sharp-angled) of the meaningless patterns in the 84- and 150-ms presentations (experiment 3). Therefore, in short times with meaningless patterns, participants selected mostly the curved version without being aware of the difference. In conclusion, presentation time, type of stimulus, and their interaction influence preference for curvature.