Neuropareidolia: diagnostic clues apropos of visual illusions

Pareidolia in Radiology Education: A Randomized Controlled Trial of Metaphoric Signs in Medical Student Teaching

OBJECTIVE

A radiology sign that references a resemblance to something which is not actually present within an image has been termed a 'metaphoric' sign. Metaphoric signs are widely described in the literature and commonly used in teaching as a form of pattern recognition, or 'pareidolia'. However, the educational benefit of metaphoric signs has not been previously assessed. We aimed to assess the utility of metaphoric signs in medical student teaching.

MATERIALS AND METHODS

Fifteen radiology cases were prepared into two lecture formats for medical student education. A 'test' lecture utilizing metaphoric radiology signs to describe the appearance of the cases and a 'control' lecture where pathology was compared to normal anatomical appearances without reference to metaphoric signs. Forty-nine volunteer medical students were randomized with cluster sampling to receive either the test or control lecture. Four days later, students were quizzed to determine retention of knowledge and to assess interest in the lecture on a visual analogue scale from 0 to 100.

RESULTS

The median interest level of the test group (69.5) was higher than the control group (50) (p = 0.001). The mean quiz score was higher in the test group (34.5) than in the control group (29) (Difference 5.5, 95% confidence interval 0.08-10.92, p = 0.047).

CONCLUSION

The use of metaphoric signs in radiology education of medical students increased interest, descriptive ability and short-term knowledge retention, compared to the same material taught with normal anatomy correlation. Metaphoric signs should be considered as a useful radiology teaching tool.

Visual Illusions in Radiology: Untrue Perceptions in Medical Images and Their Implications for Diagnostic Accuracy

Errors in radiologic interpretation are largely the result of failures of perception. This remains true despite the increasing use of computer-aided detection and diagnosis. We surveyed the literature on visual illusions during the viewing of radiologic images. Misperception of anatomical structures is a potential cause of error that can lead to patient harm if disease is seen when none is present. However, visual illusions can also help enhance the ability of radiologists to detect and characterize abnormalities. Indeed, radiologists have learned to exploit certain perceptual biases in diagnostic findings and as training tools. We propose that further detailed study of radiologic illusions would help clarify the mechanisms underlying radiologic performance and provide additional heuristics to improve radiologist training and reduce medical error.

Brief Report: Seeing the Man in the Moon: Do Children with Autism Perceive Pareidolic Faces? A Pilot Study

Faces are one of the most socially significant visual stimuli encountered in the environment, whereas pareidolias are illusions of faces arising from ambiguous stimuli in the environment. Autism spectrum disorder (ASD) is characterised by deficits in response to social stimuli. We found that children with ASD (n = 60) identify significantly fewer pareidolic faces in a sequence of ambiguous stimuli than typically developing peers. The two groups did not differ in the number of objects identified, indicating that the children with ASD had a specific lack of attention to faces. Pareidolia have considerable potential as naturalistic and easy-to-create materials for the investigation of spontaneous attention to social stimuli in children with ASD.

The potato chip really does look like Elvis! Neural hallmarks of conceptual processing associated with finding novel shapes subjectively meaningful

Clouds and inkblots often compellingly resemble something else--faces, animals, or other identifiable objects. Here, we investigated illusions of meaning produced by novel visual shapes. Individuals found some shapes meaningful and others meaningless, with considerable variability among individuals in these subjective categorizations. Repetition for shapes endorsed as meaningful produced conceptual priming in a priming test along with concurrent activity reductions in cortical regions associated with conceptual processing of real objects. Subjectively meaningless shapes elicited robust activity in the same brain areas, but activity was not influenced by repetition. Thus, all shapes were conceptually evaluated, but stable conceptual representations supported neural priming for meaningful shapes only. During a recognition memory test, performance was associated with increased frontoparietal activity, regardless of meaningfulness. In contrast, neural conceptual priming effects for meaningful shapes occurred during both priming and recognition testing. These different patterns of brain activation as a function of stimulus repetition, type of memory test, and subjective meaningfulness underscore the distinctive neural bases of conceptual fluency versus episodic memory retrieval. Finding meaning in ambiguous stimuli appears to depend on conceptual evaluation and cortical processing events similar to those typically observed for known objects. To the brain, the vaguely Elvis-like potato chip truly can provide a substitute for the King himself.

O uso de pinturas de Dalí como ferramenta para avaliação das alterações na percepção de forma e tamanho em pacientes esquizofrênicos

Estudos envolvendo portadores de esquizofrenia têm mostrado alterações severas da percepção e cognição. A maioria dos diagnósticos, entretanto, é baseada na avaliação de processos cognitivos. Nossos estudos investigaram a percepção alterada de forma e tamanho em pacientes com esquizofrenia e com depressão maior utilizando 24 pinturas de Salvador Dalí. Conduzimos dois estudos comparando grupos experimental e controle e observamos, em ambos os casos, que os portadores de esquizofrenia perceberam figuras 1,5 e 3,0 vezes maior do que os respectivos grupos controle. Em outro estudo com pacientes com depressão maior não foram observadas alterações na percepção de tamanho comparado ao grupo controle. Concluímos que este efeito de percepção de forma e tamanho alterados pode servir como marcador no diagnóstico precoce da presença de sintomas positivos na esquizofrenia. Sugerimos que estas pinturas de Salvador Dalí sejam utilizadas como ferramenta para avaliar alterações na percepção de formas e tamanhos em pacientes portadores de esquizofrenia e, assim, prevenir o agravamento dos sintomas cognitivos.