The line drawing is simple.
Four kids are eating cake around a dinner table. Seems like they’re concerned about something and the drawing reveals why. A mouse has entered the dining room and has interrupted the party.
Mom is disturbed. She’s in the foreground, pointing to the creature. The children are reacting to her, and one kid just spilled his glass of milk. There’s a dog at the head of the table, taking advantage of the distraction, greedily scarfing down birthday cake.
Seems fairly anodyne. Normal birthday get-together, unremarkable urban rodent, normal human reaction, a pet with a sweet tooth. Move along, nothing to see here, right?
Right. But only if your brain is functioning typically. Only if you aren’t experiencing a condition known as – great ready for a double-stuffed, tongue-twister here – simultanagnosia.
If you have this acquired brain injury, there are several things that won’t make sense to you in this picture. One concerns mouse and mom. You can see the rodent and you can see the mother, but you have no ability to infer that mom is pointing to the mouse.
You can’t associate the look of unease on the kids’ faces to the fact mom is reacting, either. You won’t connect the spilled milk with anything, and the dog might as well be on another planet. You perceive every person, every object, every element, but you have no idea how to put the scene together. You live in a world without inferred cause and effect. You live in the world of simultanagnosia. Scientists use drawings like these to test for its presence.
Formally defined, simultanagnosia is “… an inability to integrate individual elements of a scene into a coherent meaning despite intact recognition of visual details.”
And that’s only half the story.
MORE FOREST FROM THE TREES?
Last entry I discussed an experience that might seem similar to simultanagnosia. I mentioned “form agnosia” the failure to perceive the entirety of an object, yet still capable of identifying its constituent parts.
Simultanagnosia takes things one step further, however. It’s concerned with multiple objects.
It seems the brain is pre-occupied not only with analyzing individual features of single objects, but how scenes filled with multiple objects relate to each other. The Darwinian logic is clear. Your brain is trying to make sense of this interaction in ways that might allow it to survive another day. After all, if you can’t infer that a lion charging at you is his way of saying grace before dinner, there won’t be much of you remaining for leftovers.
We’re only beginning to understand how the brain processes and contextualizes the way individual objects relate to each other. One of the most basic functions behind this activity is to realize there actually are other objects for which an interaction is possible. Followed by the fact of the interaction itself.
Does that sound odd?
Stay tuned to our next discussion. Things are about to get much stranger than being mildly disturbed about a rodent crashing a birthday party.
REFERENCES
Birthday Party Test and Quote
De Vries, S.M. et al. "The Birthday Party Test (BPT): A New Picture Description Test to Support the Assessment of Simultanagnosia in Patients with Acquired Brain Injury." Appl Neuropsych Adult 29, no. 3 (2022): 383-96.
General references to simultanagnosia
Baugh, L.A. et al. "Agnosia." Enc Behav Neurosci (2010): 27-33.
Chechlacz, M. et al. "The Neural Underpinings of Simultanagnosia: Disconnecting the Visuospatial Attention Network." J Cogn Neurosci 24, no. 3 (2012): 718-35.