Hyperacuity and Obligatory Looking

Beginning about four months of age, the perception of detail takes another leap forward with the emergence of hyperacuity: the ability to discriminate features that are up to ten times finer than the size of the photoreceptors should theoretically permit. It is this ultrafine discrimination that allows us, for instance, to see a very slight glitch in an otherwise straight line. even though the size of the glitch is below our eyes' limit of resolution. It is not yet known how our brains perform this remarkable feat, but it is generally agreed that the necessary processing takes place in the cerebral cortex. Babies show rapid improvement on hyperacuity tests between ten and eighteen weeks of age, in accordance with the massive maturation of the visual cortex over the same period.


In the second month of life, babies exhibit another striking visual behavior that is related to the externality effect. It is called obligatory looking, and as the name implies, babies this age may fixate on a single object, sometimes for thirty minutes or more. The reason their gaze gets stuck is because this is when the visual cortex first begins exerting control over brain-stem visual centers, the net effect of which is to inhibit babies' habitual eye movements toward their peripheral visual field. So even though Ginna, now six weeks old, wants to look away from that bright lamp in front of her, an awkward struggle between her cortical and subcortical visual centers prevents her from doing so. Poor thing!


Two visual phenomena in the developing infant. One is the ability to make out visual details for which the eye does not appear physically capable of registering and the other is a conflict between the visual cortex and the brain stem that gets the baby stuck staring at something.

Folksonomies: babies vision infant development

/family and parenting/babies and toddlers (0.352758)
/health and fitness/disease (0.148681)
/science/ecology/pollution (0.137945)

visual cortex (0.903618 (negative:-0.469306)), subcortical visual centers (0.738124 (negative:-0.735594)), striking visual behavior (0.730920 (negative:-0.213059)), habitual eye movements (0.704321 (negative:-0.644932)), peripheral visual field (0.699775 (negative:-0.644932)), brain-stem visual centers (0.689224 (negative:-0.500995)), hyperacuity tests (0.634951 (neutral:0.000000)), cerebral cortex (0.628238 (positive:0.207761)), slight glitch (0.567459 (negative:-0.678510)), visual phenomena (0.545668 (negative:-0.471916)), babies exhibit (0.540668 (negative:-0.213059)), visual details (0.540212 (negative:-0.622380)), ultrafine discrimination (0.527957 (negative:-0.590793)), brain stem (0.525424 (negative:-0.622380)), times finer (0.521441 (neutral:0.000000)), massive maturation (0.516622 (negative:-0.284543)), remarkable feat (0.516568 (positive:0.214944)), awkward struggle (0.497003 (negative:-0.735594)), straight line. (0.494587 (negative:-0.678510)), necessary processing (0.488812 (positive:0.207761)), Poor thing (0.483367 (negative:-0.844453)), externality effect (0.479578 (negative:-0.213059)), bright lamp (0.478413 (negative:-0.500581)), rapid improvement (0.475588 (neutral:0.000000)), single object (0.474331 (negative:-0.284799)), net effect (0.469368 (negative:-0.427368)), age (0.356191 (negative:-0.284799)), Obligatory (0.323410 (negative:-0.471916)), ability (0.318876 (negative:-0.622380)), size (0.304032 (negative:-0.568695))

cerebral cortex:FieldTerminology (0.918899 (positive:0.207761)), Ginna:Person (0.660079 (negative:-0.618087)), eighteen weeks:Quantity (0.660079 (neutral:0.000000)), thirty minutes:Quantity (0.660079 (neutral:0.000000)), four months:Quantity (0.660079 (neutral:0.000000)), six weeks:Quantity (0.660079 (neutral:0.000000))

Brain (0.976099): dbpedia | freebase | opencyc
Cerebral cortex (0.725402): dbpedia | freebase
Eye (0.554292): dbpedia | freebase | opencyc
Visual perception (0.543187): dbpedia | freebase | opencyc
Human brain (0.506032): dbpedia | freebase
Visual system (0.442946): dbpedia | freebase | opencyc
Thalamus (0.410503): dbpedia | freebase | opencyc
Infant (0.409015): dbpedia | freebase | opencyc

 What's Going on in There? : How the Brain and Mind Develop in the First Five Years of Life
Books, Brochures, and Chapters>Book:  Eliot , Lise (2000-10-03), What's Going on in There? : How the Brain and Mind Develop in the First Five Years of Life, Bantam, Retrieved on 2011-07-18
Folksonomies: parenting babies development infants physiology