Products that contain bismuth can temporarily turn your tongue black, according to Atlas of Adult Physical Diagnosis. Other Causes If you have a black tongue, then you could have a fungus called Aspergillus niger growing on the surface of your tongue. If you have too much bacteria growing in your mouth, it could cause your tongue to appear black and hairy, according to the Mayo Clinic.
In addition, a child is said to have a cognitive delay and/or a learning disability when they are performing at least two grade levels below their peers. For example, a third grade class is learning their multiplication tables, but a student with a cognitive delay would be performing math on a first grade level.
The ability to delay gratification develops as children mature and learn to forgo less-valued short-term pleasures in favor of pursuing valued long-term goals. This ability depends on executive function (ie, cognitive control), the cognitive functions underlying effective attention deployment, self-monitoring, and planning. The preschool delay of gratification task assesses preschoolers' self-control by asking them to choose between a small immediate reward (eg, 1 marshmallow) or waiting for an unspecified time to earn a somewhat more desirable reward (eg, 2 marshmallows).