Many grandparents start to wonder if their grandchildren are unusually smart and if there's any way they can support the parents' nurture and handling of the blossoming child. It's likely that if both parents are pretty darned smart, their children will be, too. There is a strong genetic influence, after all! But, sitting down and doing school work before you start school, doesn't necessarily point to a future genius. But, figuring out what kinds of schooling and talent support a young child needs can go a long way toward facilitating the child's growth into all he or she can be. And grandparents can play a significant role in enabling that to happen.
First, any "signs" of intelligence must be viewed only as possible indicators that the child is unusually intelligent. They are not PROOF. Some children are highly intelligent and show fewer of these signs while they are still young. Some kids show many of these signs while young and are bright, but not unusually bright in every area. Being intellectually gifted doesn't necessarily mean or guarantee all kinds of achievement, high grades, success in school, or high paying jobs.
Here are some common signs or early indicators that you can look for and consider:
Alertness: Probably the leading indicator of giftedness in infants, toddlers and preschool aged children is their alertness. It is hard to assess or describe. Gifted children tend to stare intently at what people are saying or doing, they seem to be wise beyond their years even before they speak. They almost always understand what adults are talking about long before they actually start speaking themselves. This alertness leads to them soaking up everything around them whether you are directly trying to teach them or not.
Language development/high interest in language: This early development and ability generally indicates verbal giftedness, but since it is generally associated, as well, with the brain development of little girls being ahead of and different from little boys in the verbal domain, sometimes girls will be perceived as brighter than equally bright boys in the early years. The frequently more precocious verbal development of girls can confuse many adults about "how gifted" a girl is while leading to underestimates of "how gifted" a young boy is. When a little boy is very verbally advanced, though, it is a more reliable sign that he will ultimately prove to be intellectually, verbally gifted. The content of the child's vocabulary, the words they correctly use, the way they string together words to form complex meaning and sentences, is more an indicator of intellectual giftedness than is simply early or a lot of talking.
Motor skills development: Gifted babies and toddlers are more purposeful in their motor activities, perhaps, but it is a physical skill that makes them dextrous or really good at it at an early age. When a child sits up or begins to walk unassisted is not really all that related to intellectual level. Purposeful means that they, as infants, don't just "bat" at something held before them, but stare and actually try to reach for and grasp it. They "play" with objects, investigate them, turn them over and over, and taste them. In my own experience, gifted infants and babies learn very early not to taste things or "mouth" things that adults tell them not to put in their mouths. Some gifted kids become perfectionistic early on and won't try their motor skills (for an audience) before they feel they are quite good at it. This is another reason why not to get hung up on the demonstrations of motor skills as an indicator of intellectual precocity!
Perception (they're particularly perceptive): Gifted babies and toddlers are often described as being like little sponges. They soak up everything around them. They also remember what they've seen or heard or smelled and bring it up or connect to it later -- in the right context -- much to the surprise of the adults around them. All of this perception tends to be related to their particular talent areas, too, what they will eventually prove to have an enduring ability or interest in. This is all related to "engagement." Gifted kids are paying attention. (This rarely transfers to their school behavior, however, because for gifted kids, there is often very little to learn in the same-aged classroom with material and other kids who are simply "doing" and "being" something very different.)
Memory (a good memory): Fantastic memories for what falls within their interest and ability domains. They remember what you said and how you said it. They soak up what is read to them. They notice the routes you take and how to get places. They start "reading" store and street signs because they've put what they've already learned by paying attention and remembering into action. Gifted children's brains are ready to soak up material in their environment while they are younger than other children. This is why they are so advanced of others when they start school. This is why school is frustrating and boring unless the school is set up for children like them.
Good problem solving: Usually good at this, but it depends on the topic, especially for boys. Boys tend to be specialists and more single-minded than girls. This ability is why parents and teachers need to also be smart and stay one step ahead of gifted youngsters so as not to be outsmarted by them too often. You need to be prepared to be surprised. A child who quickly figures out how to put something together or make something work is showing dexterity, and often spatial reasoning, cause and effect reasoning, effective use of trial and error, and memory for what's worked before skills. A child who picks up vocabulary and tries it out on a regular basis is also showing problem-solving skills. This shows in the discussions and arguments about why they think they should be allowed to do this or that when they want to, for example.
All of these signs can occur earlier in exceptionally and profoundly gifted kids. Let me just say this, the more highly intelligent an infant is, the less likely you can leave him or her in a bouncy seat without interacting with him or her and expect him or her to be happy. Very bright infants demand attention and interaction, some call it stimulation but that's not a clear enough term in my opinion. If caregivers take the child on a walk and talk to adults or on their phone instead of interacting with their infant, they're making a huge mistake! The child isn't happy; the child is insulted; the child feels unimportant, and you're missing the chance to lead the child forward into the big, wonderful world of learning and engaging with others.
For more specifics about all of this, please read the article "How Smart Is My Child? Using the Ruf Estimates™ of Levels of Gifted", the first article under the Resources tab.