I am sure you have seen one of those advert on the Net that, at first glance, wants to invite you to answer some asinine questions (above) just so that they get some click-related revenue. Well, there is more to it than that meets the eyes. For example, that advert that asks which of two photos are male or female subjects? There were actually some scientific studies that concluded that men with feminine facial features are likely seen by women as more committed and less likely to cheat on their partners.
As for graphic that shows a collection of coloured dots that hides a numeral? That is actually an Ishihara Chart that is used to test for colour blindness. Colour blindness, by the way, afflict mostly men because the genes responsible for determining red and green perception are located in the X chromosome; because men have only one X chromosome, if this gene is somehow damaged in the single X chromosome there is no second X to fall back to in order to make fully functional eyes in terms of tri-colour visual perception.