Little girls like dolls, and little boys prefer toy cars. Is this a natural instinct or a choice under the influence of the acquired environment? In an experiment, researchers observed the preference of 3 to 8-month-old infants for toys and found that Babies stare at pink dolls significantly longer than toy trucks, while baby boys spend more time focusing on blue trucks. Therefore, researchers believe that different baby preferences for toys may be determined by sex genes. What are the assumptions implicit in the above conclusions? ['the baby has been paying attention to new things for a long time.', "baby's hobby of toys is not affected by the color of the toy.", "the difference in the placement of toy trucks and dolls will affect the baby's attention.", 'most babies are more likely to notice toys with the same or similar hue to their clothes.']