Cognitive Development PDF

Cognitive Development I. Development of depth perception: visual cliff experiment II. Piagettian stages of cognitive development III.Object permanence and reasoning in infancy I. Strengths and weaknesses of Piagettian theory II. Modeling object permanence IV. Development of self-recognition V. Mindr...

Cognitive Development I. Development of depth perception: visual cliff experiment II. Piagettian stages of cognitive development III.Object permanence and reasoning in infancy I. Strengths and weaknesses of Piagettian theory II. Modeling object permanence IV. Development of self-recognition V. Mindreading A. Pretend play B. False belief task C. Theory of mind mechanism and shared attention mechanism Depth perception: visual cliff experiment Infants who have had experience crawling develop wariness of heights 6-7 month-old infants who crawl or move around on glass show increased heart rate (fear) Younger infants who have not had experience crawling do not show fear Piagettian Stages of Cognitive Development Piaget’s theory of cognitive development Theory of how humans acquire, construct, and use knowledge Piaget observed that children of different ages made different kinds of mistakes when solving problems This led him to believe that children are not just “little adults” who know less; rather, they think and speak differently He proposed that humans progress through four developmental stages Sensorimotor stage (birth – 2 years) Children act on objects (e.g., grasping, sucking, stepping), coordinate sensory experiences (e.g., vision and hearing) from these interactions, and form schemas (internal mental representations) about objects They learn to think about aspects of the environment outside of the reach of their senses Ø Ex: Object permanence: Understanding that object continues to exist even though they cannot see it − Infants do not understand object permanence, which is why they respond to the game of peek-a-boo o Once they develop object permanence, they quickly lose interest in the game − Infants also won’t reach under cloth for toy that is hidden ☞ According to Piaget, object permanence is one of most important accomplishments of the sensorimotor stage Pre-operational stage (ages 2-7) Child develops ability to symbolize objects and events that are absent Engages in pretend play However, child still has trouble seeing things from different points of view: thinking is egocentric Ø Three-mountain task: Child is unable to describe how the mountains would look to the doll v Shift to new stage often happens quite abruptly, within a matter of a couple of weeks Understanding at this stage is based on appearances rather than principles Ø Conservation of liquid quantity “Do they have the same amount of milk or a different amount?” “Now watch what I do” (pouring contents of one glass) ➜ Child may say tall glass has more milk “Now, do they have the same amount of milk or a different amount?” Concrete operations stage (7-11) – Child develops higher order schemas called operations – understands the reversible consequences of actions o Conservation of liquid quantity o Conservation of mass quantity o Conservation of number Formal operations stage (over age 11) – Child develops ability to engage in hypothetical and deductive reasoning and to think about abstract concepts Ø Child may know that 4 + 1 is odd, that 6 + 1 and 8 + 1 are odd ➜ However, before this stage, doesn’t understand that if you add one to any even number, the result will be odd Ø Child is asked to discover what makes a pendulum go fast or slow (length of string, weight of object, or initial force that sets pendulum in motion) ➜ Before this stage, doesn’t understand that one needs to vary one factor and hold the others constant Strengths and Weaknesses of Piaget’s Theory Strengths Provides good overview of children’s thinking at different points Fascinating observations Weaknesses Stage model depicts children’s thinking as being more consistent than it actually is Figure A shows a bottle with some water in it. In Figure B, the bottle has been tilted. Draw a line to show how the water line would look. ➜ 50% or male undergraduates and 75% of female undergraduates failed this “formal operations” test! (Sholl & Liben, 1995) Later research found that children are more cognitively competent than Piaget recognized (more on this in the next slides) Understates contribution of the social world Does not explain underlying mechanisms Object Permanence and Reasoning in Infancy As mentioned, research has indicated that children are more cognitively competent than Piaget recognized Ø Ex: Object permanence − Piaget thought understanding of object permanence developed in infants around the age of 8 months − However, Renée Baillargeon argued that Piaget’s finding was rooted in lack of motor ability in infants since experiments required infant to manually search for the hidden object by pulling a cover off to reveal the object − More recent studies (described on succeeding slides) have indicated that infants as young as 3.5 months of age and perhaps younger understand that objects continue to exist when hidden, that they can’t just disappear Studies using dishabituation paradigm – Basic idea is that infants look longer at events that they find surprising – If infants perceive the event as we do, then they will look longer at the impossible or “magical” event than at the possible event Ø Baillargeon’s drawbridge experiment illustrating violation-of-expectation (VOE) Ø Babies show surprise when object seems to just disappear, demonstrating rudimentary understanding of object permanence However, infant folk physics (i.e., innate understanding of basic principles governing the behavior of physical objects) does differ from adult folk physics in certain important ways Infants place more weight on spatiotemporal continuity than on featural continuity − They do not show surprise if a green scarf disappears behind a screen and a bunch of flowers emerges at the other side of the screen − They show more surprise if a large white rabbit appears in a box, then later in a hat, without seeing a path of movement for it For adults, in contrast, featural constancy is more important − If they see a large, distinctive white rabbit appear in a box, then later in a hat, they assume it’s the same rabbit, even if they don’t immediately see a path of movement for it − If they see a green scarf turn into a bunch of flowers as it passes through a magician’s hand while maintaining its trajectory, they assume it is a different object (Gopnik and Meltzoff) Modeling Object Permanence Object permanence can be explicitly represented in a body of rules and principles Many cognitive scientists think that object permanence depends upon this sort of explicit symbolic representation However, Yuko Munakata and her collaborators have suggested an alternative neural network approach to object permanence This involves the use of recurrent neural networks (RNN) Recurrent neural networks are designed to deal with time series and sequence data In a recurrent neural network, there are feedback connections that result in the output at Time 1 serving as the input at Time 2 − This functions as a type of memory Recurrent Neural Networks A recurrent neural network (RNN) can be used to model object permanence: Top row: Schematic drawing of what appears in network’s visual field as barrier moves in front of a ball, then back to its original location Bottom row: Corresponding pattern of activation presented to the network’s input units Activation associated with “sight” of the hidden object at a previous temporal stage is transmitted to the current stage This information is then used to predict what the next set of inputs will be The network’s learning (which works via standard backpropagation) is driven by the discrepancy between the predicted input and the actual input ➜ As training progresses, the network becomes increasingly proficient at predicting the reappearance of occluded objects over longer and longer periods of occlusion Because the network learns gradually, sensitivity to object permanence is a graded phenomenon In the early stages of training, it may be strong enough to drive perceptual “expectations” but too weak to drive motor behavior (e.g., manually search for a hidden object) ✧ Applications of RNNs include − Speech recognition − Speech synthesis − Machine translation − Music composition − Time series prediction − Robot control Development of Self-Recognition Rouge test of self-recognition Spot of red rouge is surreptitiously placed on child’s nose, then child is placed in front of mirror Beginning around 18-24 months, child will respond by touching own nose to feel or rub off rouge A younger child touches mirror or tries to look behind it to find red-nosed child The only other animals capable of passing rouge test are other apes – chimpanzees, bonobos, orangutans, gorillas – dolphins, orcas, elephants, magpies, and cleaner wrasse Mindreading Mindreading is the ability to understand other people’s mental state Allows us to make sense of other people Allows us to coordinate our behavior with theirs ☞ Key to human social interaction ★ Roots of mindreading in early childhood lie in pretend play Pretend Play Pretend play, which typically emerges around 14 months, is considered a major milestone in cognitive and social development In pretend play, some of infant’s primary representations of the world and other people become “decoupled” from their usual functions while preserving their ordinary meaning Both pretend play and mindreading involve metarepresentation – use of a representation to represent another representation, rather than referring directly to the world Children with autism spectrum disorder show impoverished pretend play, as well as impairments in mindreading False Belief Task Ø False Belief (Displacement) Task – One of the best-known tests for mindreading ability – Tests whether children are able to abstract away from their own knowledge to understand that someone else can have different (and mistaken) beliefs about the world Ø Container test − Child is shown a familiar kind of container (M&Ms bag) that contains an unexpected object (marble) − Asked to predict what other person will think is inside False belief task tests children’s theory of mind mechanism (TOMM) – their ability to identify and reason about other people’s complex mental states, such as beliefs, desires, hopes, and fears Pretend play emerges during the second year of life, but children do not typically pass the false belief test until they are nearly 4 Indicates that the BELIEVES operation is much harder to acquire than the PRETENDS operation However, research by Kristine Onishi and Renée Baillargeon demonstrated that children may develop an implicit understanding of false belief well before age 4 Experiment similar to false belief displacement task measured looking time in 15month old infants Results indicated that children looked significantly longer – indicating surprise – when actor’s behavior violated expectations that someone with an understanding of false belief would have ➜ Suggests that children may develop an implicit understanding of false belief by 15 months, but that explicit understanding, involving explicit conceptual abilities manifested in verbal responses and explicit reflection, develops later There are many stepping stones to the development of TOMM, including the shared attention mechanism (SAM): occurs when infants look at objects (and take pleasure in looking at objects) because − They see that another person is looking at that object Ø I see (Mother sees the cup) OR − They see that the other person sees that they are looking at the object Ø Mother sees (I see the cup) v This requires infant to be able to embed representations – to represent that an agent is representing someone else’s representation v Makes possible a range of coordinated social behaviors and collaborative activities Children with autism spectrum disorder have difficulties with this type of joint attention − There is a strong correlation between severity of social impairments and inability to engage in joint attention ★ Attunement between caregiver and child – child’s understanding that caregiver knows how he feels – is critical for normal development Video References Videos excerpted from: Discovering Psychology: The Developing Child https://www.learner.org/series/discovering-psychology/thedeveloping-child/ Dr. Baillargeon- understanding object permanence https://www.youtube.com/watch?v=b1tQOR5L0iI Still Face Experiment Dr Edward Tronick https://www.youtube.com/watch?v=IeHcsFqK7So