The great contribution of Jean Piaget on developmental psychology is undoubtedly. However, in the past 30 years, there are a number of study criticism his suggestion, which the infant younger than six months do not have the permanent object concept. What follows is a discussion of examining when infant would acquire object concept. First, it will explain the proposition of Piaget on this topic. Then, it will examine Bower’s study which challenges and questions Piaget’s claim of the object concept. After that, it will focus on Baillargeon’s study and found out the flaw and weakness of her study by different recent research. Finally, it will draw a conclusion on the topic.
In 60s, Jean Piaget suggested the theory of cognitive development. In Piaget (1963), he started to investigate the age when the infants acquire object permanence. He considers object permanence as the most vital accomplishments. This concept makes human can separate different objects and know permanent existence of an object (Piaget, 1963). Which mean under the object concept human could understand each object is unitary entities and exist independently of third party actions (Piaget, 1963). Piaget suggested that infant younger than 8 month still did not acquire the object permanence concept (Piaget, 1963). In these infant’s mind, an object out of sight is out of mind. Piaget thought that 4–8 months infant start to develop a object concept slowly and gradually on this stage. Also, during this stage they are having a transition from egocentric (just using self-to-object view) to allocentric (could use object-to-object view) (Piaget, 1963). The main changes in this transition is that the infant start to use a viewpoint of a third person or object and seen themselves as an independent object.
In Piaget’s Blanket and Ball Study, he put a toy under a blanket, meanwhile the infant can watch the whole process (Piaget, 1977). Then observe infant searched for the hidden toy or not. This experiment, Piaget define that if the infant succeeds to discover the hidden toy, then it was an evidence of object permanence (Piaget, 1977). Since he assumed that only the infant had a mental representation can search for a hidden toy. In the result, he found that infant around 8-months-old succeeds to search for the hidden toy (Piaget, 1977). Finally, he concludes that infant around 8 months acquired object permanence, due to they can form a mental representation of the object in their brain.
Although Piaget‘s research got a high level of reliability (Harris, 1987), there is a lack of explanation for why the rest of infant (before 8 month) fails in the experiment (Mehler & Dupoux, 1994). Diamond (1988) found that the prefrontal cortex of human is related to holding representation in memory and motor response. Base on this finding, Mehler & Dupoux (1994) suggested that the infants who fail to search imply rather than the absence of an object concept. They may have an inability to coordinate the movements. Which mean if the research constructs a task that without complex motor demands, it may examine object permanence in the infant who younger than 8 months more accurately. In the study of Bower (1966; 1967), he has used a violation of expectation (VOE) paradigm to examine it. Bower gave object occlusion and reveal events in infant to watch. Some of them were possible (object slowly hidden by another) and some impossible (object slowly dissolving) (Bower, 1966). Bower through measure the changes in heart rate of infant to indicate the differences of their reaction to two events. Then through the response to infer a degree of object permanence in eight weeks old infant. However, there had a confounding effect of novelty in infant which the researcher was not noticed before the experiment (Bower, 1967). As the result, infant just interest in the possible event not impossible event. Whereas the confounding factor, it could not draw any interpretation from the data but it construct a VOE experimental framework to the latter study.
After that Bower, Broughton and Moore (1971) kept investigating the topic by using tracking tasks to 20 week-old infants. They leaded the infant track a moving object and recorded the result as it approached and passed behind a blocker. They found that the gaze of infants were disrupted when after the object pass through the blocker and switch to a different one. It implied that infants have an expectation of the original object would emerge again but disrupts by the experiment. In the other word, a 20 week-old infants may also have ability of object permanence and persistent internal representation. Their finding totally contradicted to Piaget theory.
After on, Bower and Wishart (1972) used 20 week-old infants again to take part in the experiment which leaded the infants track the object and it will occlude, darkening the room. The result showed the infants continued to track for the object on the trajectory. It supported the result of Bower et al (1971) and continues challenging Piaget’s belief.
In 80s, a researcher Baillargeon done a series of studies and experiment to criticize Piaget’s theory. Baillargeon, Spelke and Wasserman (1985) utilize VOE within a habituation method to examine infant’s mental ability. Habituation is assumed to count as the infants start looking away due to loss of interest. Two equivalent test events are shown to them based on the first habituation event. One was consistent with object properties (the possible event), and the other one was not (the impossible event) (Baillargeon et al, 1985). It is vital to note that they also assumed different degrees of dishabituation were indicated by the length of looking time between the test events. Then, of degrees of dishabituation to infer about infants’ object concept.
Baillargeon et al (1985) constructed a ‘drawbridge study’ to test the 5 months old infants. For the habituation event, the drawbridge rotated through 180° itself. In the test event, a coloured block was placed behind the drawbridge, then, the drawbridge rotated backward to the block. For the possible event, the drawbridge normally stopped at a place which the block supported it. For the impossible event, the drawbridge continue to rotate and pass through the space that occupied by the block. For these events, the drawbridge finally rotate reversed to its original position. In their finding, a youngest 14 week infants had a longer looking time at the impossible event (Baillargeon et al, 1985). Furthermore, the result had appeared several times in the latter study and confirmed by using a variety of stimuli (Baillargeon 1986; Baillargeon & Graber, 1987; Baillargeon & DeVos, 1991). As above explain. Baillargeon using the dishabituation result on the impossible event to interpret infants were surprised by the event and imply infants have an expectations about the normal rule of objects. Then, Baillargeon drew a conclusion that these inferences proved infants have a permanent object concept which substantially earlier than 8 month (Piaget’s claim).
However, there also lots of study found some flaw of Baillargeon’s study and criticise it. On the research of Bogartz, Shinskey and Speaker (1997), they found a confounding factor on Baillargeon & Graber (1987) study, indicated there could have some missed stimulus features on infant’s gaze when habituating. As the consequence, it would increase the attraction of an impossible event and confound to the experimental result (Bogartz et al, 1997).
Other criticisms about Baillargeon’s study suggest by Rivera, Wakeley and Langer (1999). They discovered that the habituation event and the impossible event of the Baillargeon’s ‘drawbridge’ studies, both event were scored longer gazing time. They interpreted that infants just prefer the event which involveed more movement and that would gain more attention of infants (remark: impossible event has 180° rotation and possible event only has 112°) (Rivera et al, 1999).
Also, Bogartz et al and Rivera et al both found the incompleteness of some VOE experimental designs which were replicating the VOE findings of (Wang, Baillargeon and Brueckner’s, 2004) were without habituation trials. They argued that it is important to complete a habituating events before testing event to produce transient preferences.
Furthermore, in the recent Baillargeon’s study, she acknowledged that her interpretation of her own VOE researches were having some flaw and may be plausible.
Due to the development of science was progressing quickly, the method of measuring cognitive thinking also progressed which bring a severe challenge to Baillargeon’s inference. Schoner and Thelen (2006) constructed the habituation and VOE task base on a dynamic field model. By their method, did not need to invoke any kind of symbolic mental representation. They just utilized the dynamic field model on modelling Baillargeon’s drawbridge’ studies and VOE tasks and treated it as “a series of perceptual events subject to basic habituation dynamics“(Schoner & Thelen, 2006; p.289). They suggested that assumptions of Baillargeon’s VOE paradigms were misleading and oversimplify the dynamics of habituation in significant which mean there were many interactions of variables were not accounted. Such as they found an order effect on VOE experiment (done by Baillargeon, 1987) when presented the impossible stimulus in order of the second. Therefore it was unable to use Baillargeon’s study to interpret about infant’s object concept and acquire it at which stage.
Although Schoner and Thelen’s model seemto overturn the result of all pervious VOE studies, some point should be pay attention. First, at the very beginning the dynamic field model is just a mathematical abstraction and it originally was designed for measuring cognitive thinking. Second, when Schoner and Thelen (2006) model Baillargeon’s study, they had assumed that the impossible event was more similar to the habituation event. Finally, they did not solve the problem of stimulus equivalence in VOE experiment.
In this paper, it has explained how Piaget interprets infant cognitive thinking and how they perceive the world and how they process the visual information. Then, it examined the view of different developmental psychologist research, mainly from Bower and Baillargeon. Finally, through a modern perceptive of Schoner & Thelen criticise Baillargeon’s study. However, in the last this paper still cannot draw a conclusion about at what age the infant would acquire object concept. Since scientists still do not have a method that could directly read infant’s or humans mind. If the researcher continues using some indirect method such as habituation VOE and interpretation of infant’s object concept. There are usually having some flaw because in the process of interpreting, it may involve certain extend of guessing (e.g in Baillargeon’s drawbridge’ studies, she observed dishabituation, then she guessed the infant was surprised, then guessed infant might have object concept.) Therefore, in this paper cannot find an exact answer to the topic question.
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