Development of feature-binding in infants

Visual perception is established by the integration of multiple features. This mechanism benefits from the ongoing interplay between feedforward and feedback loops, yet this causal connection remains unclear. Researchers have explored the role of recurrent processing in feature integration by studying an illusion called 'misbinding,' wherein visual characteristics are erroneously merged, resulting in a perception distinct from the originally presented stimuli (Wu et al., 2004). Anatomical investigations have revealed that the neural pathways responsible for recurrent connections are underdeveloped in early infants. Therefore, there is a possibility that younger infants could potentially perceive the physically presented visual information that adults miss due to misbinding. We investigated this question by employing a familiarization/novelty preference procedure. In the familiarization phase, two sheets of dots, with one sheet moving upward and the other moving downward, were presented. Importantly, the dots within the right and left regions as well as those in the remaining area on both sheets were displayed in distinct colors, either red or green. After familiarization phase, two types of trials (coherence and segregation) were conducted during the testing phase. Coherence trials showed that dots of either color moved coherently in the same direction as in the familiarization phase. Segregation trials showed that dots in the right and left areas moved in opposite directions in the center. If infants perceived misbinding, infants would look at segregation longer because of its novel stimuli. In contrast, they would look at coherence longer if no misbinding occurred. We found that older infants exhibited misbinding, whereas younger infants showed no such illusions. This means that infants older than half a year perceive incorrectly integrated visual stimuli; however, infants younger than half a year perceive physically presented stimuli without failure of feature-binding. These results suggest that the development of feedback processing contributes to feature-binding.