We lack memories from infancy and toddlerhood primarily due to the immaturity of the hippocampus and prefrontal cortex, brain regions crucial for forming and retrieving long-term memories. While babies can form short-term memories, these regions aren't developed enough to consolidate them into lasting autobiographical narratives. Further, our early understanding of the self and language, both essential for organizing and anchoring memories, is still developing. This "infantile amnesia" is common across cultures and even other mammals, suggesting it's a fundamental aspect of brain development, not simply a matter of repression or forgotten language.
A 2013 study suggests that the introduction of iodized salt in the US during the early 20th century played a significant role in raising IQ levels, particularly in iodine-deficient regions. Researchers found a correlation between iodine levels in soil (and thus food) and IQ scores, demonstrating higher IQs in areas with more iodine and a notable increase in cognitive abilities in iodine-deficient areas after iodization programs were implemented. This suggests that a simple public health intervention like iodizing salt can have a profound impact on population-level cognitive performance.
Hacker News users discuss the complexities of attributing IQ gains solely to iodine. Several commenters highlight other potential contributing factors during the same period, such as improved nutrition, education, and reduced exposure to lead. Some express skepticism about the methodology used in the study, questioning the reliability of historical IQ data and the potential for confounding variables. Others point out the importance of iodine for overall health, especially for pregnant women and developing fetuses, regardless of its impact on IQ. The genetic component of intelligence is also raised, with some arguing that iodine supplementation primarily benefits those with pre-existing iodine deficiency, rather than boosting IQ across the board. A few users share anecdotes about the noticeable cognitive improvements they experienced after addressing their own iodine deficiencies.
Summary of Comments ( 254 )
https://news.ycombinator.com/item?id=43084355
HN commenters discuss various theories related to infantile amnesia. Some suggest it's due to the underdeveloped hippocampus and prefrontal cortex in infants, crucial for memory formation and retrieval. Others point to the lack of language skills in early childhood, hindering the encoding of memories in a narrative format. The idea that early childhood experiences are too traumatic to remember is also raised, though largely dismissed. A compelling comment thread explores the difference between episodic and semantic memory, arguing that while episodic memories (specific events) are absent, semantic memories (general knowledge) from infancy might persist. Finally, some users share personal anecdotes about surprisingly early memories, questioning the universality of infantile amnesia.
The Hacker News post linked discusses the reasons why we can't remember our early childhoods, sparking a range of comments exploring various theories and personal experiences.
Several commenters discuss the idea of language acquisition being linked to memory formation. One compelling argument suggests that without language, we lack the framework to encode and retrieve memories in the way we do later in life. This is supported by another commenter who mentions that their earliest memories coincide with their first understanding of language. The idea is that language provides the structure and labels needed to organize and store experiences.
Another thread of discussion centers around the development of the hippocampus, a brain region crucial for memory formation. Commenters note that the hippocampus isn't fully developed in infants and toddlers, impacting their ability to form long-term memories. This biological explanation is complemented by observations about the constant neurogenesis happening in young brains, with the suggestion that this rapid creation of new neurons might overwrite existing memory traces.
Some commenters offer anecdotal evidence, sharing their own earliest memories and reflecting on their nature. These personal accounts range from vague sensory impressions to more concrete events, highlighting the variability of early childhood memory.
One intriguing perspective introduces the concept of "infantile amnesia" and the ongoing research surrounding it. The comment acknowledges that there is no single definitive answer, but highlights various contributing factors, including the development of the hippocampus, language acquisition, and the encoding specificity principle – the idea that memories are best retrieved in the context in which they were formed.
A few commenters question the premise of the article, suggesting that perhaps we do retain some form of pre-verbal memories, but they are inaccessible to our conscious minds. This leads to speculation about implicit memories, which influence our behavior and emotional responses without conscious recall.
Finally, some commenters offer alternative theories, including the idea that early childhood memories are repressed due to their emotional intensity or the overwhelming nature of the world from a baby's perspective. However, these suggestions are presented more as speculation rather than established theories.
Overall, the comments section provides a multifaceted discussion of infantile amnesia, exploring neurological, linguistic, and psychological perspectives. While no single definitive answer is reached, the comments offer a range of compelling theories and personal insights that shed light on this intriguing phenomenon.