Hypothesising the implications of an overdeveloped frontal lobe...
Updated: Dec 22, 2018
Although there is significant research outlining the human traits lacking with an underdeveloped and/or damaged frontal lobe, I could not find reports of overdeveloped or large frontal lobes.
Nevertheless, one prime example could be humans and primates themselves as opposed to more primitive animals (dogs, cats, etc.).
Summarizing current research, the frontal lobe is primarily utilised in higher-order complex functions, such as memory, problem-solving/strategizing ability, response choice (i.e, acting appropriately in a social setting), perceptual ability, and attention. In essence, it impaires your ability to make thoughtful decisions. Ultimately, these all tie down to one overall behavior: loss of control, and an inability to connect thoughts with actions.
With this, I can only speculate that larger frontal lobes will enhance these functions - leading to greater prudence, judgement, memory, and spatial or reasoning abilities. However, it is to be noted that ‘larger’ does not always mean ‘better’ - take the case of Albert Einstein, who had a thinner cerebral cortex and a lighter brain than most others - however, his density of neurons was much larger. Similarly is the case with poet Anatole France, who’s brain was 25% less than the average size after his death in 1924. Thus, my speculation may entirely be wrong, and a larger frontal lobe could not enhance one’s abilities at all. Yet, I stand by my theory simply because, larger lobes generally mean more neurons and thus, greater potential for connections to form, leading to higher order thinking.
However, at the same time, too many connections can be detrimental. For example, autistic children are shown to have too many synaptic connections, with abnormally lower levels of neural pruning, which is the process that gets rid of ‘unwanted’ synapses at an early age, depending on which neuron connections are used. Thus, who knows? I suppose this idea can also be applied to the frontal lobe: Maybe a larger lobe can deteriorate behavior by over-stimulating the brain: Maybe that’s why humans’ frontal lobes haven’t reached gigantic levels due to evolution by now!
Conclusively, there are three possibilities: (1) It enhances frontal-lobe function (e.g. memory and planning), (2) It has no effect, and (3) It diminishes behavior. In retrospect, my personal answer would depend on how large you mean by ‘large’: I would hypothesise that a mildly larger frontal lobe (say 1–5% above average) would not effect or even enhance cognitive ability, but any larger than that and there is a risk of declining in behavioral tasks. Let me know your thoughts!