As neuroscience rapidly encroaches on the speculative territory once occupied solely by philosophy and religion, books like Joseph Ledoux’s Synaptic Self, which attempts the unenviable task of explaining the emergence of personality via our current understanding of how the brain works, are bound to multiply, as are the difficult ontological questions they raise about such deep-rooted concerns as the nature and endurance of the self.

Although those with a spiritual slant will surely find Synaptic Self ‘s argument (in line as it is with current thinking in neuroscience) for a purely physical underpinning to the apparent “endless variety” of conscious thought somewhat unnerving — the author’s dry dismantling of love into stimulus responses and activation of “the subcortical areas presumed to be involved in attachment” isn’t exactly high romance — the fact remains that “the self,” as Ledoux notes, is a fragile entity, held together by the spider web of memory and capable of being irrecoverably altered by physical processes (i.e., physical damage to the brain oftentimes results in drastic changes to the personality, as seen in Alzheimer’s patients, etc.) For most, such dramatic examples (of which many of us are intimately and painfully familiar) from everyday life would seem to solidify the notion of the self as something wholly material, and hence available to scientific description.

Taking this for granted, Synaptic Self concerns itself with finding the locus of that self, and Ledoux offers the synapses – the junctures between neurons which are involved in the storing and channeling of information – as the most probable suspects. In this view, nature and nurture work together in synaptic connections, which are both hardwired by genes and capable of being altered by experience, to form the basis of an individual’s personality. It is, in other words, our genetic predisposition to certain behaviors, combined with learning and experience (expressed in the novel alteration of synapses) that make us detectably different from, while fundamentally the same as, our fellow humans. Memory, the imperfect rebuilding of past experiences by the present mind, then becomes the connecting tissue which holds the personality together as a cohesive whole over the course of a lifetime.

Though potentially intriguing, Ledoux’s attempt to describe the self as springing from synaptic interconnectivity comes across as at best unconvincing, with the narrative at times feeling oddly disconnected from its subject. The first and last of its eleven chapters, for instance, are the only ones that tackle the synapse/personality connection head-on. Given that, Synaptic Self functions better as a general introduction to current neuroscientific thinking on how personality is related to physical processes in the brain, though books like Pinker’s excellent (though somewhat dated) How the Mind Works accomplish this in a more readable way.

Synaptic Self frequently has the power to enthrall, especially when it manages to effectively relate its central thesis to the human condition (as in the chapter on mental illness) but this is unfortunately a rare occurrence in a book whose overarching ideas are often lost sight of in a fog of technical jargon that, while undoubtedly necessary, at times make for a dull read. This is a minor nitpick – a certain amount of disinterest sometimes has to be tolerated when learning new things, after all – but it may turn off casual readers or those without much background in neuroscience: ostensibly the book’s target audience.

Joseph Ledoux / Viking, Jan. 2002. (400 pages.)