Subliminal: The Revolution of the New Unconscious and what it Teaches Us about Ourselves

Author: Leonard Mlodinow


The contribution of the subconscious to human acts has captivated the imagination of lay people for centuries, and popularised by figures such as Sigmund Freud. This book sheds light on the scientific rather than the pseudoscientific understanding of the unconscious. The author, a leading physicist, examines the huge influence of the unconscious on our actions. It is fascinating, and concerning at the same time, that ‘…there are portions of the mind that are inaccessible to consciousness’ (page 17). The advanced psychological and functional techniques of social neuroscience have however given us ‘a new understanding of how the brain operates, and who we are as human beings’ (page 8). The author says that, with these advances, ‘we can map the neural activity that forms a person’s thoughts’ and ‘watch as different structures and substructures in the brain generate feelings and emotions’ (page 15).



The book demonstrates the profound and pervasive effect of the unconscious on human actions; for example ‘we judge products by their boxes, books by their covers….and corporations’ annual reports by their glossy finish’ (page 23). The unconscious shapes our choices, from trivial items like the detergents we buy, to significant matters such as the choice of jobs, partners, and stocks, or the judgment we pass on total strangers (page 25). The author says ‘we perceive, we remember our experiences, we make judgments, we act – and in all these endeavours we are influenced by factors we aren’t aware of‘ (page 29).


By Pere on Flikr.
By Pere on Flikr.


The considerable effect of the subconscious is consistent with the observation that it is ‘the more fundamental’ of our two-tier cognitive system (page 33), and that it probably accounts for 95% of our cognitive capacity (page 34). The book illustrates this dominance where it says ‘…whatever you are doing with your conscious mind, it is your unconscious that dominates your mental activity’ (page 35). This dominance explains why we are oblivious of our visual, verbal and auditory blind spots (pages 46 and 49), and sheds light on paradoxes such as blindsight (page 40). Whilst the subconscious has the capacity to process a huge data input, this capacity is limited. This restriction results in the phenomenon of unconscious enhancement-the unconscious, literally, fills in the gaps. The author suggests that this is often a beneficial trade-off (page 63), but one which comes at a cost in some circumstances. One example is the miscarriages of justice that have resulted from false eyewitness testimony, an issue brought to prominence by the group Innocence Project. Another example is the consequences of false memories and this derives from the work of the psychologist Hugo Munsterberg.



Ominously the unconscious also shapes our behaviours and social activities. The author explores this in chapter 4 where he recounts experiments which disturbingly show that ‘…much of our social perception….appears to proceed along pathways that are not associated with awareness, intention, or conscious effort’ (page 104). In chapters 5 and 6 we learn of the influence of unconscious non-verbal communication and social dominance, and in chapter 7 he refers to the ground-breaking work of Henri Tajfel on categorisation and stereotyping. These unconscious processes underlie prejudice, and the propensity to this is measurable with the Implicit Association Test. The final chapters of the book explore the influence of emotions and mood on personality and judgments, and review the effects of in-groups and out-groups, with reference to the social experiment of Muzafer Sherif.” target=”_blank”>

The author discussing his book at Google


I thoroughly enjoyed this enlightening book. The author has simplified what is clearly a complex and extensive subject. It is an important window into how the mind works, and how it influences our judgments. The book, laced with excellent anecdotes, sounds a cautionary note to monitor ourselves when we make decisions and pass judgments. The author refers to several classical psychological studies that underpin his themes, and each is a revelation. The consequences of subconscious influences is akin to those of false memories elucidated in The Seven Sins of Memory which I have previously reviewed.


It is an excellent read and addresses a crucial issue to healthcare and doctors. There is very little to criticise about the book and I recommend it.



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