Thoughts on Unconscious Perception

Unconscious Perception and its Role in Behaviour

The understanding of unconsciousness involves thinking about consciousness as well although it is extremely difficult to define either of these concepts.
There is substantial evidence that shows how unconscious perception of stimuli and information processing can occur and how it affects the observer’s responses. We might not be aware of the stimulus but our behaviour certainly can be influenced by it.
A lot of neurological research has been done with the help of people with brain damage to investigate both conscious and subliminal processes especially concerning vision and visual awareness or the lack of it.

Unconscious perception can be understood as a phenomena of how a stimulus can affect us, how the mind still perceives stimuli that can influence the observers’ responses, attitudes and thoughts despite of not being consciously aware of them, cannot report or detect them.
There are many processes that are continuously going on in the body and brain of which we are unaware, for example the brain has to regulate heart rate or breathing or the release of required hormones when needed. These processes happen without our conscious awareness of them and are part of the homeostasis that keeps the body functioning at an optimum level.
Many research shows that there are other subliminal processes happening either in everyday life with ordinary people or under specific circumstances such as the investigations into the visual awareness of people with brain damage suggest.

The example for how subliminal perception occurs and affects our actions – and also how rapidly it happens – in an everyday life situation is the short story of the fire fighter.
What he experienced as ‘intuition’ was a rapid, unconscious registration of information linked with an appropriate response. This is termed ‘the fear response’. He might have been aware of the danger on an unconscious level (e.g. the visual information was not lost, it was processed on a subconscious level).
He must have seen something alarming but it happened too fast for the conscious mind to be aware of the processing of that particular information but this still influenced the fire chief’s thoughts, judgements, choices and responses.

Studies done with people who have suffered damage to certain parts of their brain provide interesting examples.
An example of brain damage affecting awareness – visual perception – is the
blindsight patient D.B.’s case. He although alert and awake can be completely unaware of stimuli in his blindfield. (e.g. in the area of his visual field where there is damage to the primary visual cortex – V1). He reported not being able to see anything in this part of the visual field despite of being able to respond to stimuli, for example he made eye movements toward an outstretched hand that he could not see. His reactions betrayed that he did perceive the stimuli unconsciously.

In some cases memory and behaviour affected by damage to the brain, a condition termed prosopagnosia when the patient is unable to recognize familiar faces visually but has no problems recognizing the same person’s voice over the phone.
Recent findings by Tranel and Damasio (1985, cited in Datta 2006) provide a study with physical evidence that although consciously not aware of the emotional processes when seeing pictures of familiar faces unconsciously patients’ autonomic nervous
systems still recognized differences between familiar and unfamiliar faces.
In other words this experiment showed how prosopagnosia patients recognized familiar faces but they had no access to the processes of recognition.

Another way of studying unconsciousness is by studying ordinary people (e.g. no brain damage).
Examples include manipulation of presentation of visual images in lab studies where the stimuli are only visible for a fraction of a second. These subliminal images we would not expect participants to see and indeed they report the same.
Results from such studies show otherwise. The presentation of different pictures depicting different emotions will be perceived unconsciously and will influence the observers’ behaviour. For example people who were exposed to ‘happy’ faces shown to them for only 16 ms rated drinks at a higher value compared to participants who were shown angry’ faces.

The unconscious mind not only perceives information but will process it for meaning.
An experiment done by Marcel (1983, cited in Datta 2006) provides convincing evidence for this.
In a similar experiment of manipulation of visual images presented to participants called backward masking he used a target image that was immediately masked’ by another. He varied the speed of showing the pictures of words and the results showed that despite of participants saying they could not detect consciously the target words they were able to come up with an appropriate word to pair with the target around 90% of the times. This is well above chance (e.g. if they just guessed).
The unconsciously perceived words must have been processed for meaning otherwise they would not have been able to come up with the right word pairs.

Many emotional responses to stimuli seem to occur at a subconscious level.
In the brain the structure associated with emotional responses – amongst other tasks such as a role in memory – is the amygdala, a telencephalic structure in the forebrain.
In an experiment termed masked priming’ done by Whalen et al., (1998, cited in Datta 2006) brain scans were taken to see whether brain activity would be affected by rapid images of human facial expressions that participants were not conscious of.
Masking images of neutral faces were also shown immediately after the target pictures. The scans showed strong activation of the amygdala when the fearful’ face was shown. This means that unconsciously the participants still recognized the difference between ‘happy’ and ‘fearful’ expressions.

These examples all show the role of unconscious perception in behaviour and how behaviour can be influenced by it.
Quite often our actions are defined by and based upon processes of which we are unaware. It seems that unconscious perception leads to more automatic responses.
Such experiments as ‘backward masking’ and all studies done with ordinary participants as well as with patients who have brain damage give us insight into the lack of visual awareness, subconscious processes and their effect on behaviour.