A paper [pdf] published last year suggests that they are, in fact, separate mental processes.
William James, one of the founder of modern psychology, wrote that “everyone knows what attention is” when trying to define it.
Similarly, as neuroscientist Susan Greenfield has pointed out, scientists often rely on a ‘we all know what we’re talking about, don’t we?’ definition of consciousness.
It turns out that attention is easier to define that consciousness, and in psychology it generally refers to the preferential processing of one source of information over another.
This can be measured experimentally because it’s possible to see how experience of one thing affects performance on another task, even if the person isn’t aware of experiencing anything in the first place.
We described an example of this last week, in a study that found that people could make accurate beauty judgements for faces presented so quickly they didn’t consciously recognise them.
This study, and many others on ‘implicit’ or ‘subliminal’ perception, demonstrate that people can attend to something without being conscious of it.
Being conscious of something we haven’t attended to, and where attention is nearly absent, is a bit more tricky.
The paper, by cognitive scientists Christof Koch and Naotsugu Tsuchiya, suggests that getting ‘gist’ impressions might be one example.
Experiments show that when photographs are unexpectedly flashed up in front of participants for no more than 30ms, they don’t have time to focus on any part of it, but can report a general gist or summary of the image.
Consciousness and attention have also been shown to have opposite effects in some instances.
When participants try to find two embedded images within a rapidly flashed stream of pictures, they often fail to see the second image – an effect known as ‘attentional blink‘.
However, one study [pdf] found that distracting people during this task, actually made them better at it, they were more likely to consciously detect the second image.
Reducing their attention to the task seemed to increase their conscious awareness.
The Koch and Tsuchiya paper has many more examples if you’re interested in trying to untangle these closely related processes.