Attention needed for consciousness, not vice versa.
Is attention synonymous with consciousness? Cohen et al conclude in their paper that attention without consciousness is in fact well supported in research. This seems to make sense. It remains unclear why most organisms would need consciousness given the energy requirements to sustain it. Yet they certainly need to be able to pay attention to their environment. That is precisely why organisms possess sensory organs. Conversely, Cohen et al conclude that there is no empirical evidence yet meeting the criteria of awareness without attention. From this, they also conclude that attention is necessary for awareness (which is not the same as saying that attention is also sufficient for awareness).
Link to paper: http://www2.psychology.uiowa.edu/faculty/hollingworth/prosem/Cohen-2012-The%20attentional%20requ.pdf
You may also like to browse other neuroscience papers: https://www.thesentientrobot.com/category/neuroscience/neuroscience-academic-papers/