Vivid imagery of objects primes perception of subliminal spatial information

The integration of imagination with perception of reality is associated with numerous neurocognitive and biological adaptive functions. Given the overlap between neural processes and regions governing internally versus externally generated imagery, the interaction between these processual components of high-level vision has been studied for over a century, without yielding a satisfactory account. Opposite to traditional theories like the Perky effect or sensory boost, we hypothesized that voluntary conscious mental imagery of an object enhances the processing of unconscious incoming visual spatial information. Hence, aspects of internal imagery such as vividness or motion should drive such an interaction. We probed how subliminal spatial information might be influenced under imagery conditions. Using behavioural data, we show that imagery improves the unconscious concurrent perception of visual spatial information. This priming effect seems driven by the gradient of imagery vividness: both explicitly required by task demands and implicitly generated. We found that imagery can direct visual perception when the visual system is strongly biased towards predicting that an object is present. Because the observed results vary systematically with self-reported vividness, rather than being epiphenomenal, the subjective experience of vividness is a deterministic condition for imagery priming.