Working Memory can be conceived as a mental workspace holding and
manipulating a limited amount of recently acquired information for a limited
time. Some theories assume that it is tightly coupled with Consciousness (e.g.,
Baars & Franklin, 2003), commonly defined in experimental studies as the
ability to report the content of perception or of memory. Other theories posit
that working memory includes cognitive processes of which participants are not
conscious (e.g., Soto et al., 2011; Logie, 2016), and can be activated without
conscious intention (Hassin et al., 2009).
Here, I describe experimental work designed to investigate the possible implicit
activation of working memory without awareness. Importantly, participants
were not only unaware of the stimuli that might be held in working memory,
but also unaware that such stimuli were being presented at all. They were asked
to guess which one of four cards presented on the screen was the winning one;
one card was subliminally primed before a retention interval (which could vary
between 500, 1000, 2000 and 5000 ms). The winner, on each trial, was chosen
from amongst four blue cards, one of which had been primed, without
awareness, by a card of a different colour (red or green) using Continuous Flash
Suppression or Backward Masking.
Bayesian and classical analyses from nine experiments mostly support the null
hypothesis, thus indicating that working memory was not engaged in
performing this task. Two conceptual replications and four exact replications of
the original study by Soto et al. (2011), also failed in reproducing the original
results. In conclusion, this collection of fifteen experiments encompassing
different manipulations shows the absence of non-conscious WM retention,
questioning the generalisability of previous studies showing non-conscious WM
