Serial dependencies act directly on perception

There is good evidence that biological perceptual
systems exploit the temporal continuity in the world:
When asked to reproduce or rate sequentially presented
stimuli (varying in almost any dimension), subjects
typically err toward the previous stimulus, exhibiting socalled
''serial dependence.'' At this stage it is unclear
whether the serial dependence results from averaging
within the perceptual system, or at later stages. Here we
demonstrate that strong serial dependencies occur
within both perceptual and decision processes, with very
little contribution from the response. Using a technique
to isolate pure perceptual effects (Fritsche, Mostert, &
de Lange, 2017), we show strong serial dependence in
orientation judgements, over the range of orientations
where theoretical considerations predict the effects to
be maximal. In a second experiment we dissociate
responses from stimuli to show that serial dependence
occurs only between stimuli, not responses. The results
show that serial dependence is important for perception,
exploiting temporal redundancies to enhance perceptual
efficiency