PDF (PhD Thesis Susan Chipchase) - Nottingham eTheses ...

Participants were initially shown a practice study phase Rapid Serial
Visual Presentation (RSVP) of 10 photographs to familiarise them with the
presentation rate. All example photos were of neutral valence and were single
objects against a plain background, in contrast to the complex scenes used for
experimental stimuli. Of the 10 practice photographs, 9 appeared for 40 msec
and the last photo appeared for 160 msec. This was to aid participants’ memory
of this image which was used in the later practice task. Participants were then
shown the study phase for the first valence block (i.e. positive, negative or
neutral photos). Photographs were presented in an RSVP with 40msec
exposure per picture and no interstimulus interval.
In each study block participants were shown 30 different photographs.
Participants were shown photographs from one set of A or B, with the
unexposed set used to create matched pairs during the test phase. The use of
sets A and B for targets or distractors was counterbalanced across participants.
From each set of 30 photographs; 10 were shown once, 10 three times and 10
five times. This resulted in an RSVP stream of 90 photographs in three study
blocks with 270 photographs being shown in total across the 3 study blocks.
Each RSVP stream lasted 3.6 seconds. The order of photographs in the study
phase was randomised for each participant, with the exception that repeated
presentations of the same item were separated by at least 2 other photographs.
The selection of photos to be shown 1, 3, or 5 times in the study phase block
was randomised for each participant. A fixation cross appeared centrally for
one second before the RSVP began. Participants were not given task
instructions until after the first study phase and so were unaware of the exact
nature of the task until this time.
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