tesis doctoral - e-Spacio - Uned

309
Apéndice II
circles forming a matrix pattern. Position markers indicated where grouped patterns would be
displayed on the screen afterwards but did not provide information about the identity of the
grouped patterns placed subsequently in that position. Moreover, we manipulated the
preexposure in both conditions including three differents SOAs used in previous experiments:
1000, 257 y 86 ms The aim of Experiment 3 was to rule out alternative hypotheses, based on
an spatial account, which, as mentioned, could explain the results of Experiments 1 and 2. If
results from these experiments were exclusively due to a preattentive processing of location of
preexposured grouped patterns or a IOR effect (and, therefore, there would be no involvement
of preattentive perceptual grouping operations), then, differences between preexposure of
position markers and of grouped patterns should not appear, given that these two conditions
provide information about spatial location of grouped patterns on identification task.
The results of Experiment 3 showed a reliable difference between both types of
preexposure, indicating a shorter RT in the condition of grouped patterns. These results confirm
that preattentive processing of grouped patterns identity is possible and, therefore, that visual
grouping operations can occur in absence of attention, influencing subsequent attentional
processing. However, these results are dificult to explain by hypotheses based on a spatial
account.
The manipulation of intervals of preexposure showed the same pattern as previous
Experiments, that is, a proportional increase of RT as a function of preexposure duration.
The results from Experiment 3 suggest that the distractor inhibition hypothesis is the
more appropiate explanation for the effects. In order to obtain convergent evidence that could
rule out the alternative spatial hypotheses, we conducted Experiment 4.
Experiment 4 included two sub-experiments, 4A and 4B. Both experiments introduced
a new manipulation affecting consistency between position of grouped patterns during the
preexposure phase and the identification task. The new factor called consistency included three
different conditions: