The name is absent

102

independent of any response or decisional biases, was enhanced when the
somatosensory stimulus was on the same side as the auditory one.

There was also a marginally significant difference in criterion between the three
main conditions (F(l,19) = 2.99, p = .062). To assess the source of this marginal effect,
we conducted further paired t-tests on the c values, which should be interpreted with
caution since the main effect did not achieve significance. On the trials when no
somatosensory stimulus was delivered, participants were more likely to report feeling
an illusory somatosensory stimulus on the same side as the sound (c = 1.09) as
compared to the opposite side (c = .84; t₁9 = 2.509, p = .021) and no sound conditions (c
= .79; t_i9 = 2.243, p = .037). There was no difference in response biases for the opposite
side sound vs. the no sound conditions (t19 = .562, p = .581).

The analyses of d' values indicate that a sound on the same side as the
somatosensory stimulus significantly enhances discrimination, regardless of any
response or decisional biases that may or may not have been present. Unlike any
contributions from response biases, which have been ruled out by our signal detection
analyses, these results could have been affected by an enhanced alerting, temporal
marking, or attentional orienting effect from the sound that increased touch perception
(cf. Spence, et al. 1998). However, unlike the cross-modal attention studies by Spence,
Driver, and colleagues (Driver and Spence 1998a; Driver and Spence 1998b), in which
auditory stimuli preceded tactile ones, our stimuli were simultaneously presented,
making an alerting, marking, or orienting account of our results less likely. We return to
this issue in the General Discussion.

<<   110   111   112   113   114   115   116   >>

More intriguing information