This thesis is an attempt to evaluate findings previously reported in the research literature which
have suggested the presence of event-related correlations in electrical brain activity between
physically isolated participants. These studies are summarised in a literature review, where a
number of methodological procedures are identified and evaluated, and the evidence presented
by each study is assessed. One problem identified in this review is a lack of conceptual and
methodological continuity across previous studies investigating this effect. In order to address
this concern, a series of three experiments has been designed and conducted in an attempt
to investigate this topic using a procedure and analytical methodology which remains largely
constant across the three studies, so that their results can be comparable and cumulative. Each
of these three experiments involved the randomly-timed photic stimulation of one participant, in
order to test the hypothesis whether synchronous event-related changes in the EEG activity of
another, physically isolated (and non-stimulated) participant could be identified. An additional
question investigated is whether certain variables (such as the interpersonal relationship between
participant pairs) may be related to any such EEG correlations found between participants, as
has been suggested in previous studiesIn each of the first two studies, three groups of participants were recruited; participant
pairs who knew each other well, randomly matched pairs of strangers, and single participants
not matched with a photically stimulated partner. In both these studies significant differences
have been found in measures of evoked-alpha global field power from non-stimulated subjects in
related pairs, between periods of photic stimulation of their partners and randomly sampled con¬
trol periods of no stimulation. Similar effects have not been found in randomly matched pairs,
or in unmatched control subjects. Although these findings appeared to suggest the presence of
correlations in brain activity between related participant pairs, certain temporal characteristics
of the changes in EEG activity observed in non-stimulated subjects are not directly compatible
with such an interpretation. In the final study, only related pairs of participants were recruited
and a variation of the experimental paradigm was adopted in order to increase the overall
sample size; no evidence of a similar effect has been found in this study however.An overview of the results of the three studies is finally presented, and possible analytical
and theoretical interpretations of the findings are discussed. Although the results of the first
two studies were strongly suggestive of a genuine effect, the lack of replication of this effect in
the final study necessitates the consideration of the overall findings as inconclusive. A critical
review of the design and analytical methodology adopted in these experiments is presented and
potential improvements are suggested; a review of more recent studies using similar experimental paradigms is also presented in the final chapter, and potential avenues for future research
are proposed
