Some doubt remains about this however, because integration and synchronisation judgements still centred on similar near-veridical asynchronies (on average), click here and thus could still be subject to common synchronising mechanisms. Furthermore, any apparent differences between the measures might just reflect different criteria for deciding whether two asynchronous events from different modalities should be integrated or segmented, compared to when deciding whether
the two events are synchronous or asynchronous. The mismatch between measures was also small, though note that these measures were averaged across observers, which might conceal the true extent to which optimal timing may differ between mechanisms within individuals. Neuropsychological studies might contribute to this debate if cases could be found where brain lesions result in selective impairment of either synchronisation or integration, or joint impairment of both together. A case of the latter kind seems to be reported by Hamilton et al. (2006), where the ‘temporal mismatch’ experienced by patient AWF coincided with an eliminated McGurk effect for veridically
synchronous stimuli. However Hamilton et al. did not test McGurk under different conditions of audiovisual asynchrony. Thus the critical evidence for true interdependence of synchronisation and integration functions was lacking, which would have been provided if the McGurk effect had been reinstated in AWF, for subjectively simultaneous stimuli. From the above review it may be concluded that the question of how, or indeed whether, the brain can Alisertib minimise discrepancies in timing between
modalities and between cognitive processes, has not yet been satisfactorily resolved. Critical insights may be gained by studying individual differences between measures probing synchronisation and integration, and comparing natural variations in these measures with those acquired following brain injury. In particular, we can examine (1) whether PH is an example of a categorical ifoxetine breakdown of putative unifying mechanisms, or whether his lesions have merely shifted him along a continuum of disunity, where we may also find ourselves. We therefore ask, how unusual is PH (Experiment 1)? If highly abnormal, he could be ‘the exception that proves the rule’, that unity and synchrony are normally achieved in individuals (albeit with inaccuracies). But exceptions can also ‘prove’ rules wrong. Our evidence, of large discrepancies between our two measures in PH and surprisingly also in normal subjects, suggests that asynchrony and disunity may rule instead. We can also ask (2) whether PH’s acquired subjective asynchrony is specific to perception of audiovisual temporal order or whether this affects the temporal tuning of audiovisual integration, and also how closely measures of integration correspond with measures of synchrony, within normal individuals.