Mediating processes can be inferred from self-report data only if it can be assumed that the patient has a valid capacity for introspection. That assumption is invalid when beliefs can be shown to influence sensory perception and symptom reports. Another serious limitation of self-reporting is that the individual has only a limited awareness of his or her psychological state. Also, we cannot ignore the observations that come from the psychodynamic tradition, that unconscious or subconscious ideas also can affect and distort self-reporting. The lack of validity of self-reports is summarized by Brewin: "[T]he value of self-reports would appear to be more in their relation to intentional future actions than in any insight they might provide into complex feeling states or into the contingencies governing past behavior." A more objective procedure for obtaining information about EI/MCS patients' beliefs is clearly needed before their symptom reports can be taken at face value.