Given the series of major incidents with our MRT system, commuters’ confidence levels and perceptions of the entire rail network have definitely been affected, as confirmed by various recent polls. This is despite Singapore’s MRT system being among the world’s best systems, faults notwithstanding, said Peter Ho, former head of the civil service. By way of explanation, SMU Behavioural Sciences Institute (BSI) Director David Chan, spoke about the "power of the negative" at BSI’s annual conference themed “Public Trust in Singapore”. He made reference to psychologist Paul Rozin, who said a single cockroach will instantly ruin a bowl of cherries, but one cherry in a bowl of cockroaches does nothing to alter its appeal.