 For example, Wenzlaff and Bates found that subjects concentrating on a positive task experienced neither paradoxical effects nor rebound effects—even when challenged with cognitive load.Wenzlaff and Bates also note that the beneficiality of concentration in their study participants was optimized when the subjects employed positive thoughts.Some studies have shown that when test subjects are under what Wegner refers to as a "cognitive load" (for instance, using multiple external distractions to try to suppress a target thought), the effectiveness of thought suppression appears to be reduced.