The data were analyzed based on signal detection theory. This analysis method is used to measure the effectiveness of participants in distinguishing meaningful signals that may be present in displays from non-meaningful noise. Signal detection theory provides two dependent measures which were used to analyze recognition performance; a parametric measure of sensitivity (d′) and criterion (c) which is a measure of response bias (Green and Swets, 1966). The measure of sensitivity (d′) assesses discriminability: how well two conditions can be distinguished from one another (signal present or absent). The larger the d′ value the more sensitive a person is in discriminating between signal present and signal absent stimuli, while a value of 0 indicates chance (i.e., guessing) performance. Criterion (c) measures bias and refers to the extent to which one response (i.e., responding yes or no) is more probable than the other. If the c value is negative it indicates a bias toward “yes” responses (resulting in more “hits,” but also more “false alarms”), whereas if c is a positive value then it indicates the participants favor a bias to “no” responses, with fewer hits and fewer false alarms (MacMillan, 2002).