In part, the RF pattern's utility in the study of visual processes arises from a demonstrable integration of shape information around the pattern (Bell & Badcock,
2008; Cribb, Badcock, Maybery, & Badcock,
2016; Dickinson, Han, Bell, & Badcock,
2010; Dickinson, McGinty, Webster, & Badcock,
2012; Green, Dickinson, & Badcock,
2017a,
2017b; Hess, Wang, & Dakin,
1999; Loffler et al.,
2003; Schmidtmann, Kennedy, Orbach, & Loffler,
2012; Tan, Bowden, Dickinson, & Badcock,
2015). When cycles of modulation of a particular frequency are incrementally added to a pattern (with the remainder of the pattern completed by a circular arc) the threshold for discriminating a modulated pattern from a circle decreases at a rate that cannot be accounted for by probability summation—the increase in the probability of detection of single cycles. This implies integration of information across cycles of modulation. While a recent study using RF4 patterns of fixed phase or a small set of phases has questioned whether the rate at which threshold decreases can reliably be shown to be greater than the probability summation prediction (Baldwin, Schmidtmann, Kingdom, & Hess,
2016), thresholds for RF3 patterns, and indeed RF4 patterns, in random phase have been consistently shown to decrease almost in inverse proportion to the number of cycles of modulation present on the pattern, reflecting strong integration (Cribb et al.,
2016; Dickinson et al.,
2012). Furthermore, Dickinson, Bell, and Badcock (
2013) have shown that patterns with different frequencies of modulation (RF3 and RF6 patterns) are perfectly discriminated; that is, they can be discriminated at their thresholds for detection of modulation. Seen in the context of the communication of information, such a result is interpreted as evidence for the existence of information lines labeled for specific qualities of the pattern (Watson & Robson,
1981), in this case perhaps related to the frequency or, equivalently, the period of modulation. Dickinson et al. (
2013), however, also showed that single cycles of RF3 and RF6 modulation could not be discriminated at their threshold for detection, implying that the repetition of features on adjacent cycles of modulation is more important to discrimination performance than the modulating function itself.