Dienes, Z.
University of Sussex, Brighton, UK
One of the key domains investigating the difference between conscious and unconscious processes is implicit learning. Within the implicit learning literature, the key papers defining the “believers’” position that unconscious learning exists, and its nature, were published by Arthur Reber in the 1960s and 1970s. The paper defining the sceptics’ position, and still one of the most closely argued papers sceptical of implicit learning, is Dulany, Carlson and Dewey (1984) (DCD). I will present fresh data which, for the first time in 25 years, attempts to replicate DCD, and test alternative interpretations of their results. Reber exposed people to strings of letters, unbeknownst to subjects generated by a finite state grammar, and then asked people to classify new strings as obeying the rules or not. People could do so at above chance levels despite being unable to describe the rules. Reber argued people had acquired unconscious knowledge. DCD repeated the procedure but asked people to underline the part of the string that made it grammatical or non-grammatical. Treating these underlinings as conscious rules, he showed rule validity predicted correct classification almost perfectly. Thus, DCD argued that all the knowledge was conscious. DCD assumed that forced underlining of part of a string amounted to asserting a rule. But, for example, wondering or completely guessing where to underline is not to assert anything. I repeated DCD’s procedure but in addition asked people to report the basis of their underlining: They completely guessed, they relied on intuition, they used a rule, and they used recollection. People predominantly said they guessed (37%) or used intuition (30%). Further, underlinings only partially accounted for classification. Importantly, the underlinings largely expressed unconscious knowledge, by a metacognitive measure shown to dissociate qualitatively different types of knowledge.