First- and third-person approaches in implicit learning research

How do we find out whether someone is conscious of some information or not? A simple answer is “We just ask them”! However, things are not so simple. Here, we review recent developments in the use of subjective and objective methods in implicit learning research and discuss the highly complex methodological problems that their use raises in the domain.     

Intuitive decision making in complex situations: Somatic markers in an artificial grammar learning task

In this article, we explore the extent to which implicit learning is subtended by somatic markers, as evidenced by skin conductance measures. On each trial, subjects were asked to decide which “word” from a pair of “words” was the “correct” one. Unknown to the subjects, each “word” of a pair was constructed using a different set of rules (Grammar Aand Grammar B). A (monetary) reward was given if the subject chose the “word” from Grammar A. Choosing the Grammar B word resulted in (monetary) punishment. Skin conductance was measured during each of 100 trials. After each set of 10 trials, the subjects were asked how they selected the “correct word.” Task performance increased long before the subjects could even formulate a single relevant rule. In this preconceptual phase of the experiment, skin conductance was larger before incorrect than before correct choices. Thus, it was shown that artificial grammar learning is accompanied by a somatic marker, possibly “warning” the subject of the incorrect decision.     

Further evidence on the similarity of memory processes in the process dissociation procedure and in source monitoring

Buchner, Erdfelder, Steffens, and Martensen (1997) proposed that the memory processes involved in recognition judgments in the process dissociation procedure are the same as those involved in standard source monitoring tasks. Two extensions of that research are presented here. First, following a line of reasoning recently brought forward by Jacoby (1998), the instructions in the earlier study could have triggered different processes from those triggered by his instructions. However, with instructions conforming as closely as possible to those reported by Jacoby (1991), Experiment 1 replicated the earlier recognition judgment finding almost perfectly. Second, the memory processes underlying fame judgments in the process dissociation procedure could also resemble those involved in source monitoring tasks. Indeed, the results of Experiment 2 are compatible with the hypothesis that the same processes are involved in fame judgments given a source monitoring or a process dissociation procedure.     

Contextual modulation of prime response retrieval processes: Evidence from auditory negative priming

Contextual similarity between learning and test phase has been shown to be beneficial for memory retrieval. Negative priming is known to be caused by multiple processes; one of which is episodic retrieval. Therefore, the contextual similarity of prime and probe presentations should influence the size of the negative priming effect. This has been shown for the visual modality. In Experiment 1, an auditory four-alternative forced choice reaction time task was used to test the influence of prime-probe contextual similarity on negative priming and the processes underlying the modulation by context. The negative priming effect was larger when the auditory context was repeated than when it was changed from prime to probe. The modulation by context was exclusively caused by an increase in prime response retrieval errors in ignored repetition trials with context repetition, whereas repeating only the context but not the prime distractor did not lead to an increase in prime response retrieval. This exact pattern of results was replicated in Experiment 2. The findings suggest that contextual information is integrated with prime distractor and response information. Retrieval of the previous episode, including prime distractor, prime response, and context (event file), can be triggered when the former prime distractor is repeated, whereas a context cue alone does not retrieve the event file. This suggests an event file structure that is more complicated than its usually assumed binary structure.     

Endogenous versus exogenous change: Change detection,self and agency

The goal of this study is to characterize observers’ abilities to discriminate between endogenous (i.e., self-produced) and exogenous changes. To do so, we developed a new experimental paradigm. On each trial, participants were shown a dot pattern on the screen. Next, the pattern disappeared and participants were to reproduce it. Changes were surreptuously introduced in the stimulus, either by presenting participants anew with the dot pattern they had themselves produced on the previous trial (endogenous change) or by presenting participants with a slightly different dot pattern (exogenous changes). We analyzed awareness of the changes and behavioral adaptation to them in a dynamical manner. We observe (1) signal attenuation in the presence of endogenous change, (2) dissociation between self-attribution reports and behavioral effect of agency. We discuss the source of this sensitive attenuation as well as the relation between a minimal or core self and an extended, narrative or autobiographical self.     

Know thyself: Metacognitive networks and measures of consciousness

Subjective measures of awareness rest on the assumption that conscious knowledge is knowledge that participants know they possess. Post-Decision Wagering (PDW), recently proposed as a new measure of awareness, requires participants to place a high or a low wager on their decisions. Whereas advantageous wagering indicates awareness of the knowledge on which the decisions are based, cases in which participants fail to optimize their wagers suggest performance without awareness. Here, we hypothesize that wagering and other subjective measures of awareness reflect metacognitive capacities subtended by self-developed metarepresentations that inform an agent about its own internal states. To support this idea, we present three simulations in which neural networks learn to wager on their own responses. The simulations illustrate essential properties that are required for such metarepresentations to influence PDW as a measure of awareness. Results demonstrate a good fit to human data. We discuss the implications of this modeling work for our understanding of consciousness and its measures.     

Manipulative success and the unreal

In its original form due to Ian Hacking, entity realism postulates a criterion of manipulative success which replaces explanatory virtue as the criterion of justified scientific belief. The article analyses the foundations on which this postulate rests and identifies the conditions on which one can derive a form of entity realism from it. It then develops in detail an extensive class of counterexamples, drawing on the notion of quasi-particles in condensed matter physics. While the phenomena associated with quasi-particles pass the entity realist's criterion of manipulative success, quasi-particles themselves are illusions, and can be seen to be so even on the basis of the largely non-theoretical “home truths” that one must be ready to admit as background knowledge. Hence, Hacking's entity realism is shown to be incoherent.