Motor simulation in verbal knowledge acquisition

Recent research highlights the importance of motor processes for a wide range of cognitive functions such as object perception and language comprehension. It is unclear, however, whether the involvement of the motor system goes beyond the processing of information that is gathered through active action experiences and affects also the representation of knowledge acquired through verbal learning. We tested this prediction by varying the presence of motor interference (i.e., squeezing a ball vs. oddball detection task) while participants verbally acquired functional object knowledge and examined the effects on a subsequent object detection task. Results revealed that learning of functional object knowledge was only impaired when participants performed an effector-specific motor task while training. The present finding of an effector-specific motor interference effect on object learning demonstrates the crucial role of the motor system in the acquisition of novel object knowledge and provides support for an embodied account to perception and cognition.     

Choosing optimal causal backgrounds for causal discovery

In two experiments, we studied the strategies that people use to discover causal relationships. According to inferential approaches to causal discovery, if people attempt to discover the power of a cause, then they should naturally select the most informative and unambiguous context. For generative causes this would be a context with a low base rate of effects generated by other causes and for preventive causes a context with a high base rate. In the following experiments, we used probabilistic and/or deterministic target causes and contexts. In each experiment, participants observed several contexts in which the effect occurred with different probabilities. After this training, the participants were presented with different target causes whose causal status was unknown. In order to discover the influence of each cause, participants were allowed, on each trial, to choose the context in which the cause would be tested. As expected by inferential theories, the participants preferred to test generative causes in low base rate contexts and preventative causes in high base rate contexts. The participants, however, persisted in choosing the less informative contexts on a substantial minority of trials long after they had discovered the power of the cause. We discuss the matching law from operant conditioning as an alternative explanation of the findings.     

Positive and negative mediation as a function of whether the absent cue was previously associated with the outcome

After presenting two cues, A and B, together, later pairings of one of the cues alone with an outcome can generate changes in the associative value of the absent cue. These changes can be in the same direction as the present cue (i.e., positive mediation) or in the opposite direction to the present cue (i.e., negative mediation). We found both mediational effects in a human contingency task. In addition, we found that the direction of the change was determined by the existence of a prior association between the absent cue and the outcome. When a prior association exists, the absent cue tends to change its value in the opposite direction to the present cue, whereas when there is no prior association, the absent cue tends to change its value in the same direction as the present cue. Recent associative models (Stout & Miller, 2007 Stout, S. C. and Miller, R. R. 2007. Sometimes-competing retrieval (SOCR): A formalization of the comparator hypothesis. Psychological Review, 114: 759–783.  [Google Scholar]) can explain our results.     

Questioning implicit motor learning as instantiated by the pursuit-tracking task

The effect of concurrent visual feedback on the implicit learning of repeated segments in a task of pursuit tracking has been tested. Although this feedback makes it possible to regulate the positional error during the movement, it could also induce negative guidance effects. To test this hypothesis, a first set of participants (N?=?42) were assigned to two groups, which performed either the standard pursuit-tracking task based on the experimental paradigm of Pew (1974 Pew, R. W. 1974. Levels of analysis in motor control. Brain Research, 71: 393–400. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; group F-ST), or a task called “movement reproduction” in which the feedback was suppressed (group noF-ST). A second set of participants (N?=?26) performed in the same feedback condition groups but in a dual-task situation (F-DT and noF-DT; Experiment 2). The results appear to confirm our predictions since the participants in groups without feedback, contrary to those in groups with feedback, succeeded with practice in differentiating their performances as a function of the nature of the segments (repeated or nonrepeated) both in simple (Experiment 1) and in dual-task (Experiment 2) situations. These experiments indicate that the feedback in the pursuit-tracking task induces a guidance function potentially resulting in an easiness tracking that prevents the participants from learning the repetition.     

My word! Interference from reading object names implies a role for competition during picture name retrieval

A related word prime has been found to interfere with picture naming after unrelated intervening trials (word-to-picture interference). Recently, Stroop-type picture–word interference effects have been interpreted in terms of a postlexical response exclusion process rather than a competitive lexical selection process. An experiment is reported that examines whether word-to-picture effects could reflect response exclusion mechanisms and, more generally, strategic processing of the word prime. Forty-eight volunteer university students named aloud sequences of semantically related (and unrelated) word primes and picture targets, separated by two unrelated filler stimuli. On half of the trials, participants were asked to count backwards in threes from a random number presented immediately after naming the prime word. They were also given a surprise recall test at the end of the naming block. Results for naming times and errors indicated a main effect of relatedness; semantic interference effects were not dependent on the unfilled gap following the word prime trial and were also not tied to episodic recall of prime words. The data indicate that slowed picture naming times are more likely to emerge from processes intrinsic to word prime naming rather than controlled processing and do not readily fit the postlexical response exclusion account. The results are considered in relation to two recent accounts of interference over unrelated trials, which refer to some form of competition at, or prior to, lexical access.     

Bartlett's schema theory: The unreplicated “portrait d'homme” series from 1932

In 1932, Frederic Bartlett laid the foundation for the later schema theory. His key assumption of previous knowledge affecting the processing of new stimuli was illustrated in the famous “portrait d'homme” series. Sequenced reproductions of ambiguous stimuli showed progressive object-likeness. As Bartlett pointed out, activation of specific schemata, for instance “the face schema”, biases memory retrieval towards such schemata. In five experiments (Experiment 1, n?=?53; Experiment 2, n?=?177; Experiment 3, n?=?36; Experiment 4, n?=?6; Experiment 5, n?=?2), we tested several factors potentially influencing retrieval biases—for example, by varying the general procedure of reproduction (repeated vs. serial) and by omitting versus providing visual or semantic cues for activating face schemata. Participants inspected face-like stimuli with the caption “portrait of the human” and reproduced them repeatedly under specific conditions. None of the experiments revealed a systematic tendency towards Bartlett's described case, even when the participants were explicitly instructed to draw “a face” like the previously inspected one. In one of the “serial reproduction” experiments, we even obtained contrary effects with decreasing face-likeness over the reproduction generations. A close analysis of the original findings raises questions about the replicability of Bartlett's findings, qualifying the “portrait d'homme” series more or less as an illustrative example of the main idea of reconstructive memory.     

A positive patterning advantage with complex but not simple patterning: A cue constellation approach

Determinants of a positive patterning advantage (that is, an advantage for positive patterning over negative patterning) in human causal reasoning were examined in an experiment that compared simple patterning discriminations (A, B vs. AB) to complex patterning discriminations (AB, BC, AC vs. ABC). As predicted by a cue constellation analysis of complex discriminations, a positive patterning advantage was found with complex patterning but not with simple patterning discriminations. This result may explain why some recent studies have found a positive patterning advantage where earlier studies had failed to find one. The interaction of patterning complexity with the positive patterning advantage appears to pose problems for rule-based accounts of patterning. The results support the view that associative theories of human causal reasoning are more easily distinguished from rule-based approaches when applied to conditions that make simple rules difficult to identify or implement.     

Evidence for an expectancy-based theory of avoidance behaviour

In most studies on avoidance learning, participants receive an aversive unconditioned stimulus after a warning signal is presented, unless the participant performs a particular response. Lovibond (2006) recently proposed a cognitive theory of avoidance learning, according to which avoidance behaviour is a function of both Pavlovian and instrumental conditioning. In line with this theory, we found that avoidance behaviour was based on an integration of acquired knowledge about, on the one hand, the relation between stimuli and, on the other hand, the relation between behaviour and stimuli.     

Hebb repetition effects in visual memory: The roles of verbal rehearsal and distinctiveness

A version of the Hebb repetition task was used with faces to explore the generality of the effect in a nonverbal domain. In the baseline condition, a series of upright faces was presented, and participants were asked to reconstruct the original order. Performance in this condition was compared to another in which the same stimuli were accompanied by concurrent verbal rehearsal to examine whether Hebb learning is dependent on verbal processing. Baseline performance was also compared to a condition in which the same faces were presented inverted. This comparison was used to determine the importance in Hebb learning of being able to visually distinguish between the list items. The results produced classic serial position curves that were equivalent over conditions with Hebb repetition effects being in evidence only for upright faces and verbal suppression as having no effect. These findings are interpreted as posing a challenge to current models derived from verbal-domain data.     

Improving conditional discrimination learning and memory in five-year-old children: Differential outcomes effect using different types of reinforcement

Previous studies have demonstrated that discriminative learning is facilitated when a particular outcome is associated with each relation to be learned. When this training procedure is applied (the differential outcomes procedure; DOP), learning is faster and better than when the typical common outcomes procedure or nondifferential outcomes (NDO) is used. Our primary purpose in the two experiments reported here was to assess the potential advantage of DOP in 5-year-old children using three different strategies of reinforcement in which (a) children received a reinforcer following a correct choice (“ + ”), (b) children lost a reinforcer following an incorrect choice (“ ? ”), or (c) children received a reinforcer following a correct choice and lost one following an incorrect choice (“ + / ? ”). In Experiment 1, we evaluated the effects of the presence of DOP and different types of reinforcement on learning and memory of a symbolic delayed matching-to-sample task using secondary and primary reinforcers. Experiment 2 was similar to the previous one except that only primary reinforcers were used. The results from these experiments indicated that, in general, children learned the task faster and showed higher performance and persistence of learning whenever differential outcomes were arranged independent of whether it was differential gain, loss, or combinations. A novel finding was that they performed the task better when they lost a reinforcer following an incorrect choice (type of training “ ? ”) in both experiments. A further novel finding was that the advantage of the DOP over the nondifferential outcomes training increased in a retention test.