Short Article: Why do the Effects of Delaying Reinforcement in Animals and Delaying Feedback in Humans Differ? A Working-Memory AnalysisLieberman, David A.; Vogel, A. Carina M.; Nisbet, Jaime
doi: 10.1080/17470210701557506pmid: 17886159
Animal research has shown that reinforcement is substantially less effective when it is delayed, but in studies of human motor learning delays in providing feedback typically have much less effect. One possible explanation is that in human research participants know the response to be learned and can thus focus on it during the delay; that is not the case in experiments on animals. We tested this hypothesis using a task in which participants had minimal information on what movement was correct and found that, as in animal experiments, participants learned only when feedback was immediate. A second experiment confirmed that the effects of the delay depended on how many responses had to be held in working memory: the greater the memory load, the poorer the learning. The results point to the importance of activity during a delay on learning; implications for the teaching of motor skills are discussed.
Short Article: Asymmetrical Learning between a Tactile and Visual Serial RT TaskAbrahamse, Elger L.; Van Der Lubbe, Rob H. J.; Verwey, Willem B.
doi: 10.1080/17470210701566739pmid: 17896207
According to many researchers, implicit learning in the serial reaction-time task is predominantly motor based and therefore should be independent of stimulus modality. Previous research on the task, however, has focused almost completely on the visual domain. Here we investigated sequence learning when the imperative stimuli were presented tactilely to the fingers. Learning in this task was compared to sequence learning in a typical visual task, using very similar experimental conditions. The results indicate that sequential learning occurs in the tactile task, though to a lesser degree than in its visual counterpart. Furthermore, there was similar cross-modal transfer in both directions, meaning that transfer from the visual to the tactile task was partial. It is proposed that sequence learning involves a stimulus-specific component in the visual but not in the tactile task.
List Strength Effect without List Length Effect in Recognition MemoryBuratto, Luciano G.; Lamberts, Koen
doi: 10.1080/17470210701566713pmid: 17886194
The study of list length effects (adding items to a list affects memory for the other items) and list strength effects (strengthening some items in a list affects memory for the nonstrengthened items) is important to constrain models of memory. In recognition memory, a list length effect is generally found, whereas a list strength effect is not. Using the switched-plurality procedure in an old–new recognition task (e.g., study banana; test bananas), we found the opposite pattern. Length manipulations caused no change in memory performance, whereas strength manipulations did. The list strength effect was found when recollection was likely to operate at test (with switched-plurality lures). When recollection was unlikely to operate (with unrelated lures), the strength effect disappeared. The result was observed using both a size judgement task (which has previously produced positive list strength effects) and a pleasantness judgement task (which has not yielded list strength effects before).
Short Article: Acquired Flavour Preferences: Contextual Control of Adaptation-Level EffectsAlbertella, Lucy; Harris, Justin A.; Boakes, Robert A.
doi: 10.1080/17470210701664864pmid: 17935002
This experiment investigated the role of context in the expression of conditioned flavour preferences. Rats were trained on a mixture of almond and sucrose and were then given intermixed exposures to almond in one context (Context A) and to sucrose in a second context (Context S). Finally, choice tests were given in both contexts, with one group given almond-versus-water tests and the other almond + sucrose-versus-sucrose tests. Preference for almond over water was greater in Context A than in Context S. Conversely, preference for almond + sucrose over sucrose was greater in Context S than in Context A. These results suggest that the perceived sweetness of a flavour depends on the context in which it is presented and confirm that expression of a flavour preference depends on the type of test employed.
Short Article: Semantic Anomalies at the Borderline of Consciousness: An Eye-Tracking InvestigationBohan, Jason; Sanford, Anthony
doi: 10.1080/17470210701617219pmid: 17886160
We report an eye-tracking study in which participants read passages containing difficult-to-detect semantic anomalies. Would there be any evidence of the registration of the anomaly within the comprehension system (reflected in eye tracking) when anomalies were not noticed? Using early and late processing measures, there was no evidence for registration independent of conscious detection. Comparisons were made between detected and undetected anomalies and between these and nonanomalous controls. There was evidence of disruption to the tracking measures only when a conscious report was also made. These data fit the view that shallow semantic processing underlies the failure to detect anomalies. Implications for language processing are discussed.
Inhibitory Sensory Preconditioning Detected with a Sodium Depletion ProcedureEspinet, Alfredo; Artigas, Antonio A.; Balleine, Ernard W.
doi: 10.1080/17470210601154594pmid: 17853211
In each of two experiments, two groups of rats were exposed to three flavoured solutions: A (citric acid), B (salt), and AX (a compound of citric acid and saccharin). Both experiments used a between-subjects design in which a paired group received presentations of A followed by B, alternating with presentations of AX (i.e., A → B/AX), and an unpaired group received alternating presentations of A, B, and AX (i.e., A/B/AX). This arrangement was expected to establish X as an inhibitor of B in group paired but not in group unpaired. In Experiment 1, after preexposure all subjects received a single presentation of an XB compound, then experienced sodium depletion, and were tested for their consumption of X, which was greater in group unpaired than in group paired. In Experiment 2, after preexposure, all subjects received four presentations of a new flavour, C, in compound with B and subsequently, under sodium depletion, were tested for consumption of XC. Intake of the XC compound was less in group paired than in group unpaired. These results suggest that, in group paired, X acquired an inhibitory relationship with B both retarding the acquisition of an excitatory association with B (retardation test, Experiment 1) and reducing the response to a new stimulus, C, strongly associated to B (summation test, Experiment 2). These results provide direct evidence of inhibition between two neutral stimuli and, therefore, of inhibitory sensory preconditioning.
Serial Memory for Sound-Specified Locations: Effects of Spatial Uncertainty and Motor SuppressionGroeger, J. A.; Banks, A. P.; Simpson, P. J.
doi: 10.1080/17470210601138746pmid: 17853218
According to Parmentier and Jones (2000), serial recall of locations that are specified by a sequence of sounds is prone to temporal error and is unaffected by motor suppression during retention. Experiments are reported here that show that with increased spatial uncertainty at recall (Experiment 1) and presentation (Experiment 2), spatial rather than temporal errors predominate. This is also the case when serial recall of sound-specified locations is subject to interference from a motor suppression task (Experiment 3). Contrary to Parmentier and Jones's (2000) original report, these results suggest that the memory representation for location is not necessarily amodal but is influenced by the representational requirements of the task being performed. This is consistent with recent findings that provide evidence for a distinct spatial working memory.
Slowing down an Internal Clock: Implications for Accounts of Performance on four Timing TasksWearden, J. H.
doi: 10.1080/17470210601154610pmid: 17853194
An experiment investigated the potential effects of lowering arousal on performance on time perception tasks. Four participant groups received different tasks: Normal and episodic temporal generalization, bisection, and verbal estimation, all involving judgements of the duration of visual stimuli. Self-rated arousal during the experimental session was lowered by spacing experimental trials approximately 10 s apart. Between the early and late blocks of the experiment, performance changed on normal temporal generalization and verbal estimation, but not on episodic temporal generalization and bisection. The changes were consistent with the idea that the pacemaker of the participant's internal clock had been slowed down by the slow trial spacing. Results suggested that bisection was based on a criterion that adjusted during the experiment, whereas verbal estimation was based on preexisting standards, or those established early in the experiment.