Can practice eliminate the psychological refractory period effect?

Can people learn to perform two tasks at the same time without interference? To answer this question, the authors trained 6 participants for 36 sessions in a Psychological Refractory Period (PRP) experiment, where Task 1 required a speeded vocal response to an auditory stimulus and Task 2 required a speeded manual response to a visual stimulus. The large PRP effect found initially (353 ms in Session 1) shrank to only about 40 ms over the course of practice, disappearing entirely for 1 of the 6 participants. This reduction in the PRP effect with practice is considerably larger than has been previously reported. The obtained pattern of factor interactions between stimulus onset asynchrony and each of three task difficulty manipulations (Task 1 judgment difficulty, Task 2 stimulus contrast, and Task 2 mapping compatibility) supports a postponement (bottleneck) account of dual-task interference, both before and after practice.     

Does the isolation effect require attention?

An item that differs from the surrounding items is remembered better than an item that is consistent with its surroundings; this is known as the von Restorff effect or isolation effect (von Restorff, Psychologische Forschung, 18, 299–342, 1933). Theoretical explanations have proposed that the isolate is processed differently from control items, though some research has suggested that this processing might require more attention for semantic than for physical isolates. To test this possibility, in the present study we examined the isolation effects for physical isolates and semantic isolates under full and divided attention. Participants viewed lists of categorized words, with some lists containing either a physical or a semantic isolate, followed by immediate written free recall. Across three experiments, divided attention eliminated the semantic isolation effect but did not impact the physical isolation effect. Furthermore, semantic isolates were output earlier in recall than controls, whereas physical isolates were output more similarly to controls. These findings suggest that semantic isolation effects require attention during encoding, whereas physical isolation effects are relatively automatic.     

Does test delay eliminate collaborative inhibition?

Earlier research has demonstrated that collaborative groups recall more than individuals, but less than nominal groups (pooled performance of individuals), thus exhibiting collaborative inhibition. In two experiments, all participants were first asked to recall story material on their own. Some participants were then assigned to pairs and recalled the material collaboratively. On the other hand, the participants in the individual recall condition were asked to recall the material once again on their own. In Experiment 1, the collaborative pairs recalled less than the nominal pairs in accordance with previous studies. In Experiment 2, the timing of the initial individual recall was manipulated by inserting one week between the learning and the recall. The collaborative inhibition was eliminated in this situation. Sources of the collaborative inhibition in immediate recall and its disappearance in delayed recall are discussed in terms of the effect of cross cueing in collaborative remembering.     

Does the generation effect occur for pictures?

The generation effect is the finding that self-generated stimuli are recalled and recognized better than read stimuli. The effect has been demonstrated primarily with words. This article examines the effect for pictures in two experiments: Subjects named complete pictures (name condition) and fragmented pictures (generation condition). In Experiment 1, memory was tested in 3 explicit tasks: free recall, yes/no recognition, and a source-monitoring task on whether each picture was complete or fragmented (the complete/incomplete task). The generation effect was found for all 3 tasks. However, in the recognition and source-monitoring tasks, the generation effect was observed only in the generation condition. We hypothesized that absence of the effect in the name condition was due to the sensory or process match effect between study and test pictures and the superior identification of pictures in the name condition. Therefore, stimuli were changed from pictures to their names in Experiment 2. Memory was tested in the recognition task, complete/incomplete task, and second source-monitoring task (success/failure) on whether each picture had been identified successfully. The generation effect was observed for all 3 tasks. These results suggest that memory of structural and semantic characteristics and of success in identification of generated pictures may contribute to the generation effect.     

Does the Simon effect affect movement execution?

The present work set out to test the prediction of the dual-route response selection account of the Simon effect, which maintains that the Simon effect, and its facilitation and interference components, should show up at the response selection stage irrespective of when it takes place during processing. Previous works have shown that in the case of a movement response, two strategies can be adopted for responding. The main difference between these two response strategies consists of when response selection operations take place. The two experiments reported in the present study showed that when response selection operates clearly before movement initiations, the Simon effect shows up in reaction time and not in movement time.     

Does familiarity change in the revelation effect?

The revelation effect describes the increased tendency to call items "old" when a recognition judgment is preceded by an incidental task. Past findings show that d' for recognition decreases following revelation, evidence that the revelation effect is due to familiarity change. However, data from receiver operating characteristic curves from 3 experiments produced no evidence of changes in recognition sensitivity. The authors illustrate how the use of a single-point measure like d' can be misleading when familiarity distribution variances are unequal. Also investigated was whether the effect depends on the revelation materials used. Neither the memorability of the revelation items, their similarity to recognition probes, nor the difficulty of the task changed the size of the effect. Thus, the revelation effect is not the result of a memory retrieval mechanism and seems to be generic and all-or-nothing. These characteristics are consistent with response bias rather than familiarity change.     

Does a tool eliminate spatial compatibility effects?

Responding to a stimulus is faster and more accurate when stimulus location and response location spatially correspond than when they do not correspond (stimulus–response compatibility). In five experiments this standard compatibility effect is examined when using a T-shaped lever as a tool. Handling the lever allowed distinguishing body-related action effects (e.g., the tactile feedback from the moving finger) from external action effects (e.g., reaching at the stimulus with the lever's end-point). Results showed that the spatial relationship between stimulus and the direction of the hand movement (S-R compatibility) as well as the relationship between the stimulus and the functional end-points of the tool (S-E compatibility) determine performance. More precisely, responses were fast and less error prone when both kinds of compatibility did correspond than when they did not correspond.     

Does the testing effect depend on presentation modality?

We examined whether the testing effect generalizes to an auditory presentation modality. Five lists of unrelated words (Experiment 1) and related words (Experiment 2) were presented to participants, half of whom studied them visually and half studied them auditorily. Participants in the study-only condition performed a short distractor task following lists 1–4, whereas those in the testing condition completed a short distractor task and then attempted to recall each list. Both groups were subsequently tested on List 5 and on all five lists 30 min later. In both experiments, we found a testing effect for both List 5 and for the final cumulative recall test. However, the effect did not interact with study modality, despite the fact that proactive interference was greater following auditory study. These results have important implications for educational practice, suggesting that initial testing is important for materials presented in auditory as well as visual formats.     

Does retrieval fluency contribute to the underconfidence-with-practice effect?

Judgments of learning (JOLs) made during multiple study-test trials underestimate increases in recall performance across those trials, an effect that has been dubbed the underconfidence-with-practice (UWP) effect. In 3 experiments, the authors examined the contribution of retrieval fluency to the UWP effect for immediate and delayed JOLs. The UWP effect was demonstrated with reliable underconfidence on Trial 2 occurring for both kinds of JOL. However, in contrast to a retrieval-fluency hypothesis, fine-grained analyses indicated that the reliance of JOLs on retrieval fluency contributed minimally to the UWP effect. Our discussion focuses on the status of the retrieval-fluency hypothesis for the UWP effect.     

Does right-left prevalence occur for the Simon effect?

In four experiments, we investigated whether a right-left prevalence effect occurs for the Simon task, in which stimulus location is irrelevant, when the stimulus and the response sets vary along horizontal and vertical dimensions simultaneously. Simon effects were evident for both dimensions, and they were of similar magnitude, indicating no prevalence effect. Manipulations of the relative salience of the dimensions for the stimulus and the response sets resulted in a larger Simon effect for the more salient dimension than for the less salient one, but there was no overall prevalence effect. The results indicate that manipulations of salience affect the relative magnitudes of automatic response activation for the vertical and the horizontal dimensions but that the right-left prevalence effect is due to a coding bias in intentional response selection processes when stimulus location is relevant.     

Does the asymmetry effect inflate the temporal expansion of odd stimuli?

Tse et al. (Percept Psychophys 66:1171–1189, 2004) reported that participants tend to overestimate the duration of an oddball stimulus. The size of this effect was much larger than the one reported by Ulrich et al. (Psychol Res 70:77–87, 2006). More crucially, the effect in the study of Tse et al. already emerged at short standard durations, arguing against the arousal account proposed by Ulrich et al. This study investigated whether the oddball effect reported by Tse et al. was inflated by an asymmetry effect, that is, by an asymmetrical distribution of physical comparison durations around the duration of the standard. Experiment 1 demonstrated that an asymmetry effect could mimic an oddball effect. Therefore, we conducted Experiment 2 to replicate the results by Tse et al. employing not only their original procedure but also an adaptive procedure that rather avoids an asymmetry effect. Both psychophysical procedures in this experiment revealed an oddball effect, which, however, was of smaller size than the one reported by Tse et al. Furthermore, this effect emerged only at longer standard durations, which is in agreement with the arousal account as the underlying mechanism of this robust temporal illusion.     

Does neighborhood size really cause the word length effect?

In short-term serial recall, it is well-known that short words are remembered better than long words. This word length effect has been the cornerstone of the working memory model and a benchmark effect that all models of immediate memory should account for. Currently, there is no consensus as to what determines the word length effect. Jalbert and colleagues (Jalbert, Neath, Bireta, & Surprenant, 2011a; Jalbert, Neath, & Surprenant, 2011b) suggested that neighborhood size is one causal factor. In six experiments we systematically examined their suggestion. In Experiment 1, with an immediate serial recall task, multiple word lengths, and a large pool of words controlled for neighborhood size, the typical word length effect was present. In Experiments 2 and 3, with an order reconstruction task and words with either many or few neighbors, we observed the typical word length effect. In Experiment 4 we tested the hypothesis that the previous abolition of the word length effect when neighborhood size was controlled was due to a confounded factor: frequency of orthographic structure. As predicted, we reversed the word length effect when using short words with less frequent orthographic structures than the long words, as was done in both of Jalbert et al.’s studies. In Experiments 5 and 6, we again observed the typical word length effect, even if we controlled for neighborhood size and frequency of orthographic structure. Overall, the results were not consistent with the predictions of Jalbert et al. and clearly showed a large and reliable word length effect after controlling for neighborhood size.     

Separating the wheat from the chaff: does discriminating between diagnostic and nondiagnostic information eliminate the dilution effect?

The dilution effect refers to the finding that judgments are often unduly influenced by nondiagnostic information, producing regressive judgment. Because the dilution effect is a problem in various domains, strategies to control the impact of nondiagnostic information were explored by drawing on a perceptual and a conversational account of the dilution effect. Three experiments (n = 259) demonstrate that explicit instructions to discriminate between diagnostic and nondiagnostic information did not reduce the dilution effect. Rather, consistent with a perceptual explanation but not consistent with a conversational explanation, the dilution effect disappeared only when participants engage in perceptual control, that is, when they actively remove nondiagnostic pieces of information before making a judgment. Copyright © 2004 John Wiley & Sons, Ltd.     

Does length or neighborhood size cause the word length effect?

Jalbert, Neath, Bireta, and Surprenant (2011) suggested that past demonstrations of the word length effect, the finding that words with fewer syllables are recalled better than words with more syllables, included a confound: The short words had more orthographic neighbors than the long words. The experiments reported here test two predictions that would follow if neighborhood size is a more important factor than word length. In Experiment 1, we found that concurrent articulation removed the effect of neighborhood size, just as it removes the effect of word length. Experiment 2 demonstrated that this pattern is also found with nonwords. For Experiment 3, we factorially manipulated length and neighborhood size, and found only effects of the latter. These results are problematic for any theory of memory that includes decay offset by rehearsal, but they are consistent with accounts that include a redintegrative stage that is susceptible to disruption by noise. The results also confirm the importance of lexical and linguistic factors on memory tasks thought to tap short-term memory.     

Does the contextual interference effect last over extended transfer trials?

The contextual interference effect (random practice yields better transfer and retention compared to blocked practice) detected in a study of 24 boys and 33 girls randomly selected (M age = 10.5 yr., SD = .6) performing a linear positioning motor task seemed to dissipate in extended transfer trials.     

Does limiting pre-movement time during practice eliminate the benefit of practicing while expecting to teach?

Past research has revealed practicing and studying a motor skill with the expectation of teaching it to another person increases the amount of time participants spend preparing for movement during practice trials of the skill. However, it is unknown whether the increased motor preparation time explains the benefit of expecting to teach on motor learning. To address this question, we had participants practice golf putting with the expectation of teaching the skill to another participant the following day or the expectation of being tested on the skill the following day. We limited the motor preparation time for half of the participants who expected to teach and half of the participants who expected to test, and allowed the remaining participants to take as much motor preparation time as they liked. All participants were tested on their putting the next day. We predicted that participants who expected to teach would exhibit superior posttest performance, but this benefit would be exclusive to those participants who also practiced with unlimited motor preparation. Although the current data did not support this hypothesis, we also conducted an exploratory analysis in which we aggregated data from two prior experiments. This cumulative analysis suggested that expecting to teach does indeed enhance motor learning, but not through motor preparation during practice.     

Does geomagnetic activity effect extrasensory perception?

Data from two kinds of experiments for extrasensory perception were retrospectively analysed for possible relationships with local geomagnetic activity (K-index). ESP scores from 70 Ganzfeld sessions (telepathy-clairvoyance) were found significantly related to high geomagnetic activity of the day prior to the experimental sessions (rs = 0.23, n = 70, P = 0.03, one-tailed) but not to the geomagnetic activity of day of the sessions (rs = 0.03, n = 70, n.s.). The same relationship was found in experiments which consisted mostly of 80 trials clairvoyance computer games per subject (rs = 0.10, n = 269, P = 0.05, one-tailed). The results partially confirm Persinger's earlier findings on three independent samples, i.e. that spontaneous paranormal experience tend to occur on a day of low geomagnetic activity which is preceded by days of high geomagnetic activity.     

Does response mode affect amount recalled or the magnitude of the testing effect?

The testing effect is the finding that retrieval practice can enhance recall on future tests. One unanswered question is whether first-test response mode (writing or speaking the answer) affects final-test performance (and whether final-test response mode itself matters). An additional unsettled issue is whether written and oral recall lead to differences in the amount recalled. In three experiments, we examined these issues: whether subjects can recall more via typing or speaking; whether typing or speaking answers on a first test can lead to better final-test performance (and whether an interaction occurs with final-test response mode) and whether any form of overt response leads to better final-test performance as compared to covert retrieval (thinking of the answer but not producing it). Subjects studied paired associates; took a first test by typing, speaking, or thinking about responses; and then took a second test in which the answers were either spoken or typed. The results revealed few differences between typing and speaking during recall, and no difference in the size of the testing effect on the second test. Furthermore, an initial covert retrieval yielded roughly the same benefit to future test performance as did overt retrieval. Thus, the testing effect was quite robust across these manipulations. The practical implication for learning is that covert retrieval provides as much benefit to later retention as does overt retrieval and that both can be effective study strategies.     

Does quality of sleep mediate the effect of depression on hopelessness?

The objectives of the study were to evaluate the relationship between sleep quality, depression, and hopelessness in advanced cancer patients and whether sleep quality mediated the effect of depression on hopelessness. The final sample consisted of 102 advanced cancer patients under palliative treatment. Patients completed the Greek Pittsburgh Sleep Quality Index, a sleep quality instrument, the Greek Beck Depression Inventory for measuring depression, and finally the Beck Hopelessness Scale. Patients' performance status was assessed by their overall physical functioning, as defined by the Eastern Cooperative Oncology Group. Depression was highly associated with hopelessness (r = .52, p<.001). Statistically significant associations were found between sleep quality with hopelessness (r = .37, p<.001), as well as with depression (r = .36, p<.001). Mediation analyses indicated that depression influenced hopelessness directly as well as indirectly by its effect on sleep quality. About 14.58% of the variation in hopelessness was explained by depression; 4% of the variance in hopelessness explained by depression was accounted for by the mediation pathway indicating that sleep quality mediated the relationship between depression and hopelessness. Similarly, in the reverse mediation analysis, depression mediated the relationship between sleep quality and hopelessness; 43% of the variation in hopelessness was explained by sleep quality. In conclusion, some of the effect of depression on hopelessness was mediated by sleep quality, but depression had a direct effect on hopelessness as well. Additionally, some of the effect of sleep quality on hopelessness was mediated by depression. The current findings are important because improving sleep quality by treating depression may contribute to decreased hopelessness scores and vice versa: Treating depression by improving sleep quality may also contribute to lower hopelessness scores.     

Does the compatibility effect in the race Implicit Association Test reflect familiarity or affect?

In the Implicit Association Test (IAT; Greenwald, McGhee, & Schwartz, 1998) involving race classification (white vs. black), an apparent compatibility effect is found between the “pleasant” attribute and the “white” category. This race IAT effect has been interpreted in terms of “implicit prejudice”—that is, more positive evaluation of whites than of blacks that is not open to consciousness. We suggested instead that the race IAT effect is better interpreted in terms of the salience asymmetry account proposed by Rothermund and Wentura (2004), whereby greater familiarity with the white category makes it more salient. Evidence that has been presented against the familiarity interpretation is considered, and alternative interpretations of findings related to the race IAT effect are discussed.