Mechanisms underlying the production effect for singing.

The production effect is defined as better memory for items that were read aloud compared with items that were read silently. Quinlan and Taylor (2013) expanded the findings of the production effect by demonstrating that singing items produces even better recognition performance than reading aloud, and argued that this was due to enhanced relative distinctiveness. The current study tested three alternative accounts. In Experiment 1, we explored whether singing results in a larger production effect because it is deemed more bizarre than reading aloud. To address this, we tested a sample for whom singing does not seem bizarre: experienced singers. They also showed better recognition of items that were sung compared with those that were read aloud. In Experiment 2, we determined that singing appears to take longer than either reading aloud or reading silently; however, the possible effect of production time was further explored in Experiment 3. We did this by instructing participants to sing quickly, read aloud slowly, or read silently. Altering relative production times resulted in no discernible changes in subsequent recognition performance. Finally, in Experiment 4, we explored whether singing might strengthen the memory trace relative to reading aloud. We tested this by manipulating the production instruction between subjects. This eliminated the recognition advantage for both reading items aloud as well as for singing them aloud. Having ruled out these alternatives, we argue that singing improves subsequent recognition because it offers more distinctive elements than either reading aloud or reading silently. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Decomposing item-method directed forgetting of emotional pictures: Equivalent costs and no benefits.

Using an item-method directed forgetting task, we presented negative, neutral, and positive photographic pictures, one at a time, each followed by an instruction to remember or forget. We determined that the directed forgetting effect, defined as better subsequent recognition of to-be-remembered (TBR) items than to-be-forgotten (TBF) items, was equivalent across negative, neutral, and positive pictures. To disentangle the underlying costs (i.e., decrease in memory for TBF items) and benefits (i.e., increase in memory for TBR items), we compared recognition memory performance in the directed forgetting task to that of a novel within-subjects remember-all control condition (Experiment 1) and to a between-subjects remember-all control group (Experiment 2). We observed costs without benefits across all three emotions-negative, neutral, and positive-in both experiments. These results demonstrate that equivalent directed forgetting effects for emotional stimuli are not attributable to different underlying component processes. Instead, our results suggest that selection for encoding is accomplished in similar ways, regardless of emotional content.

A preliminary investigation into the neural basis of the production effect.

Items that are produced (e.g., read aloud) during encoding typically are better remembered than items that are not produced (e.g., read silently). This "production effect" has been explained by distinctiveness: Produced items have more distinct features than nonproduced items, leading to enhanced retrieval. The goal of the current study was to use electroencephalography (EEG) to examine the neural basis of the production effect. During study, participants were presented with words that they were required to read silently, read aloud, or sing while EEG data were recorded. Subsequent memory performance was tested using a yes/no recognition test. Analysis focused on the event-related brain potentials (ERPs) evoked by the encoding instruction cue for each instruction condition. Our data revealed enhanced memory performance for produced items and a greater P300 ERP amplitude for instructions to sing or read aloud compared with instructions to read silently. Our results demonstrate that the amplitude of the P300 is modulated by at least 1 aspect of production, vocalization (singing/reading aloud relative to reading silently), and are consistent with the distinctiveness account of the production effect. The ERP methodology is a viable tool for investigating the production effect. (PsycINFO Database Record

"I never forget a face, but in your case I'll be glad to make an exception": Intentional forgetting of emotional faces.

The current study used the item-method directed forgetting paradigm to determine whether there are limits on the ability to intentionally forget angry faces. During the study phase, faces were presented, 1 at a time, each followed by an instruction to remember or forget. Following the presentation of all faces, participants performed a yes-no recognition test. In 2 experiments that varied only the presentation duration of the face (500 ms vs. 1,000 ms), we observed an overall directed forgetting effect, with greater recognition of faces studied with remember rather than forget instructions; the magnitude of this effect did not vary with emotional expression. We interpret these results in light of the proposal that priority processing of angry faces benefits the speed of forming an enduring long-term memory trace rather than increasing the strength of that trace.

Enhancing the production effect in memory.

The production effect is the finding that subsequent memory is better for words that are produced than for words that are not produced. Whereas the current literature demonstrates that reading aloud is the most effective form of production, the distinctiveness account used to explain the production effect predicts that there is nothing special about reading aloud per se: Other forms of vocal production that include an additional distinct element should produce even greater subsequent memory benefits than reading aloud. To test this, we presented participants with study words that they were instructed to read aloud loudly, read aloud, or read silently (Experiment 1); sing, read aloud, or read silently (Experiment 2); and sing, read aloud loudly, read aloud, or read silently (Experiment 3). We observed that both reading items aloud loudly (Experiments 1 and 3) and singing items (Experiments 2 and 3) at study resulted in greater subsequent recognition than reading items aloud in a normal voice; singing had a larger memory benefit than reading aloud loudly (Experiment 3). Our findings support the distinctiveness hypothesis by demonstrating that there are other forms of production, such as singing and reading aloud loudly that have a more pronounced effect on memory than reading aloud.

Interplay of the production and picture superiority effects: a signal detection analysis.

Three experiments explored the interaction between the production effect (greater memory for produced compared to non-produced study items) and the picture superiority effect (greater memory for pictures compared to words). Pictures and words were presented in a blocked (E1) or mixed (E2, E3) design, each accompanied by an instruction to silently name (non-produced condition) or quietly mouth (produced condition) the corresponding referent. Memory was then tested for all study items as well as an equal number of foil items using a speeded (E1, E2) or self-paced (E3) yes-no recognition task. Experiments 1, 2, and 3 all revealed a small but reliable production × stimulus interaction. Production was also found to result in a liberal shift in response bias that could result in the overestimation of the production effect when measured using hits instead of sensitivity. Together our findings suggest that the application of multiple distinctive processes at study produces an especially discriminative memory trace at test, more so than the summation of each process individually.

Stability of central binaural sound localization mechanisms in mammals, and the Heffner hypothesis.

Heffner (2004) provided an overview of data on the evolutionary pressures on sound localization acuity in mammals. Her most important finding was that sound localization acuity was most strongly correlated with width of field of best vision. This correlation leaves unexplained the mechanism through which evolutionary pressures affect localization acuity in different mammals. A review of the neurophysiology of binaural sound localization cue coding, and the behavioural performance it supports, led us to two hypotheses. First, there is little or no evidence that the neural mechanisms for coding binaural sound location cues, or the dynamic range of the code, vary across mammals. Rather, the neural coding mechanism is remarkably constant both across species, and within species across frequency. Second, there is no need to postulate that evolutionary pressures are exerted on the cue coding mechanism itself. We hypothesize instead that the evolutionary pressure may be on the organism's ability to exploit a 'lower envelope principle' (after Barlow, 1972).

Directed forgetting: Comparing pictures and words.

The authors investigated directed forgetting as a function of the stimulus type (picture, word) presented at study and test. In an item-method directed forgetting task, study items were presented 1 at a time, each followed with equal probability by an instruction to remember or forget. Participants exhibited greater yes-no recognition of remember than forget items for each of the 4 study-test conditions (picture-picture, picture-word, word-word, word-picture). However, this difference was significantly smaller when pictures were studied than when words were studied. This finding demonstrates that the magnitude of the directed forgetting effect can be reduced by high item memorability, such as when the picture superiority effect is operating. This suggests caution in using pictures at study when the goal of an experiment is to examine potential group differences in the magnitude of the directed forgetting effect.