Directed forgetting of faces: the role of response criterion

In two experiments, we examined recognition for faces following item method directed forgetting. During testing, participants reported whether the face was a new face or, if they thought it was a studied face, they identified the instruction paired with the face during study. In both experiments, the proportion of new faces falsely recognized and classified as forget faces exceeded those falsely recognized and classified as remember faces. Despite the use of different response criteria during testing, participants showed greater discrimination accuracy when identifying remember faces than when identifying forget faces. Taken together, these data patterns indicate that participants employed a strength-based criterion when responding. Specifically, participants responding to new faces were more likely to classify those faces as forget faces from study rather than as remember faces from study.     

Arousal, valence, and memory for detail

A common finding in the emotion-memory literature is that memory is enhanced for positively arousing stimuli and negatively arousing stimuli relative to neutral stimuli. We tested the notion that post-stimulus elaboration is responsible for these effects. Post-stimulus elaboration refers to the process of thinking about an event (after its offset) more frequently or more in-depth. We tested the hypothesis by presenting participants with 36 slides depicting events that varied in arousal (low and high) and valence (positive and negative). The opportunity for elaboration was manipulated by requiring participants, during the interslide interval, to complete addition problems, simply view the addition problems, or view a blank slide. Cued recall memory was tested for central and background details. Based on the post-stimulus elaboration hypothesis it was expected that the greatest memory decline would occur for the central details of negatively and positively arousing slides when participants were required to complete addition problems (i.e., a distractor task x arousal x detail interaction). Contrary to the hypothesis, we found that filling the inter-slide interval with a distractor task decreased memory for negative stimuli compared to positive stimuli. This effect was independent of arousal. We also found that arousal increased central detail memory for positive and negative stimuli and background detail memory for positive stimuli but not for negative stimuli. This interaction was explained on the basis of pre-attentive encoding and cue utilisation. It was concluded that in order to understand the complex relationship between emotion and memory, future studies should include, as a minimum, the variables of valence, arousal, and detail.     

Emotional stimuli, divided attention, and memory

The emotion-memory literature has shown that negative emotional arousal enhances memory. S. A. Christianson (1992) proposed that preattentive processing could account for this emotion-memory relationship. Two experiments were conducted to test Christianson's theory. In Experiment 1, participants were exposed to neutral and negative arousing slides. In Experiment 2, participants were exposed to neutral, negative arousing, and positive arousing slides. In both experiments, the aforementioned variable was factorially combined with a divided-attention or non-divided-attention condition. The authors predicted that, in contrast to the nondivided condition, dividing attention would adversely impact neutral and positive stimuli more than negative stimuli. The hypothesis was supported; participants recalled more high negative-arousal slides than positive or neutral slides when their attention was divided rather than nondivided.     

Memory for emotionally arousing stimuli: a comparison of younger and older adults

The authors compared emotional memory in younger (aged 18-32 years) and older (aged 59-84 years) adults. Previous researchers who investigated the emotionmemory relationship in younger adults consistently showed that emotional arousal enhances memory for central detail. The present authors' goal was to determine whether a similar effect could be found with older adults. Younger and older adults viewed a series of 12 slides, accompanied by a taped narrative, that showed emotionally arousing or neutral scenes in the middle phase (Slides 5-8). Participants then completed recognition tests that were scored for central detail, peripheral detail, and gist. The results indicated that, although younger adults showed higher performance than older adults did, both groups showed increased memory for central detail. In contrast, the authors found no such enhancement for peripheral detail or gist in either group. These results indicated that the arousal manipulation produced a similar effect on memory in younger and older adults. Furthermore, these results were consistent with the notion of poststimulus elaboration, which is the continued processing of central detail after the termination of an arousing event.     

Emotion, directed forgetting, and source memory

We investigated the role of emotion on item and source memory using the item method of directed forgetting (DF) paradigm. We predicted that emotion would produce source memory impairment because emotion would make it more difficult to distinguish between to-be-remembered (R items) and to-be-forgotten items (F items) by making memory strength of R and F items similar to each other. Participants were presented with negatively arousing, positively arousing, and neutral pictures. After each picture, they received an instruction to remember or forget the picture. At retrieval, participants were asked to recall both R and F items and indicate whether each item was an R or F item. Recall was higher for the negatively arousing than for the positively arousing or neutral pictures. Further, DF occurred for the positively arousing and neutral pictures, whereas DF was not significant for the negatively arousing pictures. More importantly, the negatively arousing pictures, particularly the ones with violent content, showed a higher tendency of producing misattribution errors than the other picture types, supporting the notion that negative emotion may produce source memory impairment, even though it is still not clear whether the impairment occurs at encoding or retrieval.     

Goal-oriented, flexible use of numerical operations by monkeys

Previous studies have shown that elementary aspects of numerical abilities have developed in non-human primates. In the present study, we explored the potential for the development of a novel ability in the use of numerical operations by macaque monkeys (Macaca fuscata): adequate selection of a series of numerical actions toward achieving a behavioral goal. We trained monkeys to use a pair of devices to selectively add or subtract items to/from a digital array in order to match a previously viewed sample array. The monkeys determined whether to add or subtract on the basis of the feedback about numerosity given to the monkeys, which was displayed as an outcome of each step of the numerical operation. We also found that monkeys adapted flexibly to changes in the numerical rule that determined the relationship between device use and numerical operation. Our model analysis found that the numerosity-based model was a better fit for the monkeys’ performance than was the reward-expectation-based model. Such a capacity for goal-oriented selection of numerical operations suggests a mechanism by which monkeys use numerical representations for purposeful behaviors.     

Cultural differences in asymmetric beliefs of interpersonal knowledge in vertical and horizontal relationships

Previous studies have reported that our interpersonal knowledge shows an asymmetry; that is, we tend to believe that we know and understand other people's thoughts and feelings better than other people know and understand our own thoughts and feelings. In the present study, the authors compared American (114 men, 192 women) and Korean (99 men and 98 women) students to examine whether the asymmetry is greater in collectivistic than in individualistic culture in two types of relationships: horizontal (with best friends) and vertical (with parents). On all three items--Know, Understand, and Visibility--asymmetry was found for both horizontal and vertical relationships. Further, the Understand and Visibility items showed greater asymmetry for the Korean group than for the American group. It was concluded that asymmetry is greater in collectivistic than in individualistic culture. The cultural differences can be explained by self-consistency, sensitivity to social consequences, parent-child interaction, and living arrangement.     

Binary Refinement Implies Discrete Exponentiation

Working in the weakening of constructive Zermelo-Fraenkel set theory in which the subset collection scheme is omitted, we show that the binary re.nement principle implies all the instances of the exponentiation axiom in which the basis is a discrete set. In particular binary re.nement implies that the class of detachable subsets of a set form a set. Binary re.nement was originally extracted from the fullness axiom, an equivalent of subset collection, as a principle that was su.cient to prove that the Dedekind reals form a set. Here we show that the Cauchy reals also form a set. More generally, binary refinement ensures that one remains in the realm of sets when one starts from discrete sets and one applies the operations of exponentiation and binary product a finite number of times. Presented by Victor Marek     

Relationship between annual household income and suicidal ideation: a cross-sectional study

Previous studies have shown that high income was associated with low risk of death by suicide; however, the extent to which household income reduces suicidal ideation remains unclear. We performed a survey to examine the relationship between annual household income and suicidal ideation and determine the level of annual household income at which suicidal ideation no longer decreased as income increased. In total, 94,131 members of Internet survey panels were recruited as participants by a major Japanese Internet survey company in 2016. The participants completed a self-administered questionnaire consisting of items pertaining to demographics, annual household income, and suicidal ideation. We performed logistic regression analysis with suicidal ideation as the dependent variable and income level as the independent variable. The results showed that odds ratios for suicidal ideation decreased as annual household incomes increased, with sex, age, educational level, marital status, and parenthood adjusted for; however, once annual household incomes exceeded 8 million JPY (approximately 77,700 USD), the risk of suicidal ideation no longer decreased. We conclude that suicidal ideation was negatively associated with annual household income and 8 million JPY (approximately 77,700 USD) is a threshold beyond which further increases in income no longer reduce individuals’ suicidal ideation.     

Segregation accuracy in item‐method directed forgetting across multiple tests

Two experiments examined recall across tests following item‐method directed‐forgetting instructions and the varying of presentation duration of items at study. For both immediate testing (Experiment 1) and delayed testing (Experiment 2), accurate recall of remember instruction items (R‐items) exceeded the accurate recall of forget instruction items (F‐items). However, some F‐items from study were inaccurately recalled as R‐items and R‐items from study as F‐items. Inaccurate recall persisted across tests for both immediate and delayed recall and increased across tests for immediate recall. We view the R‐item advantage in accurate recall as consistent with the account they receive more rehearsal at study than do F‐items. We view inaccurate recall as reflecting the bias to report items retrieved on an immediate test lacking instructional tags as F‐items. On delayed tests, items retrieved lacking instructional tags are first assessed against a criterion point on a memory‐strength continuum and those with strength above the criterion reported as R‐items and those below the criterion as F‐items.