Hypermnesia in free recall and cued recall

In three experiments, categorized lists and both free recall and cued recall tests were used to examine hypermnesia. In Experiment 1, materials were drawn from obvious and nonobvious categories in an attempt to vary the amount of relational processing at encoding. The study materials in Experiment 2 consisted of a long word list that comprised several exemplars from each of a number of common categories. In Experiment 3, a single exemplar was drawn from each of 45 categories. In each experiment, similar magnitudes of hypermnesia were obtained on free and cued recall tests. Examination of the specific items recalled across tests indicated that similar processes underlie the hypermnesic effect for both test conditions. Implications of the results for extant accounts of the hypermnesic effect are discussed. It is concluded that the dynamics of retrieval processes change in a systematic fashion across repeated tests and the retention interval following study and that an adequate account of the nature of these changes in retrieval dynamics is essential to our understanding of hypermnesia and related phenomena.     

Stress-induced Fos-like Immunoreactivity in the Pons and the Medulla Oblongata of Rats

Immunoreactivity of the immediate early gene c-fos was used to investigate changes in the activity of brainstem neurons in response to acute stressors like immobilization, formalin-induced pain, cold exposure, hemorrhage and insulin-induced hypoglycemia. Different stressors induced Fos-like immunoreactivity in different pontine and medullary neurons. A single, 3 hour immobilization was found to be a very strong stimulus that activated brainstem catecholaminergic (tyrosine hydroxylase-immunopositive) neurons and cells in the raphe and certain pontine tegmental nuclei, as well as in the reticular formation. Pain, induced by a subcutaneous injection of formalin was also effective on catecholamine-synthesizing neurons and on others cells in the nucleus of the solitary tract. Cold exposure activated cells mainly in the sensory spinal trigeminal and parabrachial nuclei and in the so-called "pontine thermoregulatory area". Moderate Fos-like immunoreactivity was induced by a hypotonic (25%) hemorrhage in medullary catecholaminergic neurons, the nucleus of the solitary tract and the Barrington nucleus. Among stressful stimuli used, insulin-induced hypoglycemia elicited the smallest Fos activation in the lower brainstem. The present observations indicate that different stressors may use different neuronal pathways in the central organization of the stress response.     

The incidence of false memories in native and non-native speakers

The current study consisted of four experiments that utilised a novel approach to investigating false memories. Each of the experiments in the current study investigated individuals with varying experience with different languages. Experiment 1 tested participants in both their native and secondary languages as well as monolingual English speakers, while Experiment 2 assessed native Spanish speakers using both English and Spanish associative lists. Experiment 3 examined the illusory memories in monolingual Spanish speakers in both English and Spanish, while Experiment 4 investigated false memories in monolingual English speakers in both English and Spanish. Results indicated that memory for list items and critical lures was greatest when the lists were presented in the participants' primary language. Results can be explained by either activation-based or fuzzy-trace theories.     

The own-age bias in face recognition: a meta-analytic and theoretical review

A large number of studies have examined the finding that recognition memory for faces of one's own age group is often superior to memory for faces of another age group. We examined this own-age bias (OAB) in the meta-analyses reported. These data showed that hits were reliably greater for same-age relative to other-age faces (g = 0.23) and that false alarms were reliably less likely for same-age compared with other-age faces (g = -0.23). Further meta-analyses of measures of signal detection demonstrated that, although no difference in response criterion was evident (g = -0.01), discriminability was reliably better for same-age compared with other-age faces (g = 0.37). As well, children, younger adults, and older adults exhibited superior discriminability for same-age compared with other-age age faces. Thus, the OAB appears to be a robust effect that influences the accuracy of face recognition. Theoretical accounts of the OAB have generally suggested that it reflects more extensive, recent experiences with one's own age group relative to other-age groups. Additional analyses were supportive of this account as the OAB was present even for groups (e.g., older adults) that had prior experiences as members of another age group. However, the most comprehensive account of the OAB will also likely invoke mechanisms suggested by social-cognitive theories.     

Effects of Encoding Tasks on the Own-Age Face Recognition Bias

In the current study, we evaluated the own-age face recognition bias by using various encoding tasks to evaluate the robustness and potential limitations of the own-age bias. One hundred sixty young adults studied photographs of children, young adults, middle-aged adults, and older adults and were assigned to one of four encoding conditions (i.e., age estimate, attractiveness rating, friendliness rating, and a face search task). Subsequent recognition tests revealed a robust own-age bias such that participants recognized own-age faces better than other-age faces regardless of encoding task. The current study showed that encoding tasks that focus on socially relevant characteristics (i.e., attractiveness ratings and friendliness ratings) do not eliminate or weaken the own-age bias compared to tasks that specifically focus on the age of the face. These findings indicate that in-group/out-group categorization requires little conscious processing and may be automatic, which is consistent with Sporer's (2001) in-group/out-group model (IOM) of facial processing.     

Examining differences in the levels of false memories in children and adults using child-normed lists

Several previous studies have demonstrated that children, when compared with adults, exhibit both lower levels of veridical memory and fewer intrusions when given semantically associated lists. However, researchers have drawn these conclusions using semantically associated word lists that were normed with adults, which may not lead to the same level of activation or gist generation in children. In the current study, the authors used similar associative word lists normed with children and then evaluated the memory of children and adults using these newly normed lists as well as the typical adult-normed lists. Results indicate that children showed lower true and false memories with both the child-normed and adult-normed lists. Thus, these data suggest that the negative relationship between age and false memories in the Deese-Roediger-McDermott (DRM; J. Deese, 1959; H. L. Roediger & K. B. McDermott, 1995) paradigm is not an artifact of the age group used to construct the lists.     

Distinguishing between memory illusions and actual memories using phenomenological measurements and explicit warnings

Previous research has demonstrated that the false memory effect is robust and that false memories are essentially indistinguishable from memories for events that actually occurred. The current study used several techniques intended to eliminate false memories (source monitoring decisions, confidence ratings, remember/know judgments, and explicit warnings). A robust false memory effect was found in each experiment. However, participants were able to differentiate false memories and actual memories when using specific phenomenological tasks. The current findings provide insight into basic human memory processes.     

Recognition performance level and the magnitude of the misinformation effect in eyewitness memory

The issue of whether misleading postevent information affects performance on the modified recognition test introduced by McCloskey and Zaragoza (1985) was examined in a meta-analysis. Results indicated that a misinformation effect can be obtained with the modified test. The meta-analysis also revealed that recognition hit rates are higher in studies that yield a misinformation effect than in studies in which the misinformation effect is not significant. The data from the meta-analysis were also used to assess whether the misinformation effect is related to the length of the retention interval. Results showed that a misinformation effect is more likely to be obtained with long retention intervals, although in the available data there is a confound between the length of the retention interval and the recognition level obtained.     

Selective disruption of hypermnesia for pictures and words

In this study, we investigated the effects of various interpolated tasks on hypermnesia (improved recall across repeated tests) for pictures and words. In five experiments, subjects studied either pictures or words and then completed two free-recall tests, with varying activities interpolated between the tests. The tasks performed between tests were varied to test several hypotheses concerning the possible factor(s) responsible for disruption of the hypermnesic effect. In each experiment, hypermnesia was obtained in a control condition in which there was no interpolated task between tests. The remaining conditions showed that the effect of the interpolated tasks was related to the overlap of the cognitive processes involved in encoding the target items and performing the interpolated tasks. When pictures were used as the target items, no hypermnesia was obtained when subjects engaged in imaginal processing interpolated tasks, even when these tasks involved materials that were very distinct from the target items. When words were used as the target items, no hypermnesia was obtained when the interpolated tasks required verbal/linguistic processing, even when the items used in these tasks were auditorily presented. The results are discussed in terms of a strength-based model of associative memory.