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.     

Comparison of the efficacy of two name-learning techniques: expanding rehearsal and name-face imagery

Two name-learning techniques were compared: expanding rehearsal and name-face imagery. Participants studied name-face associations and were given a cued recall test in which they were presented with a face and were to recall the name. They were presented with either an expanding rehearsal schedule (expanding condition), a distinctive facial feature coupled with a word phonologically similar to the last name and an interactive image linking the name and facial feature (name-face imagery condition), or a no memory (control) strategy. The expanding rehearsal schedule led to superior name learning relative to the name-face imagery and control conditions after a 15-min (Experiment 1) or 48-hr (Experiment 2) retention interval. In Experiment 3, the retrieval practice explanation was tested but not supported; we argue that an encoding variability interpretation is consistent with the overall pattern of results. Applied implications are also discussed.     

Generative processing and false memories: when there is no cost

Encoding manipulations (e.g., levels of processing) that facilitate retention often result in greater numbers of false memories, a pattern referred to as the more is less effect (M. P. Toglia, J. S. Neuschatz, & K. A. Goodwin, 1999). The present experiments explored false memories under generative processing. In Experiments 1-3, using Deese-Roediger-McDermott (DRM) lists with items that were either read or generated, the authors found recognition and recall tests indicated generation effects for true memories but no increases in false memories (i.e., generation at no cost). In Experiment 4, in a departure from the DRM methodology, a cuing procedure resulted in a more is less pattern for congruous generation,and a no cost pattern for incongruous generation. This highlights the critical distinction between these encoding contexts.     

Effective warnings in the Deese-Roediger-McDermott false-memory paradigm: the role of identifiability

These experiments document that warnings can substantially reduce false memories in the Deese-Roediger-McDermott (DRM) paradigm when the critical items are easily identifiable. Participants in a norming study identified the critical item after hearing a list of words. The lists with critical items that could be identified by the largest proportion of participants (high identifiable [HI] lists) and the smallest proportion of participants (low identifiable [LI] lists) were used in the experiment. Participants heard lists of words (e.g., bed, rest, doze) related to a critical item (e.g., sleep) and were warned about the nature of the lists before the study phase. The results indicated that warnings reduced false recognition of critical items for HI lists but not LI lists.     

Assessing the effectiveness of warnings and the phenomenological characteristics of false memories

The phenomenology of false memories was investigated in three experiments in which participants heard two experimenters read lists of items that were related to critical nonpresented items. In Experiments 1, following a recognition memory test, participants rated the phenomenological characteristics of their memories immediately and after a 48-hour delay. False recognition was prevalent and on several dimensions participants rated their true memories as more vivid than their false memories. In Experiments 2 and 3, following the study phase, participants were warned about the phenomenological differences between true and false memories and were instructed to use this information to avoid reporting nonpresented items. This type of warning was ineffective at reducing false recall (Experiment 2) and false recognition (Experiment 3) relative to unwarned participants. Importantly, the inability of explicit warnings to impact illusory recollections demonstrates that the false memories cannot be attributed simply to a criterion shift.     

The effect of memory schemata on memory and the phenomenological experience of naturalistic situations

Two experiments document the effect of memory schemata in naturalistic situations. Participants in both experiments watched a short videotaped lecture in which the instructor enacted several schema‐consistent actions (e.g. writing on a whiteboard) and schema‐inconsistent actions (e.g. smoking a cigarette). Following the videotaped lecture, participants completed a recognition test and rated the phenomenological content of their memories. In both experiments, memory was more accurate for schema‐inconsistent actions than for schema‐consistent actions. Participants also indicated that their memories of schema‐inconsistent actions were more vivid than schema‐consistent actions. Interestingly, in Experiment 2, the false memory rate for typical items increased across both 48‐hour and one week retention intervals. These results have important implications for the processes of normal human memory in everyday situations. Copyright © 2002 John Wiley & Sons, Ltd.     

Assessing the effectiveness of warnings and the phenomenological characteristics of false memories

The phenomenology of false memories was investigated in three experiments in which participants heard two experimenters read lists of items that were related to critical nonpresented items. In Experiments 1, following a recognition memory test, participants rated the phenomenological characteristics of their memories immediately and after a 48-hour delay. False recognition was prevalent and on several dimensions participants rated their true memories as more vivid than their false memories. In Experiments 2 and 3, following the study phase, participants were warned about the phenomenological differences between true and false memories and were instructed to use this information to avoid reporting nonpresented items. This type of warning was ineffective at reducing false recall (Experiment 2) and false recognition (Experiment 3) relative to unwarned participants. Importantly, the inability of explicit warnings to impact illusory recollections demonstrates that the false memories cannot be attributed simply to a criterion shift.     

Effects of mugshot commitment on lineup performance in young and older adults

Two experiments assessed the effects of mugshot commitment on the ability to make a subsequent lineup identification. Young (17–37 years) and older (55–87 years) participants viewed a crime video featuring a younger (20 years) or older (64 years) culprit. Some participants viewed a 50‐photograph culprit‐absent mugbook. Following a 1‐week delay, participants returned to view a culprit present lineup. In Experiment 1, mugbook choosers tended to select their prior selection in the lineup and mugbook nonchoosers tended to reject the lineup. In Experiment 2, mugshot choosers rejected a lineup that did not contain their prior selection. Commitment to a prior selection and commitment to a selection strategy were the cause of the majority of lineup errors. As previously reported, mugshot exposure harms subsequent lineup identification, and this appears to be primarily the result of commitment effects. Copyright © 2008 John Wiley & Sons, Ltd.