Recognition Memory in Pigeons for Stimuli Presented Repeatedly: Perceptual Learning or Reduced Associative Interference?

There is good evidence that the medial prefrontal cortex (mPFC) is involved in different aspects of recognition memory. However, the mPFC is a heterogeneous structure, and the contribution of the prelimbic (PL) and infralimbic (IL) cortices to recognition memory has not been investigated. Similarly, the role of different neuromodulators within the mPFC in these processes is poorly understood. To this end, we tested animals with 6-hydroxydopamine (6-OHDA) lesions of the PL and IL mPFC on three tests of object recognition memory that required judgments about recency, object location, and object identity. In the recency task, lesions to both PL and IL severely impaired animals' ability to differentiate between old (earlier presented) and recently presented familiar objects. Relative to sham and PL animals, the IL lesion also disrupted performance on the object location task. However, both lesions left novel object recognition intact. These data confirm previous reports that the mPFC is not required for discriminations based on the relative familiarity of individual objects. However, these results demonstrate that catecholamines within the PL cortex are crucial for relative recency judgments and suggest a possible role for neural processing within the IL in the integration of information about object location.

Although the majority of research on human memory has concentrated on a person's ability to recall or recognize items as having been presented in a particular situation, the effects of memory are also revealed in a person's performance of a perceptual task. Prior experience with material can make that material more easily identified or comprehended in perceptually difficult situations. Unlike with standard retention tests, effects of prior experience on a perceptual task do not logically require that a person be aware that he or she is remembering. Indeed, amnesic patients purportedly show effects of practice in their subsequent performance of a perceptual or motor task even though they profess that they do not remember having engaged in that prior experience. The experiments that are reported were designed to explore the relationship between the more aware autobiographical form of memory that is measured by a recognition memory test and the less aware form of memory that is expressed in perceptual learning. Comparisons of effects on perceptual learning and recognition memory reveal two classes of variables. Variables such as the level of processing of words during study influenced recognition memory, although they had no effect on subsequent perceptual recognition. A study presentation of a word had as large an effect on its later perceptual recognition when recognition memory performance was very poor as it did when recognition memory performance was near perfect. In contrast, variables such as the number and the spacing of repetitions produced parallel effects on perceptual recognition and recognition memory. Following Mandler and others, it is suggested that there are two bases for recognition memory. If an item is readily perceived so that it seems to "jump out" from the page, a person is likely to judge that he or she has previously seen the item in the experimental situation. Variables that influence ease of perceptual recognition, then, can also have an effect on recognition memory, so parallel effects are found. The second basis for recognition memory involves elaboration of a word's study context and depends on such factors as level of processing during study--factors that are not important for perceptual recognition of isolated words. Comparisons of perceptual recognition and recognition memory are shown to be useful for determining how a variable has its effect. Effects of study on perceptual recognition appear to be totally due to memory for physical or graphemic information. Results reported are also relevant to theories of perceptual learning. A single presentation of an item is shown to have large and long-lasting effects on its later perceptual recognition. At least partially, effects of study on perceptual recognition depend on the same variables as do effects on more standard memory tests.

Two functionally distinct forms of recognition memory have been identified in human and nonhuman species-the ability to recollect qualitative information about previous events, and the ability to differentiate between familiar and novel stimuli. Separate dual-process theories have been developed in the animal and human literatures to account for these findings. However, it is not clear whether these theories describe the same two underlying memory processes. On the basis of animal studies of medial temporal lobe function, familiarity is expected to exhibit disproportionately fast forgetting compared with recollection over short retention intervals. We tested this prediction in healthy human subjects by examining recognition forgetting rates across a range of 8-32 intervening items and found significant forgetting in the accuracy of familiarity-based discriminations and no evidence of forgetting in the accuracy of recollection-based discriminations. In agreement with the results from nonhuman species, the present results indicate that item familiarity decreases more rapidly than recollection over short retention intervals.

3 experiments varying the interval between 2 presentations of paired associates were reported. Other pairs filled the spacing and retention intervals. Pairs consisting of a word and a number as well as pairs consisting of 2 words showed a superiority at 8 sec. and longer retention intervals when presentations were spaced. Increasing the spacing interval beyond 8 sec. did not increase recall, when a 2-sec. rate of presentation was used. A 2-factor explanation of the findings was suggested, in which cue learning was the major factor influencing recall at longer retention intervals, while a 2nd factor was confounded with cue learning at short retention intervals. An initial investigation varying the time interval between two presentations of an individual pair of associates has been reported (Peterson, Hillner, & Saltzman, 1962). Using a technique described earlier (Peterson, Saltzman, Hillner, & Land, 1962), presentations of other pairs of words and numbers filled both a spacing interval between two presentations and a retention interval from second presentation to test for recall. It was found that the retention curve after a 0-sec. spacing interval was higher at the 2- and 4-sec. retention intervals than the retention curve after an 8-sec. spacing interval. However, at the 8- and 16-sec. retention intervals the superiority was reversed. If one assumes that the retention curve reflects retained amount of learning in a simple way, then the finding of poorer retention the longer the interval between presentations seems quite reasonable. The retention curve drops off rapidly after one presentation and hence when a second increment to associative strength is given after an interval the summed

Auditory memory of 2 rhesus monkeys was tested in a serial probe recognition task. Lists of four environmental or natural sounds were followed by a retention interval and a test. The test matched one of the list items on half of the trials. The retention interval was varied across sessions. Six experiments showed similar results and changes in the serial position function. At short retention intervals, there was good memory for first list items (primacy effect) and poor memory for last list items. At intermediate retention intervals, memory improved for last list items (recency effect). At long retention intervals (20 s and 30 s), the recency effect was strong, and the primacy effect had dissipated. These auditory primacy and recency effects and their changes with retention interval were opposite to those for visual memory. Implications for processes and mechanisms of memory are discussed.

Emotional and neutral stimuli may differ in recognition memory. Research focusing on consolidation and encoding processes has offered several explanations of this differentiation. In this study, two experiments were conducted to test how recognition memory differs from emotional and neutral stimuli in the light of these explanations. In Experiment 1, the effects of different retention intervals and an interference task were tested. Consolidation studies claim that both retention intervals and interference tasks provide memory advantages for emotional stimuli compared to neutral stimuli. In Experiment 2, the effects of presentation style (pure or mixed lists) and semantic relatedness were tested and were suggested as effective during the encoding process. Experiment 1 included 120 student participants and 60 students participated in Experiment 2. Participants’ recognition memory performance was measured using signal detection analysis. Data from Experiment 1 indicated that neither the retention interval nor the interference task had significant effects on emotional recognition memory. However, emotion had a significant effect because participants presented a more liberal response bias toward emotional than neutral words and demonstrated a poorer recognition of these words than the neutral ones. Experiment 2 indicated that neither the presentation style nor semantic relatedness had significant effects on emotional recognition memory. On the other hand, emotion had a significant effect consistent with the first experiment. The liberal response bias shift and poorer recognition accuracy of emotional compared to neutral words were replicated. As a result, these two experiments using signal detection analysis demonstrated that the variables expected to be effective during the consolidation and encoding processes did not affect emotional recognition memory. However, the finding that emotion causes poorer recognition accuracy and higher liberal response bias in both experiments suggests that the function of emotion in memory may be the provision of liberal response bias rather than accuracy.

In their 1994 publication, Starkes and Lindley considered whether perceptual skill could be trained through the observation of video simulations of sport situations. We return to this topic 20 years later and provide a critical review of the subsequent research on perceptual learning in sport. We reflect on the implications from recent empirical evidence, which indicates that perceptual expertise in sport is best captured using experimental methods that allow participants to perceive and act (i.e., produce an interceptive action) against an opponent in real-time. Despite the pertinent implications that these findings have for the training of perceptual skill, until now, a review has not been forthcoming. Specifically, we consider the implications of an ecological approach to perceptual learning for training interventions in sport. We provide a critical review of current literature, before focussing on an ecological theory of learning as a framework for our perspective. We then overview two contemporary topics in ecological psychology - continuum of contact and between-participant variability in perception-action - before considering the implications of our perspective for future research.

Part-list cuing with prose material: When cuing is detrimental and when it is not

Electrophysiological correlates of proactive interference in the ‘Recent Probes’ verbal working memory task

Working memory (WM) is known to be impaired in patients with stroke experiencing unilateral spatial neglect (USN). Here, we examined in a systematic manner three WM components: memory of object identity, memory of object location, and binding between object identity and location. Moreover, we used two different retention intervals to isolate maintenance from other mnemonic and perceptual processes. Fourteen USN first-event stroke patients with right-hemisphere damage were tested in two different WM experiments using long and short retention intervals and an analog response scale. Patients exhibited more identification errors for items displayed on the contralesional side. Localization errors were also more prominent in the contralesional side, especially after a long retention interval. These localization errors were often a result of swap errors, that is, erroneous localizations of correctly identified contralesional objects in correctly memorized locations of ipsilesional objects. We conclude that a key WM deficit in USN is a lateralized impairment in binding between the identity of an object and its spatial tag.

ABSTRACTYou may find some images easier to remember than others. Recent studies of visual memory have found remarkable levels of consistency for this inter-item variability across observers, suggesting that memorability can be considered an intrinsic image property. The current study replicated and extended previous results, while adopting a more traditional visual long-term memory task with retention intervals of 20 min, one day, and one week, as opposed to the previously used repeat-detection task, which typically relied on short retention intervals (5 min). Our memorability rank scores show levels of consistency across observers in line with those reported in previous research. They correlate strongly with previous quantifications and appear stable over time. Furthermore, we show that the way consistency of memorability scores increases with the number of responses per image follows the Spearman–Brown formula. Interestingly, our results also seem to show an increase in consistency with an increase in retention interval. Supported by simulated data, this effect is attributed to a decrease of extraneous influences on recognition over time. Finally, we also provide evidence for a log-linear, rather than linear, decline of the raw memorability scores over time, with more memorable images declining less strongly.

The conscious quality of eyewitness memory for misinformation after different retention intervals was investigated in two experiments. Participants viewed computer-projected slides depicting a crime (encoding phase), read a narrative containing misinformation, and took a recall test about the original event. Remember/know judgments were made for each response. A "remember" judgment indicated that the participant vividly recalled seeing a detail in the encoding phase. A "know" judgment indicated that the participant believed that a detail was presented but did not vividly remember it. Generally, misinformation was more likely to be associated with a know judgment than with a remember judgment after a short retention interval. This outcome suggests that, in many cases, misleading information is judged as having a different subjective quality than memory for actual events. However, over a relatively long retention interval, misinformation that simply added new information about the event was more often judged as remembered.

In this paper, we report four experiments aimed at extending the distinction between recognition memory and perceptual memory introduced by Jacoby and Dallas (1981). In Experiment 1, we show that dissociation of the two types of memory can be demonstrated with pictures as stimuli and with naming latency and recognition scores as responses. The depth-of-processing manipulation affects recognition but not naming, whereas both are influenced by prior exposure. Experiment 2 is a replication of the naming procedure, with a smaller set of stimuli and instructions emphasizing speed. Experiments 3 and 4 extend the paradigm to include children from 5 to 10 years old. Experiment 3 demonstrates the usual effect of depth of processing on recognition, but, in contrast to the adult data of Experiment 1, there is an analogous effect upon subsequent naming latencies. Examination of the data suggests this may be a spurious result. If not, it means either that the two memory types are not independent in children or that the “deep” subjects were implicitly naming during encoding. In Experiment 4, we test perceptual memory directly, replacing naming latency with tachistoscopic recognition. This results only in an effect of prior exposure, and not depth of processing. The results support the idea that perceptual memory is distinguishable from recognition memory, and that it is developmentally stable.

Sleep-dependency of episodic-like memory consolidation in rats

Recognition memory is considered to be supported by two different memory processes, i.e., the explicit recollection of information about a previous event and an implicit process of recognition based on an acontextual sense of familiarity. Both types of memory supposedly rely on distinct memory systems. Sleep is known to enhance the consolidation of memories, with the different sleep stages affecting different types of memory. In the present study, we used the process-dissociation procedure to compare the effects of sleep on estimates of explicit (recollection) and implicit (familiarity) memory formation on a word-list discrimination task. Subjects studied two lists of words before a 3-h retention interval of sleep or wakefulness, and recognition was tested afterward. The retention intervals were positioned either in the early night when sleep is dominated by slow-wave sleep (SWS), or in the late night, when sleep is dominated by REM sleep. Sleep enhanced explicit recognition memory, as compared with wakefulness (P < 0.05), whereas familiarity was not affected by sleep. Moreover, explicit recognition was particularly enhanced after sleep in the early-night retention interval, and especially when the words were presented with the same contextual features as during learning, i.e., in the same font (P < 0.05). The data indicate that in a task that allows separating the contribution of explicit and implicit memory, sleep particularly supports explicit memory formation. The mechanism of this effect appears to be linked to SWS.