The effect of varying alveolar carbon dioxide levels on free recall

A recent study suggested that students who have increased minute ventilation receive poorer grades. The present study was interested in determining the role alveolar carbon dioxide (CO2) levels play with cognitive abilities. A free recall task was used to examine list learning under two conditions of alveolar CO2 level: normal and decreased. The results suggested that decreased alveolar CO2 level affect the participant's ability to rehearse and recall information. It was concluded that conditions that reduce alveolar CO2 levels, such as hyperventilation resulting from stress, nervousness, or inappropriate breathing habits, can lead to poorer learning. If these conditions produce a habitual breathing pattern, the academic performance of the individual may suffer.     

The subordination effect: Evidence from self-paced reading and recall

Engelkamp and Rummer (2002) demonstrated that auditorily presented subordinate causal sentences are better retained than coordinate sentences. This subordination effect was explained by suggesting that subordinate sentences are merged more easily in memory than coordinate sentences. The present paper enlarges Engelkamp and Rummer's findings with respect to three aspects. First, it demonstrates that the subordination effect can only be found if a verbatim but not a content related recall score is used. Second, using self-paced reading, it demonstrates a processing advantage for subordinate sentences. This reading time advantage was only observed if the subordinate clause preceded the matrix clause. Third, it excludes an alternative explanation of the subordination effect which attributes memory differences to the fact that the critical causal conjunction word was presented earlier in subordinate than in coordinate sentences. In sum, our findings suggest a direct contribution of syntactic information to sentence regeneration.     

Persistence of the spacing effect in free recall under varying incidental learning conditions

In three incidental learning experiments, an attempt was made to eliminate the processing deficit under massed presentation that is assumed to be responsible for the spacing effect in free recall, according to the attenuation of attention hypothesis. This was to be accomplished in Experiment I by requiring subjects to attend specifically to the total exposure duration of each item and in Experiments II and III by requiring subjects to rate the successive occurrences of repeated items on different semantic rating scales. The results of the three experiments consistently showed that these manipulations were ineffective in eliminating the spacing effect. Subsidiary analyses indicated that the activities involved in doing the semantic rating tasks do not provide direct access to retrieval cues useful for subsequent recall. Instead, it appears that, in order to perform the semantic rating tasks reliably, subjects must compare the to-be-rated item with previously rated items, and this comparison process may serve as the source of retrieval cues for subsequent recall.     

Examining the relationship between free recall and immediate serial recall: The serial nature of recall and the effect of test expectancy

In two experiments, we examined the relationship between free recall and immediate serial recall (ISR), using a within-subjects (Experiment 1) and a between-subjects (Experiment 2) design. In both experiments, participants read aloud lists of eight words and were precued or postcued to respond using free recall or ISR. The serial position curves were U-shaped for free recall and showed extended primacy effects with little or no recency for ISR, and there was little or no difference between recall for the precued and the postcued conditions. Critically, analyses of the output order showed that although the participants started their recall from different list positions in the two tasks, the degree to which subsequent recall was serial in a forward order was strikingly similar. We argue that recalling in a serial forward order is a general characteristic of memory and that performance on ISR and free recall is underpinned by common memory mechanisms.     

Learning the value of money from stochastically varying prices

In 3 experiments, the authors investigated learning of the value of money from product prices in an unfamiliar currency when the prices are proportional to quantity. In support of the second stage of a hypothesized 2-stage process of learning, Experiment 1, in which 32 undergraduates participated, shows that response times for inferences of quantity are longer when participants are presented with quantity-price pairs than when they are presented with price-quantity pairs. Experiments 2 and 3, in which 54 and 34 undergraduates participated, respectively, show that (a) stochastic price variation causes systematic errors in the learning of unit prices from quantity-price pairs as a result of judgmental regression effects and (b) in support of the 2-stage learning hypothesis, inferences of quantity are the inverse of the learned unit prices.     

The effect of pictorial detail and elaboration on children's retention.

In a visual memory task, two degrees of stimulus detail were compared to test Reese's hypothesis that stimulus detail would facilitate retention of paired associates for young children. Stimuli were presented in an elaborated or nonelaborated fashion so that the effect of detail on retention of both types of materials could be investigated. Four and 5 year-old children were included to assess a reported developmental trend that elaboration facilitates retention for older children but fails to do so for younger children. Both age groups performed equally well, and detail had no effect. Elaboration aided retention significantly. A second study, in which difficulty of the task was increased, yielded equivalent results. The constraints on performance by recall and recognition tasks were discussed.     

The effect of non-verbal information on the recall of negation

The influence of non-verbal information on storage of different versions of negated sentences was investigated in a one-trial learning experiment. The negation governed either the subject, the object, or the predicate of the sentence. One group was presented with the sentences together with pictures. Another group the sentences only. The picture which was shown with a sentence represented the sentence content with an alternative for the negated concept. It was found that pictorial information had an effect on the recall of the sentences and that this effect is different for the different sentence versions.     

The effect of encoding training on perceptual recall

The effect of encoding training on tachistoscopic performance was measured by training groups of Ss in either an octal or a standardized English encoding of nine place binary numbers. A control group of Ss was allowed to encode ad lib during an equivalent training period. Performance was measured before, during and after the encoding training. It was found that imposing a code on S impaired tachistoscopic performance both during and for some time after the encoding training. Possible reasons for this effect are discussed.     

The word-length effect in probed and serial recall

The word-length effect in immediate serial recall has been explained as the possible consequence of rehearsal processes or of output processes. In the first experiment adult subjects heard lists of five long or short words while engaging in articulatory suppression during presentation. Full serial recall or probed recall for a single item followed the list either immediately or after a 5-second delay to encourage rehearsal. The word-length effect was not influenced by recall delay, but was much smaller in probed than in serial recall. Examination of the serial position curves suggested that this might be due to a recency component operating in probed recall. Experiment 2 confirmed a word-length-insensitive recency effect in probed recall and showed that this was resistant to an auditory suffix, unlike the small recency effect found in serial recall. Experiment 3 used visual presentation without concurrent articulation. Under these conditions there was no recency effect for either recall method, but the word-length effect was again much smaller in probed than in serial recall. This was confirmed in Experiment 4, in which the presentation of serial and probed recall was randomized across trials, showing that the differences between recall methods could not be due to encoding strategies. We conclude that for visual presentation, at least part of the word-length effect originates in output processes. For auditory presentation the position is less clear, as serial and probed recall appear to draw on different resources. The nature of the output processes that may give rise to word-length effects is discussed.     

Conditional recall and the frequency effect in the serial recall task: an examination of item-to-item associativity

The frequency effect in short-term serial recall is influenced by the composition of lists. In pure lists, a robust advantage in the recall of high-frequency (HF) words is observed, yet in alternating mixed lists, HF and low-frequency (LF) words are recalled equally well. It has been argued that the preexisting associations between all list items determine a single, global level of supportive activation that assists item recall. Preexisting associations between items are assumed to be a function of language co-occurrence; HF?CHF associations are high, LF?CLF associations are low, and mixed associations are intermediate in activation strength. This account, however, is based on results when alternating lists with equal numbers of HF and LF words were used. It is possible that directional association between adjacent list items is responsible for the recall patterns reported. In the present experiment, the recall of three forms of mixed lists??those with equal numbers of HF and LF items and pure lists??was examined to test the extent to which item-to-item associations are present in serial recall. Furthermore, conditional probabilities were used to examine more closely the evidence for a contribution, since correct-in-position scoring may mask recall that is dependent on the recall of prior items. The results suggest that an item-to-item effect is clearly present for early but not late list items, and they implicate an additional factor, perhaps the availability of resources at output, in the recall of late list items.     

The effect of mood-context on visual recognition and recall memory

Although it is widely known that memory is enhanced when encoding and retrieval occur in the same state, the impact of elevated stress/arousal is less understood. This study explores mood-dependent memory's effects on visual recognition and recall of material memorized either in a neutral mood or under higher stress/arousal levels. Participants' (N = 60) recognition and recall were assessed while they experienced either the same o a mismatched mood at retrieval. The results suggested that both visual recognition and recall memory were higher when participants experienced the same mood at encoding and retrieval compared with those who experienced a mismatch in mood context between encoding and retrieval. These findings offer support for a mood dependency effect on both the recognition and recall of visual information.     

Witnesses in action: the effect of physical exertion on recall and recognition

Understanding memory performance under different operational conditions is critical in many occupational settings. To examine the effect of physical exertion on memory for a witnessed event, we placed two groups of law-enforcement officers in a live, occupationally relevant scenario. One group had previously completed a high-intensity physical-assault exercise, and the other had not. Participants who completed the assault exercise showed impaired recall and recognition performance compared with the control group. Specifically, they provided significantly less accurate information concerning critical and incidental target individuals encountered during the scenario, recalled less briefing information, and provided fewer briefing updates than control participants did. Exertion was also associated with reduced accuracy in identifying the critical target from a lineup. These results support arousal-based competition accounts proposing differential allocation of resources under physiological arousal. These novel findings relating to eyewitness memory performance have important implications for victims, ordinary citizens who become witnesses, and witnesses in policing, military, and related operational contexts.     

The Hopkins Verbal Learning Test: an in-depth analysis of recall patterns

One of the earliest signs of dementia is memory issues and verbal word lists, such as the Hopkins Verbal Learning Test (HVLT), are successfully used for screening. To gain insight in how memory is affected in dementia, and to further improve the efficacy of the HVLT, in-depth analysis of the recall patterns of dementia cases and controls was conducted. Dementia cases and controls were matched for factors that can affect performance, such as age, gender and education level. Word frequency, syllable length, and orthographic neighbourhood size did not differ in the Indonesian version of the HVLT, nor did these characteristics affect recall. However dementia cases showed consistent and poor recall across the three trials; with the worst recall for the “human shelter” category and best recall for the “animals” category. Dementia cases also showed impaired accessibility of all categories with reduced subsequent recall from accessed categories and reduced primacy and recency levels. Finally, dementia cases exhibited lower levels of re-remembering and recalling new words, and higher levels of immediate forgetting and never recalling words. It was concluded that utilising the extra information provided by the in-depth analyses of the recall patterns could be beneficial to improve dementia screening.