Factors that affect recall

Attention

The effect of attention on memory recall has surprising results. It seems that the only time attention largely affects memory is during the encoding phase. During this phase, performing a parallel task can severely impair retrieval success.^[37] It is believed that this phase requires much attention to properly encode the information at hand, and thus a distractor task does not allow proper input and reduces the amount of information learned. Experiments have been done that suggest that the early encoding phase, in which words are identified, is the source of the word frequency effect. Because rarer words (low frequency) are composed of unusual and features that may be difficult to encode, they require more attention. Differences in letter frequency were controlled for. Next, we considered the late phase of encoding, in which meaning is elaborated and connected to the participants’ semantic network. The experimenters explored the hypothesis that semantic information does not contribute to the word frequency effect and found a mirror patterned normative frequency effect when words were studied and tested. When study, test, or both involved objects, the mirror pattern was disrupted and normative frequency had little or no effect on recognition memory. Much of the recognition memory literature has focused on distinguishing between memory models based on the nature of retrieval from memory.^[38] However, when looking at the effect of attention on memory retrieval, it has been found that there are only slight inconsistent impairments. This evidence suggests that memory retrieval is an automatic process. One effect of attention on memory recall is that of latency and retrieval time.^[39] This is especially evident in free recall.^[40] The competition provided at the time of recall due to divided attention slows down the process, yet has little to no effect on its accuracy. Another possible finding for the minimal effect of divided attention is that the process of recall may include less parallel processing than other memory processes.^[41] It has also been observed that different parts of the brain are at work depending on whether one is recalling with full rather than divided attention.^[42] Evidence for this comes from fMRI data. Performing a secondary task concurrently with a study task has a detrimental effect on later memory for studied items. To investigate the mechanisms underlying this effect, the processing resources available for an incidental encoding task were varied by manipulating secondary task difficulty. Greater activity at study for words later remembered versus words later forgotten-were identified in the left ventral inferior frontal gyrus and the left anterior hippocampus. These effects did not vary according to whether the encoding task was performed concurrently with the easy or the hard secondary task. However, as secondary task difficulty increased, study-item activity declined and auditory-item activity increased in dorsolateral prefrontal and superior parietal regions that have been proved to be in the support of executive and control functions. The findings suggest that dividing attention during encoding influences the probability of engaging the encoding operations that support later episodic memory, but does not alter the nature of the operations themselves. The findings further suggest that the probability of engaging these encoding operations depends on the level of general processing resources engaged in service of the study task.^[43]

Motivation

Motivation is a factor that encourages a person to perform and succeed at the task at hand. It can be in the form of presented incentive, or personal fear of failure.^[44] Any form of motivation thus generally leads a person to better recall. In an experiment done by Roebers, Moga and Schneider (2001), participants were placed in either forced report, free report or free report plus incentive groups. In each group, they found that the amount of correct information recalled did not differ, yet in the group where participants were given an incentive they had higher accuracy results.^[45] This means that presenting participants with an encouragement to provide correct information motivates them to be more precise. However, this is only true if the perception is that success is providing correct information. When it is believed that success is the completion of the task rather than the accuracy of that completion, the number of responses is higher, yet its accuracy is lowered. This shows that the results are dependent on how success is defined to the participant. In the Roebers, Moga and Schneider (2001) experiment, the participants that were placed in the forced response group had the lowest overall accuracy. They had no motivation to provide accurate responses and were forced to respond even when they were unsure of the answer. Another study done by Hill RD, Storandt M, Simeone C tests the impact of memory skills training and external reward on free recall of serial word lists.^[46] In contrast to older learners, similar effects were seen in children.^[47] Two studies were conducted to test incentive magnitude effects on free recall. Experiment I examined whether two incentive levels would differentially influence rehearsal of words paired with the incentive values. Fifth and eighth graders and college adults were tested in conditions in which they were instructed to (a) do all rehearsal overtly or (b) engage in a counting task subsequent to item presentation and refrain from overt and covert rehearsal. College subjects rehearsed and recalled significantly more 10¢ than 1¢ words. Eighth graders tended to favor 10¢ items in recall and rehearsal, but the differences were of questionable reliability. Fifth graders failed to produce reliable Incentive Level effects. Experiment II showed that fifth graders, as well as older subjects, recalled more high-incentive words under standard free-recall instructions in which rehearsal was presumed to be covert. Results support theories emphasizing rehearsal as a mediator of incentive level effects on learning. These results lead to the conclusion that depending on how success is defined to the person, motivation increases a person’s inclination to succeed at appropriate recall.^[45]

Interference

In the absence of interference, there are two factors at play when recalling a list of items: the recency and the primacy effects. The recency effect occurs when the short-term memory is used to remember the most recent items, and the primacy effect occurs when the long-term memory has encoded the earlier items. The recency effect can be eliminated if there is a period of interference between the input and the output of information extending longer than the holding time of short-term memory (15–30 seconds). This occurs when a person is given subsequent information to recall preceding the recall of the initial information.^[48] The primacy effect, however, is not affected by the interference of recall. The elimination of the last few items from memory is due to the displacement of these items from short term memory, by the distracting task. As they have not been recited and rehearsed, they are not moved into long-term memory and are thus lost. A task as simple as counting backwards can change memory recall; however an empty delay interval has no effect.^[49] This is because the person can continue to rehearse the items in their working memory to be remembered without interference. Cohen (1989) found that there is better recall for an action in the presence of interference if that action is physically performed during the encoding phase.^[49] It has also been found that recalling some items can interfere and inhibit the recall of other items.^[50] Another stream of thought and evidence suggests that the effects of interference on recency and primacy are relative, determined by the ratio rule (retention interval to inter item presentation distractor rate) and they exhibit time-scale invariance.^[51] Three experiments investigated serial position effects in immediate and final free recall. Each word in a 10-item list was both preceded and followed by a 15-sec period of distraction activity. In Experiment 1, half of the lists were immediately followed by either a recall test or a recognition test; the remaining lists were not tested, but were followed by a different distraction activity. After presentation of all lists, a final recall or recognition test was given. Primacy was observed only in immediate free recall and in all final tests following immediate free recall, demonstrating that primacy develops from a free-recall storage strategy. No recency was observed in Experiment 1. In Experiment 2, every list was followed by an immediate free-recall test, with a final free-recall test after the last list. The primacy results of Experiment 1 were replicated. Furthermore, the appearance of recency in Expriment 2 suggests that recency results from a retrieval strategy that failed to develop in Experiment 1 because some lists were not tested immediately. To eliminate an artifact account, Experiment 3 used an experimenter-paced distractor task and replicated the findings of Experiment 2, which used a subject-paced distractar task. Contrary to previous claims, the pattern of results in the continuous distractor paradigm is seen as completely consistent with the account offered by multistore models of serial position effects in standard free recall.

Context

Context-dependency effects on recall are typically interpreted as evidence that the characteristics of the environment are encoded as part of the memory trace and can be used to enhance retrieval of the other information in the trace.^[52] In other words, you can recall more when the environments are similar in both the learning and recall phases. Context cues appear to be important in the retrieval of newly learned meaningful information. In a classic study by Godden and Baddelley (1975), they demonstrated that deep-sea divers recalled their training more effectively when trained underwater, rather than being trained on land.^[53] An academic application would be that students may perform better on exams by studying in silence, because exams are usually done in silence.^[54]

State-dependent memory

State-dependent retrieval is demonstrated when material learned under the influence of a drug is best recalled in that same drug state. A study by Carter and Cassady (1998) showed this effect with antihistamine.^[55] In other words, if you study while on hay fever tablets, then you will recall more of what you studied if you test yourself while on antihistamines in comparison to testing yourself while not on antihistamines after having studied on antihistamines.

A study by Block and Ghoneim (2000) found that, relative to a matched group of healthy, non-drug-using controls, heavy marijuana use is associated with small but significant impairments in memory retrieval.^[56]Cannabis induces loss of internal control and cognitive impairment, especially impairment of attention and memory, for the duration of the intoxication period.^[57]

Stimulants, such as cocaine, amphetamines or caffeine are known to improve recall in humans.^[58] However, the effect of prolonged use of stimulants on cognitive functioning is very different from the impact on one-time users. Some researchers have found stimulant use to lower recall rates in humans after prolonged usage. MDMA users are found to exhibit difficulties encoding information into long-term memory, display impaired verbal learning, are more easily distracted, and are less efficient at focusing attention on complex tasks. The degree of executive impairment increases with the severity of use, and the impairments are relatively long-lasting. Chronic cocaine users display impaired attention, learning, memory, reaction time and cognitive flexibility.^[57] Whether or not stimulants have a positive or negative effect on recall depends on how much is used and for how long.

Gender

Consistently, females perform better than males on episodic memory tasks including delayed recall and recognition. However, males and females do not differ on working, immediate and semantic memory tasks. In general, neuro-psychological observations suggest that anterior lesions cause greater deficits in females than in male. It has been proposed that the gender differences in memory performance reflect underlying differences in the strategies used to process information, rather than anatomical differences. However, gender differences in cerebral asymmetry received support from morphometric studies showing a greater leftward asymmetry in males than in females, meaning that men and women use each side of their brain to a different extent.^[59] There is also evidence for a negative recall bias found in women, which means females in general are more likely than males to recall their mistakes.^[60] In a eyewitness study done by Dan Yarmey (1991) from the University of Guelph, he found that women were significantly more accurate than men in accuracy of recall for weight of suspects.^[61]

Phenomena

The phenomenological account of recall is referred to as metacognition, or "knowing about knowing". This includes many states of conscious awareness known as feeling-of-knowing states, such as the tip-of-the-tongue state. It has been suggested that metacognition serves a self-regulatory purpose whereby the brain can observe errors in processing and actively devote resources to resolving the problem. It is considered an important aspect of cognition that can aid in the development of successful learning strategies that can also be generalized to other situations.^[62]