Comparing the immediate free recall of verbal and visuo-spatial stimuli:List length, capacity and output order effects in single- and dual-modality tasks

When participants are presented with a list of words, and are asked to recall the items in any order (Immediate Free Recall; IFR), they tend to initiate their recall with the first list item when presented with short lists and with one of the last four items in longer lists. Chapter 2 examined whether this tendency necessitates a language-based retrieval mechanism by replicating and extending this finding in verbal and visuo-spatial IFR. The observed similarities between the two modalities are argued to be reflective of either a domain-general retrieval mechanism that operates on all stimuli at all timescales, or two domain-specific mechanisms that operate in quasi-identical ways. To distinguish between these two possibilities, Chapter 3 compared capacity and output order effects in both stimulus domains in single- and dual-modality IFR tasks. The number of items recalled in dual-modality IFR suggest partially independent capacities, but the output orders across the two modalities were greatly constrained; findings that cannot be fully explained through either a domain-general or domain-specific framework. Additionally, participants' tendency to alternate across modalities may be due to one-to-one associations of auditory words with the contemporaneous visuo-spatial locations. Consequently, Chapter 4 examined whether this alternating output strategy is still present when list structure is completely randomised and the items temporally off-set. I argue that this tendency is not entirely due to some form of binding but may, at least in part, reflect the most efficient way of outputting a mixed-modality list. Moreover, the asymmetry in the recall accuracy of the two modalities is due to increased number of to-be-recalled stimuli rather than increased output interference. I suggest that overall, a domain-general approach, such as the Embedded Processes model (Cowan, 2005), coupled with a forward-ordered retrieval mechanism based on temporal grouping (Farrell, 2012) is better placed to account for these novel findings

Towards augmented human memory: Retrieval-induced forgetting and retrieval practice in an interactive, end-of-day review

We report six experiments that examined the contention that an end-of-day review could lead to augmentation in human memory. In Experiment 1, participants in the study phase were presented with a campus tour of different to-be-remembered objects in different university locations. Each to-be-remembered object was presented with an associated specific comment. Participants were then shown the location name and photographs of half of the objects from half of the locations, and they were asked to try to name the object and recall the associated comment specific to each item. Following a filled delay, participants were presented with the name of each campus location and were asked to free recall the to-be-remembered objects. Relative to the recall from the unpracticed location categories, participants recalled the names of significantly more objects that they practiced (retrieval practice) and significantly fewer unpracticed objects from the practiced locations (retrieval-induced forgetting, RIF). These findings were replicated in Experiment 2 using a campus scavenger hunt in which participants selected their own stimuli from experimenter’s categories. Following an examination of factors that maximized the effects of RIF and retrieval practice in the laboratory (Experiment 3), we applied these findings to the campus scavenger hunt task to create different retrieval practice schedules to maximize and minimize recall of items based on experimenter-selected (Experiment 4) and participant-selected items using both category-cued free recall (Experiment 5) and item-specific cues (Experiment 6). Our findings support the claim that an interactive, end-of-day review could lead to augmentation in human memory

First things first: Similar list length and output order effects for verbal and nonverbal stimuli.

When participants are presented with a short list of unrelated words and they are instructed that they may recall in any order, they nevertheless show a very strong tendency to recall in forward serial order. Thus, if asked to recall in any order: "hat, mouse, tea, stairs," participants often respond "hat, mouse, tea, stairs" even though there was no forward order requirement of the task. In 4 experiments, we examined whether this tendency is language-specific, reflecting mechanisms involved with speech perception, speech production, and/or verbal short-term memory. Specifically, we examined whether we would observe similar findings when participants were asked to recall, in any order, lists of between 1 and 15 nonverbal stimuli, such as visuospatial locations (Experiment 1, Experiment 3, Experiment 4), or touched facial locations (Experiment 2). Contrary to a language-specific explanation, we found corresponding tendencies (albeit somewhat reduced) in the immediate free recall of these nonverbal stimuli. We conclude that the tendency to initiate recall of a short sequence of items with the first item is a general property of memory, which may be augmented by verbal coding

Did I say dog or cat? A study of semantic error detection and correction in children

While naturalistic studies of spontaneous speech suggest that young children can monitor their speech, the mechanisms for detection and correction of speech errors in children are not well understood. In particular, there is little research on monitoring semantic errors in this population. This study provides a systematic investigation of detection and correction of semantic errors in children between the ages of 5 and 8, as they produced sentences to describe simple visual events involving nine highly familiar animals (the moving animals task). Results showed that older children made fewer errors and corrected a larger proportion of the errors that they made than younger children. We then tested the prediction of a production-based account of error monitoring that the strength of the language production system, and specifically its semantic-lexical component, should be correlated with the ability to detect and repair semantic errors. Strength of semantic-lexical mapping, as well as lexical-phonological mapping, was estimated individually for children by fitting their error patterns, obtained from an independent picture naming task, to a computational model of language production (Foygel & Dell, 2000). Children’s picture naming performance was predictive of their ability to monitor their semantic errors, above and beyond age. This relationship was specific to the strength of the semantic-lexical part of the system, as predicted by the production-based monitor

Temporal isolation effects in immediate recall

Three experiments examined temporal isolation effects (TIEs), the recall advantage for stimuli separated by increased inter-stimulus intervals. Prior research suggests that TIEs are observed in immediate free recall (IFR) using longer lists, but are weaker or absent in immediate serial recall (ISR) using shorter lists. Using digit-filled intervals to reduce rehearsal, IFR and ISR benefitted overall from longer pre-item intervals and shorter post-item intervals, using lists of 7, 17, and 5 words (Experiments 1–3, respectively). Consistent with a grouping account, the first words recalled were often preceded by longer pre-item intervals and transitions tended to be between neighboring items separated by shorter intervals. Using 7-item lists with unfilled intervals (Experiment 3), both IFR and ISR benefitted from longer post-item intervals (possibly due to rehearsal), and once the first responses were removed, there was no effect of pre-item interval on either task. These similar findings encourage the theoretical integration of ISR and IFR

Did I say dog or cat? A study of semantic error detection and correction in children

Although naturalistic studies of spontaneous speech suggest that young children can monitor their speech, the mechanisms for detection and correction of speech errors in children are not well understood. In particular, there is little research on monitoring semantic errors in this population. This study provides a systematic investigation of detection and correction of semantic errors in children between the ages of 5 and 8 years as they produced sentences to describe simple visual events involving nine highly familiar animals (the moving animals task). Results showed that older children made fewer errors and corrected a larger proportion of the errors that they made than younger children. We then tested the prediction of a production-based account of error monitoring that the strength of the language production system, and specifically its semantic–lexical component, should be correlated with the ability to detect and repair semantic errors. Strength of semantic–lexical mapping, as well as lexical–phonological mapping, was estimated individually for children by fitting their error patterns, obtained from an independent picture-naming task, to a computational model of language production. Children’s picture-naming performance was predictive of their ability to monitor their semantic errors above and beyond age. This relationship was specific to the strength of the semantic–lexical part of the system, as predicted by the production-based monitor

RECAPP-XPR: A smartphone application for presenting and recalling experimentally controlled stimuli over longer timescales

We report two experiments that used smartphone applications for presenting and recalling verbal stimuli over extended timescales. In Experiment 1, we used an iPhone application that we had developed, called RECAPP-XPR, to present 76 participants with a single list of eight words presented at a rate of one word every hour, followed by a test of free recall an hour later. The experiment was exceptionally easy to schedule, taking only between 5 and 10 min to set up using a web-based interface. RECAPP-XPR randomly samples the stimuli, presents the stimuli, and collects the free recall data. The stimuli disappear shortly after they have been presented, and RECAPP-XPR collects data on when each stimulus was viewed. In Experiment 2, the study was replicated using the widely used image-sharing application Snapchat. A total of 197 participants were tested by 38 student experimenters, who manually presented the stimuli as “snaps” of experimentally controlled stimuli using the same experimental rates that had been used in Experiment 1. Like all snaps, these stimuli disappeared from view after a very short interval. In both experiments, we observed significant recall advantages for the first and last list items (primacy and recency effects, respectively), and there were clear tendencies to make more transitions at output between near-neighboring items, with a forward-ordered bias, consistent with temporal contiguity effects. The respective advantages and disadvantages of RECAPP-XPR and Snapchat as experimental software packages are discussed, as is the relationship between single-study-list smartphone experiments and long-term recency studies of real-world events

Serial position, output order, and list length effects for words presented on smartphones over very long intervals

Three experiments examined whether or not benchmark findings observed in the immediate retrieval from episodic memory are similarly observed over much greater time-scales. Participants were presented with experimentally-controlled lists of words at the very slow rate of one word every hour using an iPhone recall application, RECAPP, which was also used to recall the words in either any order (free recall: Experiments 1 to 3) or the same order as presented (serial recall: Experiment 3). We found strong temporal contiguity effects, weak serial position effects with very limited recency, and clear list length effects in free recall; clear primacy effects and classic error gradients in serial recall; and recency effects in a final two-alternative forced choice recognition task (Experiments 2 and 3). Our findings extend the timescales over which temporal contiguity effects have been observed, but failed to find consistent evidence for strong long-term recency effects with experimenter-controlled stimuli