Figure 1
Experimental procedure.
Table 1
Group characteristics.
| CHARACTERISTICS | IMMEDIATE-AM | IMMEDIATE-PM | SLEEP (AKA DELAY-AM) | WAKE (AKA DELAY-PM) |
|---|---|---|---|---|
| N before exclusion | 130 | 127 | 134 | 143 |
| N after exclusion | 124 | 124 | 120 | 120 |
| Mean age (SD) | 22.24 (2.18) | 22.34 (2.03) | 22.18 (1.93) | 22.25 (1.93) |
| Gender (Female: Male: Other) | 68 : 54 : 2 | 77 : 46 : 1 | 62 : 57 : 1 | 58 : 61 : 1 |
| Ethnicity (Asian: Black/Caribbean: Latino: Mixed: Other: White) | 11 : 6: 0: 9: 1: 97 | 21: 4: 0: 7: 1: 91 | 9: 7: 0: 6: 0: 98 | 13: 4: 1: 4: 2: 96 |
| Education Attainment (A Level: Degree: GCSE: Postgrad: Vocational) | 47: 44: 6: 25: 2 | 54: 48: 3: 16: 3 | 58: 45: 3: 13: 1 | 51: 45: 2: 20: 2 |
| Mean SSS rating at study (SD) | 2.58 (0.98) | 2.64 (1.12) | 2.66 (0.96) | 2.58 (0.98) |
| Mean SSS rating at test (SD) | 2.73 (1.04) | 2.95 (1.29) | 2.63 (1.21) | 2.67 (1.18) |
| Mean rMEQ score (SD) | 15.89 (1.67) | 15.59 (1.91) | 15.72 (1.83) | 15.53 (1.99) |
| Mean N of intervening hr between study & test (SD) | NA | NA | 12.22 (0.74) | 12.14 (0.81) |
[i] Notes. (1) SSS stands for Stanford Sleepiness Scale (Hoddes et al., 1973) and ranges from 1 to 6, with higher values indicating greater sleepiness. (2) rMEQ stands for reduced Morningness/Eveningness Questionnaire (Adan & Almirall, 1991); it ranges from 5 to 25, with higher values indicating greater preference for morning.
Table 2
The 20 DRM wordlists used in the experiment.
| CRITICAL LURE OF EACH LIST | FALSE RECALL PROBABILITY (STADLER ET AL., 1999) | LIST ITEMS (ARRANGED IN THE ORDER OF PRESENTATION IN STUDY) |
|---|---|---|
| Window | 65 | door, glass, pane, shade, ledge, sill, house, open |
| Sleep | 61 | bed, rest, awake, tired, dream, wake, snooze, blanket |
| Doctor | 60 | nurse, sick, lawyer, medicine, health, hospital, dentist, physician |
| Smell | 60 | nose, breathe, sniff, aroma, hear, see, nostril, whiff |
| Chair | 54 | table, sit, legs, seat, couch, desk, recliner, sofa |
| Smoke | 54 | cigarette, puff, blaze, billows, pollution, ashes, cigar, chimney |
| Sweet | 54 | sour, candy, sugar, bitter, good, taste, tooth, nice |
| Rough | 53 | smooth, bumpy, road, tough, sandpaper, jagged, ready, coarse |
| Needle | 52 | thread, pin, eye, sewing, sharp, point, prick, thimble |
| Rubbish (Note 1) | 49 | garbage, waste, can, refuse, sewage, bag, junk, trash (Note 1) |
| Anger | 49 | mad, fear, hate, rage, temper, fury, ire, wrath |
| Soft | 46 | hard, light, pillow, plush, loud, cotton, fur, touch |
| City | 46 | town, crowded, state, capital, streets, subway, country, New York |
| Cup | 45 | mug, saucer, tea, measuring, coaster, lid, handle, coffee |
| Cold | 44 | hot, snow, warm, winter, ice, wet, frigid, chilly |
| Mountain | 42 | hill, valley, climb, summit, top, molehill, peak, plain |
| Slow | 42 | fast, lethargic, stop, listless, snail, cautious, delay, traffic |
| River | 42 | water, stream, lake, Thames (Note 2), boat, tide, swim, flow |
| Spider | 37 | web, insect, bug, fright, fly, arachnid, crawl, tarantula |
| Foot | 35 | shoe, hand, toe, kick, sandals, soccer, yard, walk |
[i] Note 1. In Roediger et al. (2001), the critical lure for this list was trash, with rubbish being one of the list items. We used rubbish as the critical lure and trash as a list item because the former is the preferred term in British English.
Note 2. The original word in Roediger et al. was Mississippi. We replaced it with Thames.
Figure 2
Mean proportion of words recalled in each of the serial positions, summarised across the Immediate and Delay groups.
Figure 3
Number of correct recalls across the Sleep and Wake groups. Each dot represents an individual participant and the error bars represent 95% confidence intervals.
Table 3
File descriptions.
| FOLDER NAMES | FILE NAMES | DESCRIPTION | DATA TYPE |
|---|---|---|---|
| 1. Study phase data | Order_of_Presentation_In_Study_Phase.csv | This spreadsheet shows the sequence of list presentation during the study phase for each participant. Since each participant saw 160 words presented one after the other and since there are 534 participants (before exclusion), this dataset has 160 × 534 observations (= 85440 observations). | Primary data |
| DRMwordlists_used.csv | This shows the 20 DRM wordlists used in the experiment. | Material | |
| 2. Recall data | full.csv | This is the raw free recall data, showing participants’ responses exactly as they were put down, maintaining their original spelling and sequence. This dataset encompassed all 534 participants and has (160 studied list words + 20 lures) × 534 observations. | Primary data |
| lure_final.csv | This is a simplified dataset, showing whether a critical lure was produced by a participant (Note that data from the 46 excluded participants were NOT included in this dataset, hence a sample size of 488). Number of observations = 488 × 20 critical lures = 9760 | Processed data | |
| studied_final.csv | This is a simplified dataset, showing whether a studied list word was recalled by a participant (Note that data from the 46 excluded participants were NOT included in this dataset, hence a sample size of 488). Number of observations = 488 × 160 studied words = 78080 | Processed data | |
| 3. Survey data | demographic_survey.csv | This is the demographic survey (e.g., age, gender, ethnicity) that participants filled out in the study phase. It also contains sleepiness rating. | Primary data |
| rMEQ_survey.csv | This contains all the data from the reduced morningness/evening Questionnaire (rMEQ; Adan & Almirall, 1991). This survey also asked participants to indicate how bright/noisy their immediate surrounding is, their sleep duration/quality the night before and whether they had a period of nap between sessions (Wake group only). | Primary data | |
| 4. Miscellaneous | List_of_Excluded_ParticipantIDs.csv | This spreadsheet shows the IDs of the 46 participants who met our pre-registered exclusion criteria. | Processed data |
| Encoding_Test_Time.csv | This spreadsheet shows the times at which a participant started the study and test phases. Given 534 participants (before exclusion), this dataset has 534 observations. | Primary data |
Table 4
Percentage of participants who falsely recalled a critical lure and the relative ranks of each lure in Stadler et al (1999) and our data.
| CRITICAL LURES | PERCENTAGE OF PARTICIPANTS WHO FALSELY RECALLED THE LURE(RELATIVE RANK WHERE 1 HAS THE HIGHEST PERCENTAGE AMONG THE 20 LURES) | ||
|---|---|---|---|
| STADLER ET AL. (N = 205) | IMMEDIATE GROUPS (N = 248) | DELAY GROUPS (N = 240) | |
| Window | 65% (1) | 14.5% (7) | 14.6% (7) |
| Sleep | 61% (2) | 16.9% (3) | 15% (6) |
| Doctor | 60% (3) | 18.1% (2) | 15.8% (4) |
| Smell | 60% (3) | 12.1% (11) | 12.5% (9) |
| Chair | 54% (5) | 13.7% (8) | 21.2% (2) |
| Smoke | 54% (5) | 16.5% (5) | 15.8% (4) |
| Sweet | 54% (5) | 13.3% (10) | 11.7% (10) |
| Rough | 53% (8) | 12.1% (11) | 10.4% (13) |
| Needle | 52% (9) | 14.9% (6) | 14.6% (7) |
| Anger | 49% (10) | 13.7% (8) | 10% (14) |
| Rubbish | 49% (10) This is the percentage for ‘trash’ | 5.6% (19) | 7.1% (20) |
| City | 46% (12) | 9.7% (14) | 9.6% (16) |
| Soft | 46% (12) | 8.9% (15) | 10% (14) |
| Cup | 45% (14) | 7.3% (18) | 8.3% (18) |
| Cold | 44% (15) | 29.4% (1) | 25.8% (1) |
| Mountain | 42% (16) | 10.1% (13) | 11.7% (10) |
| River | 42% (16) | 16.9% (3) | 19.6% (3) |
| Slow | 42% (16) | 5.2% (20) | 8.8% (17) |
| Spider | 37% (19) | 7.7% (17) | 10.8% (12) |
| Foot | 35% (20) | 8.5% (16) | 8.3% (18) |
| Mean | 49.5% | 12.76% | 13.08% |
[i] Note. (1) A percentage of 50% means that half of the sample size falsely recalled that lure. (2) The bold items are those whose relative ranks differed by >= 5 between Stadler et al. and our Immediate groups.