Expert Chess Memory: Revisiting the Chunking Hypothesis

May combine two claims.

Holding and Reynolds found skill did not correlate with recall of briefly shown random positions, but search effectiveness did correlate with skill.

“In their study, the skill of subjects (from 1000 to 2200 ELO) did not correlate with the recall of random positions 3 shown for a few seconds, but effectiveness of the search for the best move in these positions did correlate with skill.”

• cites Holding and Reynolds (1982) sourceSupported

May combine two claims.

Frey and Adesman found chunk presentation produced better recall than column presentation and better recall than presenting the entire position for the same total time.

“Chunk presentation produced better recall than column presentation; and, in fact, better recall than presentation of the entire position for the same length of time (12 s).”

• cites Frey and Adesman (1976) sourceSupported

Not yet classified.

Studies with interfering material show such material does not interfere much with chess memory, implying some information is rapidly transferred to long-term memory.

“However, studies using interfering material in intervening tasks (Charness, 1974;Cooke, Atlas, Lane, & Berger, 1993;Frey & Adesman, 1976, Gobet & Simon, in press-a) have shown that this material does not interfere much with chess memory, thus implying that, as the interfering tasks reduce retention in STM, some information has to be transferred rapidly to LTM.”

• cites Charness, 1974Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Cooke, Atlas, Lane, & Berger, 1993 sourceNot checked — no full text of the source
• cites Frey & Adesman, 1976 sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Wixted and Rohrer (1994) reported inconclusive results on latencies within clusters, with some studies showing increases and others not.

“Wixted and Rohrer (1994) report inconclusive results on the latencies within clusters: in some studies, latencies increased with position, but did not in other studies.”

• cites Wixted and Rohrer (1994) sourceSupported

May combine two claims.

Finding such large chunks supports template theory, since skill-level differences in chunk count were small and the count fell within the supposed capacity of visual short-term memory.

“The large size of chunks we have found adds support to the template theory, inasmuch as the difference in the number of chunks by skill was small and as this number was within the supposed capacity of visual STM (Zhang & Simon, 1985).”

• cites Zhang & Simon, 1985 sourceSupported

May combine two claims.

Between-glance latencies were longer than Chase and Simon's (means around 3 s), possibly reflecting strategy differences.

“BGP latencies are longer than those found by Chase and Simon (means around 3 s), which may reflect differences in strategies used by our subjects.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

After subtracting mouse-movement time, 79.5% of within-glance latencies were below 2 s, with a median of 1.37 s and a mode of 1.13 s, reasonably agreeing with Chase and Simon's data.

“About 79.5% of the corrected WGP latencies are now below 2 s, with a median of 1.37 s and a mode of 1.13 s, in reasonable agreement with the Chase and Simon's data.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

For this study's subjects, the median within-glance latency was 2.63 s and the mode was about 2.37 s.

“For our subjects, the median is 2.63 s and the mode is about 2.37 s.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

No subject refused to copy or recall a random position, but the task elicited deep negative feelings.

“Although no subject actually refused to copy (or to recall) 4 a random position, this task elicited deep negative feelings.”

May combine two claims.

In the copy task, the authors' subjects, especially Masters, studied the stimulus for dozens of seconds before placing the first piece and later rarely revisited it, unlike Chase and Simon's subjects.

“Their subjects studied the stimulus position for a short time (a few seconds), then replaced a few pieces on the copy board, repeating this cycle until all pieces had been replaced.Our subjects (especially the Masters) studied the stimulus position for some dozens of seconds before placing the first piece; later, they rarely revisited the stimulus.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The times were consistent across the three skill levels and close to Chase and Simon's, though slightly slower even after mouse correction.

“The times, consistent for our three skill levels, are close to Chase and Simon's, although a little slower even after the correction for the mouse.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Using Fitts' Law correction, the corrected within-glance latency distribution had a median of 1.49 s and a mode of 1.25 s.

“The corrected distribution of WGP latencies has now a median of 1.49 and a mode of 1.25.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Regardless of strategy, subjects had to correct numerous color errors.

“Whatever strategy was used, subjects had to correct numerous color errors.”

May combine two claims.

Stronger players initially tried to replace pieces by semantic groups, then switched to systematic line-by-line or column-by-column reconstruction when encountering difficulty.

“Stronger players tended initially to try to replace pieces by semantic groups; then, encountering difficulty, switched to reconstructing the position in a more systematic way, roughly line by line or column by column.”

May combine two claims.

In this experiment, 79.5% of within-glance latencies and 1.11% of between-glance latencies were under 2 s; 89.3% and 4.4%, respectively, were under 2.5 s.

“In the present experiment, 79.5% of the WGP latencies (against only 1.11% of the BGP latencies) are less than 2 s, and 89.3% (against 4.4%) are below 2.5 s.”

May combine two claims.

The between-glance latency distribution had small peaks at 3.75 and 5.75 s and a median of 7.3 s.

“The between-glance latency distribution has small peaks at 3.75 and 5.75 s and a median at 7.3 s.”

May combine two claims.

In random positions, Masters were faster than other players (97.0, 98.8, 128.4 s) but slower than predicted from their game-position times.

“In the random positions, Masters are faster than the others (97.0, 98.8, 128.4 s), but slower than would be predicted from their times in game positions.”

May combine two claims.

The data generally agree well with Chase and Simon's earlier experiments, with some differences in chunk sizes and numbers more compatible with revised template theory.

“We will show that our data generally agree well with the data from the earlier experiments of Chase and Simon (1973a and b), with some differences in sizes and numbers of chunks that are more compatible with the revised template theory than with the chunking theory in its original form.”

• cites Chase and Simon (1973a and b)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

With random positions, Masters studied the stimulus in longer glances than weaker players but returned to it less often.

“With random positions, Masters tend to study the stimulus in longer glances than those of weaker players, but to return less often to look at the stimulus position.”

May combine two claims.

The mean of median largest chunks for random positions was constant across skill levels (6.3 pieces, sd = 2.1, in copy; 4.6 pieces, sd = 1.7, in recall, pooled) and well above what visual encoding of individual pieces in STM would predict.

“Note also that the mean of the median largest chunks for random positions is constant across skill levels (6.3 pieces [sd = 2.1] in the copy task and 4.6 pieces [sd = 1.7] in the recall task, for all subjects pooled) and is well over what would be predicted by a theory postulating the visual encoding of individual pieces in STM.”

May combine two claims.

For game positions, chunk size varied with skill level F(2,23) = 11.81, p < .001, but did not differ significantly between copy and recall F(1,23) = 1.56, ns; the interaction was not significant.

“For game positions, the size of chunks varies with skill levels [F(2,23) = 11.81,p<.001], but size does not differ significantly between the copy and recall tasks [F(1,23) = 1.56, ns.]The interaction term is not statistically significant.”

May combine two claims.

Main effects of skill F(2,23) = 4.84, p < .05 and type of presentation F(1,23) = 240.1, p < .001 were significant; the interaction was marginally significant F(2,23) = 3.23, p < .06.

“The main effects of skill [F(2,23) = 4.84, MS e = 1.50, p <.05] and type of presentation [F(1,23) = 240.1,MS e = 1.68, p <.001] are significant, while the interaction is only marginally significant [F(2,23) = 3.23, MS e = 1.68, p <.06].”

May combine two claims.

For Masters, the mean of median largest chunks was 16.8 in recall and 14 in copying.

“For the Masters, the mean of the median largest chunks is 16.8 for the recall task, and 14 for the copying task.”

May combine two claims.

Agreement between latency-based and relation-based chunk definitions was 72% for copy game, 64% for copy random, 74% for recall game, and 70% for recall random; all chi-squares had p < .0001.

“The percentage of placements classified consistently by the two methods is 72% for the task of copying game positions, 64% for copying random positions, 74% for recalling game positions, and 70% for recalling random positions.All four tables have chi-squares with probabilities below .0001.”

May combine two claims.

Below 1.8 s, placements with 3 or 4 relations dominated over those with 0 or 1 relation; above 2.2 s the pattern shifted; in the 1.8-2.2 s interval few and many relations were almost equal.

“Below 1.8 s, placements having 3 or 4 relations dominate over placements with 0 or 1 relation.Above 2.2 s, the pattern is shifted.In the interval 1.8-2.2s, which includes the value of 2 s we have selected as a cut-off, the numbers with few and many relations are almost equal.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Table 1 shows median latencies between successive pieces for each relation combination in the copy task, for random and game positions, within and between glances, averaged over subjects, with little difference between skill levels.

“Table 1, columns 2-3 and 5-6 show, averaged over all subjects (there was little difference in latency statistics between skill levels), the median latencies between the placement of two successive pieces for each combination of relations, for the Copy task in Random and Game positions, within and between glances.”

May combine two claims.

Within-chunk latencies increased modestly by about 50% over 30 pieces, while between-chunk latencies increased by a factor of 2 over the same interval.

“The within-chunk latencies do show a modest increase of about 50% over 30 pieces, but the between-chunk latencies increase by a factor of 2 over the same interval.”

May combine two claims.

Age did not correlate significantly with recall of game positions (r = .06) or random positions (r = -.36), though the latter correlation was stronger.

“Age also did not correlate significantly with recall of game positions (r = .06) or of random positions (r = -.36 ), though the observed correlation was stronger for the latter.”

May combine two claims.

Figure 3 shows a clear negative correlation between number of relations and latencies in the recall task, similar to Chase and Simon's Figure 5.

“Figure 3, which plots latency as a function of the number of relations in the recall task, for both short and long latencies combined (skill levels and types of positions are pooled), shows a clear negative correlation between number of relations and latencies, giving results similar to Figure 5 of Chase and Simon (1973a).”

• cites Chase and Simon (1973a)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

In Figure 4, within-chunk placements with few relations were below chance and those with several relations were above chance; between-chunk placements were flatter and closer to chance.

“From the Figure , we see that, for within-chunk conditions, the placements having few relations are below chance, while the placements having several relations are well above chance.Between-chunk placements, with a flatter trend, are overall much closer to chance.”

May combine two claims.

The strict systematic strategy was used by only one Master on his second random board, while Experts and Class A players used it in copying 38% of random boards.

“The strict systematic strategy was used by only one Master, on his second random board; but Experts and Class A players used this strategy in copying 38% of the random boards.”

May combine two claims.

The strategy was used by 22% of Experts and 33% of Class A players on the first board, and by 56% of Experts and 42% of Class A players on the second.

“The strategy was used by 22% of Experts and 33% of Class A players on the first board, 56% of Experts and 42% of Class A players on the second.”

May combine two claims.

Correlations with number of relations for within-chunk conditions were .81 for copy game within-glance, .68 for copy random within-glance, .86 for recall game short latencies, and .79 for recall random short latencies.

“The correlations with number of relations for the within-chunk conditions are: copy game, withinglance: .81;copy random, within-glance: .68;recall game, short latencies: .86;recall random, short latencies: .79.”

May combine two claims.

The correlation between remaining items in this study's Table 2 and Chase and Simon's Table 7 is .78, accounting for 61% of the variance.

“Leaving aside the data for recall of random positions, which were not computed by Chase and Simon, and the a priori probabilities, the correlation between the remaining items in our Table 2 and the corresponding items in Chase and Simon's (1973a) Table 7 is .78,accounting for 61% of the variance in the correlation coefficients.”

• cites Chase and Simon's (1973a)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

In game positions, 27 cases had two opposing same-kind pieces attacking each other with no other relation, giving probability .001 for the AS relation; 8,978 cases had none of the five relations, giving probability .335 for the null relation.

“For example, in 27 cases in game positions, two opposing pieces of the same kind attacked each other (and had no other relation), giving a probability of .001for the AS relation; and in 8,978 cases a pair of pieces had none of the five chess relations, giving a probability of .335for the null relation.”

May combine two claims.

Within-chunk deviations from a priori probabilities were highly correlated with number of relations, while between-chunk deviations had a weaker correlation.

“In agreement with the theory, the within-chunk deviations from a priori probabilities are highly correlated with the number of relations, while this correlation is weaker for the between-chunk deviations.”

May combine two claims.

Correlations for between-chunk conditions were .61 for copy game between-glance, .56 for copy random between-glance, .69 for recall game long latencies, and .31 for recall random long latencies.

“The correlations with the between-chunk conditions are: copy game, between-glance: .61;copy random, betweenglance: .56;recall game, long latencies: .69;recall random, long latencies: .31.”

May combine two claims.

In this study, all four correlations of latencies with numbers of relations were negative, though some were not statistically significant.

“We find the same pattern in our data: all four correlations of latencies with numbers of relations are negative, although some are not statistically significant.”

May combine two claims.

All but one of the within-glance copy latencies were below 2 s; the exception was the attack-only relation in game positions, occurring in 0.5% of observations.

“Finally, all but one of the latencies of the within-glance condition of the copying task are below 2 s, the exception being the case where there is only a relation of attack with game positions (this case occurs only in 0.5 % of the observations).”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The comparable data computed for this study were very similar to Chase and Simon's, so the comparison was summarized rather than reproducing the full table.

“We have computed the comparable data for our experiments, but as the two sets of data are very similar, we will summarize the comparison with Chase and Simon instead of reproducing our table in full.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Correlations with age were .22 for game-position interpiece latency and .10 for mouse-move time; for random positions they were .26 and .01.

“We obtained the following correlations with age: (a) for game positions: interpiece latency (.22), time to move the mouse (.10);(b) for random positions: interpiece latency (.26); time to move the mouse (.01).”

May combine two claims.

Subjects produced fewer chunks in recall than in copy, reflecting that multiple chunks need not be held in short-term memory during copy.

“Subjects produce fewer chunks in the recall task than in the copy task, which simply reflects the fact that multiple chunks do not have to be held in STM in the copy task.”

May combine two claims.

For within-glance copy placements, Spearman's rho was -.77 in game positions and -.84 in random positions.

“For the withinglance copy placements in game positions, Spearman's rho correlation is -.77, and in the random positions the correlation is -.84.”

May combine two claims.

The shortest times occurred with PCS and DPCS relations, which mainly appear with pawn formations.

“The shortest times are obtained with the PCS and DPCS relations, which mainly appear with pawn formations.”

May combine two claims.

Although the study found some skill-level differences in chunk counts, as Chase and Simon did, the ordering of those counts by skill was wholly different between the two studies.

“Although we did find, as Chase and Simon did, some differences in the number of chunks between skill levels, the ordering of numbers by skill was wholly different in the two studies.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

In the copy task, chunk count falls as skill rises; in the recall task it follows an inverted U, with Class A players recalling the fewest chunks, and the Masters-Class A difference is under one chunk.

“The number of chunks replaced is inversely related to skill level for the copy task, while it shows an inverted U-curve for the recall task, with Class A players recalling the least chunks.Note that the difference between Masters and Class A players is small in the recall task: less than one chunk.”

May combine two claims.

Across skill levels, there was little difference in the nature of chunks; all skill levels showed the same pattern of relations, which justified pooling skill levels in presenting results.

“In general, there was little difference among skill levels in the nature of the chunks: all show the same pattern of relations, which led us to pool the skill levels in the presentation of results.”

May combine two claims.

Same Type, Color, and Proximity relations strongly predict latency for placements within the same chunk, but not for placements in two different chunks.

“In summary, the relations of Same Type, Color and Proximity play a major role in predicting the latency when successive placements belong to the same chunk, but not when they belong to two different chunks.”

May combine two claims.

Masters' between-glance latencies are much slower on random positions than on game positions, whereas Experts and Class A players maintain similar rhythms across both position types.

“Besides, Masters show an interesting pattern: in contrast with the other players, their BGPs are much slower with random positions than with game positions.This difference accounts for almost the whole of the (marginal) interaction effect of Type of position x Skill : Experts and Class A players keep almost the same rhythm for the BGPs in both game and random positions.”

May combine two claims.

There was some indication that stronger players were slightly superior with random positions, a result not present in Chase and Simon's data.

“There was some indication that they were slightly superior also with random positions, a result that did not appear in Chase and Simon's data.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

How much a chess relation matters for placement order tracks its frequency, though proximity matters more than frequency alone would suggest.

“The importance of relations for sequence of placements is closely related to the frequency of their occurrence, although proximity has a larger role than its frequency would predict.”

May combine two claims.

Numbers of chess relations in within-glance copy placements and within-2-s recall placements were strongly correlated, as were between-glance copy and over-2-s recall placements.

“Second, numbers of chess relations in within-glance placements in the copy task and in placements within 2 s in the recall task were strongly correlated, as were numbers of relations in between-glance placements in the copy task and placements over 2 s in the recall task.”

May combine two claims.

Latencies for within-glance placements are much shorter than for between-glance placements, with a significant main effect of placement mode.

“important difference between WGP and BGP: WGP latencies are much shorter than BGP.ANOVA indicates this main effect of Mode of placement [F(1, 22) = 90.74,MS e = 10.3, p<.001].”

May combine two claims.

In game positions Masters recalled almost three times as many pieces as Class A players, but in random positions only about 1.5 times as many.

“In particular, Masters recalled nearly three times as many pieces as Class players in game positions, but only 1 1/2 times as many in random positions.”

May combine two claims.

The 2-s boundary is only an approximation but seems reasonable; in the copy-task replication, 79.5% of within-glance latencies versus 1.11% of between-glance latencies were under 2 s.

“Although the 2-s boundary is only an approximation, it seems to be a reasonable approximation, for in our replication of the copy task, 79.5 % of the latencies for placements within a glance (as against only 1.11% of the latencies for placements between glances) were less than 2 s.”

May combine two claims.

The size of chunks increased with skill, accounting for skilled players' superiority in recall.

“Third, the size of chunks increased with skill, accounting for skilled players' superiority in the recall task.”

May combine two claims.

Average references back to the stimulus decline with chess skill, and game positions need fewer such references than random positions.

“The mean number of references to the stimulus decreases with chess skill, and game positions require fewer references (2.5, 4.9, 7.2) than random positions (6.8, 10.8, 12.0).”

May combine two claims.

The paper's data do not show a systematic increase in within-chunk latencies for successive chunks over the recall period, nor substantial differences of that kind.

“This does not imply that there will be any systematic increase over the period of recall in within-chunk latencies for successive chunks, nor do our data show substantial differences of this kind.”

May combine two claims.

Strong players tend to make faster between-glance placements in game positions than amateurs, but not within-glance placements.

“Third, strong players tend make faster between-glance placements in game positions than amateurs, but not within-glance placements.”

May combine two claims.

In the recall task, interpiece latencies for pieces sharing two or more chess relations with their predecessors increase only slightly over successive placements, while latencies for pieces sharing zero or one relation increase strongly, with the latter slope more than twice the former.

“Our data showed that, when we plot the latencies of pieces that have 2 or more chess relations with their predecessors, we find a small trend in size over time; when we plot the latencies of pieces that have 0-1 chess relations with their predecessors, we find a strong positive trend, with the latter slope more than twice the former.”

May combine two claims.

Correct recall for game positions was 92.0% (Masters), 57.1% (Experts), and 32.2% (Class A); for random positions it was 19.0%, 13.8%, and 12.4%, respectively.

“With game positions, the percentages of pieces correctly recalled are 92.0,57.1 and 32.2 for Masters, Experts and Class players, respectively.The corresponding percentages for random positions are 19.0,13.8 and 12.4.”

May combine two claims.

Latencies show no main effect of skill or position type and no other two- or three-way interactions, apart from a marginal skill-by-type interaction.

“No main effect of Skill [F(2, 22) = 0.32, MS e = 13.5] or of Type of position [F(1, 22) = 1.63,MS e = 2.15] are found.A marginal interaction is signaled for Skill x Type of position [F(2, 22) =3.17, MS e = 2.15, p=.062].There are no other two-way or three-way interactions”

May combine two claims.

Freyhoff, Gruber and Ziegler found Masters created larger clusters at all partitioning levels than class B players, and basic-level chunks corresponded to Chase and Simon's chunks.

“Masters created larger clusters at all levels of partitioning than did class B players.In addition, the chunks they detected at the basic level corresponded to the chunks identified by Chase and Simon (1973a).”

• cites Freyhoff, Gruber and Ziegler (1992)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Chase and Simon (1973a)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Even small chunks can suggest good moves in tactical situations, and chunks or small constellations allow recognition of position types.

“although even small chunks can suggest good moves in tactical situations, and chunks or small constellations of them allow recognition of positions of particular types.”

May combine two claims.

Chase and Simon's experiment was exploratory and studied only one Master, one Expert, and one Class A player.

“Chase and Simon carried out little more than an exploratory experiment.They studied only a single Master, a single Expert and a single Class A player.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The number of units decreased and their size increased with expertise, with stronger players using overlapping sorting criteria that grouped chunks together.

“However, the number of units decreased and their size increased with expertise, stronger players using overlapping sorting criteria that grouped chunks together.”

May combine two claims.

Pattern recognition facilitates generation of moves and plans during search and allows rapid precise evaluation of positions encountered during search.

“Pattern recognition then facilitates the generation of moves and plans during search and allows a rapid and precise evaluation of positions met during search.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

MAPP simulated several experimental findings, including a Class A player's recall percentage, types of pieces replaced, and chess relations between successive pieces.

“A computer program, MAPP (Simon and Gilmartin, 1973), simulated several experimental findings, including the percentage of pieces recalled by a class A player, 1 the types of pieces replaced and the chess relations between successive pieces in the reconstruction.”

• cites Simon and Gilmartin, 1973 sourceNot checked — no full text of the source

May combine two claims.

Pawn structures provide information about squares for pieces and typical pawn moves for given structures.

“Pawn structures provide information about the squares on which pieces should be placed (e.g. a Knight in front of an isolated pawn) and also about typical pawn moves for given structures.”

Classified as probably not a substantial claim.

In Chase and Simon's study, using physical boards and pieces meant hand capacity could have limited apparent chunk sizes.

“In addition, as the subjects used actual chess boards and pieces, the maximum number of pieces they could grasp in one hand could have limited apparent chunk sizes.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Charness found better recall when pieces were grouped by chunking relations than by columns, and poorest recall in random order, for both verbal and visual one-at-a-time presentation.

“Charness found better recall in the chunking condition than in the column condition, and poorest recall in the random condition.The same results were found when pieces were presented visually, one at a time (Charness, 1974).”

• cites Charness, 1974Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Gruber found experts asked about the past and future path of the game, plans, and evaluations, while novices asked about locations of single pieces.

“Gruber (1991) also found that, when allowed to ask questions about an as yet unseen position, chess experts asked about the past and future path of the game, about plans and evaluations, while novices asked about the locations of single pieces”

• cites Gruber (1991)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim. May combine two claims.

Holding challenged this assumption on grounds that pawn structures generate few moves, chunks are too small, and pattern recognition cannot explain look-ahead.

“Holding (1985,1992) has challenged this assumption on the grounds that (a) most chess patterns consist of pawns, 2 and pawn structures do not generate many moves; (b) that most chess patterns found by Chase and Simon (1973a,b) are too small to provide useful information; and (c) that pattern recognition is not sufficient to explain chess skill, because it applies only to the initial moves from the”

• cites Holding (1985,1992)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Chase and Simon (1973a,b)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

In Freyhoff et al., 74.6% of pieces within partitions shared three or more relations, compared with 67.6% in Chase and Simon's recall data.

“In particular, 74.6% of the pieces within partitions shared three or more relations, as compared with 67.6% in Chase and Simon's data for the recall task.”

• cites Freyhoff, Gruber and Ziegler (1992)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

In Freyhoff et al., average chunk size was 3.6 pieces for masters and 2.7 for class B players, close to Chase and Simon's 2.5 and 2.1.

“First, their size was, on average, 3.6 pieces for masters, and 2.7 pieces for class B players-reasonably close, given differences in the types of positions used, to Chase and Simon's 2.5 pieces for the Master and 2.1 pieces for the Class A player.”

• cites Freyhoff, Gruber and Ziegler (1992)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Chunks, especially large templates, can provide information about position class, heuristics, plans, and partial evaluation.

“Although Chase and Simon only mention chunks as eliciting (initial or subsequent) moves, chunks, especially the large chunks we call templates, can also provide information about the class to which the position belongs, about heuristics, plans, partial evaluation of the position and so on.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim.

Chase and Simon proposed that Masters rapidly access long-term memory by recognizing familiar piece constellations that cue chunks.

“Chase and Simon (1973b) proposed that Masters access information in long-term memory (LTM) rapidly by recognizing familiar constellations of pieces on the board, the patterns acting as cues that trigger access to the chunks.”

• cites Chase and Simon (1973b)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim.

Because one chunk in short-term memory gives access to multiple pieces, masters recall positions very well.

“Because storing one chunk in STM gives access to a number of pieces, masters perform remarkably well in recall tasks.”

• cites Chase and Simon (1973b)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Chase and Simon explicitly stated that pattern recognition generates base moves and subsequent moves triggered by patterns in the mind's eye during search.

“On the contrary, Chase and Simon (1973b, pp. 268-272) stated explicitly that recognition of patterns is used not only to generate base moves but also subsequent moves triggered by patterns in the”

• cites Chase and Simon (1973b)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim.

One central thesis of the chunking model is that recognized chunks cue heuristic suggestions for good moves.

“One central thesis of the chunking model is that chunks act as cues that, when recognized, evoke access to heuristic suggestions for good moves.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Simon and Gilmartin estimated that chess expertise requires between 10,000 and 100,000 chunks in memory.

“Simon and Gilmartin estimated that expertise in chess would require between 10,000 and 100,000 chunks in memory (in the literature, this range is often reported simply as 50,000 chunks).”

• cites Simon and GilmartinNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim.

Chase and Simon (1973a) found that skill-related differences in copying and recalling chess positions come from experts storing thousands of chunks in long-term memory.

“the finding of Chase and Simon (1973a) that the differences in ability of chess players at different skill levels to copy and to recall positions are attributable to the experts' storage of thousands of chunks (patterned clusters of pieces) in long-term memory.”

• cites Chase and Simon (1973a)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The Master in Chase and Simon's study was relatively inactive in chess and performed substantially worse than other Masters tested in similar tasks.

“Moreover, the Master was rather inactive in chess at the time of the experiments and performed substantially less well than other Masters who have been tested in the same or similar tasks.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim.

According to chunking theory, pairs of pieces with many relations are more likely to be noticed together and chunked.

“According to the theory, pairs of pieces that have numerous relations are more likely to be noticed together, hence chunked.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Chase and Simon's memory theory implies that recognized chunks would suggest good moves to masters.

“Finally, Chase and Simon's theory of memory implies that chunks, upon recognition, would suggest good moves to the masters.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim.

Because chunks are linked to possible moves, chess masters can usually choose good moves with only moderate look-ahead search.

“Because these chunks are associated with possible moves, chess masters can generally choose good moves with only moderate look-ahead search.”

• cites Chase and Simon (1973b)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim.

Chase and Simon proposed that during brief presentation players recognize familiar chunks and place pointers to them in limited-size short-term memory.

“Chase and Simon (1973b) proposed that, during the brief presentation of a chess position, players recognize already familiar chunks on the board and place pointers to these chunks in a short-term memory of limited size.”

• cites Chase and Simon (1973b)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim. May combine two claims.

Gobet and Simon propose a modified model consistent with recent expert memory models and accounting for rapid encoding by chess masters.

“Gobet and Simon (in press-a) propose a modified model that is in accord with other recent models of expert memory (e.g., Richman, Staszewski & Simon, 1995), and accounts for the rapid encoding shown by chess masters.”

• cites Gobet and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Richman, Staszewski & Simon, 1995 sourceNot checked — no full text of the source

May combine two claims.

Replications are rare in chess psychology research, and the data supporting the two-second boundary for delimiting chunks had never been replicated experimentally.

“Replications are rare in chess psychology research (Charness, 1988;Gobet, 1993), and the data supporting the 2-s boundary for delimiting chunks have never been replicated experimentally.”

• cites Charness, 1988Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Gobet, 1993Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

In the original study, subjects picked up several pieces simultaneously, so hand capacity could limit the number grasped and thus estimated chunk size.

“Second, subjects in the original study replaced pieces by picking up several of them simultaneously.Hand capacity will limit the number of pieces that can be grasped, hence the estimated size of chunks.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The program design made it difficult to access the stimulus and return in under one second, possibly motivating fewer and longer references to the stimulus.

“Note also that, because of the design of the program, it was difficult to access the stimulus position and come back to the reconstruction board in less than one second, which may have provided one motive for fewer and longer references to the stimulus.”

May combine two claims.

Templates contain pointers to plans, moves, strategical and tactical concepts, and other templates, acquired at normal learning rates of 5 to 10 seconds per chunk.

“Finally, templates contain pointers to symbols representing plans, moves, strategical and tactical concepts, as well as other templates.These pointers are also acquired at normal learning rates (i.e., 5 to 10 seconds per chunk).”

Classified as probably not a substantial claim.

The template hypothesis and supporting evidence predict that strong players should replace positions in chunks or templates larger than those identified by Chase and Simon.

“The template hypothesis and the evidence supporting it predict that strong players should replace positions in chunks (templates) larger than the ones identified by Chase and Simon (1973a).”

• cites Chase and Simon (1973a)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

The modified theory asserts that chunks are accessed through a discrimination net.

“The modified theory asserts that-as in the chunking theory-chunks are accessed through a discrimination net.”

May combine two claims.

Several authors have identified difficulties in Chase and Simon's method for defining chunks, including reaction-time identification, overlapping or nested chunks, erroneous replacements, and single-burst recall.

“Several authors (Freyhoff, Gruber & Ziegler, 1992;Gold & Opwis, 1992;Holding, 1985;Reitman, 1976) have seen difficulties in Chase and Simon's method for defining chunks, among the most important of them: (a) difficulty in identifying chunks by reaction times, (b) impossibility of capturing overlapping or nested chunks, (c) difficulty in assigning pieces erroneously replaced and (d) the assumption”

• cites Freyhoff, Gruber & Ziegler, 1992Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Gold & Opwis, 1992Not checked — no full text of the source
• cites Holding, 1985Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S1 (asserted).

This latency increase could account for the observed larger average size of early chunks than late chunks.

“This could account for the observed larger average size of the early than of the late chunks.”

Probably not a substantial claim: may not pass S3 (load-bearing).

This behavioral difference may be related to differences in how stimuli were presented and responses made in the two experiments.

“This difference in behavior may be related to the differences in the ways in which stimuli were presented and responses made in the two sets of experiments.”

Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

There is warrant for further testing Chase and Simon's method for identifying chunks because of infelicities in the original study, criticisms of the technique, evidence of higher-level perception, a template-theory prediction about chunk size, and the small number of subjects.

“Still, there is warrant for testing further the validity of Chase and Simon's method for identifying chunks: infelicities in the original study; criticisms of the technique used; evidence that Masters perceive a position at a higher level than 4-5 piece chunks; a different prediction of the template theory about the size of chunks; the small number of subjects.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S1 (asserted), S4 (based). May combine two claims.

If the relation between number of relations joining a pair and likelihood of rapid perception is confirmed, then relation counts and latencies provide converging evidence about chunks.

“In addition, if the close relation between the number of relations joining a pair of pieces and the likelihood of the pair being perceived in rapid succession were confirmed, then numbers of relations, on the one hand, and latencies, on the other, provide converging evidence about the numbers, sizes and character of the chunks that experts perceive.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The model and reconstruction positions were slightly shifted and different in size to prevent subjects using iconic memory to superimpose them.

“The two positions (the model and the position being reconstructed) were slightly shifted and of a different size, in order to avoid subjects' using iconic memory to superimpose one on the other.”

May combine two claims.

Chase and Simon found that pairs within chunks identified by copy and recall methods showed the same pattern of relations, but a different pattern from pairs in different chunks.

“Chase and Simon found that pairs of pieces within chunks identified by the copy and recall methods showed the same pattern of relations, but a different pattern from that shown by pairs of pieces belonging to different chunks.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim.

The first position was omitted to remove learning effects.

“To remove learning effects, the first position is omitted from the following analysis.”

May combine two claims.

These objections are serious for cutting a position into precise chunks but not fundamental for analyses relating chunks to distributions of relations between pieces.

“These objections raise serious difficulties if the goal is to cut a chess position into precise chunks but are not fundamental for analyses that relate chunks to the distributions of relations between pieces, as is the case for Chase and Simon's (1973a) study and the present one.”

• cites Chase and Simon (1973a)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Templates themselves are built slowly at normal long-term memory learning rates, though their slots can be filled rapidly.

“Notice that, although slots in templates can be filled rapidly, hence serve essentially as augments to STM in the domain of expertise, the templates themselves are built up slowly, at normal LTM learning rates.”

Classified as probably not a substantial claim. May combine two claims.

This prediction is at variance with Chase and Simon's findings, which were based on only one Master.

“This is of course at variance with their findings (which, we have noted, were based on the performance of only a single Master).”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

These results undermine the hypothesis that a piece pattern can be recognized independently of its board position and support the 50,000-chunk estimate.

“These results undermine the hypothesis that a pattern of pieces can be recognized independently of its position on the chessboard and add support to the estimate of 50,000 chunks.”

Not yet classified.

Alternative techniques such as partitioning and sorting provide converging evidence supporting Chase and Simon's original results.

“Moreover, as we have seen above, various alternative techniques (partitioning, sorting) provide converging evidence that supports the original results of Chase and Simon.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Pooling results from the two experiments was justified because there was no difference between experimental groups nor interaction with the variables discussed.

“We decided to pool the results from the two experiments, as there was no difference between the two experimental groups nor any interaction of experimental group with the variables discussed below.”

Probably not a substantial claim: may not pass S4 (based). May combine two claims. The quote only partly states this claim.

The new experimental procedure eliminates the two potential problems of hand capacity and random grasping.

“Our new experimental procedure eliminates these two potential problems.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The non-random order of presenting random before game positions was judged acceptable because the study was not primarily comparing reconstruction levels of game and random conditions.

“As in the case of the copy task, we judged the confounding due to the non-random order of presentation to be acceptable, because we were not primarily interested in comparing the levels of reconstruction of the game and random conditions.”

Classified as probably not a substantial claim. May combine two claims.

According to the chunking model, during recall pieces are encoded in limited-size short-term memory and no new information is added to long-term memory.

“According to the chunking model, pieces are encoded in a STM of limited size during the recall task and no new information is then added to LTM.”

May combine two claims.

In Chase and Simon's data, 80% of within-glance latencies were under 2 s, with a median near 1 s and a mode near 0.5 s.

“In their data, 80% of the WGP latencies were less than 2 s, with a median around 1 s and a mode around 0.5 s (estimated from their graph).”

• cites Chase and Simon (1973a)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Templates contain pattern information and slots that can be instantiated with new information in seconds.

“Templates, besides containing information about a pattern of pieces, as chunks do, possess slots (variables that can be instantiated) in which some new information can be stored in a matter of seconds.”

May combine two claims.

Most reviewed criticisms were due to misinterpretation of chunking theory or pointed to the need for rapid long-term memory encoding, now met by template theory.

“Most of the criticisms we have reviewed were either due to misinterpretation of the chunking theory or pointed toward the necessity for postulating some kind of rapid encoding into LTM, a requirement that is now met in the template theory (Gobet & Simon, in press-a).”

• cites Gobet & SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim.

Holding argued that 2,500 chunks may suffice if chunks encode relations but not piece locations.

“Holding (1985Holding ( , 1992) ) argued that this number is much too large, and that as few as 2,500 chunks may account for the results obtained in recall experiments, by assuming that the chunks encode relations between pieces but not the location of these pieces.”

• cites Holding (1985, 1992)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing).

Table 6 of Chase and Simon gives probabilities of different relation combinations in various experimental conditions.

“Table 6 of Chase and Simon (1973a) gives the probabilities of the presence of different combinations of relations in the various experimental conditions.”

• cites Chase and Simon (1973a)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Not yet classified.

Despite apparatus differences, statistics from the current experiments agree closely with those reported by Chase and Simon.

“In spite of the difference in apparatus, the statistics derived from the current experiments agree closely with those reported by Chase and Simon (1973a).”

• cites Chase and Simon (1973a)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim. May combine two claims.

Chase and Simon found that small average latencies in the copy task correlate with many relations, and large latencies with few relations.

“Chase and Simon had found that small average latencies in the copy task correlate with a large number of relations between successive pieces, while large average latencies correlate with few relations.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Chase and Simon found chunk-size differences: their Master averaged 3.8 pieces for the first chunk in middle game positions, Class A averaged 2.6, and the beginner averaged 2.4; the median largest chunk per position was 5 pieces for the Master with game positions.

“In the recall task, 5 Chase and Simon (1973a) did find a difference in chunk size between their subjects, their Master obtaining, for the first chunk replaced with middle game positions, a mean of 3.8 pieces, while the Class A player had a mean of 2.6 pieces and the beginner a mean of 2.4 pieces.The median largest chunk per position was 5 pieces for the Master with game positions.”

• cites Chase and Simon (1973a)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim.

The chunking hypothesis predicts more attack, defense, proximity, shared color, and shared type relations within a chunk than across a chunk boundary.

“The chunking hypothesis predicts that there would be many more relations of attack, defense, proximity, shared color and shared type of piece between successive pieces within the same chunk than between successive pieces on opposite sides of a chunk boundary.”

• cites Chase and Simon (1973a)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S1 (asserted), S4 (based).

If the same processes determine latencies in copy and recall, then relations in the two tasks should be highly correlated.

“In addition, if the same processes determine the latencies in both the copy and recall tasks, then there should be a high correlation between the relations in the two tasks.”

Classified as probably not a substantial claim. May combine two claims.

Chunking theory predicts inter-piece latencies stay roughly constant within a chunk, but between-chunk latencies may increase with the number of pieces previously placed.

“The chunking theory predicts that the inter-piece latencies will stay more or less constant when pairs of pieces belong to a chunk, but that the inter-piece latencies between chunks may increase as a function of the number of pieces previously placed.”

Probably not a substantial claim: may not pass S1 (asserted), S4 (based).

If chunk boundaries are indicated by latencies greater than 2 s, then relations between successive pieces should differ for short versus long latencies.

“If chunk boundaries are indicated by latencies > 2 s, then the relations between successive pieces should be different with short than with long latencies between them.”

Classified as probably not a substantial claim.

Template theory predicts experts develop larger chunks with practice than the original chunking theory predicts.

“The template theory predicts that experts develop larger chunks with practice than are predicted by the original chunking theory.”

May combine two claims.

The two chunk-definition methods produce quite similar segmentations, and findings would hold about equally if a chunk were defined as consecutive pieces each with two or more relations to the previous piece.

“Thus, the two methods of defining chunks produce quite similar segmentations of the output, and the findings reported in Chase and Simon's paper and in this paper would hold about equally well if we defined a chunk as a set of consecutively placed pieces each of which has 2 or more chess relations with the piece previously placed.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S4 (based).

Between-chunk slowdown would follow if players first replace salient chunks and then search longer for less salient, less easily recognized chunks.

“The slowdown between chunks would follow if the players first replace salient chunks, then have to search a little longer to find the less salient, and therefore less easily recognized chunks.”

Classified as probably not a substantial claim.

This finding was troublesome for the original model because it postulated that skill differences in recall were due to chunk size, not chunk capacity of short-term memory.

“This was one of the most troublesome of their findings, for the original model postulated that the difference in recall between players of different skills was to be explained by chunk size differences not by differences in the chunk capacity of short-term memory.”

May combine two claims.

Two analyses extending Chase and Simon showed considerable agreement in predicting chunk membership using relations or latencies, and between-chunk latencies lengthen significantly over time while within-chunk latencies only slightly.

“Finally, in two analyses extending Chase and Simon's, we showed that there was a considerable agreement in predicting whether a piece belongs to a chunk using either the number of relations or the latencies, and that the between-chunk latencies lengthen significantly over time, but the withinchunk latencies only slightly.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Within-chunk patterns of relations in copy and recall differ from between-chunk patterns, which more closely resemble randomly selected pairs.

“All of these correlations show that within-chunk patterns of relations, whether in the copy or recall task, are quite different from between-chunk patterns, the latter resembling more closely the relations between pairs of pieces selected randomly.”

Classified as probably not a substantial claim.

Recall-task latency statistics were not shown because separating within-chunk from between-chunk placements by latency would confound independent with dependent variables.

“We do not show the statistics for the recall task, as the separation of within-chunk from between-chunk placements in that task on the basis of latency would confound independent with dependent variables.”

Probably not a substantial claim: may not pass S1 (asserted), S4 (based). May combine two claims.

Within-glance copy relations should correlate with rapid recall placements of 2 s or less, and between-glance copy relations with slow recall placements over 2 s.

“Specifically, the relations for within-glance placements in the copying experiments should correlate with those for rapid placements (≤ 2 s) in the recall experiments and the relations for between-glance placements in the former should correlate with those for slow placements (> 2 s), in the latter.”

May combine two claims.

None of the age correlations were significant at p = .10, so age did not much affect mouse-move time or compromise the chunk cut-off estimates.

“As none of the correlations were significant at p = .10,we may conclude that age did not much affect time to move the mouse or compromise our estimate of chunk cut-offs.”

Classified as probably not a substantial claim.

The constant within-chunk latency prediction follows from chunks being stored in long-term memory, with recovery speed independent of when they are copied or replaced.

“The former follows from the fact that chunks are postulated to be stored in LTM, and speed of recovery of their successive elements should be independent of the time when they are copied or replaced.”

May combine two claims.

Since recall-task chunk counts were similar for the strongest and weakest skill levels, the results support the hypothesis that strong players use templates supplemented by smaller chunks to encode information rapidly.

“As the number of chunks in the recall task differ little between the strongest skill level and the weakest, this supports the hypothesis that strong players use templates, supplemented by smaller chunks, to encode information rapidly.”

May combine two claims.

The positions used in the recall task are not, as far as can be judged, typical opening situations, and position typicality probably did not inflate the chunk-size estimate.

“While this is somewhat possible for the positions of the copy task, the positions we have used in the recall task do not, as far we can judge, belong to typical openings situations (see Appendix A), and it is unlikely that the typicality of positions has inflated our estimate of the size of chunks.”

Probably not a substantial claim: may not pass S4 (based). May combine two claims.

A time-sharing strategy during serialized placement ought to flatten inter-piece latencies and eliminate chunks.

“Such a time-sharing strategy should however level the inter-piece latencies and destroy chunks.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

A further possible reason for the Master-level chunk-size gap between Chase and Simon's study and the current one is that their Master was somewhat rusty (71.5% middle-game recall vs 92% for current Masters) and, in his mid-forties, may have replaced pieces more slowly, leading some chunks to be split during scoring.

“Another possible factor in the differences in chunk size at Master level between the Chase and Simon experiments and ours is that their Master was somewhat out of practice (a score of only 71.5% for recall of middle game positions, as compared with 92% for our Masters), and, being in his mid-forties, may have been slower in replacing pieces, causing some chunks to be divided in scoring them.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

In both cases, the player had studied that position or position type long enough to build large, well-differentiated templates for it.

“In both cases, the player has spent enough time studying this position or type of position to have acquired large, well differentiated templates for it.”

• cites Chase & Simon, 1973aNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Chess skill rests both on recognizing familiar chunks during play and on exploring moves and judging their consequences.

“The correct claim, and the one actually made by Chase and Simon and in this paper, is that skill in playing chess depends both on (a) recognizing familiar chunks in chess positions while playing games, and (b) exploring possible moves and evaluating their consequences.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Masters do not have better motor skills for placing pieces; computer-and-mouse experience was evenly spread across subjects, and skill level explains under 0.3% of variance in mouse-movement time.

“(It cannot be assumed that Masters have superior motor skills in placing pieces, for experience with the use of computer and mouse was evenly distributed among the subjects in our experiments-skill level accounts for less than 0.3 % of the variance when used to predict the time to move the mouse.)”

May combine two claims.

The paper's message is that chunks are larger than estimated by Chase and Simon, but that the relation pattern between successively placed pieces differs radically depending on whether the pieces belong to the same chunk.

“Summarized in one sentence, the message of this paper is that chunks are larger than estimated by Chase and Simon, but that, as they showed, the pattern of relations between two pieces placed successively are radically different when the pieces do or do not belong to the same chunk.”

• cites Chase and SimonNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Large chunks are organized around templates holding information that strong players acquire over years of practice about typical, familiar positions; these templates offer quickly fillable slots for further chunks about the current position.

“Our explanation is that the large chunks are built around templates that encode information, acquired by strong players over years of practice, about typical and familiar positions, and that provide rapidly fillable slots for additional chunks of information about the current position.”

May combine two claims.

With a physical board and pieces, the largest possible chunk is constrained by how many pieces a hand can grasp; the current apparatus removes that constraint.

“When a physical chessboard and pieces are used, the maximum chunk size is limited by the number of pieces the hand can grasp; with our present apparatus, it is not limited in this way.”

May combine two claims.

Strong players' advantage on game positions stems not from chunk count-Masters replaced only one chunk more than Class A players in the recall task-but from having a few large chunks.

“The superiority of strong players for game positions is then due not to the number of chunks (Masters replaced only one chunk more than Class A players, in the recall task), but to the presence of a few large chunks.”

May combine two claims.

Results based on 26 subjects support the major findings of Chase and Simon and corroborate the hypothesis that the same information-processing mechanisms operating on chunks in long-term memory determine time intervals in both copy and recall tasks.

“These results, based on a larger sample (26 subjects) than that of the earlier experiment, support the major findings of Chase and Simon (1973a) and corroborate their hypothesis that the same information processing mechanisms, operating on chunks stored in long-term memory, determine the time intervals in both the copy and recall tasks.”

• cites Chase and Simon (1973a)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The serialization confound does not explain why artificial concatenation would affect Masters more than Class A players; Class A players' biggest chunks (6-7 pieces at most) are not unusually large and can be accounted for by common patterns such as castling.

“It is unclear why this should be the case more with Masters than with Class A players.The latters' larger chunks (at most 6-7 pieces) are not unusually large and can easily be explained, for example, by a few common patterns, like castling positions.”

May combine two claims.

The biggest chunks of stronger players are considerably more complex than those of weaker players, so important qualitative differences may exist in these large templates.

“However, as the largest chunks of highly skilled players are much more complex than those of weaker players, important qualitative differences may be present in these large templates.”