Expertise effect in enumeration: subitizing or counting? Roy Allen & Peter McGeorge

Introduction Previous MOT research: Previous MOT research: Suggests the initial activation of a limited number (circa 3/4) of preattentive indexes (Pylyshyn & Storm, 1988);Suggests the initial activation of a limited number (circa 3/4) of preattentive indexes (Pylyshyn & Storm, 1988); That modality-specific (visuospatial) attentional processes are involved during the static period of target acquisition (strategies?), and;That modality-specific (visuospatial) attentional processes are involved during the static period of target acquisition (strategies?), and; Central executive (general attentional) processes predominate during dynamic target tracking (iterating strategies?) (Allen, McGeorge, Pearson & Milne, 2006)Central executive (general attentional) processes predominate during dynamic target tracking (iterating strategies?) (Allen, McGeorge, Pearson & Milne, 2006)

Also significant expertise/practice effect amongst: Also significant expertise/practice effect amongst: radar operators (Allen, McGeorge, Pearson & Milne, 2004), and;radar operators (Allen, McGeorge, Pearson & Milne, 2004), and; action video game players (Green & Bavelier, 2006).action video game players (Green & Bavelier, 2006). experts better than novices at the MOT task (circa 5/12 versus 3/12); experts better than novices at the MOT task (circa 5/12 versus 3/12); And more resilient to the effect of a secondary visuo-verbal task (circa 4/12 versus 2/12) (Allen et al., 2004). And more resilient to the effect of a secondary visuo-verbal task (circa 4/12 versus 2/12) (Allen et al., 2004).

How does this effect arise? How does this effect arise? May be due to Experts: May be due to Experts: better visuospatial strategies, or the strategies more effective mobilisation (Allen et al., 2004);better visuospatial strategies, or the strategies more effective mobilisation (Allen et al., 2004); better fidelity of memory or their faster speed of processing (Green and Bavelier, 2006).better fidelity of memory or their faster speed of processing (Green and Bavelier, 2006).

Trick and Pylyshyn (1993, 1994) - preattentive indexes that underpin performance on the MOT task also fundamental to enumeration tasks where fast, consistently accurate quantification is associated with the number of active indexes, Trick and Pylyshyn (1993, 1994) - preattentive indexes that underpin performance on the MOT task also fundamental to enumeration tasks where fast, consistently accurate quantification is associated with the number of active indexes, Might therefore expect expertise effect in enumeration tasks. Might therefore expect expertise effect in enumeration tasks. Green and Bavelier (2006) and Allen and McGeorge (2006) have reported this but only for > 4 items, i.e. within counting, not subitizing, range. Green and Bavelier (2006) and Allen and McGeorge (2006) have reported this but only for > 4 items, i.e. within counting, not subitizing, range.

However, no work to date has looked at experts dual-task resilience in enumeration. Our paradigm: However, no work to date has looked at experts dual-task resilience in enumeration. Our paradigm: Stimuli Stimuli 1 – 8 quasi-randomly arranged plus signs (+s) in a 3 x 3 grid within a 50mm dia circle at the centre of the monitor. Items jittered so as not to form straight lines;1 – 8 quasi-randomly arranged plus signs (+s) in a 3 x 3 grid within a 50mm dia circle at the centre of the monitor. Items jittered so as not to form straight lines; Presented silently then with a simultaneous tone (low-400hz, medium – 700hz, high – 1000hz), counterbalanced for pitch and ear (subsequently collapsed over ear)Presented silently then with a simultaneous tone (low-400hz, medium – 700hz, high – 1000hz), counterbalanced for pitch and ear (subsequently collapsed over ear)

Pilot study Pilot study 2 novice groups - for each trial: 2 novice groups - for each trial: Ignore tone, indicate number of items (fast but accurate) using numeric keys above QWERTY keys – passive dual task (affect subitizing range?),Ignore tone, indicate number of items (fast but accurate) using numeric keys above QWERTY keys – passive dual task (affect subitizing range?), React to tone, still indicate number of items (fast but accurate) but switch between numeric keys above QWERTY keys and numeric keypad dependent upon tone pitch – active dual task (affect counting range?);React to tone, still indicate number of items (fast but accurate) but switch between numeric keys above QWERTY keys and numeric keypad dependent upon tone pitch – active dual task (affect counting range?); Presentation time was 26ms (2 x refresh rate).Presentation time was 26ms (2 x refresh rate).

Task x Number of items (F(3.02, 93.64) = 5.21, MSE = , p <.01, p 2 = 0.14) Task x Number of items (F(3.02, 93.64) = 5.21, MSE = , p <.01, p 2 = 0.14) Task only produces significant performance differences (independent t-tests) for 4- (t(31) = 3.46, p <.006), 5- (t(31) = 4.30, p <.006) & 6-item (t(31) = 4.02, p <.006) trials. Task only produces significant performance differences (independent t-tests) for 4- (t(31) = 3.46, p <.006), 5- (t(31) = 4.30, p <.006) & 6-item (t(31) = 4.02, p <.006) trials.

REACT condition clearly has debilitating effect over counting (>3) range, REACT condition clearly has debilitating effect over counting (>3) range, no effect of IGNORE condition, i.e. no reduction in performance across subitizing range, no effect of IGNORE condition, i.e. no reduction in performance across subitizing range, curiously, in REACT condition RTs to tone trials were slower, yet in IGNORE condition RTs to tone trials were significantly faster (Tone x Task (F(1, 31) = 11.36, MSE = , p <.01, p 2 = 0.27) curiously, in REACT condition RTs to tone trials were slower, yet in IGNORE condition RTs to tone trials were significantly faster (Tone x Task (F(1, 31) = 11.36, MSE = , p <.01, p 2 = 0.27)

First experiment: First experiment: previous REACT condition group versus matched group of prospective radar operators, before training (i.e., passed requisite aptitude tests)previous REACT condition group versus matched group of prospective radar operators, before training (i.e., passed requisite aptitude tests) presentation times were 26ms and 208ms (refresh multiples) – subitizing/counting?presentation times were 26ms and 208ms (refresh multiples) – subitizing/counting?

Expert x Number of items (F(3.02, ) = 8.79, MSE = , p <.01, p 2 = 0.23) Expert x Number of items (F(3.02, ) = 8.79, MSE = , p <.01, p 2 = 0.23) Task only produces significant performance differences (independent t-tests) for 6 (t(30) = 5.49, p <.006) & 7 (t(30) = 3.78, p <.006) items Task only produces significant performance differences (independent t-tests) for 6 (t(30) = 5.49, p <.006) & 7 (t(30) = 3.78, p <.006) items

Unusually, prospective experts 5-item performance poorer than 6- item though RTs were sig. faster (i.e., no greater cognitive load in former). Also: Unusually, prospective experts 5-item performance poorer than 6- item though RTs were sig. faster (i.e., no greater cognitive load in former). Also: Tone x Number of items (F(4.05, ) = 5.37, MSE = , p <.01, p 2 = 0.15) Tone x Number of items (F(4.05, ) = 5.37, MSE = , p <.01, p 2 = 0.15) Task only produces a significant performance difference, as judged by paired t-tests, for 5- (t(31) = 3.17, p <.006) & 8-item (t(31) = 3.02, p <.006)trials. Task only produces a significant performance difference, as judged by paired t-tests, for 5- (t(31) = 3.17, p <.006) & 8-item (t(31) = 3.02, p <.006)trials.

Why does the REACT condition only affect prospective experts on 5-item trials? Why does the REACT condition only affect prospective experts on 5-item trials? Indexes amodal? Task-switching – response keys and subitizing/counting? Indexes amodal? Task-switching – response keys and subitizing/counting? Greater variability at 5-item trials; decrease in performance primarily due to under-estimation Greater variability at 5-item trials; decrease in performance primarily due to under-estimation

Second experiment: Second experiment: previous prospective radar operators, before training versus same group after basic training (5 weeks)previous prospective radar operators, before training versus same group after basic training (5 weeks) presentation times were 26ms and 208ms (refresh multiples) – subitizing/counting?presentation times were 26ms and 208ms (refresh multiples) – subitizing/counting? Crucial finding – effect of tone (or task- switching) at 5-item trials disappears with trainingCrucial finding – effect of tone (or task- switching) at 5-item trials disappears with training

When (before/after training) x Tone (present/absent) x Number of items (1 – 8) (F(2.86, 34.29) = 3.64 MSE = , p <.01, p 2 = 0.23 When (before/after training) x Tone (present/absent) x Number of items (1 – 8) (F(2.86, 34.29) = 3.64 MSE = , p <.01, p 2 = item trials differ significantly t(14) = 3.06, p <.01 5-item trials differ significantly t(14) = 3.06, p <.01

No significant differences No significant differences

Preliminary studies – presently repeating, but: Preliminary studies – presently repeating, but: A secondary, switching task, directed by an auditory tone, seems to have a debilitating effect on enumeration, but only within the counting not subitizing range; A secondary, switching task, directed by an auditory tone, seems to have a debilitating effect on enumeration, but only within the counting not subitizing range; Prospective experts out-perform novices on the dual- task enumeration task, but only in counting range; Prospective experts out-perform novices on the dual- task enumeration task, but only in counting range; Prospective experts performance seems to dip at 5- item trials, but this effect disappears after training Prospective experts performance seems to dip at 5- item trials, but this effect disappears after training