Table 3
The Newman-Keuls multiple comparison for subjects' partial-report
performance at the 0-msec ISI in various sessions and their whole-report
performance (Experiment 1)
|
WRa |
P1b |
Session P2c |
T1d |
T2e | ||
|
3.52 |
4.64 |
5.62 |
5.85 |
6.38 | ||
|
WR |
3.52 |
1.12 |
2.10* |
2.33* |
2.86 | |
|
P1 |
4.64 |
0.98 |
1.21 |
1.74 | ||
|
P2 |
5.62 |
0.23 |
0.76 | |||
|
T1 |
5.86 |
0.53 | ||||
aWR = whole report; bP1 = first practice session; cP2 = second practice session
dT1 = first test session; eT2 = second test session; *Significant at 0.05 level by the
Newman-Keuls multiple comparison test. The critical values for two-, three-, four-, and
five-step differences are 1.41, 1.70, 1.88 and 1.99, respectively.
Discussion
Results from this experiment differ from those of Merikle's (1980) study as a result of an
important procedural difference. When the partial-report cue was presented before or
simultaneously with stimulus onset, Merikle obtained data consistent with the
display-instruction compatibility hypothesis. When the partial-report cue was presented
(in accordance with the methodological assumption of the partial-report task; see
Coltheart, 1980) at or after stimulus offset, the compatibility hypothesis was not
supported. It can be suggested that the display-instruction compatibility hypothesis is
incorrect.
It is observed here that the basic large-capacity finding is obtained only when subjects
have 96 trials of practice on the partial-report task. This procedural feature should no
longer be ignored in future applications of the partial-report task.
EXPERIMENT 2
Why is the basic sensory fording observed by some investigators (e.g., Sperling, 1960;
Turvey & Kravetz, 1970; von Wright, 1968), but not by others (e.g., Dick, 1969, 1971,
1974; Merikle, 1980)? Although we have rejected the display-instruction compatibility
hypothesis as an explanation of the large-capacity finding, it remains to be seen whether
the perceptual grouping hypothesis can account for the basic sensory finding.
Merikle (1980) gave his subjects a circular array of eight alphanumeric items for 50
msec. Four of the eight items were letters, and four were digits. On half of the occasions,