Factorial comparison of working memory models.
Three questions have been prominent in the study of visual working memory limitations: (a) What is the nature of mnemonic precision (e.g., quantized or continuous)? (b) How many items are remembered? (c) To what extent do spatial binding errors account for working memory failures? Modeling studies have typically focused on comparing possible answers to a single one of these questions, even though the result of such a comparison might depend on the assumed answers to both others. Here, we consider every possible combination of previously proposed answers to the individual questions. Each model is then a point in a 3-factor model space containing a total of 32 models, of which only 6 have been tested previously. We compare all models on data from 10 delayed-estimation experiments from 6 laboratories (for a total of 164 subjects and 131,452 trials). Consistently across experiments, we find that (a) mnemonic precision is not quantized but continuous and not equal but variable across items and trials; (b) the number of remembered items is likely to be variable across trials, with a mean of 6.4 in the best model (median across subjects); (c) spatial binding errors occur but explain only a small fraction of responses (16.5% at set size 8 in the best model). We find strong evidence against all 6 documented models. Our results demonstrate the value of factorial model comparison in working memory.
Department of Engineering, University of Cambridge.
Ronald
R
van den Berg
Department of Psychology, University of Oregon.
Edward
E
Awh
Center for Neural Science and Department of Psychology, New York University.
Wei Ji
WJ
Ma
D001288:Attention; D003627:Data Interpretation, Statistical; D005163:Factor Analysis, Statistical; D006801:Humans; D016013:Likelihood Functions; D008570:Memory, Short-Term / Q000502:physiology*; D008960:Models, Psychological; D015233:Models, Statistical; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D010364:Pattern Recognition, Visual / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012153:Retention, Psychology / Q000502:physiology; D016008:Statistical Distributions