Parameters
Several aspects of Multilink can be seen as fixated components of the architecture. For instance, there are minimum and maximum values of the activation, there is a fixed relationship between word frequency and resting level activation (RLA), and connection strengths between different codes (orthography, phonology, semantics, and language nodes) are fixated. The simulations of all studies discussed in papers have been conducted with only one setting of the parameters!
Log word frequency is used to set the resting level activation of words to a value between -0.2 and 0.0. It can be shown mathematically that this leads to a good fit with lexical decision data (Thul, Conklin, & Dijkstra, in preparation).
What follows is a listing of the Multilink model parameters, grouped by category.
Network basics
Parameter
Description
Standard value
min_act
Minimum activation value
-0.2
max_act
Maximum activation value
1.0
decay_rate
Decay rate per cycle/tick
0.07
min_rest
Minimum resting level
-0.2
max_rest
Maximum resting level
0.0
max_opb
Maximum occurrences per billion
0.6402259325203161
Resting level activations
Parameter
Description
Standard value
I_rest
Input node resting level
max_act
L_rest
Language node resting level
min_rest
O_rest
Orthographic node resting level
min_rest + opb * (Math.abs(min_rest) / max_obp)
S_rest
Semantic node resting level
min_rest
P_rest
Phonological node resting level
min_rest
IO_alpha
Input/Output node resting level
let score = (max_l - dist) / (double) max_l;
if (score > 0.0) { return IO_multiplier * Math.pow(score, 3); }
else { return 0.0; }
Connection weights
Parameter
Connection
Kind
Standard value
LO_alpha
Language/Orthographic
Facilitation
0.0
LP_alpha
Language/Phonological
Facilitation
0.0
OL_alpha
Orthographic/Language
Facilitation
0.0
OP_alpha
Orthographic/Phonological
Facilitation
0.03
OS_alpha
Orthographic/Semantic
Facilitation
0.03
PL_alpha
Phonological/Language
Facilitation
0.0
PO_alpha
Phonological/Orthographic
Facilitation
0.03
PS_alpha
Phonological/Semantic
Facilitation
0.3
SO_alpha
Semantic/Orthographic
Facilitation
0.03
SP_alpha
Semantic/Phonological
Facilitation
0.3
LO_gamma
Language/Orthographic
Inhibition
0.0
LP_gamma
Language/Phonological
Inhibition
0.0
OL_gamma
Language/Orthographic
Inhibition
0.0
OO_gamma
Orthographic/Orthographic
Inhibition
0.0
PL_gamma
Phonological/Language
Inhibition
0.0
PP_gamma
Phonological/Phonological
Inhibition
0.0
SS_gamma
Semantic/Semantic
Inhibition
-0.05
Input multipliers
Parameter
Description
Standard value
IO_multiplier
Input/Output weight multiplier
0.2
SS_multiplier
Semantic/Semantic association multiplier
0.0
Task weights
Parameter
Description
Standard value
criterion_value
Recognition threshold value
0.72
shortlist_input_threshold
Word translation shortlist input value
0.7
shortlist_output_threshold
Word translation shortlist output value
0.7
timestep_multiplier
Cycle->RT timestep multiplier
1.0
timestep_adder
Cycle->RT timestep base value
0.0
Task weights
Parameter
Description
Standard value
criterion_value
Recognition threshold value
0.72
shortlist_input_threshold
Word translation shortlist input value
0.7
shortlist_output_threshold
Word translation shortlist output value
0.7
timestep_multiplier
Cycle->RT timestep multiplier
1.0
timestep_adder
Cycle->RT timestep base value
0.0