Researchers then dutifully documented that chimps can interpret abstract lexigrams
on keyboards and arrange them in meaningful sequences.
Lexigrams (Set C) were created by combining three graphical elements (e.
Transitivity probes consisted of trials in which the participant was required to select among lexigrams upon hearing dictated sample stimuli.
They include the composition of the lexigrams
possibly leading to faulty stimulus control, the order of testing phases, the possibility that repeated testing may have led to delayed emergence, and the possibility of inadvertent cueing due to the use of table top training methods conducted by the experimenter.
Instructors could include others, such as pictograms SYMS and OAKLAN, PREMACK cards, lexigrams and several SIGSYM systems.
Instructors could include other graphic sign systems: iconic pictograms SYMS and OAKLAN, the original non-iconic PREMACK cards, their iconic extension (Deich and Hodges, 1977), the modification by Carrier (1974) with colour coding and the lexigrams (Romski, Sevcick and Pate, 1988).
Over the years, several studies have used a stimulus equivalence paradigm to teach simple reading skills (Sidman, Cresson, & Willson-Morris, 1974) as well as a variety of other practical skills to individuals with disabilities including manual signing (Osborne & Gatch, 1989; VanBiervliet, 1977); pre-arithmetic skills (Gast, Vanbiervliet, & Spradlin, 1979); spelling (Stromer & Mackay, 1992, 1993; Mackay, 1985); name-face matching (Cowley, Green, & Braunling-McMorrow, 1992); shopping skills (Taylor & O'Reilly, 2000); monetary skills (McDonagh, McIlvane, & Stoddard, 1984); relations among objects, spoken words, and lexigrams (Brady & McLean, 2000); and relations among consonants, spoken words, and pictures (Carr et al.
Recently, Brady and McLean (2000) examined whether 4 individuals with severe developmental disabilities and limited verbal repertoires were able to demonstrate equivalence relations with objects, spoken words, and lexigrams.
A chimpanzee's (Pan troglodytes) long-term retention of lexigrams
Identity matching-to-sample training was conducted using three colors and three lexigrams for each stimulus set.
For each set, three colors were used as sample stimuli and three lexigrams were used as comparison stimuli.
Given the presentation of a sample visual food, selection of the corresponding lexigram
from an array of lexigrams
produced a taste of that food (cf.