A computer game for the measurement of auditory discrimination has been developed for people with hearing difficulty, such as those with cohlea implants, unable to use standard tests, such as children, or foreign language learners who do not hear specific distinctions. To evaluate the efficiency of the game, Experiment 1 assessed the categorical perception of a phoneme continuum, /ra/-/la/, using native English speakers (NE) and native Japanese speakers (NJ). NE showed a categorical perception whereas NJ did not. The similarity of phoneme perception between subjects obtained by an analysis of the response latencies recorded during the game was highly correlated with the results obtained by an identification task that is typically used in categorical perception experiments. In Experiment 2, we assessed the effect of increasing the intensity of one of the phonemes along the continuum. NJ's perceptual maps of/ra/-/la/phonemes were sensitive to this intensity change. NE's perceptual maps, on the other hand, were not affected. In Experiment 3, we show that an amplitude randomization of ±5 dB counterbalanced this cross-cultural effect. These results suggest that counterbalancing distracting cues (i.e.,other than the target) in a discrimination task such as this game may be especually useful for non-native or hearing-disabled people. This computer game is also effective in producing perceptual maps of English vowels in children with cochlear implants or hearing aids.

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This study compared the efficiency of three procedures in forming stimulus classes. In a "linear" procedure, which had been used in a stimulus equivalence paradigm, stimuli were trained serially by using matching-to-sample (i.e., A [sampIe]→B [comparison], B→C, and C→D for A・B・C・D class). In a "circular" procedure, stimuli were trained circularly (i.e.,A→B, B→C, C→D, and D→A), while in a "symmetry-reinforced" procedure the roles of sample and comparison stimuli alternated with each other (i.e., A→B, B→C, C→D, B→A, C→B, and D→C). Experiment 1 compared the linear with the circular procedure. The proportion of subjects who showed the formation of two classes was larger in the linear procedure group (five of eight) than in the circular procedure group (three of eight). Mean reaction times of the former were significantly shorter than those of the latter. Using a within-subject design with eight subjects, Experiment 2 again compared the two procedures, but no significant differences were found. Experiment 3 compared the symmetry-reinforced procedure with the linear one, using a within-subject design with eight subjects. The number of classes formed was not much different between the two procedures. However, mean reaction times for the former were significantly shorter than those for the latter. The procedure used in stimulus equivalence (i.e., the linear procedure) may be efficient to form stimulus classes, although its efficiency may be limited.

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This study investigated the effect of nodal distance (i.e., the numbers of nodes separating two members of equivalence classes) on respondently-conditioned skin conductance responses (SCRs) . In Condition 1, after two four-member equivalence classes (i.e., A1・Bl・Cl・D1 and A2・B2・C2・D2) were formed by seven subjects, D1 was presented with electric shock, and D2 was not. The transfer of the function of conditioning from D1 to other members of the same class was then examined by presenting all members of two classes and measuring SCRs to them. Mean SCR data showed some evidence of the transfer. Moreover, mean SCR to A1 separated by two nodes (i.e., Bl and Cl) from D1 was smaller than that to Cl separated by no node. This result could be regarded as some evidence of the effect of nodal distance on SCRs. In Condition 2, seven other subjects were exposed to the satme procedure, except that the testing for equivalence was conducted after the testing for transfer. The transfer and the effect of nodal distance were not evident on mean SCR data. A modified version of this experiment has to be conducted to further clarify the effect of nodal distance on respondently-conditioned responses.

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