Cue-recruitment for extrinsic signals after training with low information stimuli

Abstract

Cue-recruitment occurs when a previously ineffective signal comes to affect the perceptual appearance of a target object, in a manner similar to the trusted cues with which the signal was put into correlation during training. Jain, Fuller and Backus reported that extrinsic signals, those not carried by the target object itself, were not recruited even after extensive training. However, recent studies have shown that training using weakened trusted cues can facilitate recruitment of intrinsic signals. The current study was designed to examine whether extrinsic signals can be recruited by putting them in correlation with weakened trusted cues. Specifically, we tested whether an extrinsic visual signal, the rotary motion direction of an annulus of random dots, and an extrinsic auditory signal, direction of an auditory pitch glide, can be recruited as cues for the rotation direction of a Necker cube. We found learning, albeit weak, for visual but not for auditory signals. These results extend the generality of the cue-recruitment phenomenon to an extrinsic signal and provide further evidence that the visual system learns to use new signals most quickly when other, long-trusted cues are unavailable or unreliable.

Figure 1. Design of stimuli used in the study.

A) Layout of the stimulus used in Experiment 1. B) Layout of the visual stimulus used in Experiment 2.

Figure 2. Structure of typical training and test trials presented in Experiment 1.

Figure 3. Data show recruitment of extrinsic unimodal signal for construction of visual appearance.

A) Participants' (N = 14) mean performance on training (black squares) and test trials (red circles) as function of number of training trials in Experiment 1. The light dotted lines show individual performance for each participant. B) Participants' performance on training (black squares, filled symbol shows mean performance) and test trials (red circles, filled symbol shows mean performance) for the entire session as measured in Z-score units.

Figure 4. Data show lack of learning for crossmodal extrinsic signal in Experiment 2A.

A) Participants' (N = 6) mean performance on training (black squares) and test trials (red circles) as function of number of training trials in Experiment 2A. The light dotted lines show individual performance for each participant. B) Participants' performance on training (black squares, filled symbol shows mean performance) and test trials (red circles, filled symbol shows mean performance) for the entire session as measured in Z-score units.

Figure 5. Data show lack of learning for crossmodal extrinsic signal in Experiment 2B.

Participants' individual and mean stereo-pulse duration thresholds required maintaining 79% correct performance for Control and Learning groups in Experiment 2B. The data do not agree with our prediction that duration thresholds would be smaller in the learning group, so the sound cue appears not to have been recruited.