Table 1.

The strength of extinction as indexed by the amount of signal-specific spontaneous recovery of the extinguished response

Subject	(A) Extinction Day 1 SSRE	(B) Extinction Day 3 SSRE	(C) Spontaneous Recovery SSRE	(D) Final Strength of Extinction*
Amb 10	0.9	4.6	8.8	−113*
Amb 11	14.1	3.4	2.0	−13
Amb 13	1.4	−0.6	0.3	+42
Amb 14	1.9	0.7	−0.5	−99
Amb 15	15.1	4.7	35.5	+297
Amb 16	26.8	6.9	10.6	+19
Amb 17	2.7	−0.4	3.3	+119
Amb 18	35.6	15.3	14.8	−2
Amb 19	12.7	1.2	−0.6	−16
Amb 20	6.7	3.3	1.3	−62
Amb 21	17.1	2.8	0.4	−17

Values in columns A–C are “SSRE” indices [see EQ. 3 and EQ. 4]. Actual Extinction (Column D) is the percentage of the extinguished response (i.e., the change in SSRE values in extinction) that returns in spontaneous recovery (i.e., the change in SSRE values in spontaneous recovery) [see EQ. 5; expressed by column heading: D = (C−B/B−A) × 100%].

^*“Final Strength of Extinction” is expressed as the percentage of the behavioral extinguished response that spontaneously recovers after a 2-day delay. For example, 0% indicates no behavioral recovery and 100% indicates complete response recovery. A positive value greater than 100% indicates that the bar-pressing response magnitude during the spontaneous recovery test exceeded the original amount of bar-pressing during the first extinction session (Day 1). Negative values indicate continued extinction rather than response recovery. Thus, the more negative the value, the stronger the extinction.