An attempt to condition the pupillary response.

Abstract

This paper describes an attempt to condition the pupillary response to an auditory stimulus. Conditioning of the pupil is not new. It was reported as early as 1916 by Watson (10). In spite of the many experiments which have been performed since then (1,2,4,6,7,8,9), there is no clear understanding of the necessary and sufficient conditions for the production of this conditioned response. In fact, there is considerable disagreement as to whether the pupil can be conditioned at all (8, 9). In view of the contradictory findings in this field, the recently published experimental results of Baker (1) and Metzner and Baker ( 7) are startling in their implications. Not only do they report conditioning of the pupillary response but also they claim that conditioning was established in two trials provided the auditory stimulus was below the 'conscious limen' (1, p. 13). Baker presents evidence to show that if the auditory stimulus is below this limen, a conditioned response of the 'disturbance' type can be shown to exist at the second simultaneous presentation of light and tone, and the 'final form' response appears at the third trial. This final form response is very stable and very specific. He also states that if the auditory stimulus is supraliminal, a much longer series of paired presentations (from 29 to 105 trials) is necessary to obtain the CR.These results seemed important enough for the theory of conditioning to warrant a repetition of the experiment. The results of this repetition are reported in the following pages. APPARATUS The apparatus (Fig. i) consisted of three parts: the pupillometer, the recording device, and the stimulating instruments. The pupillometer was a modification of similar devices described by Baker (l), and Ferree and Rand (3), and utilized the

Time Perception and Conditioning an Autonomic Response in Human Infants

“…On the other hand, studies with adult human Ss have failed to provide clear evidence of pupillary reflex conditionability. Early investigations reporting successful conditioned consuiction and/or dilation in human adult Ss (Baker, 1938;Cason, 1922;Hudgins, 1933) have not withstood the test of replication (Crasilneck & McCranie, 1956;Hilgard, Miller, & Ohlson, 1941;Steckle, 1936;Steckle & Renshaw, 1934;Wedell, Taylor, & Skolnick, 1940;Young, 1954Young, , 1958.…”

Classical Conditioning of Human Pupillary Constriction

“…Day 1: The S's auditory threshold was de termined by a modified method of limits, which was the same method as Wedell, Taylor, and Skolnick (1940) used. First a single pair of ascending and descending series was admin istered and an approximate value of threshold was estimated for each S. Then beginning about 5 decibels above the threshold thus de termined, the E set the tone switch either on or off and signaled the S. The duration of the tone, when presented, was approximately 5 sec.…”

“…Results from these studies, however, are not consistent. In some studies pupillary reflex was success fully conditioned (Baker, 1938;Cason, 1927;Gerall et al, 1957;Gerall & Wood-ward, 1958;Girden, 1942;Hallow & Stagner, 1933;Hallow, 1940;Hilgard & Ohlson, 1939;Hudgins, 1933;Kotake & Mihama, 1951 ;Kotake & Mihama, 1952;Kotoliarevsky, 1935;Metzner & Baker, 1939;Mihama, 1954;Mihama & Kotake, 1954;Ten Cate, 1934;Watson, 1916), while in others it was not (Crasil neck & McCranie, 1956;Hilgard et al, 1941;Hilgard et al, 1949;Steckle & Renshaw, 1934;Steckle, 1936;Wedell et al, 1940;Young, 1954;Young, 1958).…”

“…It is of interest to notice that most of the studies in which electric shock was used as the UCS, pupillary dilation was successfully conditioned (Ger all et al, 1957;Ger all & Woodward, 1958;Gilden , 1942;Hallow & Stagner, 1933;Hallow, 1940), while in most of the studies in which light stimulus was used as the UCS, pupillary constriction was not successfully conditioned (Crasil neck & McCranie, 1956;Hilgard et al, 1941;Hilgard et al, 1949;Steckle & Renshaw, 1934;Steckle, 1936;Wedell et al, 1940;Young, 1954). In view of the weight of persistent failures to obtain the pupillary conditioned reflex based on light, Hilgard, Miller, & Ohlson (1941) remarked : "Unless satisfactory pupillary conditioning can be obtained, classical con ditioning theory will have to be revised" (p.689).…”

Intensity of conditioned stimulus and rate of conditioning.

“…At the present time there is no evidence that strength of conditioning, distinguished from response strength, is a function of the intensity of the conditioned stimulus." It is true that Baker (i) has contended that 'subliminal' stimuli, when used as conditioned stimuli, lead to faster conditioning than do supraliminal stimuli; but the work of Wedell, Taylor and Skolnick (12) and that of Hilgard and Ohlson (4) make Baker's conclusions open to serious question.…”