Rupert Sheldrake - Experimental Test Of The Hypothesis Of Formative Causation.pdf - Rupert Sheldrake - dakinilover

Rivista di Biologia - Biology Forum 86 (3/4), 1992, 431-44; 86 (3/4), 431-44, (1992)

An experimental test of the hypothesis of formative causation

by Rupert Sheldrake

ABSTRACT: The hypothesis of formative causation predicts that as animals of a given species learn a new

pattern of behaviour, other similar animals will subsequently tend to learn the same thing more readily all over the

world, a a result of a process called morphic resonance. The more that learn it, the easier it should become for

others. This possibility was tested with day- old chicks using a simple learned response, a conditioned aversion. The

test took place in the laboratory of Steven Rose, a sceptic, following a standard procedure used routinely in his

laboratory, and was carried out blind by a summer student who knew nothing of the purpose of the experiment nor of

morphic resonance. The chicks were exposed either to a test stimulus, a small yellow light-emitting diode (LED), or a

control stimulus, a chrome bead. Half an hour after pecking the stimulus, the control chicks received an injection of

saline solution, and the test chicks an injection of lithium chloride, which made them mildly sick. They were then

tested three hours later, each chick being exposed sequentially to the control and the test stimulus, when most test

birds were averse to pecking the yellow LED, but not averse to pecking the control bead. The response of the chicks

was measured by recording the latency, the time delay in seconds before they first pecked the stimulus. The same

experimental procedure was repeated for 37 days. If morphic resonance were occurring, successive batches of

chicks should have shown an increasing aversion to the yellow LED, even in the initial training procedure, by morphic

resonance from their averse predecessors. The controls should have shown no such increasing aversion. I think the

results are consistent with such an effect, which shows up with a high degree of statistical significance (p < 0.01)

when the aversion to the yellow bead is measured relative to the control. Rose disagrees with this interpretation.

1. Introduction

2. Experimental design

3. Materials and methods

4. Results

5. Discussion

1. INTRODUCTION

The hypothesis of formative causation, which I first proposed in 1981 (SHELDRAKE, 1981)

postulates that organisms are subject to an influence from previous similar organisms by a process

called morphic resonance. Through morphic resonance, each member of a species draws upon, and

in turn contributes to, a pooled or collective memory. Thus, for example, if animals learn a new skill in

one place, similar animals raised under similar conditions should subsequently tend to learn the same

thing more readily all over the world. Likewise, people should tend to learn more readily what others

have already learnt, even in the absence of any known means of connection or communication. In the

human realm, this hypothesis resembles C.G. Jung's postulate of the collective unconscious

(SHELDRAKE, 1988). The hypothesis also applies in the chemical and physical realms, and predicts,

for example, that crystals of new compounds should become easier to crystallize all over the world

the more often they are made. There is already circumstantial evidence that this actually happens

(SHELDRAKE, 1981; 1988).

The hypothesis of formative causation raises many theoretical and philosophical questions, which I

have discussed in detail in my books (SHELDRAKE, 1981; 1988; 1990), but as a scientific

hypothesis, its value has to be assessed by empirical tests. Most experimental tests of this

hypothesis to date have involved human learning, and results so far have supported it (SHELDRAKE,

1986; 1988; MAHLBERG, 1987; ERTEL, 1992).

When I first proposed the hypothesis of formative causation in 1981, it aroused considerable

controversy, and was attacked in an editorial in Nature entitled "A Book for Burning?" (ANON, 1981).

As a result of this attack, Steven Rose of the Biology Department at the Open University in Britain,

wrote to me offering facilities in his laboratory for testing the hypothesis in the learning of animals. We

discussed this possibility soon afterwards, but for various practical reasons, nothing came of it. In

1988, as a result of an article I wrote on morphic resonance in The Guardian, a British newspaper,

Rose wrote an attack on the concept and publicly repeated his offer to test this "seemingly absurd

hypothesis" in his laboratory (ROSE, 1988). This time, it was possible to take up the offer. Funding

was available, and a summer student, Ms Amanda Harrison, was appointed to carry out the

experiment in the summer of 1990. She knew nothing of morphic resonance, and was deliberately not

informed of the hypothesis being tested until the experiments were completed. Thus the experiment

described below was performed blind. The design was agreed in advance by Rose and myself, and

we both recorded our predictions before the experiment began. Rose predicted that the experiment

would show no morphic resonance effects; I predicted that it would.

2. EXPERIMENTAL DESIGN

The research of Rose and his group is largely centred on biochemical changes in the brains of chicks

following various kinds of learning. In designing an experimental test of morphic resonance together,

Rose and I decided that it would be best to use a technique routinely employed in his laboratory,

namely a form of learning involving conditioned aversion. Day-old chicks peck at small bright objects

placed in their immediate environment, and they normally do so with little hesitation. But if they peck

something distasteful, such as a bead coated with a bitter substance, then they show a strong

tendency to avoid pecking it again, even many hours later. They are not averse to pecking beads of

different colours, showing that this response involves a specific kind of learning, known in the

literature as "one-trial passive avoidance learning" (CHERKIN, 1969). A similar response occurs even

with tasteless beads if, after pecking, the chicks are made temporarily sick by an injection of lithium

chloride. Thereafter, they show a strong tendency to avoid those beads. In Rose's laboratory this

behavioural response is regularly used in experiments on learning and memory. The chicks are

exposed to a stimulus, such as a shiny chromium-plated bead or small coloured light. Most peck at it

quickly. Half an hour later they are injected with lithium chloride; they are then tested with the same

stimulus four hours later, and also with a control stimulus to which they have not been made averse.

Under these conditions, most chicks show a strong aversion to the test stimulus but not to the control

stimulus. Control chicks injected with saline solution do not show any comparable specific aversion.

In the present experiment, this kind of aversive response was brought about in chicks exposed to a

small yellow light, a stimulus not previously used in experiments of this kind. Control chicks pecked at

a chromium-plated bead. Exactly the same experiment was performed with fresh batches of day-old

chicks for 37 days, spread over ten weeks. According to the hypothesis of formative causation,

subsequent batches of chicks should have a progressive tendency to avoid pecking the yellow light.

They should be influenced by the experience of previous similar chicks, even though they had never

met them, and without any possibility of communication by conventionally-recognized means. This

effect should happen as a result of cumulative morphic resonance from the previous chicks that had

developed an aversion to the yellow light. This increasing aversion in naive chicks should be

measurable in terms of an increase in the time-lag between being exposed to the stimulus and

pecking at it, or in other words an increasing latency. Meanwhile control birds should show no such

tendency to avoid pecking chrome beads. In addition, the increasing aversion to pecking the yellow

light should also be apparent in control chicks after being injected with saline solution. Rose is very

sceptical about the hypothesis of formative causation, and made the common-sense prediction that

there would he no progressive aversion to pecking the yellow light. The predictions as recorded in

advance were as follows:

Rose: "No secular trends apparent; latencies to peck the illuminated bead after ten weeks are no

different from those on week I, and the differences between latencies for illuminated and chrome

beads, if they occur, are also unchanged."

Sheldrake: "There is a secular trend; the latency to first peck of the illuminated bead increases by the

tenth week, while the latency to peck the chrome bead remains unchanged."

Rose and I both embarked on this research in the conviction that a scientific hypothesis, however

radical, can and should be tested by experiment. We both hoped for a clear-cut result, and our

original intention was to publish the results of this experiment jointly. However, we disagreed over the

interpretation of the data, and Rose decided he did not want to publish the results as we had planned.

I am therefore writing this paper without Rose, but inviting him to comment on it.

3. MATERIALS AND METHODS

The general procedures follow those used by Rose and his colleagues, as described by BARBER et

al. (1989), using chicks of the domestic hen, Gallus gallus domesticus. Ross Chunky chicks of both

sexes were hatched in the laboratory and held in a communal incubator until they were 24 to 36

hours old, when they were transferred to metal pens, lined with coloured cardboard, at the beginning

of each experiment, and were kept under red lights. Two chicks were placed in each pen to minimize

isolation stress. One of each pair was marked with a spot of dye so that the two could be

distinguished. They were allowed to acclimatize for 1-1.5 hr before being presented with a 4 mm

chromium-plated bead or a yellow light-emitting diode (LED) to initiate pecking activity. The

chromium-plated bead and diode were on hand-held rods, and the LED was powered by a 9V battery.

Both chicks in a given pen were exposed to the same stimulus, either the control or LED, and the

assignment of treatments to pens was randomized. In the initial training period, each chick was

exposed to the control or LED for a period of 30s, and the number of seconds taken to the first peck

was recorded with a stopwatch. This figure is referred to as the latency. The number of pecks was

also recorded. Chicks that did not peck at all within the test period were recorded as having a latency

of 30s, and these "untrained" chicks were dropped from the experiment, although they were left in

their pens.

Half an hour after the training period, each trained bird was injected intraperitoneally with O.I ml of

0.9% NaCI in the case of control birds, or I.OM LiCI in 0.9% NaCI for the birds trained with the LED.

These injections were carried out by Rose or one of his colleagues while the student, Amanda

Harrison, was not in the room. She was thus unaware of the treatments administered to the birds and

was working "blind". Three hours after these injections, each bird was tested sequentially by Harrison

with both stimuli, first the chrome bead and then the yellow LED. The latency to first peck, up to a

maximum of 30s, was recorded. Exactly the same procedure was followed every day for 37 days. The

experiment was carried out on Tuesdays to Fridays inclusive in the period from 20 July to 21

September 1990. On all days except Fridays between 10 to 18 test birds were used, together with

similar numbers of controls; on Fridays about half as many birds were used.

There were considerable fluctuations from day to day in the average latency of chicks when pecking

at the control and test beads. Variations in general levels of activity are well known to researchers on

chicks; the day-old birds may be sluggish one day, while those hatching a few days later may be

hyperactive. Such fluctuations are associated with changes in the weather, particularly with the

barometric pressure around the twelfth day of incubation (BATESON, 1974). In order to smooth out

such fluctuations, and also to compensate for variation in sample size from day to day, the data for

successive three-day periods were pooled (days 7-9, 10-12, and so on. The last sample included

data for the last four days). The data were analysed in several different ways:

1. By the standard method used by Rose and his colleagues (e.g. BARBER et al 1989). The

number of chicks not pecking at the stimulus within the first ten seconds was divided by the

total number tested, giving a proportional measure of aversion.

2. By calculating the mean latency.

3. By calculating latencies in terms of trimmed means. This procedure, sometimes referred to as

Winsorizing, involves omitting the upper and lower 15% of the observations in any given

sample and provides a more robust statistical measure than straightforward means (HOWELL,

1987).

Changes over time were analysed by computer using a linear regression program.

4. RESULTS

The effects of practice by the experimenter

The results clearly reveal how Harrison improved as an experimenter through practice. This is hardly

surprising; she was learning on the job, and had never worked with chicks before. This experimenter

effect is evident in the data shown in Fig. 1. Both test and control birds were trained more

successfully as time went on; in other words, a higher proportion of the birds pecked at the yellow

light or chrome bead within the initial 30s training period. This effect was greatest with the yellow light

over the first six days, and corresponds to the fact that Harrison initially experienced greater difficulty

learning to manipulate the rod with the yellow LED that the rod with the chromium plated bead. The

former was larger and more bulky.

Fig. I - Proportion of chicks successfully trained on the 37 days of the experiment (number

of chicks that pecked at the stimulus within 30s divided by the total number tested). A value

of 1.0 meant that all chicks pecked within 30s.

For the analysis of overall trends, it seemed best to exclude the initial period when this experimenter

practice effect was so pronounced, since it overshadowed the differential pattern of change in

response to the control and test stimuli. I therefore omitted the data for the first six days from the

analysis. (The overall pattern of results described below remained essentially the same if the initial

three to twelve days were excluded; the exact number of days omitted was not critical within this

range.)

Changes in initial latencies

Unexpectedly, there was a change in latency in the control birds as time went on (Fig. 2). They

showed a clear tendency to peck sooner at the chromium-plated beads as the experiment

progressed; the mean latency declined from about thirteen to eight seconds. (This effect was

statistically significant at the 0.02 level using mean latencies; by the proportional method, p= 0.09.)

Fig. 2 - Proportion of naive chicks in successive three-day periods that did not peck within

the first 10s at the control stimulus, the chromium-plated bead during the initial training

procedure (p= 0.091).

Although neither Rose nor I had anticipated such a trend in the control data, we agree that it was

probably due to an experimenter practice effect (cf. Fig. 1); as Harrison became more experienced at

testing the chicks, they tended to peck more readily at the chromium-plated bead. By contrast, in the

test birds there was no such pattern of declining latency. Indeed, using the proportional method of

analysis of Rose and his colleagues, there was a tendency for latencies to increase (Fig. 3).

Fig. 3 - Proportion of naive chicks in successive three-day periods that did not peck within

the first 10s at the test stimulus, the yellow LED, during the initial training procedure (p=

0.610).

The crucial question in the present experiment is whether there is a progressive difference between

the behaviour of the control and test birds. This difference can be seen by subtracting the average

latency for control birds from the average latency for test birds in each period (Fig 4). This procedure

enables fluctuations due to changes in atmospheric pressure and other environmental factors to be

controlled for. The results show a statistically significant increase in the latency with the test beads

relative to the controls (p= 0.009 using Rose's proportional criterion; p= 0.007 using mean latencies;

p= 0.008 using trimmed means).

Rupert Sheldrake - Experimental Test Of The Hypothesis Of Formative Causation.pdf

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